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x509_crt.c (103921B)

---

 /*
  *  X.509 certificate parsing and verification
  *
  *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */
 /*
  *  The ITU-T X.509 standard defines a certificate format for PKI.
  *
  *  http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
  *  http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
  *  http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
  *
  *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
  *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
  *
  *  [SIRO] https://cabforum.org/wp-content/uploads/Chunghwatelecom201503cabforumV4.pdf
  */
 
 #include "common.h"
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 
 #include "mbedtls/x509_crt.h"
 #include "x509_internal.h"
 #include "mbedtls/error.h"
 #include "mbedtls/oid.h"
 #include "mbedtls/platform_util.h"
 
 #include <string.h>
 
 #if defined(MBEDTLS_PEM_PARSE_C)
 #include "mbedtls/pem.h"
 #endif
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "psa/crypto.h"
 #include "psa_util_internal.h"
 #include "mbedtls/psa_util.h"
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 #include "pk_internal.h"
 
 #include "mbedtls/platform.h"
 
 #if defined(MBEDTLS_THREADING_C)
 #include "mbedtls/threading.h"
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
 #ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
 #endif
 #include <windows.h>
 #else
 #include <time.h>
 #endif
 #endif
 
 #if defined(MBEDTLS_FS_IO)
 #include <stdio.h>
 #if !defined(_WIN32) || defined(EFIX64) || defined(EFI32)
 #include <sys/types.h>
 #include <sys/stat.h>
 #if defined(__MBED__)
 #include <platform/mbed_retarget.h>
 #else
 #include <dirent.h>
 #endif /* __MBED__ */
 #include <errno.h>
 #endif /* !_WIN32 || EFIX64 || EFI32 */
 #endif
 
 /*
  * Item in a verification chain: cert and flags for it
  */
 typedef struct {
     mbedtls_x509_crt *crt;
     uint32_t flags;
 } x509_crt_verify_chain_item;
 
 /*
  * Max size of verification chain: end-entity + intermediates + trusted root
  */
 #define X509_MAX_VERIFY_CHAIN_SIZE    (MBEDTLS_X509_MAX_INTERMEDIATE_CA + 2)
 
 /* Default profile. Do not remove items unless there are serious security
  * concerns. */
 const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default =
 {
     /* Hashes from SHA-256 and above. Note that this selection
      * should be aligned with ssl_preset_default_hashes in ssl_tls.c. */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA256) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA384) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA512),
     0xFFFFFFF, /* Any PK alg    */
 #if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
     /* Curves at or above 128-bit security level. Note that this selection
      * should be aligned with ssl_preset_default_curves in ssl_tls.c. */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP256R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP384R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP521R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP256R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP384R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP512R1) |
     0,
 #else /* MBEDTLS_PK_HAVE_ECC_KEYS */
     0,
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
     2048,
 };
 
 /* Next-generation profile. Currently identical to the default, but may
  * be tightened at any time. */
 const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
 {
     /* Hashes from SHA-256 and above. */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA256) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA384) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA512),
     0xFFFFFFF, /* Any PK alg    */
 #if defined(MBEDTLS_ECP_C)
     /* Curves at or above 128-bit security level. */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP256R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP384R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP521R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP256R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP384R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_BP512R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP256K1),
 #else
     0,
 #endif
     2048,
 };
 
 /*
  * NSA Suite B Profile
  */
 const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_suiteb =
 {
     /* Only SHA-256 and 384 */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA256) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_MD_SHA384),
     /* Only ECDSA */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_PK_ECDSA) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_PK_ECKEY),
 #if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
     /* Only NIST P-256 and P-384 */
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP256R1) |
     MBEDTLS_X509_ID_FLAG(MBEDTLS_ECP_DP_SECP384R1),
 #else /* MBEDTLS_PK_HAVE_ECC_KEYS */
     0,
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
     0,
 };
 
 /*
  * Empty / all-forbidden profile
  */
 const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_none =
 {
     0,
     0,
     0,
     (uint32_t) -1,
 };
 
 /*
  * Check md_alg against profile
  * Return 0 if md_alg is acceptable for this profile, -1 otherwise
  */
 static int x509_profile_check_md_alg(const mbedtls_x509_crt_profile *profile,
                                      mbedtls_md_type_t md_alg)
 {
     if (md_alg == MBEDTLS_MD_NONE) {
         return -1;
     }
 
     if ((profile->allowed_mds & MBEDTLS_X509_ID_FLAG(md_alg)) != 0) {
         return 0;
     }
 
     return -1;
 }
 
 /*
  * Check pk_alg against profile
  * Return 0 if pk_alg is acceptable for this profile, -1 otherwise
  */
 static int x509_profile_check_pk_alg(const mbedtls_x509_crt_profile *profile,
                                      mbedtls_pk_type_t pk_alg)
 {
     if (pk_alg == MBEDTLS_PK_NONE) {
         return -1;
     }
 
     if ((profile->allowed_pks & MBEDTLS_X509_ID_FLAG(pk_alg)) != 0) {
         return 0;
     }
 
     return -1;
 }
 
 /*
  * Check key against profile
  * Return 0 if pk is acceptable for this profile, -1 otherwise
  */
 static int x509_profile_check_key(const mbedtls_x509_crt_profile *profile,
                                   const mbedtls_pk_context *pk)
 {
     const mbedtls_pk_type_t pk_alg = mbedtls_pk_get_type(pk);
 
 #if defined(MBEDTLS_RSA_C)
     if (pk_alg == MBEDTLS_PK_RSA || pk_alg == MBEDTLS_PK_RSASSA_PSS) {
         if (mbedtls_pk_get_bitlen(pk) >= profile->rsa_min_bitlen) {
             return 0;
         }
 
         return -1;
     }
 #endif /* MBEDTLS_RSA_C */
 
 #if defined(MBEDTLS_PK_HAVE_ECC_KEYS)
     if (pk_alg == MBEDTLS_PK_ECDSA ||
         pk_alg == MBEDTLS_PK_ECKEY ||
         pk_alg == MBEDTLS_PK_ECKEY_DH) {
         const mbedtls_ecp_group_id gid = mbedtls_pk_get_ec_group_id(pk);
 
         if (gid == MBEDTLS_ECP_DP_NONE) {
             return -1;
         }
 
         if ((profile->allowed_curves & MBEDTLS_X509_ID_FLAG(gid)) != 0) {
             return 0;
         }
 
         return -1;
     }
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
 
     return -1;
 }
 
 /*
  * Like memcmp, but case-insensitive and always returns -1 if different
  */
 static int x509_memcasecmp(const void *s1, const void *s2, size_t len)
 {
     size_t i;
     unsigned char diff;
     const unsigned char *n1 = s1, *n2 = s2;
 
     for (i = 0; i < len; i++) {
         diff = n1[i] ^ n2[i];
 
         if (diff == 0) {
             continue;
         }
 
         if (diff == 32 &&
             ((n1[i] >= 'a' && n1[i] <= 'z') ||
              (n1[i] >= 'A' && n1[i] <= 'Z'))) {
             continue;
         }
 
         return -1;
     }
 
     return 0;
 }
 
 /*
  * Return 0 if name matches wildcard, -1 otherwise
  */
 static int x509_check_wildcard(const char *cn, const mbedtls_x509_buf *name)
 {
     size_t i;
     size_t cn_idx = 0, cn_len = strlen(cn);
 
     /* We can't have a match if there is no wildcard to match */
     if (name->len < 3 || name->p[0] != '*' || name->p[1] != '.') {
         return -1;
     }
 
     for (i = 0; i < cn_len; ++i) {
         if (cn[i] == '.') {
             cn_idx = i;
             break;
         }
     }
 
     if (cn_idx == 0) {
         return -1;
     }
 
     if (cn_len - cn_idx == name->len - 1 &&
         x509_memcasecmp(name->p + 1, cn + cn_idx, name->len - 1) == 0) {
         return 0;
     }
 
     return -1;
 }
 
 /*
  * Compare two X.509 strings, case-insensitive, and allowing for some encoding
  * variations (but not all).
  *
  * Return 0 if equal, -1 otherwise.
  */
 static int x509_string_cmp(const mbedtls_x509_buf *a, const mbedtls_x509_buf *b)
 {
     if (a->tag == b->tag &&
         a->len == b->len &&
         memcmp(a->p, b->p, b->len) == 0) {
         return 0;
     }
 
     if ((a->tag == MBEDTLS_ASN1_UTF8_STRING || a->tag == MBEDTLS_ASN1_PRINTABLE_STRING) &&
         (b->tag == MBEDTLS_ASN1_UTF8_STRING || b->tag == MBEDTLS_ASN1_PRINTABLE_STRING) &&
         a->len == b->len &&
         x509_memcasecmp(a->p, b->p, b->len) == 0) {
         return 0;
     }
 
     return -1;
 }
 
 /*
  * Compare two X.509 Names (aka rdnSequence).
  *
  * See RFC 5280 section 7.1, though we don't implement the whole algorithm:
  * we sometimes return unequal when the full algorithm would return equal,
  * but never the other way. (In particular, we don't do Unicode normalisation
  * or space folding.)
  *
  * Return 0 if equal, -1 otherwise.
  */
 static int x509_name_cmp(const mbedtls_x509_name *a, const mbedtls_x509_name *b)
 {
     /* Avoid recursion, it might not be optimised by the compiler */
     while (a != NULL || b != NULL) {
         if (a == NULL || b == NULL) {
             return -1;
         }
 
         /* type */
         if (a->oid.tag != b->oid.tag ||
             a->oid.len != b->oid.len ||
             memcmp(a->oid.p, b->oid.p, b->oid.len) != 0) {
             return -1;
         }
 
         /* value */
         if (x509_string_cmp(&a->val, &b->val) != 0) {
             return -1;
         }
 
         /* structure of the list of sets */
         if (a->next_merged != b->next_merged) {
             return -1;
         }
 
         a = a->next;
         b = b->next;
     }
 
     /* a == NULL == b */
     return 0;
 }
 
 /*
  * Reset (init or clear) a verify_chain
  */
 static void x509_crt_verify_chain_reset(
     mbedtls_x509_crt_verify_chain *ver_chain)
 {
     size_t i;
 
     for (i = 0; i < MBEDTLS_X509_MAX_VERIFY_CHAIN_SIZE; i++) {
         ver_chain->items[i].crt = NULL;
         ver_chain->items[i].flags = (uint32_t) -1;
     }
 
     ver_chain->len = 0;
 
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
     ver_chain->trust_ca_cb_result = NULL;
 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
 }
 
 /*
  *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
  */
 static int x509_get_version(unsigned char **p,
                             const unsigned char *end,
                             int *ver)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                     MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
                                     0)) != 0) {
         if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
             *ver = 0;
             return 0;
         }
 
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
     }
 
     end = *p + len;
 
     if ((ret = mbedtls_asn1_get_int(p, end, ver)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_VERSION, ret);
     }
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_VERSION,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return 0;
 }
 
 /*
  *  Validity ::= SEQUENCE {
  *       notBefore      Time,
  *       notAfter       Time }
  */
 static int x509_get_dates(unsigned char **p,
                           const unsigned char *end,
                           mbedtls_x509_time *from,
                           mbedtls_x509_time *to)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_DATE, ret);
     }
 
     end = *p + len;
 
     if ((ret = mbedtls_x509_get_time(p, end, from)) != 0) {
         return ret;
     }
 
     if ((ret = mbedtls_x509_get_time(p, end, to)) != 0) {
         return ret;
     }
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_DATE,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return 0;
 }
 
 /*
  * X.509 v2/v3 unique identifier (not parsed)
  */
 static int x509_get_uid(unsigned char **p,
                         const unsigned char *end,
                         mbedtls_x509_buf *uid, int n)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     if (*p == end) {
         return 0;
     }
 
     uid->tag = **p;
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &uid->len,
                                     MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
                                     n)) != 0) {
         if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
             return 0;
         }
 
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
     }
 
     uid->p = *p;
     *p += uid->len;
 
     return 0;
 }
 
 static int x509_get_basic_constraints(unsigned char **p,
                                       const unsigned char *end,
                                       int *ca_istrue,
                                       int *max_pathlen)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
 
