KNOWN_BUGS (21924B)
1 _ _ ____ _ 2 ___| | | | _ \| | 3 / __| | | | |_) | | 4 | (__| |_| | _ <| |___ 5 \___|\___/|_| \_\_____| 6 7 Known Bugs 8 9 These are problems and bugs known to exist at the time of this release. Feel 10 free to join in and help us correct one or more of these. Also be sure to 11 check the changelog of the current development status, as one or more of these 12 problems may have been fixed or changed somewhat since this was written. 13 14 1. HTTP 15 16 2. TLS 17 2.1 IMAPS connection fails with Rustls error 18 2.5 Client cert handling with Issuer DN differs between backends 19 2.7 Client cert (MTLS) issues with Schannel 20 2.11 Schannel TLS 1.2 handshake bug in old Windows versions 21 2.13 CURLOPT_CERTINFO results in CURLE_OUT_OF_MEMORY with Schannel 22 2.14 mbedTLS and CURLE_AGAIN handling 23 24 3. Email protocols 25 3.1 IMAP SEARCH ALL truncated response 26 3.2 No disconnect command 27 3.4 AUTH PLAIN for SMTP is not working on all servers 28 3.5 APOP authentication fails on POP3 29 3.6 POP3 issue when reading small chunks 30 31 4. Command line 32 4.1 -T /dev/stdin may upload with an incorrect content length 33 4.2 -T - always uploads chunked 34 35 5. Build and portability issues 36 5.1 OS400 port requires deprecated IBM library 37 5.2 curl-config --libs contains private details 38 5.3 LDFLAGS passed too late making libs linked incorrectly 39 5.6 Cygwin: make install installs curl-config.1 twice 40 5.11 configure --with-gssapi with Heimdal is ignored on macOS 41 5.12 flaky CI builds 42 5.13 long paths are not fully supported on Windows 43 5.15 Unicode on Windows 44 45 6. Authentication 46 6.2 MIT Kerberos for Windows build 47 6.3 NTLM in system context uses wrong name 48 6.5 NTLM does not support password with Unicode 'SECTION SIGN' character 49 6.6 libcurl can fail to try alternatives with --proxy-any 50 6.7 Do not clear digest for single realm 51 6.8 Heimdal memory leaks 52 6.9 SHA-256 digest not supported in Windows SSPI builds 53 6.10 curl never completes Negotiate over HTTP 54 6.11 Negotiate on Windows fails 55 6.13 Negotiate against Hadoop HDFS 56 57 7. FTP 58 7.4 FTP with ACCT 59 7.12 FTPS directory listing hangs on Windows with Schannel 60 61 9. SFTP and SCP 62 9.1 SFTP does not do CURLOPT_POSTQUOTE correct 63 9.2 wolfssh: publickey auth does not work 64 9.3 Remote recursive folder creation with SFTP 65 9.4 libssh blocking and infinite loop problem 66 9.5 Cygwin: "WARNING: UNPROTECTED PRIVATE KEY FILE!" 67 9.6 wolfssh: all tests fail 68 69 10. Connection 70 10.1 --interface with link-scoped IPv6 address 71 10.2 Does not acknowledge getaddrinfo sorting policy 72 73 11. Internals 74 11.1 gssapi library name + version is missing in curl_version_info() 75 11.2 error buffer not set if connection to multiple addresses fails 76 11.4 HTTP test server 'connection-monitor' problems 77 11.5 Connection information when using TCP Fast Open 78 11.6 test cases sometimes timeout 79 11.7 CURLOPT_CONNECT_TO does not work for HTTPS proxy 80 11.8 WinIDN test failures 81 11.9 setting a disabled option should return CURLE_NOT_BUILT_IN 82 83 12. LDAP 84 12.1 OpenLDAP hangs after returning results 85 12.2 LDAP on Windows does authentication wrong? 86 12.3 LDAP on Windows does not work 87 12.4 LDAPS requests to ActiveDirectory server hang 88 89 13. TCP/IP 90 13.2 Trying local ports fails on Windows 91 92 15. CMake 93 15.1 cmake outputs: no version information available 94 15.6 uses -lpthread instead of Threads::Threads 95 15.7 generated .pc file contains strange entries 96 15.13 CMake build with MIT Kerberos does not work 97 98 16. aws-sigv4 99 16.2 aws-sigv4 does not handle multipart/form-data correctly 100 101 17. HTTP/2 102 17.1 HTTP/2 prior knowledge over proxy 103 17.2 HTTP/2 frames while in the connection pool kill reuse 104 17.3 ENHANCE_YOUR_CALM causes infinite retries 105 17.4 HTTP/2 + TLS spends a lot of time in recv 106 107 18. HTTP/3 108 18.1 connection migration does not work 109 18.2 quiche: QUIC connection is draining 110 111 19. RTSP 112 19.1 Some methods do not support response bodies 113 114 ============================================================================== 115 116 1. HTTP 117 118 2. TLS 119 120 2.1 IMAPS connection fails with Rustls error 121 122 https://github.com/curl/curl/issues/10457 123 124 2.5 Client cert handling with Issuer DN differs between backends 125 126 When the specified client certificate does not match any of the 127 server-specified DNs, the OpenSSL and GnuTLS backends behave differently. 