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author | Rod Vagg <rod@vagg.org> | 2018-06-15 16:39:28 +1000 |
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committer | Anatoli Papirovski <apapirovski@mac.com> | 2018-06-24 23:27:12 -0700 |
commit | 831821bcf50e722072b0aeac93aacd2c09caae57 (patch) | |
tree | 8096175888219942bb744c8b06ac2470d0003c21 /deps/openssl | |
parent | c7c52127ec993803f82e17d5631738c38fb1e1e0 (diff) | |
download | android-node-v8-831821bcf50e722072b0aeac93aacd2c09caae57.tar.gz android-node-v8-831821bcf50e722072b0aeac93aacd2c09caae57.tar.bz2 android-node-v8-831821bcf50e722072b0aeac93aacd2c09caae57.zip |
deps: float 0c27d793 from openssl (ECDSA blinding)
Pending OpenSSL 1.1.0i release.
Refs: https://www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/
PR-URL: https://github.com/nodejs/node/pull/21345
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Shigeki Ohtsu <ohtsu@ohtsu.org>
Reviewed-By: James M Snell <jasnell@gmail.com>
Upstream: https://github.com/openssl/openssl/commit/0c27d793
Original commit message:
Add blinding to an ECDSA signature
Keegan Ryan (NCC Group) has demonstrated a side channel attack on an
ECDSA signature operation. During signing the signer calculates:
s:= k^-1 * (m + r * priv_key) mod order
The addition operation above provides a sufficient signal for a
flush+reload attack to derive the private key given sufficient signature
operations.
As a mitigation (based on a suggestion from Keegan) we add blinding to
the operation so that:
s := k^-1 * blind^-1 (blind * m + blind * r * priv_key) mod order
Since this attack is a localhost side channel only no CVE is assigned.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Diffstat (limited to 'deps/openssl')
-rw-r--r-- | deps/openssl/openssl/crypto/ec/ecdsa_ossl.c | 70 |
1 files changed, 63 insertions, 7 deletions
diff --git a/deps/openssl/openssl/crypto/ec/ecdsa_ossl.c b/deps/openssl/openssl/crypto/ec/ecdsa_ossl.c index 72e2f0f28b..449be0e92a 100644 --- a/deps/openssl/openssl/crypto/ec/ecdsa_ossl.c +++ b/deps/openssl/openssl/crypto/ec/ecdsa_ossl.c @@ -210,7 +210,8 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, EC_KEY *eckey) { int ok = 0, i; - BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL; + BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *blind = NULL; + BIGNUM *blindm = NULL; const BIGNUM *order, *ckinv; BN_CTX *ctx = NULL; const EC_GROUP *group; @@ -243,8 +244,18 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, } s = ret->s; - if ((ctx = BN_CTX_new()) == NULL || - (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) { + ctx = BN_CTX_secure_new(); + if (ctx == NULL) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE); + goto err; + } + + BN_CTX_start(ctx); + tmp = BN_CTX_get(ctx); + m = BN_CTX_get(ctx); + blind = BN_CTX_get(ctx); + blindm = BN_CTX_get(ctx); + if (blindm == NULL) { ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_MALLOC_FAILURE); goto err; } @@ -284,18 +295,64 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, } } - if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) { + /* + * The normal signature calculation is: + * + * s := k^-1 * (m + r * priv_key) mod order + * + * We will blind this to protect against side channel attacks + * + * s := k^-1 * blind^-1 * (blind * m + blind * r * priv_key) mod order + */ + + /* Generate a blinding value */ + do { + if (!BN_rand(blind, BN_num_bits(order) - 1, BN_RAND_TOP_ANY, + BN_RAND_BOTTOM_ANY)) + goto err; + } while (BN_is_zero(blind)); + BN_set_flags(blind, BN_FLG_CONSTTIME); + BN_set_flags(blindm, BN_FLG_CONSTTIME); + BN_set_flags(tmp, BN_FLG_CONSTTIME); + + /* tmp := blind * priv_key * r mod order */ + if (!BN_mod_mul(tmp, blind, priv_key, order, ctx)) { ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); goto err; } - if (!BN_mod_add_quick(s, tmp, m, order)) { + if (!BN_mod_mul(tmp, tmp, ret->r, order, ctx)) { ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); goto err; } + + /* blindm := blind * m mod order */ + if (!BN_mod_mul(blindm, blind, m, order, ctx)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } + + /* s : = (blind * priv_key * r) + (blind * m) mod order */ + if (!BN_mod_add_quick(s, tmp, blindm, order)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } + + /* s:= s * blind^-1 mod order */ + if (BN_mod_inverse(blind, blind, order, ctx) == NULL) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } + if (!BN_mod_mul(s, s, blind, order, ctx)) { + ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); + goto err; + } + + /* s := s * k^-1 mod order */ if (!BN_mod_mul(s, s, ckinv, order, ctx)) { ECerr(EC_F_OSSL_ECDSA_SIGN_SIG, ERR_R_BN_LIB); goto err; } + if (BN_is_zero(s)) { /* * if kinv and r have been supplied by the caller don't to @@ -317,9 +374,8 @@ ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len, ECDSA_SIG_free(ret); ret = NULL; } + BN_CTX_end(ctx); BN_CTX_free(ctx); - BN_clear_free(m); - BN_clear_free(tmp); BN_clear_free(kinv); return ret; } |