     /*
      * BasicConstraints ::= SEQUENCE {
      *      cA                      BOOLEAN DEFAULT FALSE,
      *      pathLenConstraint       INTEGER (0..MAX) OPTIONAL }
      */
     *ca_istrue = 0; /* DEFAULT FALSE */
     *max_pathlen = 0; /* endless */
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     if (*p == end) {
         return 0;
     }
 
     if ((ret = mbedtls_asn1_get_bool(p, end, ca_istrue)) != 0) {
         if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
             ret = mbedtls_asn1_get_int(p, end, ca_istrue);
         }
 
         if (ret != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         if (*ca_istrue != 0) {
             *ca_istrue = 1;
         }
     }
 
     if (*p == end) {
         return 0;
     }
 
     if ((ret = mbedtls_asn1_get_int(p, end, max_pathlen)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     /* Do not accept max_pathlen equal to INT_MAX to avoid a signed integer
      * overflow, which is an undefined behavior. */
     if (*max_pathlen == INT_MAX) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_INVALID_LENGTH);
     }
 
     (*max_pathlen)++;
 
     return 0;
 }
 
 /*
  * ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
  *
  * KeyPurposeId ::= OBJECT IDENTIFIER
  */
 static int x509_get_ext_key_usage(unsigned char **p,
                                   const unsigned char *end,
                                   mbedtls_x509_sequence *ext_key_usage)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
     if ((ret = mbedtls_asn1_get_sequence_of(p, end, ext_key_usage, MBEDTLS_ASN1_OID)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     /* Sequence length must be >= 1 */
     if (ext_key_usage->buf.p == NULL) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_INVALID_LENGTH);
     }
 
     return 0;
 }
 
 /*
  * SubjectKeyIdentifier ::= KeyIdentifier
  *
  * KeyIdentifier ::= OCTET STRING
  */
 static int x509_get_subject_key_id(unsigned char **p,
                                    const unsigned char *end,
                                    mbedtls_x509_buf *subject_key_id)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len = 0u;
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                     MBEDTLS_ASN1_OCTET_STRING)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     subject_key_id->len = len;
     subject_key_id->tag = MBEDTLS_ASN1_OCTET_STRING;
     subject_key_id->p = *p;
     *p += len;
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return 0;
 }
 
 /*
  * AuthorityKeyIdentifier ::= SEQUENCE {
  *        keyIdentifier [0] KeyIdentifier OPTIONAL,
  *        authorityCertIssuer [1] GeneralNames OPTIONAL,
  *        authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL }
  *
  *    KeyIdentifier ::= OCTET STRING
  */
 static int x509_get_authority_key_id(unsigned char **p,
                                      unsigned char *end,
                                      mbedtls_x509_authority *authority_key_id)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len = 0u;
 
     if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     if (*p + len != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     ret = mbedtls_asn1_get_tag(p, end, &len,
                                MBEDTLS_ASN1_CONTEXT_SPECIFIC);
 
     /* KeyIdentifier is an OPTIONAL field */
     if (ret == 0) {
         authority_key_id->keyIdentifier.len = len;
         authority_key_id->keyIdentifier.p = *p;
         /* Setting tag of the keyIdentfier intentionally to 0x04.
          * Although the .keyIdentfier field is CONTEXT_SPECIFIC ([0] OPTIONAL),
          * its tag with the content is the payload of on OCTET STRING primitive */
         authority_key_id->keyIdentifier.tag = MBEDTLS_ASN1_OCTET_STRING;
 
         *p += len;
     } else if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     if (*p < end) {
         /* Getting authorityCertIssuer using the required specific class tag [1] */
         if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                         MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED |
                                         1)) != 0) {
             /* authorityCertIssuer and authorityCertSerialNumber MUST both
                be present or both be absent. At this point we expect to have both. */
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
         /* "end" also includes the CertSerialNumber field so "len" shall be used */
         ret = mbedtls_x509_get_subject_alt_name_ext(p,
                                                     (*p+len),
                                                     &authority_key_id->authorityCertIssuer);
         if (ret != 0) {
             return ret;
         }
 
         /* Getting authorityCertSerialNumber using the required specific class tag [2] */
         if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                         MBEDTLS_ASN1_CONTEXT_SPECIFIC | 2)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
         authority_key_id->authorityCertSerialNumber.len = len;
         authority_key_id->authorityCertSerialNumber.p = *p;
         authority_key_id->authorityCertSerialNumber.tag = MBEDTLS_ASN1_INTEGER;
         *p += len;
     }
 
     if (*p != end) {
         return MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
     }
 
     return 0;
 }
 
 /*
  * id-ce-certificatePolicies OBJECT IDENTIFIER ::=  { id-ce 32 }
  *
  * anyPolicy OBJECT IDENTIFIER ::= { id-ce-certificatePolicies 0 }
  *
  * certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation
  *
  * PolicyInformation ::= SEQUENCE {
  *     policyIdentifier   CertPolicyId,
  *     policyQualifiers   SEQUENCE SIZE (1..MAX) OF
  *                             PolicyQualifierInfo OPTIONAL }
  *
  * CertPolicyId ::= OBJECT IDENTIFIER
  *
  * PolicyQualifierInfo ::= SEQUENCE {
  *      policyQualifierId  PolicyQualifierId,
  *      qualifier          ANY DEFINED BY policyQualifierId }
  *
  * -- policyQualifierIds for Internet policy qualifiers
  *
  * id-qt          OBJECT IDENTIFIER ::=  { id-pkix 2 }
  * id-qt-cps      OBJECT IDENTIFIER ::=  { id-qt 1 }
  * id-qt-unotice  OBJECT IDENTIFIER ::=  { id-qt 2 }
  *
  * PolicyQualifierId ::= OBJECT IDENTIFIER ( id-qt-cps | id-qt-unotice )
  *
  * Qualifier ::= CHOICE {
  *      cPSuri           CPSuri,
  *      userNotice       UserNotice }
  *
  * CPSuri ::= IA5String
  *
  * UserNotice ::= SEQUENCE {
  *      noticeRef        NoticeReference OPTIONAL,
  *      explicitText     DisplayText OPTIONAL }
  *
  * NoticeReference ::= SEQUENCE {
  *      organization     DisplayText,
  *      noticeNumbers    SEQUENCE OF INTEGER }
  *
  * DisplayText ::= CHOICE {
  *      ia5String        IA5String      (SIZE (1..200)),
  *      visibleString    VisibleString  (SIZE (1..200)),
  *      bmpString        BMPString      (SIZE (1..200)),
  *      utf8String       UTF8String     (SIZE (1..200)) }
  *
  * NOTE: we only parse and use anyPolicy without qualifiers at this point
  * as defined in RFC 5280.
  */
 static int x509_get_certificate_policies(unsigned char **p,
                                          const unsigned char *end,
                                          mbedtls_x509_sequence *certificate_policies)
 {
     int ret, parse_ret = 0;
     size_t len;
     mbedtls_asn1_buf *buf;
     mbedtls_asn1_sequence *cur = certificate_policies;
 
     /* Get main sequence tag */
     ret = mbedtls_asn1_get_tag(p, end, &len,
                                MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
     if (ret != 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
     }
 
     if (*p + len != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     /*
      * Cannot be an empty sequence.
      */
     if (len == 0) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     while (*p < end) {
         mbedtls_x509_buf policy_oid;
         const unsigned char *policy_end;
 
         /*
          * Get the policy sequence
          */
         if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                         MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         policy_end = *p + len;
 
         if ((ret = mbedtls_asn1_get_tag(p, policy_end, &len,
                                         MBEDTLS_ASN1_OID)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         policy_oid.tag = MBEDTLS_ASN1_OID;
         policy_oid.len = len;
         policy_oid.p = *p;
 
         /*
          * Only AnyPolicy is currently supported when enforcing policy.
          */
         if (MBEDTLS_OID_CMP(MBEDTLS_OID_ANY_POLICY, &policy_oid) != 0) {
             /*
              * Set the parsing return code but continue parsing, in case this
              * extension is critical.
              */
             parse_ret = MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
         }
 
         /* Allocate and assign next pointer */
         if (cur->buf.p != NULL) {
             if (cur->next != NULL) {
                 return MBEDTLS_ERR_X509_INVALID_EXTENSIONS;
             }
 
             cur->next = mbedtls_calloc(1, sizeof(mbedtls_asn1_sequence));
 
             if (cur->next == NULL) {
                 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                          MBEDTLS_ERR_ASN1_ALLOC_FAILED);
             }
 
             cur = cur->next;
         }
 
         buf = &(cur->buf);
         buf->tag = policy_oid.tag;
         buf->p = policy_oid.p;
         buf->len = policy_oid.len;
 
         *p += len;
 
         /*
          * If there is an optional qualifier, then *p < policy_end
          * Check the Qualifier len to verify it doesn't exceed policy_end.
          */
         if (*p < policy_end) {
             if ((ret = mbedtls_asn1_get_tag(p, policy_end, &len,
                                             MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) !=
                 0) {
                 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
             }
             /*
              * Skip the optional policy qualifiers.
              */
             *p += len;
         }
 
         if (*p != policy_end) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                      MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
         }
     }
 
     /* Set final sequence entry's next pointer to NULL */
     cur->next = NULL;
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return parse_ret;
 }
 
 /*
  * X.509 v3 extensions
  *
  */
 static int x509_get_crt_ext(unsigned char **p,
                             const unsigned char *end,
                             mbedtls_x509_crt *crt,
                             mbedtls_x509_crt_ext_cb_t cb,
                             void *p_ctx)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
     unsigned char *end_ext_data, *start_ext_octet, *end_ext_octet;
 
     if (*p == end) {
         return 0;
     }
 
     if ((ret = mbedtls_x509_get_ext(p, end, &crt->v3_ext, 3)) != 0) {
         return ret;
     }
 
     end = crt->v3_ext.p + crt->v3_ext.len;
     while (*p < end) {
         /*
          * Extension  ::=  SEQUENCE  {
          *      extnID      OBJECT IDENTIFIER,
          *      critical    BOOLEAN DEFAULT FALSE,
          *      extnValue   OCTET STRING  }
          */
         mbedtls_x509_buf extn_oid = { 0, 0, NULL };
         int is_critical = 0; /* DEFAULT FALSE */
         int ext_type = 0;
 
         if ((ret = mbedtls_asn1_get_tag(p, end, &len,
                                         MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         end_ext_data = *p + len;
 
         /* Get extension ID */
         if ((ret = mbedtls_asn1_get_tag(p, end_ext_data, &extn_oid.len,
                                         MBEDTLS_ASN1_OID)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         extn_oid.tag = MBEDTLS_ASN1_OID;
         extn_oid.p = *p;
         *p += extn_oid.len;
 
         /* Get optional critical */
         if ((ret = mbedtls_asn1_get_bool(p, end_ext_data, &is_critical)) != 0 &&
             (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         /* Data should be octet string type */
         if ((ret = mbedtls_asn1_get_tag(p, end_ext_data, &len,
                                         MBEDTLS_ASN1_OCTET_STRING)) != 0) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
         }
 
         start_ext_octet = *p;
         end_ext_octet = *p + len;
 
         if (end_ext_octet != end_ext_data) {
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                      MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
         }
 
         /*
          * Detect supported extensions
          */
         ret = mbedtls_oid_get_x509_ext_type(&extn_oid, &ext_type);
 
         if (ret != 0) {
             /* Give the callback (if any) a chance to handle the extension */
             if (cb != NULL) {
                 ret = cb(p_ctx, crt, &extn_oid, is_critical, *p, end_ext_octet);
                 if (ret != 0 && is_critical) {
                     return ret;
                 }
                 *p = end_ext_octet;
                 continue;
             }
 
             /* No parser found, skip extension */
             *p = end_ext_octet;
 
             if (is_critical) {
                 /* Data is marked as critical: fail */
                 return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                          MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
             }
             continue;
         }
 