128 The github discussion may contain a solution. 129 130 See https://github.com/curl/curl/issues/1411 131 132 2.7 Client cert (MTLS) issues with Schannel 133 134 See https://github.com/curl/curl/issues/3145 135 136 2.11 Schannel TLS 1.2 handshake bug in old Windows versions 137 138 In old versions of Windows such as 7 and 8.1 the Schannel TLS 1.2 handshake 139 implementation likely has a bug that can rarely cause the key exchange to 140 fail, resulting in error SEC_E_BUFFER_TOO_SMALL or SEC_E_MESSAGE_ALTERED. 141 142 https://github.com/curl/curl/issues/5488 143 144 2.13 CURLOPT_CERTINFO results in CURLE_OUT_OF_MEMORY with Schannel 145 146 https://github.com/curl/curl/issues/8741 147 148 2.14 mbedTLS and CURLE_AGAIN handling 149 150 https://github.com/curl/curl/issues/15801 151 152 3. Email protocols 153 154 3.1 IMAP SEARCH ALL truncated response 155 156 IMAP "SEARCH ALL" truncates output on large boxes. "A quick search of the 157 code reveals that pingpong.c contains some truncation code, at line 408, when 158 it deems the server response to be too large truncating it to 40 characters" 159 https://curl.se/bug/view.cgi?id=1366 160 161 3.2 No disconnect command 162 163 The disconnect commands (LOGOUT and QUIT) may not be sent by IMAP, POP3 and 164 SMTP if a failure occurs during the authentication phase of a connection. 165 166 3.4 AUTH PLAIN for SMTP is not working on all servers 167 168 Specifying "--login-options AUTH=PLAIN" on the command line does not seem to 169 work correctly. 170 171 See https://github.com/curl/curl/issues/4080 172 173 3.5 APOP authentication fails on POP3 174 175 See https://github.com/curl/curl/issues/10073 176 177 3.6 POP3 issue when reading small chunks 178 179 CURL_DBG_SOCK_RMAX=4 ./runtests.pl -v 982 180 181 See https://github.com/curl/curl/issues/12063 182 183 4. Command line 184 185 4.1 -T /dev/stdin may upload with an incorrect content length 186 187 -T stats the path to figure out its size in bytes to use it as Content-Length 188 if it is a regular file. 189 190 The problem with that is that, on BSDs and some other UNIXes (not Linux), 191 open(path) may not give you a file descriptor with a 0 offset from the start 192 of the file. 193 194 See https://github.com/curl/curl/issues/12177 195 196 4.2 -T - always uploads chunked 197 198 When the `<` shell operator is used. curl should realise that stdin is a 199 regular file in this case, and that it can do a non-chunked upload, like it 200 would do if you used -T file. 201 202 See https://github.com/curl/curl/issues/12171 203 204 5. Build and portability issues 205 206 5.1 OS400 port requires deprecated IBM library 207 208 curl for OS400 requires QADRT to build, which provides ASCII wrappers for 209 libc/POSIX functions in the ILE, but IBM no longer supports or even offers 210 this library to download. 211 212 See https://github.com/curl/curl/issues/5176 213 214 5.2 curl-config --libs contains private details 215 216 "curl-config --libs" include details set in LDFLAGS when configure is run 217 that might be needed only for building libcurl. Further, curl-config --cflags 218 suffers from the same effects with CFLAGS/CPPFLAGS. 