         /* Forbid repeated extensions */
         if ((crt->ext_types & ext_type) != 0) {
             return MBEDTLS_ERR_X509_INVALID_EXTENSIONS;
         }
 
         crt->ext_types |= ext_type;
 
         switch (ext_type) {
             case MBEDTLS_X509_EXT_BASIC_CONSTRAINTS:
                 /* Parse basic constraints */
                 if ((ret = x509_get_basic_constraints(p, end_ext_octet,
                                                       &crt->ca_istrue, &crt->max_pathlen)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_X509_EXT_KEY_USAGE:
                 /* Parse key usage */
                 if ((ret = mbedtls_x509_get_key_usage(p, end_ext_octet,
                                                       &crt->key_usage)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE:
                 /* Parse extended key usage */
                 if ((ret = x509_get_ext_key_usage(p, end_ext_octet,
                                                   &crt->ext_key_usage)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_X509_EXT_SUBJECT_KEY_IDENTIFIER:
                 /* Parse subject key identifier */
                 if ((ret = x509_get_subject_key_id(p, end_ext_data,
                                                    &crt->subject_key_id)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_X509_EXT_AUTHORITY_KEY_IDENTIFIER:
                 /* Parse authority key identifier */
                 if ((ret = x509_get_authority_key_id(p, end_ext_octet,
                                                      &crt->authority_key_id)) != 0) {
                     return ret;
                 }
                 break;
             case MBEDTLS_X509_EXT_SUBJECT_ALT_NAME:
                 /* Parse subject alt name
                  * SubjectAltName ::= GeneralNames
                  */
                 if ((ret = mbedtls_x509_get_subject_alt_name(p, end_ext_octet,
                                                              &crt->subject_alt_names)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_X509_EXT_NS_CERT_TYPE:
                 /* Parse netscape certificate type */
                 if ((ret = mbedtls_x509_get_ns_cert_type(p, end_ext_octet,
                                                          &crt->ns_cert_type)) != 0) {
                     return ret;
                 }
                 break;
 
             case MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES:
                 /* Parse certificate policies type */
                 if ((ret = x509_get_certificate_policies(p, end_ext_octet,
                                                          &crt->certificate_policies)) != 0) {
                     /* Give the callback (if any) a chance to handle the extension
                      * if it contains unsupported policies */
                     if (ret == MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE && cb != NULL &&
                         cb(p_ctx, crt, &extn_oid, is_critical,
                            start_ext_octet, end_ext_octet) == 0) {
                         break;
                     }
 
                     if (is_critical) {
                         return ret;
                     } else
                     /*
                      * If MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE is returned, then we
                      * cannot interpret or enforce the policy. However, it is up to
                      * the user to choose how to enforce the policies,
                      * unless the extension is critical.
                      */
                     if (ret != MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE) {
                         return ret;
                     }
                 }
                 break;
 
             default:
                 /*
                  * If this is a non-critical extension, which the oid layer
                  * supports, but there isn't an x509 parser for it,
                  * skip the extension.
                  */
                 if (is_critical) {
                     return MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE;
                 } else {
                     *p = end_ext_octet;
                 }
         }
     }
 
     if (*p != end) {
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return 0;
 }
 
 /*
  * Parse and fill a single X.509 certificate in DER format
  */
 static int x509_crt_parse_der_core(mbedtls_x509_crt *crt,
                                    const unsigned char *buf,
                                    size_t buflen,
                                    int make_copy,
                                    mbedtls_x509_crt_ext_cb_t cb,
                                    void *p_ctx)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t len;
     unsigned char *p, *end, *crt_end;
     mbedtls_x509_buf sig_params1, sig_params2, sig_oid2;
 
     memset(&sig_params1, 0, sizeof(mbedtls_x509_buf));
     memset(&sig_params2, 0, sizeof(mbedtls_x509_buf));
     memset(&sig_oid2, 0, sizeof(mbedtls_x509_buf));
 
     /*
      * Check for valid input
      */
     if (crt == NULL || buf == NULL) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     /* Use the original buffer until we figure out actual length. */
     p = (unsigned char *) buf;
     len = buflen;
     end = p + len;
 
     /*
      * Certificate  ::=  SEQUENCE  {
      *      tbsCertificate       TBSCertificate,
      *      signatureAlgorithm   AlgorithmIdentifier,
      *      signatureValue       BIT STRING  }
      */
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERR_X509_INVALID_FORMAT;
     }
 
     end = crt_end = p + len;
     crt->raw.len = (size_t) (crt_end - buf);
     if (make_copy != 0) {
         /* Create and populate a new buffer for the raw field. */
         crt->raw.p = p = mbedtls_calloc(1, crt->raw.len);
         if (crt->raw.p == NULL) {
             return MBEDTLS_ERR_X509_ALLOC_FAILED;
         }
 
         memcpy(crt->raw.p, buf, crt->raw.len);
         crt->own_buffer = 1;
 
         p += crt->raw.len - len;
         end = crt_end = p + len;
     } else {
         crt->raw.p = (unsigned char *) buf;
         crt->own_buffer = 0;
     }
 
     /*
      * TBSCertificate  ::=  SEQUENCE  {
      */
     crt->tbs.p = p;
 
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
     }
 
     end = p + len;
     crt->tbs.len = (size_t) (end - crt->tbs.p);
 
     /*
      * Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
      *
      * CertificateSerialNumber  ::=  INTEGER
      *
      * signature            AlgorithmIdentifier
      */
     if ((ret = x509_get_version(&p, end, &crt->version)) != 0 ||
         (ret = mbedtls_x509_get_serial(&p, end, &crt->serial)) != 0 ||
         (ret = mbedtls_x509_get_alg(&p, end, &crt->sig_oid,
                                     &sig_params1)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     if (crt->version < 0 || crt->version > 2) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERR_X509_UNKNOWN_VERSION;
     }
 
     crt->version++;
 
     if ((ret = mbedtls_x509_get_sig_alg(&crt->sig_oid, &sig_params1,
                                         &crt->sig_md, &crt->sig_pk,
                                         &crt->sig_opts)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     /*
      * issuer               Name
      */
     crt->issuer_raw.p = p;
 
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
     }
 
     if ((ret = mbedtls_x509_get_name(&p, p + len, &crt->issuer)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     crt->issuer_raw.len = (size_t) (p - crt->issuer_raw.p);
 
     /*
      * Validity ::= SEQUENCE {
      *      notBefore      Time,
      *      notAfter       Time }
      *
      */
     if ((ret = x509_get_dates(&p, end, &crt->valid_from,
                               &crt->valid_to)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     /*
      * subject              Name
      */
     crt->subject_raw.p = p;
 
     if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
                                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT, ret);
     }
 
     if (len && (ret = mbedtls_x509_get_name(&p, p + len, &crt->subject)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     crt->subject_raw.len = (size_t) (p - crt->subject_raw.p);
 
     /*
      * SubjectPublicKeyInfo
      */
     crt->pk_raw.p = p;
     if ((ret = mbedtls_pk_parse_subpubkey(&p, end, &crt->pk)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
     crt->pk_raw.len = (size_t) (p - crt->pk_raw.p);
 
     /*
      *  issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
      *                       -- If present, version shall be v2 or v3
      *  subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
      *                       -- If present, version shall be v2 or v3
      *  extensions      [3]  EXPLICIT Extensions OPTIONAL
      *                       -- If present, version shall be v3
      */
     if (crt->version == 2 || crt->version == 3) {
         ret = x509_get_uid(&p, end, &crt->issuer_id,  1);
         if (ret != 0) {
             mbedtls_x509_crt_free(crt);
             return ret;
         }
     }
 
     if (crt->version == 2 || crt->version == 3) {
         ret = x509_get_uid(&p, end, &crt->subject_id,  2);
         if (ret != 0) {
             mbedtls_x509_crt_free(crt);
             return ret;
         }
     }
 
     if (crt->version == 3) {
         ret = x509_get_crt_ext(&p, end, crt, cb, p_ctx);
         if (ret != 0) {
             mbedtls_x509_crt_free(crt);
             return ret;
         }
     }
 
     if (p != end) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     end = crt_end;
 
     /*
      *  }
      *  -- end of TBSCertificate
      *
      *  signatureAlgorithm   AlgorithmIdentifier,
      *  signatureValue       BIT STRING
      */
     if ((ret = mbedtls_x509_get_alg(&p, end, &sig_oid2, &sig_params2)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     if (crt->sig_oid.len != sig_oid2.len ||
         memcmp(crt->sig_oid.p, sig_oid2.p, crt->sig_oid.len) != 0 ||
         sig_params1.tag != sig_params2.tag ||
         sig_params1.len != sig_params2.len ||
         (sig_params1.len != 0 &&
          memcmp(sig_params1.p, sig_params2.p, sig_params1.len) != 0)) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERR_X509_SIG_MISMATCH;
     }
 
     if ((ret = mbedtls_x509_get_sig(&p, end, &crt->sig)) != 0) {
         mbedtls_x509_crt_free(crt);
         return ret;
     }
 
     if (p != end) {
         mbedtls_x509_crt_free(crt);
         return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_FORMAT,
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
     return 0;
 }
 
 /*
  * Parse one X.509 certificate in DER format from a buffer and add them to a
  * chained list
  */
 static int mbedtls_x509_crt_parse_der_internal(mbedtls_x509_crt *chain,
                                                const unsigned char *buf,
                                                size_t buflen,
                                                int make_copy,
                                                mbedtls_x509_crt_ext_cb_t cb,
                                                void *p_ctx)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *crt = chain, *prev = NULL;
 
     /*
      * Check for valid input
      */
     if (crt == NULL || buf == NULL) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     while (crt->version != 0 && crt->next != NULL) {
         prev = crt;
         crt = crt->next;
     }
 
     /*
      * Add new certificate on the end of the chain if needed.
      */
     if (crt->version != 0 && crt->next == NULL) {
         crt->next = mbedtls_calloc(1, sizeof(mbedtls_x509_crt));
 
         if (crt->next == NULL) {
             return MBEDTLS_ERR_X509_ALLOC_FAILED;
         }
 
         prev = crt;
         mbedtls_x509_crt_init(crt->next);
         crt = crt->next;
     }
 
     ret = x509_crt_parse_der_core(crt, buf, buflen, make_copy, cb, p_ctx);
     if (ret != 0) {
         if (prev) {
             prev->next = NULL;
         }
 
         if (crt != chain) {
             mbedtls_free(crt);
         }
 
         return ret;
     }
 
     return 0;
 }
 
 int mbedtls_x509_crt_parse_der_nocopy(mbedtls_x509_crt *chain,
                                       const unsigned char *buf,
                                       size_t buflen)
 {
     return mbedtls_x509_crt_parse_der_internal(chain, buf, buflen, 0, NULL, NULL);
 }
 
 int mbedtls_x509_crt_parse_der_with_ext_cb(mbedtls_x509_crt *chain,
                                            const unsigned char *buf,
                                            size_t buflen,
                                            int make_copy,
                                            mbedtls_x509_crt_ext_cb_t cb,
                                            void *p_ctx)
 {
     return mbedtls_x509_crt_parse_der_internal(chain, buf, buflen, make_copy, cb, p_ctx);
 }
 
 int mbedtls_x509_crt_parse_der(mbedtls_x509_crt *chain,
                                const unsigned char *buf,
                                size_t buflen)
 {
     return mbedtls_x509_crt_parse_der_internal(chain, buf, buflen, 1, NULL, NULL);
 }
 
 /*
  * Parse one or more PEM certificates from a buffer and add them to the chained
  * list
  */
 int mbedtls_x509_crt_parse(mbedtls_x509_crt *chain,
                            const unsigned char *buf,
                            size_t buflen)
 {
 #if defined(MBEDTLS_PEM_PARSE_C)
     int success = 0, first_error = 0, total_failed = 0;
     int buf_format = MBEDTLS_X509_FORMAT_DER;
 #endif
 
     /*
      * Check for valid input
      */
     if (chain == NULL || buf == NULL) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     /*
      * Determine buffer content. Buffer contains either one DER certificate or
      * one or more PEM certificates.
      */
 #if defined(MBEDTLS_PEM_PARSE_C)
     if (buflen != 0 && buf[buflen - 1] == '\0' &&
         strstr((const char *) buf, "-----BEGIN CERTIFICATE-----") != NULL) {
         buf_format = MBEDTLS_X509_FORMAT_PEM;
     }
 
     if (buf_format == MBEDTLS_X509_FORMAT_DER) {
         return mbedtls_x509_crt_parse_der(chain, buf, buflen);
     }
 #else
     return mbedtls_x509_crt_parse_der(chain, buf, buflen);
 #endif
 
 #if defined(MBEDTLS_PEM_PARSE_C)
     if (buf_format == MBEDTLS_X509_FORMAT_PEM) {
         int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
         mbedtls_pem_context pem;
 
         /* 1 rather than 0 since the terminating NULL byte is counted in */
         while (buflen > 1) {
             size_t use_len;
             mbedtls_pem_init(&pem);
 
             /* If we get there, we know the string is null-terminated */
             ret = mbedtls_pem_read_buffer(&pem,
                                           "-----BEGIN CERTIFICATE-----",
                                           "-----END CERTIFICATE-----",
                                           buf, NULL, 0, &use_len);
 
             if (ret == 0) {
                 /*
                  * Was PEM encoded
                  */
                 buflen -= use_len;
                 buf += use_len;
             } else if (ret == MBEDTLS_ERR_PEM_BAD_INPUT_DATA) {
                 return ret;
             } else if (ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT) {
                 mbedtls_pem_free(&pem);
 
                 /*
                  * PEM header and footer were found
                  */
                 buflen -= use_len;
                 buf += use_len;
 
                 if (first_error == 0) {
                     first_error = ret;
                 }
 
                 total_failed++;
                 continue;
             } else {
                 break;
             }
 
             ret = mbedtls_x509_crt_parse_der(chain, pem.buf, pem.buflen);
 
             mbedtls_pem_free(&pem);
 
             if (ret != 0) {
                 /*
                  * Quit parsing on a memory error
                  */
                 if (ret == MBEDTLS_ERR_X509_ALLOC_FAILED) {
                     return ret;
                 }
 
                 if (first_error == 0) {
                     first_error = ret;
                 }
 
                 total_failed++;
                 continue;
             }
 
             success = 1;
         }
     }
 
     if (success) {
         return total_failed;
     } else if (first_error) {
         return first_error;
     } else {
         return MBEDTLS_ERR_X509_CERT_UNKNOWN_FORMAT;
     }
 #endif /* MBEDTLS_PEM_PARSE_C */
 }
 
 #if defined(MBEDTLS_FS_IO)
 /*
  * Load one or more certificates and add them to the chained list
  */
 int mbedtls_x509_crt_parse_file(mbedtls_x509_crt *chain, const char *path)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n;
     unsigned char *buf;
 
     if ((ret = mbedtls_pk_load_file(path, &buf, &n)) != 0) {
         return ret;
     }
 
     ret = mbedtls_x509_crt_parse(chain, buf, n);
 
     mbedtls_zeroize_and_free(buf, n);
 
     return ret;
 }
 
 int mbedtls_x509_crt_parse_path(mbedtls_x509_crt *chain, const char *path)
 {
     int ret = 0;
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
     int w_ret;
     WCHAR szDir[MAX_PATH];
     char filename[MAX_PATH];
     char *p;
     size_t len = strlen(path);
 
     WIN32_FIND_DATAW file_data;
     HANDLE hFind;
 
     if (len > MAX_PATH - 3) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     memset(szDir, 0, sizeof(szDir));
     memset(filename, 0, MAX_PATH);
     memcpy(filename, path, len);
     filename[len++] = '\\';
     p = filename + len;
     filename[len++] = '*';
 
     /*
      * Note this function uses the code page CP_ACP which is the system default
      * ANSI codepage. The input string is always described in BYTES and the
      * output length is described in WCHARs.
      */
     w_ret = MultiByteToWideChar(CP_ACP, 0, filename, (int) len, szDir,
                                 MAX_PATH - 3);
     if (w_ret == 0) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     hFind = FindFirstFileW(szDir, &file_data);
     if (hFind == INVALID_HANDLE_VALUE) {
         return MBEDTLS_ERR_X509_FILE_IO_ERROR;
     }
 
     len = MAX_PATH - len;
     do {
         memset(p, 0, len);
 
         if (file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
             continue;
         }
         w_ret = WideCharToMultiByte(CP_ACP, 0, file_data.cFileName,
                                     -1, p, (int) len, NULL, NULL);
         if (w_ret == 0) {
             ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
             goto cleanup;
         }
 
         w_ret = mbedtls_x509_crt_parse_file(chain, filename);
         if (w_ret < 0) {
             ret++;
         } else {
             ret += w_ret;
         }
     } while (FindNextFileW(hFind, &file_data) != 0);
 
     if (GetLastError() != ERROR_NO_MORE_FILES) {
         ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
     }
 
 cleanup:
     FindClose(hFind);
 #else /* _WIN32 */
     int t_ret;
     int snp_ret;
     struct stat sb;
     struct dirent *entry;
     char entry_name[MBEDTLS_X509_MAX_FILE_PATH_LEN];
     DIR *dir = opendir(path);
 
     if (dir == NULL) {
         return MBEDTLS_ERR_X509_FILE_IO_ERROR;
     }
 
 #if defined(MBEDTLS_THREADING_C)
     if ((ret = mbedtls_mutex_lock(&mbedtls_threading_readdir_mutex)) != 0) {
         closedir(dir);
         return ret;
     }
 #endif /* MBEDTLS_THREADING_C */
 
     memset(&sb, 0, sizeof(sb));
 
     while ((entry = readdir(dir)) != NULL) {
         snp_ret = mbedtls_snprintf(entry_name, sizeof(entry_name),
                                    "%s/%s", path, entry->d_name);
 
         if (snp_ret < 0 || (size_t) snp_ret >= sizeof(entry_name)) {
             ret = MBEDTLS_ERR_X509_BUFFER_TOO_SMALL;
             goto cleanup;
         } else if (stat(entry_name, &sb) == -1) {
             if (errno == ENOENT) {
                 /* Broken symbolic link - ignore this entry.
                     stat(2) will return this error for either (a) a dangling
                     symlink or (b) a missing file.
                     Given that we have just obtained the filename from readdir,
                     assume that it does exist and therefore treat this as a
                     dangling symlink. */
                 continue;
             } else {
                 /* Some other file error; report the error. */
                 ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
                 goto cleanup;
             }
         }
 
         if (!S_ISREG(sb.st_mode)) {
             continue;
         }
 
         // Ignore parse errors
         //
         t_ret = mbedtls_x509_crt_parse_file(chain, entry_name);
         if (t_ret < 0) {
             ret++;
         } else {
             ret += t_ret;
         }
     }
 
 cleanup:
     closedir(dir);
 
 #if defined(MBEDTLS_THREADING_C)
     if (mbedtls_mutex_unlock(&mbedtls_threading_readdir_mutex) != 0) {
         ret = MBEDTLS_ERR_THREADING_MUTEX_ERROR;
     }
 #endif /* MBEDTLS_THREADING_C */
 
 #endif /* _WIN32 */
 
     return ret;
 }
 #endif /* MBEDTLS_FS_IO */
 
 #if !defined(MBEDTLS_X509_REMOVE_INFO)
 #define PRINT_ITEM(i)                               \
     do {                                            \
         ret = mbedtls_snprintf(p, n, "%s" i, sep);  \
         MBEDTLS_X509_SAFE_SNPRINTF;                 \
         sep = ", ";                                 \
     } while (0)
 
 #define CERT_TYPE(type, name)          \
     do {                               \
         if (ns_cert_type & (type)) {   \
             PRINT_ITEM(name);          \
         }                              \
     } while (0)
 
 #define KEY_USAGE(code, name)      \
     do {                           \
         if (key_usage & (code)) {  \
             PRINT_ITEM(name);      \
         }                          \
     } while (0)
 
 static int x509_info_ext_key_usage(char **buf, size_t *size,
                                    const mbedtls_x509_sequence *extended_key_usage)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const char *desc;
     size_t n = *size;
     char *p = *buf;
     const mbedtls_x509_sequence *cur = extended_key_usage;
     const char *sep = "";
 
     while (cur != NULL) {
         if (mbedtls_oid_get_extended_key_usage(&cur->buf, &desc) != 0) {
             desc = "???";
         }
 
         ret = mbedtls_snprintf(p, n, "%s%s", sep, desc);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         sep = ", ";
 
         cur = cur->next;
     }
 
     *size = n;
     *buf = p;
 
     return 0;
 }
 
 static int x509_info_cert_policies(char **buf, size_t *size,
                                    const mbedtls_x509_sequence *certificate_policies)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const char *desc;
     size_t n = *size;
     char *p = *buf;
     const mbedtls_x509_sequence *cur = certificate_policies;
     const char *sep = "";
 
     while (cur != NULL) {
         if (mbedtls_oid_get_certificate_policies(&cur->buf, &desc) != 0) {
             desc = "???";
         }
 
         ret = mbedtls_snprintf(p, n, "%s%s", sep, desc);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         sep = ", ";
 
         cur = cur->next;
     }
 
     *size = n;
     *buf = p;
 
     return 0;
 }
 
 /*
  * Return an informational string about the certificate.
  */
 #define BEFORE_COLON    18
 #define BC              "18"
 int mbedtls_x509_crt_info(char *buf, size_t size, const char *prefix,
                           const mbedtls_x509_crt *crt)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n;
     char *p;
     char key_size_str[BEFORE_COLON];
 
     p = buf;
     n = size;
 
     if (NULL == crt) {
         ret = mbedtls_snprintf(p, n, "\nCertificate is uninitialised!\n");
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         return (int) (size - n);
     }
 
     ret = mbedtls_snprintf(p, n, "%scert. version     : %d\n",
                            prefix, crt->version);
     MBEDTLS_X509_SAFE_SNPRINTF;
     ret = mbedtls_snprintf(p, n, "%sserial number     : ",
                            prefix);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_x509_serial_gets(p, n, &crt->serial);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_snprintf(p, n, "\n%sissuer name       : ", prefix);
     MBEDTLS_X509_SAFE_SNPRINTF;
     ret = mbedtls_x509_dn_gets(p, n, &crt->issuer);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_snprintf(p, n, "\n%ssubject name      : ", prefix);
     MBEDTLS_X509_SAFE_SNPRINTF;
     ret = mbedtls_x509_dn_gets(p, n, &crt->subject);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_snprintf(p, n, "\n%sissued  on        : " \
                                  "%04d-%02d-%02d %02d:%02d:%02d", prefix,
                            crt->valid_from.year, crt->valid_from.mon,
                            crt->valid_from.day,  crt->valid_from.hour,
                            crt->valid_from.min,  crt->valid_from.sec);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_snprintf(p, n, "\n%sexpires on        : " \
                                  "%04d-%02d-%02d %02d:%02d:%02d", prefix,
                            crt->valid_to.year, crt->valid_to.mon,
                            crt->valid_to.day,  crt->valid_to.hour,
                            crt->valid_to.min,  crt->valid_to.sec);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_snprintf(p, n, "\n%ssigned using      : ", prefix);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     ret = mbedtls_x509_sig_alg_gets(p, n, &crt->sig_oid, crt->sig_pk,
                                     crt->sig_md, crt->sig_opts);
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     /* Key size */
     if ((ret = mbedtls_x509_key_size_helper(key_size_str, BEFORE_COLON,
                                             mbedtls_pk_get_name(&crt->pk))) != 0) {
         return ret;
     }
 
     ret = mbedtls_snprintf(p, n, "\n%s%-" BC "s: %d bits", prefix, key_size_str,
                            (int) mbedtls_pk_get_bitlen(&crt->pk));
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     /*
      * Optional extensions
      */
 
     if (crt->ext_types & MBEDTLS_X509_EXT_BASIC_CONSTRAINTS) {
         ret = mbedtls_snprintf(p, n, "\n%sbasic constraints : CA=%s", prefix,
                                crt->ca_istrue ? "true" : "false");
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if (crt->max_pathlen > 0) {
             ret = mbedtls_snprintf(p, n, ", max_pathlen=%d", crt->max_pathlen - 1);
             MBEDTLS_X509_SAFE_SNPRINTF;
         }
     }
 
     if (crt->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME) {
         ret = mbedtls_snprintf(p, n, "\n%ssubject alt name  :", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if ((ret = mbedtls_x509_info_subject_alt_name(&p, &n,
                                                       &crt->subject_alt_names,
                                                       prefix)) != 0) {
             return ret;
         }
     }
 
     if (crt->ext_types & MBEDTLS_X509_EXT_NS_CERT_TYPE) {
         ret = mbedtls_snprintf(p, n, "\n%scert. type        : ", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if ((ret = mbedtls_x509_info_cert_type(&p, &n, crt->ns_cert_type)) != 0) {
             return ret;
         }
     }
 
     if (crt->ext_types & MBEDTLS_X509_EXT_KEY_USAGE) {
         ret = mbedtls_snprintf(p, n, "\n%skey usage         : ", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if ((ret = mbedtls_x509_info_key_usage(&p, &n, crt->key_usage)) != 0) {
             return ret;
         }
     }
 
     if (crt->ext_types & MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE) {
         ret = mbedtls_snprintf(p, n, "\n%sext key usage     : ", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if ((ret = x509_info_ext_key_usage(&p, &n,
                                            &crt->ext_key_usage)) != 0) {
             return ret;
         }
     }
 
     if (crt->ext_types & MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES) {
         ret = mbedtls_snprintf(p, n, "\n%scertificate policies : ", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
 
         if ((ret = x509_info_cert_policies(&p, &n,
                                            &crt->certificate_policies)) != 0) {
             return ret;
         }
     }
 
     ret = mbedtls_snprintf(p, n, "\n");
     MBEDTLS_X509_SAFE_SNPRINTF;
 
     return (int) (size - n);
 }
 
 struct x509_crt_verify_string {
     int code;
     const char *string;
 };
 
 #define X509_CRT_ERROR_INFO(err, err_str, info) { err, info },
 static const struct x509_crt_verify_string x509_crt_verify_strings[] = {
     MBEDTLS_X509_CRT_ERROR_INFO_LIST
     { 0, NULL }
 };
 #undef X509_CRT_ERROR_INFO
 
 int mbedtls_x509_crt_verify_info(char *buf, size_t size, const char *prefix,
                                  uint32_t flags)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     const struct x509_crt_verify_string *cur;
     char *p = buf;
     size_t n = size;
 
     for (cur = x509_crt_verify_strings; cur->string != NULL; cur++) {
         if ((flags & cur->code) == 0) {
             continue;
         }
 
         ret = mbedtls_snprintf(p, n, "%s%s\n", prefix, cur->string);
         MBEDTLS_X509_SAFE_SNPRINTF;
         flags ^= cur->code;
     }
 
     if (flags != 0) {
         ret = mbedtls_snprintf(p, n, "%sUnknown reason "
                                      "(this should not happen)\n", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;
     }
 
     return (int) (size - n);
 }
 #endif /* MBEDTLS_X509_REMOVE_INFO */
 
 int mbedtls_x509_crt_check_key_usage(const mbedtls_x509_crt *crt,
                                      unsigned int usage)
 {
     unsigned int usage_must, usage_may;
     unsigned int may_mask = MBEDTLS_X509_KU_ENCIPHER_ONLY
                             | MBEDTLS_X509_KU_DECIPHER_ONLY;
 
     if ((crt->ext_types & MBEDTLS_X509_EXT_KEY_USAGE) == 0) {
         return 0;
     }
 
     usage_must = usage & ~may_mask;
 
     if (((crt->key_usage & ~may_mask) & usage_must) != usage_must) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     usage_may = usage & may_mask;
 
     if (((crt->key_usage & may_mask) | usage_may) != usage_may) {
         return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
     }
 
     return 0;
 }
 
 int mbedtls_x509_crt_check_extended_key_usage(const mbedtls_x509_crt *crt,
                                               const char *usage_oid,
                                               size_t usage_len)
 {
     const mbedtls_x509_sequence *cur;
 
     /* Extension is not mandatory, absent means no restriction */
     if ((crt->ext_types & MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE) == 0) {
         return 0;
     }
 
     /*
      * Look for the requested usage (or wildcard ANY) in our list
      */
     for (cur = &crt->ext_key_usage; cur != NULL; cur = cur->next) {
         const mbedtls_x509_buf *cur_oid = &cur->buf;
 
         if (cur_oid->len == usage_len &&
             memcmp(cur_oid->p, usage_oid, usage_len) == 0) {
             return 0;
         }
 
         if (MBEDTLS_OID_CMP(MBEDTLS_OID_ANY_EXTENDED_KEY_USAGE, cur_oid) == 0) {
             return 0;
         }
     }
 
     return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
 }
 
 #if defined(MBEDTLS_X509_CRL_PARSE_C)
 /*
  * Return 1 if the certificate is revoked, or 0 otherwise.
  */
 int mbedtls_x509_crt_is_revoked(const mbedtls_x509_crt *crt, const mbedtls_x509_crl *crl)
 {
     const mbedtls_x509_crl_entry *cur = &crl->entry;
 
     while (cur != NULL && cur->serial.len != 0) {
         if (crt->serial.len == cur->serial.len &&
             memcmp(crt->serial.p, cur->serial.p, crt->serial.len) == 0) {
             return 1;
         }
 
         cur = cur->next;
     }
 
     return 0;
 }
 
 /*
  * Check that the given certificate is not revoked according to the CRL.
  * Skip validation if no CRL for the given CA is present.
  */
 static int x509_crt_verifycrl(mbedtls_x509_crt *crt, mbedtls_x509_crt *ca,
                               mbedtls_x509_crl *crl_list,
                               const mbedtls_x509_crt_profile *profile,
                               const mbedtls_x509_time *now)
 {
     int flags = 0;
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     psa_algorithm_t psa_algorithm;
 #else
     const mbedtls_md_info_t *md_info;
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
     size_t hash_length;
 
     if (ca == NULL) {
         return flags;
     }
 
     while (crl_list != NULL) {
         if (crl_list->version == 0 ||
             x509_name_cmp(&crl_list->issuer, &ca->subject) != 0) {
             crl_list = crl_list->next;
             continue;
         }
 
         /*
          * Check if the CA is configured to sign CRLs
          */
         if (mbedtls_x509_crt_check_key_usage(ca,
                                              MBEDTLS_X509_KU_CRL_SIGN) != 0) {
             flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
             break;
         }
 
         /*
          * Check if CRL is correctly signed by the trusted CA
          */
         if (x509_profile_check_md_alg(profile, crl_list->sig_md) != 0) {
             flags |= MBEDTLS_X509_BADCRL_BAD_MD;
         }
 
         if (x509_profile_check_pk_alg(profile, crl_list->sig_pk) != 0) {
             flags |= MBEDTLS_X509_BADCRL_BAD_PK;
         }
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
         psa_algorithm = mbedtls_md_psa_alg_from_type(crl_list->sig_md);
         if (psa_hash_compute(psa_algorithm,
                              crl_list->tbs.p,
                              crl_list->tbs.len,
                              hash,
                              sizeof(hash),
                              &hash_length) != PSA_SUCCESS) {
             /* Note: this can't happen except after an internal error */
             flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
             break;
         }
 #else
         md_info = mbedtls_md_info_from_type(crl_list->sig_md);
         hash_length = mbedtls_md_get_size(md_info);
         if (mbedtls_md(md_info,
                        crl_list->tbs.p,
                        crl_list->tbs.len,
                        hash) != 0) {
             /* Note: this can't happen except after an internal error */
             flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
             break;
         }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
 
         if (x509_profile_check_key(profile, &ca->pk) != 0) {
             flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
         }
 
         if (mbedtls_pk_verify_ext(crl_list->sig_pk, crl_list->sig_opts, &ca->pk,
                                   crl_list->sig_md, hash, hash_length,
                                   crl_list->sig.p, crl_list->sig.len) != 0) {
             flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
             break;
         }
 
 #if defined(MBEDTLS_HAVE_TIME_DATE)
         /*
          * Check for validity of CRL (Do not drop out)
          */
         if (mbedtls_x509_time_cmp(&crl_list->next_update, now) < 0) {
             flags |= MBEDTLS_X509_BADCRL_EXPIRED;
         }
 
         if (mbedtls_x509_time_cmp(&crl_list->this_update, now) > 0) {
             flags |= MBEDTLS_X509_BADCRL_FUTURE;
         }
 #else
         ((void) now);
 #endif
 
         /*
          * Check if certificate is revoked
          */
         if (mbedtls_x509_crt_is_revoked(crt, crl_list)) {
             flags |= MBEDTLS_X509_BADCERT_REVOKED;
             break;
         }
 
         crl_list = crl_list->next;
     }
 
     return flags;
 }
 #endif /* MBEDTLS_X509_CRL_PARSE_C */
 
 /*
  * Check the signature of a certificate by its parent
  */
 static int x509_crt_check_signature(const mbedtls_x509_crt *child,
                                     mbedtls_x509_crt *parent,
                                     mbedtls_x509_crt_restart_ctx *rs_ctx)
 {
     size_t hash_len;
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];
 #if !defined(MBEDTLS_USE_PSA_CRYPTO)
     const mbedtls_md_info_t *md_info;
     md_info = mbedtls_md_info_from_type(child->sig_md);
     hash_len = mbedtls_md_get_size(md_info);
 
     /* Note: hash errors can happen only after an internal error */
     if (mbedtls_md(md_info, child->tbs.p, child->tbs.len, hash) != 0) {
         return -1;
     }
 #else
     psa_algorithm_t hash_alg = mbedtls_md_psa_alg_from_type(child->sig_md);
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
 
     status = psa_hash_compute(hash_alg,
                               child->tbs.p,
                               child->tbs.len,
                               hash,
                               sizeof(hash),
                               &hash_len);
     if (status != PSA_SUCCESS) {
         return MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED;
     }
 
 #endif /* MBEDTLS_USE_PSA_CRYPTO */
     /* Skip expensive computation on obvious mismatch */
     if (!mbedtls_pk_can_do(&parent->pk, child->sig_pk)) {
         return -1;
     }
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     if (rs_ctx != NULL && child->sig_pk == MBEDTLS_PK_ECDSA) {
         return mbedtls_pk_verify_restartable(&parent->pk,
                                              child->sig_md, hash, hash_len,
                                              child->sig.p, child->sig.len, &rs_ctx->pk);
     }
 #else
     (void) rs_ctx;
 #endif
 
     return mbedtls_pk_verify_ext(child->sig_pk, child->sig_opts, &parent->pk,
                                  child->sig_md, hash, hash_len,
                                  child->sig.p, child->sig.len);
 }
 
 /*
  * Check if 'parent' is a suitable parent (signing CA) for 'child'.
  * Return 0 if yes, -1 if not.
  *
  * top means parent is a locally-trusted certificate
  */
 static int x509_crt_check_parent(const mbedtls_x509_crt *child,
                                  const mbedtls_x509_crt *parent,
                                  int top)
 {
     int need_ca_bit;
 
     /* Parent must be the issuer */
     if (x509_name_cmp(&child->issuer, &parent->subject) != 0) {
         return -1;
     }
 
     /* Parent must have the basicConstraints CA bit set as a general rule */
     need_ca_bit = 1;
 
     /* Exception: v1/v2 certificates that are locally trusted. */
     if (top && parent->version < 3) {
         need_ca_bit = 0;
     }
 
     if (need_ca_bit && !parent->ca_istrue) {
         return -1;
     }
 
     if (need_ca_bit &&
         mbedtls_x509_crt_check_key_usage(parent, MBEDTLS_X509_KU_KEY_CERT_SIGN) != 0) {
         return -1;
     }
 
     return 0;
 }
 
 /*
  * Find a suitable parent for child in candidates, or return NULL.
  *
  * Here suitable is defined as:
  *  1. subject name matches child's issuer
  *  2. if necessary, the CA bit is set and key usage allows signing certs
  *  3. for trusted roots, the signature is correct
  *     (for intermediates, the signature is checked and the result reported)
  *  4. pathlen constraints are satisfied
  *
  * If there's a suitable candidate which is also time-valid, return the first
  * such. Otherwise, return the first suitable candidate (or NULL if there is
  * none).
  *
  * The rationale for this rule is that someone could have a list of trusted
  * roots with two versions on the same root with different validity periods.
  * (At least one user reported having such a list and wanted it to just work.)
  * The reason we don't just require time-validity is that generally there is
  * only one version, and if it's expired we want the flags to state that
  * rather than NOT_TRUSTED, as would be the case if we required it here.
  *
  * The rationale for rule 3 (signature for trusted roots) is that users might
  * have two versions of the same CA with different keys in their list, and the
  * way we select the correct one is by checking the signature (as we don't
  * rely on key identifier extensions). (This is one way users might choose to
  * handle key rollover, another relies on self-issued certs, see [SIRO].)
  *
  * Arguments:
  *  - [in] child: certificate for which we're looking for a parent
  *  - [in] candidates: chained list of potential parents
  *  - [out] r_parent: parent found (or NULL)
  *  - [out] r_signature_is_good: 1 if child signature by parent is valid, or 0
  *  - [in] top: 1 if candidates consists of trusted roots, ie we're at the top
  *         of the chain, 0 otherwise
  *  - [in] path_cnt: number of intermediates seen so far
  *  - [in] self_cnt: number of self-signed intermediates seen so far
  *         (will never be greater than path_cnt)
  *  - [in-out] rs_ctx: context for restarting operations
  *
  * Return value:
  *  - 0 on success
  *  - MBEDTLS_ERR_ECP_IN_PROGRESS otherwise
  */
 static int x509_crt_find_parent_in(
     mbedtls_x509_crt *child,
     mbedtls_x509_crt *candidates,
     mbedtls_x509_crt **r_parent,
     int *r_signature_is_good,
     int top,
     unsigned path_cnt,
     unsigned self_cnt,
     mbedtls_x509_crt_restart_ctx *rs_ctx,
     const mbedtls_x509_time *now)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *parent, *fallback_parent;
     int signature_is_good = 0, fallback_signature_is_good;
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     /* did we have something in progress? */
     if (rs_ctx != NULL && rs_ctx->parent != NULL) {
         /* restore saved state */
         parent = rs_ctx->parent;
         fallback_parent = rs_ctx->fallback_parent;
         fallback_signature_is_good = rs_ctx->fallback_signature_is_good;
 
         /* clear saved state */
         rs_ctx->parent = NULL;
         rs_ctx->fallback_parent = NULL;
         rs_ctx->fallback_signature_is_good = 0;
 
         /* resume where we left */
         goto check_signature;
     }
 #endif
 
     fallback_parent = NULL;
     fallback_signature_is_good = 0;
 
     for (parent = candidates; parent != NULL; parent = parent->next) {
         /* basic parenting skills (name, CA bit, key usage) */
         if (x509_crt_check_parent(child, parent, top) != 0) {
             continue;
         }
 
         /* +1 because stored max_pathlen is 1 higher that the actual value */
         if (parent->max_pathlen > 0 &&
             (size_t) parent->max_pathlen < 1 + path_cnt - self_cnt) {
             continue;
         }
 
         /* Signature */
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
 check_signature:
 #endif
         ret = x509_crt_check_signature(child, parent, rs_ctx);
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
         if (rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS) {
             /* save state */
             rs_ctx->parent = parent;
             rs_ctx->fallback_parent = fallback_parent;
             rs_ctx->fallback_signature_is_good = fallback_signature_is_good;
 
             return ret;
         }
 #else
         (void) ret;
 #endif
 
         signature_is_good = ret == 0;
         if (top && !signature_is_good) {
             continue;
         }
 
 #if defined(MBEDTLS_HAVE_TIME_DATE)
         /* optional time check */
         if (mbedtls_x509_time_cmp(&parent->valid_to, now) < 0 ||    /* past */
             mbedtls_x509_time_cmp(&parent->valid_from, now) > 0) {  /* future */
             if (fallback_parent == NULL) {
                 fallback_parent = parent;
                 fallback_signature_is_good = signature_is_good;
             }
 
             continue;
         }
 #else
         ((void) now);
 #endif
 
         *r_parent = parent;
         *r_signature_is_good = signature_is_good;
 
         break;
     }
 
     if (parent == NULL) {
         *r_parent = fallback_parent;
         *r_signature_is_good = fallback_signature_is_good;
     }
 
     return 0;
 }
 
 /*
  * Find a parent in trusted CAs or the provided chain, or return NULL.
  *
  * Searches in trusted CAs first, and return the first suitable parent found
  * (see find_parent_in() for definition of suitable).
  *
  * Arguments:
  *  - [in] child: certificate for which we're looking for a parent, followed
  *         by a chain of possible intermediates
  *  - [in] trust_ca: list of locally trusted certificates
  *  - [out] parent: parent found (or NULL)
  *  - [out] parent_is_trusted: 1 if returned `parent` is trusted, or 0
  *  - [out] signature_is_good: 1 if child signature by parent is valid, or 0
  *  - [in] path_cnt: number of links in the chain so far (EE -> ... -> child)
  *  - [in] self_cnt: number of self-signed certs in the chain so far
  *         (will always be no greater than path_cnt)
  *  - [in-out] rs_ctx: context for restarting operations
  *
  * Return value:
  *  - 0 on success
  *  - MBEDTLS_ERR_ECP_IN_PROGRESS otherwise
  */
 static int x509_crt_find_parent(
     mbedtls_x509_crt *child,
     mbedtls_x509_crt *trust_ca,
     mbedtls_x509_crt **parent,
     int *parent_is_trusted,
     int *signature_is_good,
     unsigned path_cnt,
     unsigned self_cnt,
     mbedtls_x509_crt_restart_ctx *rs_ctx,
     const mbedtls_x509_time *now)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_x509_crt *search_list;
 
     *parent_is_trusted = 1;
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     /* restore then clear saved state if we have some stored */
     if (rs_ctx != NULL && rs_ctx->parent_is_trusted != -1) {
         *parent_is_trusted = rs_ctx->parent_is_trusted;
         rs_ctx->parent_is_trusted = -1;
     }
 #endif
 
     while (1) {
         search_list = *parent_is_trusted ? trust_ca : child->next;
 
         ret = x509_crt_find_parent_in(child, search_list,
                                       parent, signature_is_good,
                                       *parent_is_trusted,
                                       path_cnt, self_cnt, rs_ctx, now);
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
         if (rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS) {
             /* save state */
             rs_ctx->parent_is_trusted = *parent_is_trusted;
             return ret;
         }
 #else
         (void) ret;
 #endif
 
         /* stop here if found or already in second iteration */
         if (*parent != NULL || *parent_is_trusted == 0) {
             break;
         }
 
         /* prepare second iteration */
         *parent_is_trusted = 0;
     }
 
     /* extra precaution against mistakes in the caller */
     if (*parent == NULL) {
         *parent_is_trusted = 0;
         *signature_is_good = 0;
     }
 
     return 0;
 }
 
 /*
  * Check if an end-entity certificate is locally trusted
  *
  * Currently we require such certificates to be self-signed (actually only
  * check for self-issued as self-signatures are not checked)
  */
 static int x509_crt_check_ee_locally_trusted(
     mbedtls_x509_crt *crt,
     mbedtls_x509_crt *trust_ca)
 {
     mbedtls_x509_crt *cur;
 
     /* must be self-issued */
     if (x509_name_cmp(&crt->issuer, &crt->subject) != 0) {
         return -1;
     }
 
     /* look for an exact match with trusted cert */
     for (cur = trust_ca; cur != NULL; cur = cur->next) {
         if (crt->raw.len == cur->raw.len &&
             memcmp(crt->raw.p, cur->raw.p, crt->raw.len) == 0) {
             return 0;
         }
     }
 
     /* too bad */
     return -1;
 }
 
 /*
  * Build and verify a certificate chain
  *
  * Given a peer-provided list of certificates EE, C1, ..., Cn and
  * a list of trusted certs R1, ... Rp, try to build and verify a chain
  *      EE, Ci1, ... Ciq [, Rj]
  * such that every cert in the chain is a child of the next one,
  * jumping to a trusted root as early as possible.
  *
  * Verify that chain and return it with flags for all issues found.
  *
  * Special cases:
  * - EE == Rj -> return a one-element list containing it
  * - EE, Ci1, ..., Ciq cannot be continued with a trusted root
  *   -> return that chain with NOT_TRUSTED set on Ciq
  *
  * Tests for (aspects of) this function should include at least:
  * - trusted EE
  * - EE -> trusted root
  * - EE -> intermediate CA -> trusted root
  * - if relevant: EE untrusted
  * - if relevant: EE -> intermediate, untrusted
  * with the aspect under test checked at each relevant level (EE, int, root).
  * For some aspects longer chains are required, but usually length 2 is
  * enough (but length 1 is not in general).
  *
  * Arguments:
  *  - [in] crt: the cert list EE, C1, ..., Cn
  *  - [in] trust_ca: the trusted list R1, ..., Rp
  *  - [in] ca_crl, profile: as in verify_with_profile()
  *  - [out] ver_chain: the built and verified chain
  *      Only valid when return value is 0, may contain garbage otherwise!
  *      Restart note: need not be the same when calling again to resume.
  *  - [in-out] rs_ctx: context for restarting operations
  *
  * Return value:
  *  - non-zero if the chain could not be fully built and examined
  *  - 0 is the chain was successfully built and examined,
  *      even if it was found to be invalid
  */
 static int x509_crt_verify_chain(
     mbedtls_x509_crt *crt,
     mbedtls_x509_crt *trust_ca,
     mbedtls_x509_crl *ca_crl,
     mbedtls_x509_crt_ca_cb_t f_ca_cb,
     void *p_ca_cb,
     const mbedtls_x509_crt_profile *profile,
     mbedtls_x509_crt_verify_chain *ver_chain,
     mbedtls_x509_crt_restart_ctx *rs_ctx)
 {
     /* Don't initialize any of those variables here, so that the compiler can
      * catch potential issues with jumping ahead when restarting */
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     uint32_t *flags;
     mbedtls_x509_crt_verify_chain_item *cur;
     mbedtls_x509_crt *child;
     mbedtls_x509_crt *parent;
     int parent_is_trusted;
     int child_is_trusted;
     int signature_is_good;
     unsigned self_cnt;
     mbedtls_x509_crt *cur_trust_ca = NULL;
     mbedtls_x509_time now;
 
 #if defined(MBEDTLS_HAVE_TIME_DATE)
     if (mbedtls_x509_time_gmtime(mbedtls_time(NULL), &now) != 0) {
         return MBEDTLS_ERR_X509_FATAL_ERROR;
     }
 #endif
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     /* resume if we had an operation in progress */
     if (rs_ctx != NULL && rs_ctx->in_progress == x509_crt_rs_find_parent) {
         /* restore saved state */
         *ver_chain = rs_ctx->ver_chain; /* struct copy */
         self_cnt = rs_ctx->self_cnt;
 
         /* restore derived state */
         cur = &ver_chain->items[ver_chain->len - 1];
         child = cur->crt;
         flags = &cur->flags;
 
         goto find_parent;
     }
 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
 
     child = crt;
     self_cnt = 0;
     parent_is_trusted = 0;
     child_is_trusted = 0;
 
     while (1) {
         /* Add certificate to the verification chain */
         cur = &ver_chain->items[ver_chain->len];
         cur->crt = child;
         cur->flags = 0;
         ver_chain->len++;
         flags = &cur->flags;
 
 #if defined(MBEDTLS_HAVE_TIME_DATE)
         /* Check time-validity (all certificates) */
         if (mbedtls_x509_time_cmp(&child->valid_to, &now) < 0) {
             *flags |= MBEDTLS_X509_BADCERT_EXPIRED;
         }
 
         if (mbedtls_x509_time_cmp(&child->valid_from, &now) > 0) {
             *flags |= MBEDTLS_X509_BADCERT_FUTURE;
         }
 #endif
 
         /* Stop here for trusted roots (but not for trusted EE certs) */
         if (child_is_trusted) {
             return 0;
         }
 
         /* Check signature algorithm: MD & PK algs */
         if (x509_profile_check_md_alg(profile, child->sig_md) != 0) {
             *flags |= MBEDTLS_X509_BADCERT_BAD_MD;
         }
 
         if (x509_profile_check_pk_alg(profile, child->sig_pk) != 0) {
             *flags |= MBEDTLS_X509_BADCERT_BAD_PK;
         }
 
         /* Special case: EE certs that are locally trusted */
         if (ver_chain->len == 1 &&
             x509_crt_check_ee_locally_trusted(child, trust_ca) == 0) {
             return 0;
         }
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
 find_parent:
 #endif
 
         /* Obtain list of potential trusted signers from CA callback,
          * or use statically provided list. */
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
         if (f_ca_cb != NULL) {
             mbedtls_x509_crt_free(ver_chain->trust_ca_cb_result);
             mbedtls_free(ver_chain->trust_ca_cb_result);
             ver_chain->trust_ca_cb_result = NULL;
 
             ret = f_ca_cb(p_ca_cb, child, &ver_chain->trust_ca_cb_result);
             if (ret != 0) {
                 return MBEDTLS_ERR_X509_FATAL_ERROR;
             }
 
             cur_trust_ca = ver_chain->trust_ca_cb_result;
         } else
 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
         {
             ((void) f_ca_cb);
             ((void) p_ca_cb);
             cur_trust_ca = trust_ca;
         }
 
         /* Look for a parent in trusted CAs or up the chain */
         ret = x509_crt_find_parent(child, cur_trust_ca, &parent,
                                    &parent_is_trusted, &signature_is_good,
                                    ver_chain->len - 1, self_cnt, rs_ctx,
                                    &now);
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
         if (rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS) {
             /* save state */
             rs_ctx->in_progress = x509_crt_rs_find_parent;
             rs_ctx->self_cnt = self_cnt;
             rs_ctx->ver_chain = *ver_chain; /* struct copy */
 
             return ret;
         }
 #else
         (void) ret;
 #endif
 
         /* No parent? We're done here */
         if (parent == NULL) {
             *flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED;
             return 0;
         }
 
         /* Count intermediate self-issued (not necessarily self-signed) certs.
          * These can occur with some strategies for key rollover, see [SIRO],
          * and should be excluded from max_pathlen checks. */
         if (ver_chain->len != 1 &&
             x509_name_cmp(&child->issuer, &child->subject) == 0) {
             self_cnt++;
         }
 
         /* path_cnt is 0 for the first intermediate CA,
          * and if parent is trusted it's not an intermediate CA */
         if (!parent_is_trusted &&
             ver_chain->len > MBEDTLS_X509_MAX_INTERMEDIATE_CA) {
             /* return immediately to avoid overflow the chain array */
             return MBEDTLS_ERR_X509_FATAL_ERROR;
         }
 
         /* signature was checked while searching parent */
         if (!signature_is_good) {
             *flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED;
         }
 
         /* check size of signing key */
         if (x509_profile_check_key(profile, &parent->pk) != 0) {
             *flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
         }
 
 #if defined(MBEDTLS_X509_CRL_PARSE_C)
         /* Check trusted CA's CRL for the given crt */
         *flags |= x509_crt_verifycrl(child, parent, ca_crl, profile, &now);
 #else
         (void) ca_crl;
 #endif
 
         /* prepare for next iteration */
         child = parent;
         parent = NULL;
         child_is_trusted = parent_is_trusted;
         signature_is_good = 0;
     }
 }
 
 #ifdef _WIN32
 #ifdef _MSC_VER
 #pragma comment(lib, "ws2_32.lib")
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #elif (defined(__MINGW32__) || defined(__MINGW64__)) && _WIN32_WINNT >= 0x0600
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #else
 /* inet_pton() is not supported, fallback to software version */
 #define MBEDTLS_TEST_SW_INET_PTON
 #endif
 #elif defined(__sun)
 /* Solaris requires -lsocket -lnsl for inet_pton() */
 #elif defined(__has_include)
 #if __has_include(<sys/socket.h>)
 #include <sys/socket.h>
 #endif
 #if __has_include(<arpa/inet.h>)
 #include <arpa/inet.h>
 #endif
 #endif
 
 /* Use whether or not AF_INET6 is defined to indicate whether or not to use
  * the platform inet_pton() or a local implementation (below).  The local
  * implementation may be used even in cases where the platform provides
  * inet_pton(), e.g. when there are different includes required and/or the
  * platform implementation requires dependencies on additional libraries.
  * Specifically, Windows requires custom includes and additional link
  * dependencies, and Solaris requires additional link dependencies.
  * Also, as a coarse heuristic, use the local implementation if the compiler
  * does not support __has_include(), or if the definition of AF_INET6 is not
  * provided by headers included (or not) via __has_include() above.
  * MBEDTLS_TEST_SW_INET_PTON is a bypass define to force testing of this code //no-check-names
  * despite having a platform that has inet_pton. */
 #if !defined(AF_INET6) || defined(MBEDTLS_TEST_SW_INET_PTON) //no-check-names
 /* Definition located further below to possibly reduce compiler inlining */
 static int x509_inet_pton_ipv4(const char *src, void *dst);
 
 #define li_cton(c, n) \
     (((n) = (c) - '0') <= 9 || (((n) = ((c)&0xdf) - 'A') <= 5 ? ((n) += 10) : 0))
 
 static int x509_inet_pton_ipv6(const char *src, void *dst)
 {
     const unsigned char *p = (const unsigned char *) src;
     int nonzero_groups = 0, num_digits, zero_group_start = -1;
     uint16_t addr[8];
     do {
         /* note: allows excess leading 0's, e.g. 1:0002:3:... */
         uint16_t group = num_digits = 0;
         for (uint8_t digit; num_digits < 4; num_digits++) {
             if (li_cton(*p, digit) == 0) {
                 break;
             }
             group = (group << 4) | digit;
             p++;
         }
         if (num_digits != 0) {
             MBEDTLS_PUT_UINT16_BE(group, addr, nonzero_groups);
             nonzero_groups++;
             if (*p == '\0') {
                 break;
             } else if (*p == '.') {
                 /* Don't accept IPv4 too early or late */
                 if ((nonzero_groups == 0 && zero_group_start == -1) ||
                     nonzero_groups >= 7) {
                     break;
                 }
 
                 /* Walk back to prior ':', then parse as IPv4-mapped */
                 int steps = 4;
                 do {
                     p--;
                     steps--;
                 } while (*p != ':' && steps > 0);
 
                 if (*p != ':') {
                     break;
                 }
                 p++;
                 nonzero_groups--;
                 if (x509_inet_pton_ipv4((const char *) p,
                                         addr + nonzero_groups) != 0) {
                     break;
                 }
 
                 nonzero_groups += 2;
                 p = (const unsigned char *) "";
                 break;
             } else if (*p != ':') {
                 return -1;
             }
         } else {
             /* Don't accept a second zero group or an invalid delimiter */
             if (zero_group_start != -1 || *p != ':') {
                 return -1;
             }
             zero_group_start = nonzero_groups;
 
             /* Accept a zero group at start, but it has to be a double colon */
             if (zero_group_start == 0 && *++p != ':') {
                 return -1;
             }
 
             if (p[1] == '\0') {
                 ++p;
                 break;
             }
         }
         ++p;
     } while (nonzero_groups < 8);
 
     if (*p != '\0') {
         return -1;
     }
 
     if (zero_group_start != -1) {
         if (nonzero_groups > 6) {
             return -1;
         }
         int zero_groups = 8 - nonzero_groups;
         int groups_after_zero = nonzero_groups - zero_group_start;
 
         /* Move the non-zero part to after the zeroes */
         if (groups_after_zero) {
             memmove(addr + zero_group_start + zero_groups,
                     addr + zero_group_start,
                     groups_after_zero * sizeof(*addr));
         }
         memset(addr + zero_group_start, 0, zero_groups * sizeof(*addr));
     } else {
         if (nonzero_groups != 8) {
             return -1;
         }
     }
     memcpy(dst, addr, sizeof(addr));
     return 0;
 }
 
 static int x509_inet_pton_ipv4(const char *src, void *dst)
 {
     const unsigned char *p = (const unsigned char *) src;
     uint8_t *res = (uint8_t *) dst;
     uint8_t digit, num_digits = 0;
     uint8_t num_octets = 0;
     uint16_t octet;
 
     do {
         octet = num_digits = 0;
         do {
             digit = *p - '0';
             if (digit > 9) {
                 break;
             }
 
             /* Don't allow leading zeroes. These might mean octal format,
              * which this implementation does not support. */
             if (octet == 0 && num_digits > 0) {
                 return -1;
             }
 
             octet = octet * 10 + digit;
             num_digits++;
             p++;
         } while (num_digits < 3);
 
         if (octet >= 256 || num_digits > 3 || num_digits == 0) {
             return -1;
         }
         *res++ = (uint8_t) octet;
         num_octets++;
     } while (num_octets < 4 && *p++ == '.');
     return num_octets == 4 && *p == '\0' ? 0 : -1;
 }
 
 #else
 
 static int x509_inet_pton_ipv6(const char *src, void *dst)
 {
     return inet_pton(AF_INET6, src, dst) == 1 ? 0 : -1;
 }
 
 static int x509_inet_pton_ipv4(const char *src, void *dst)
 {
     return inet_pton(AF_INET, src, dst) == 1 ? 0 : -1;
 }
 
 #endif /* !AF_INET6 || MBEDTLS_TEST_SW_INET_PTON */ //no-check-names
 
 size_t mbedtls_x509_crt_parse_cn_inet_pton(const char *cn, void *dst)
 {
     return strchr(cn, ':') == NULL
             ? x509_inet_pton_ipv4(cn, dst) == 0 ? 4 : 0
             : x509_inet_pton_ipv6(cn, dst) == 0 ? 16 : 0;
 }
 
 /*
  * Check for CN match
  */
 static int x509_crt_check_cn(const mbedtls_x509_buf *name,
                              const char *cn, size_t cn_len)
 {
     /* try exact match */
     if (name->len == cn_len &&
         x509_memcasecmp(cn, name->p, cn_len) == 0) {
         return 0;
     }
 
     /* try wildcard match */
     if (x509_check_wildcard(cn, name) == 0) {
         return 0;
     }
 
     return -1;
 }
 
 static int x509_crt_check_san_ip(const mbedtls_x509_sequence *san,
                                  const char *cn, size_t cn_len)
 {
     uint32_t ip[4];
     cn_len = mbedtls_x509_crt_parse_cn_inet_pton(cn, ip);
     if (cn_len == 0) {
         return -1;
     }
 
     for (const mbedtls_x509_sequence *cur = san; cur != NULL; cur = cur->next) {
         const unsigned char san_type = (unsigned char) cur->buf.tag &
                                        MBEDTLS_ASN1_TAG_VALUE_MASK;
         if (san_type == MBEDTLS_X509_SAN_IP_ADDRESS &&
             cur->buf.len == cn_len && memcmp(cur->buf.p, ip, cn_len) == 0) {
             return 0;
         }
     }
 
     return -1;
 }
 
 static int x509_crt_check_san_uri(const mbedtls_x509_sequence *san,
                                   const char *cn, size_t cn_len)
 {
     for (const mbedtls_x509_sequence *cur = san; cur != NULL; cur = cur->next) {
         const unsigned char san_type = (unsigned char) cur->buf.tag &
                                        MBEDTLS_ASN1_TAG_VALUE_MASK;
         if (san_type == MBEDTLS_X509_SAN_UNIFORM_RESOURCE_IDENTIFIER &&
             cur->buf.len == cn_len && memcmp(cur->buf.p, cn, cn_len) == 0) {
             return 0;
         }
     }
 
     return -1;
 }
 
 /*
  * Check for SAN match, see RFC 5280 Section 4.2.1.6
  */
 static int x509_crt_check_san(const mbedtls_x509_sequence *san,
                               const char *cn, size_t cn_len)
 {
     int san_ip = 0;
     int san_uri = 0;
     /* Prioritize DNS name over other subtypes due to popularity */
     for (const mbedtls_x509_sequence *cur = san; cur != NULL; cur = cur->next) {
         switch ((unsigned char) cur->buf.tag & MBEDTLS_ASN1_TAG_VALUE_MASK) {
             case MBEDTLS_X509_SAN_DNS_NAME:
                 if (x509_crt_check_cn(&cur->buf, cn, cn_len) == 0) {
                     return 0;
                 }
                 break;
             case MBEDTLS_X509_SAN_IP_ADDRESS:
                 san_ip = 1;
                 break;
             case MBEDTLS_X509_SAN_UNIFORM_RESOURCE_IDENTIFIER:
                 san_uri = 1;
                 break;
             /* (We may handle other types here later.) */
             default: /* Unrecognized type */
                 break;
         }
     }
     if (san_ip) {
         if (x509_crt_check_san_ip(san, cn, cn_len) == 0) {
             return 0;
         }
     }
     if (san_uri) {
         if (x509_crt_check_san_uri(san, cn, cn_len) == 0) {
             return 0;
         }
     }
 
     return -1;
 }
 
 /*
  * Verify the requested CN - only call this if cn is not NULL!
  */
 static void x509_crt_verify_name(const mbedtls_x509_crt *crt,
                                  const char *cn,
                                  uint32_t *flags)
 {
     const mbedtls_x509_name *name;
     size_t cn_len = strlen(cn);
 
     if (crt->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME) {
         if (x509_crt_check_san(&crt->subject_alt_names, cn, cn_len) == 0) {
             return;
         }
     } else {
         for (name = &crt->subject; name != NULL; name = name->next) {
             if (MBEDTLS_OID_CMP(MBEDTLS_OID_AT_CN, &name->oid) == 0 &&
                 x509_crt_check_cn(&name->val, cn, cn_len) == 0) {
                 return;
             }
         }
 
     }
 
     *flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
 }
 
 /*
  * Merge the flags for all certs in the chain, after calling callback
  */
 static int x509_crt_merge_flags_with_cb(
     uint32_t *flags,
     const mbedtls_x509_crt_verify_chain *ver_chain,
     int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
     void *p_vrfy)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned i;
     uint32_t cur_flags;
     const mbedtls_x509_crt_verify_chain_item *cur;
 
     for (i = ver_chain->len; i != 0; --i) {
         cur = &ver_chain->items[i-1];
         cur_flags = cur->flags;
 
         if (NULL != f_vrfy) {
             if ((ret = f_vrfy(p_vrfy, cur->crt, (int) i-1, &cur_flags)) != 0) {
                 return ret;
             }
         }
 
         *flags |= cur_flags;
     }
 
     return 0;
 }
 
 /*
  * Verify the certificate validity, with profile, restartable version
  *
  * This function:
  *  - checks the requested CN (if any)
  *  - checks the type and size of the EE cert's key,
  *    as that isn't done as part of chain building/verification currently
  *  - builds and verifies the chain
  *  - then calls the callback and merges the flags
  *
  * The parameters pairs `trust_ca`, `ca_crl` and `f_ca_cb`, `p_ca_cb`
  * are mutually exclusive: If `f_ca_cb != NULL`, it will be used by the
  * verification routine to search for trusted signers, and CRLs will
  * be disabled. Otherwise, `trust_ca` will be used as the static list
  * of trusted signers, and `ca_crl` will be use as the static list
  * of CRLs.
  */
 static int x509_crt_verify_restartable_ca_cb(mbedtls_x509_crt *crt,
                                              mbedtls_x509_crt *trust_ca,
                                              mbedtls_x509_crl *ca_crl,
                                              mbedtls_x509_crt_ca_cb_t f_ca_cb,
                                              void *p_ca_cb,
                                              const mbedtls_x509_crt_profile *profile,
                                              const char *cn, uint32_t *flags,
                                              int (*f_vrfy)(void *,
                                                            mbedtls_x509_crt *,
                                                            int,
                                                            uint32_t *),
                                              void *p_vrfy,
                                              mbedtls_x509_crt_restart_ctx *rs_ctx)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_pk_type_t pk_type;
     mbedtls_x509_crt_verify_chain ver_chain;
     uint32_t ee_flags;
 
     *flags = 0;
     ee_flags = 0;
     x509_crt_verify_chain_reset(&ver_chain);
 
     if (profile == NULL) {
         ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA;
         goto exit;
     }
 
     /* check name if requested */
     if (cn != NULL) {
         x509_crt_verify_name(crt, cn, &ee_flags);
     }
 
     /* Check the type and size of the key */
     pk_type = mbedtls_pk_get_type(&crt->pk);
 
     if (x509_profile_check_pk_alg(profile, pk_type) != 0) {
         ee_flags |= MBEDTLS_X509_BADCERT_BAD_PK;
     }
 
     if (x509_profile_check_key(profile, &crt->pk) != 0) {
         ee_flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
     }
 
     /* Check the chain */
     ret = x509_crt_verify_chain(crt, trust_ca, ca_crl,
                                 f_ca_cb, p_ca_cb, profile,
                                 &ver_chain, rs_ctx);
 
     if (ret != 0) {
         goto exit;
     }
 
     /* Merge end-entity flags */
     ver_chain.items[0].flags |= ee_flags;
 
     /* Build final flags, calling callback on the way if any */
     ret = x509_crt_merge_flags_with_cb(flags, &ver_chain, f_vrfy, p_vrfy);
 
 exit:
 
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
     mbedtls_x509_crt_free(ver_chain.trust_ca_cb_result);
     mbedtls_free(ver_chain.trust_ca_cb_result);
     ver_chain.trust_ca_cb_result = NULL;
 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
     if (rs_ctx != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS) {
         mbedtls_x509_crt_restart_free(rs_ctx);
     }
 #endif
 
     /* prevent misuse of the vrfy callback - VERIFY_FAILED would be ignored by
      * the SSL module for authmode optional, but non-zero return from the
      * callback means a fatal error so it shouldn't be ignored */
     if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
         ret = MBEDTLS_ERR_X509_FATAL_ERROR;
     }
 
     if (ret != 0) {
         *flags = (uint32_t) -1;
         return ret;
     }
 
     if (*flags != 0) {
         return MBEDTLS_ERR_X509_CERT_VERIFY_FAILED;
     }
 
     return 0;
 }
 
 
 /*
  * Verify the certificate validity (default profile, not restartable)
  */
 int mbedtls_x509_crt_verify(mbedtls_x509_crt *crt,
                             mbedtls_x509_crt *trust_ca,
                             mbedtls_x509_crl *ca_crl,
                             const char *cn, uint32_t *flags,
                             int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                             void *p_vrfy)
 {
     return x509_crt_verify_restartable_ca_cb(crt, trust_ca, ca_crl,
                                              NULL, NULL,
                                              &mbedtls_x509_crt_profile_default,
                                              cn, flags,
                                              f_vrfy, p_vrfy, NULL);
 }
 
 /*
  * Verify the certificate validity (user-chosen profile, not restartable)
  */
 int mbedtls_x509_crt_verify_with_profile(mbedtls_x509_crt *crt,
                                          mbedtls_x509_crt *trust_ca,
                                          mbedtls_x509_crl *ca_crl,
                                          const mbedtls_x509_crt_profile *profile,
                                          const char *cn, uint32_t *flags,
                                          int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                          void *p_vrfy)
 {
     return x509_crt_verify_restartable_ca_cb(crt, trust_ca, ca_crl,
                                              NULL, NULL,
                                              profile, cn, flags,
                                              f_vrfy, p_vrfy, NULL);
 }
 
 #if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
 /*
  * Verify the certificate validity (user-chosen profile, CA callback,
  *                                  not restartable).
  */
 int mbedtls_x509_crt_verify_with_ca_cb(mbedtls_x509_crt *crt,
                                        mbedtls_x509_crt_ca_cb_t f_ca_cb,
                                        void *p_ca_cb,
                                        const mbedtls_x509_crt_profile *profile,
                                        const char *cn, uint32_t *flags,
                                        int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                        void *p_vrfy)
 {
     return x509_crt_verify_restartable_ca_cb(crt, NULL, NULL,
                                              f_ca_cb, p_ca_cb,
                                              profile, cn, flags,
                                              f_vrfy, p_vrfy, NULL);
 }
 #endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
 
 int mbedtls_x509_crt_verify_restartable(mbedtls_x509_crt *crt,
                                         mbedtls_x509_crt *trust_ca,
                                         mbedtls_x509_crl *ca_crl,
                                         const mbedtls_x509_crt_profile *profile,
                                         const char *cn, uint32_t *flags,
                                         int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
                                         void *p_vrfy,
                                         mbedtls_x509_crt_restart_ctx *rs_ctx)
 {
     return x509_crt_verify_restartable_ca_cb(crt, trust_ca, ca_crl,
                                              NULL, NULL,
                                              profile, cn, flags,
                                              f_vrfy, p_vrfy, rs_ctx);
 }
 
 
 /*
  * Initialize a certificate chain
  */
 void mbedtls_x509_crt_init(mbedtls_x509_crt *crt)
 {
     memset(crt, 0, sizeof(mbedtls_x509_crt));
 }
 
 /*
  * Unallocate all certificate data
  */
 void mbedtls_x509_crt_free(mbedtls_x509_crt *crt)
 {
     mbedtls_x509_crt *cert_cur = crt;
     mbedtls_x509_crt *cert_prv;
 
     while (cert_cur != NULL) {
         mbedtls_pk_free(&cert_cur->pk);
 
 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
         mbedtls_free(cert_cur->sig_opts);
 #endif
 
         mbedtls_asn1_free_named_data_list_shallow(cert_cur->issuer.next);
         mbedtls_asn1_free_named_data_list_shallow(cert_cur->subject.next);
         mbedtls_asn1_sequence_free(cert_cur->ext_key_usage.next);
         mbedtls_asn1_sequence_free(cert_cur->subject_alt_names.next);
         mbedtls_asn1_sequence_free(cert_cur->certificate_policies.next);
         mbedtls_asn1_sequence_free(cert_cur->authority_key_id.authorityCertIssuer.next);
 
         if (cert_cur->raw.p != NULL && cert_cur->own_buffer) {
             mbedtls_zeroize_and_free(cert_cur->raw.p, cert_cur->raw.len);
         }
 
         cert_prv = cert_cur;
         cert_cur = cert_cur->next;
 
         mbedtls_platform_zeroize(cert_prv, sizeof(mbedtls_x509_crt));
         if (cert_prv != crt) {
             mbedtls_free(cert_prv);
         }
     }
 }
 
 #if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
 /*
  * Initialize a restart context
  */
 void mbedtls_x509_crt_restart_init(mbedtls_x509_crt_restart_ctx *ctx)
 {
     mbedtls_pk_restart_init(&ctx->pk);
 
     ctx->parent = NULL;
     ctx->fallback_parent = NULL;
     ctx->fallback_signature_is_good = 0;
 
     ctx->parent_is_trusted = -1;
 
     ctx->in_progress = x509_crt_rs_none;
     ctx->self_cnt = 0;
     x509_crt_verify_chain_reset(&ctx->ver_chain);
 }
 
 /*
  * Free the components of a restart context
  */
 void mbedtls_x509_crt_restart_free(mbedtls_x509_crt_restart_ctx *ctx)
 {
     if (ctx == NULL) {
         return;
     }
 
     mbedtls_pk_restart_free(&ctx->pk);
     mbedtls_x509_crt_restart_init(ctx);
 }
 #endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
 
 int mbedtls_x509_crt_get_ca_istrue(const mbedtls_x509_crt *crt)
 {
     if ((crt->ext_types & MBEDTLS_X509_EXT_BASIC_CONSTRAINTS) != 0) {
         return crt->MBEDTLS_PRIVATE(ca_istrue);
     }
     return MBEDTLS_ERR_X509_INVALID_EXTENSIONS;
 }
 
 #endif /* MBEDTLS_X509_CRT_PARSE_C */