219 220 5.3 LDFLAGS passed too late making libs linked incorrectly 221 222 Compiling latest curl on HP-UX and linking against a custom OpenSSL (which is 223 on the default loader/linker path), fails because the generated Makefile has 224 LDFLAGS passed on after LIBS. 225 226 See https://github.com/curl/curl/issues/14893 227 228 5.6 Cygwin: make install installs curl-config.1 twice 229 230 https://github.com/curl/curl/issues/8839 231 232 5.11 configure --with-gssapi with Heimdal is ignored on macOS 233 234 ... unless you also pass --with-gssapi-libs 235 236 https://github.com/curl/curl/issues/3841 237 238 5.12 flaky CI builds 239 240 We run many CI builds for each commit and PR on github, and especially a 241 number of the Windows builds are flaky. This means that we rarely get all CI 242 builds go green and complete without errors. This is unfortunate as it makes 243 us sometimes miss actual build problems and it is surprising to newcomers to 244 the project who (rightfully) do not expect this. 245 246 See https://github.com/curl/curl/issues/6972 247 248 5.13 long paths are not fully supported on Windows 249 250 curl on Windows cannot access long paths (paths longer than 260 characters). 251 However, as a workaround, the Windows path prefix \\?\ which disables all 252 path interpretation may work to allow curl to access the path. For example: 253 \\?\c:\longpath. 254 255 See https://github.com/curl/curl/issues/8361 256 257 5.15 Unicode on Windows 258 259 Passing in a Unicode filename with -o: 260 261 https://github.com/curl/curl/issues/11461 262 263 Passing in Unicode character with -d: 264 265 https://github.com/curl/curl/issues/12231 266 267 Windows Unicode builds use homedir in current locale 268 269 The Windows Unicode builds of curl use the current locale, but expect Unicode 270 UTF-8 encoded paths for internal use such as open, access and stat. The 271 user's home directory is retrieved via curl_getenv in the current locale and 272 not as UTF-8 encoded Unicode. 273 274 See https://github.com/curl/curl/pull/7252 and 275 https://github.com/curl/curl/pull/7281 276 277 Cannot handle Unicode arguments in non-Unicode builds on Windows 278 279 If a URL or filename cannot be encoded using the user's current codepage then 280 it can only be encoded properly in the Unicode character set. Windows uses 281 UTF-16 encoding for Unicode and stores it in wide characters, however curl 282 and libcurl are not equipped for that at the moment except when built with 283 _UNICODE and UNICODE defined. Except for Cygwin, Windows cannot use UTF-8 as 284 a locale. 285 286 https://curl.se/bug/?i=345 287 https://curl.se/bug/?i=731 288 https://curl.se/bug/?i=3747 289 290 NTLM authentication and Unicode 291 292 NTLM authentication involving Unicode username or password only works 293 properly if built with UNICODE defined together with the Schannel backend. 294 The original problem was mentioned in: 295 https://curl.se/mail/lib-2009-10/0024.html 296 https://curl.se/bug/view.cgi?id=896 297 298 The Schannel version verified to work as mentioned in 299 https://curl.se/mail/lib-2012-07/0073.html 300 301 6. Authentication 302 303 6.2 MIT Kerberos for Windows build 304 305 libcurl fails to build with MIT Kerberos for Windows (KfW) due to KfW's 306 library header files exporting symbols/macros that should be kept private to 307 the KfW library. See ticket #5601 at https://krbdev.mit.edu/rt/ 308 309 6.3 NTLM in system context uses wrong name 310 311 NTLM authentication using SSPI (on Windows) when (lib)curl is running in 312 "system context" makes it use wrong(?) username - at least when compared to 313 what winhttp does. See https://curl.se/bug/view.cgi?id=535 314 315 6.5 NTLM does not support password with Unicode 'SECTION SIGN' character 316 317 https://en.wikipedia.org/wiki/Section_sign 318 https://codepoints.net/U+00A7 SECTION SIGN 319 https://github.com/curl/curl/issues/2120 320 321 6.6 libcurl can fail to try alternatives with --proxy-any 322 323 When connecting via a proxy using --proxy-any, a failure to establish an 324 authentication causes libcurl to abort trying other options if the failed 325 method has a higher preference than the alternatives. As an example, 326 --proxy-any against a proxy which advertise Negotiate and NTLM, but which 327 fails to set up Kerberos authentication does not proceed to try 328 authentication using NTLM. 329 330 https://github.com/curl/curl/issues/876 331 332 6.7 Do not clear digest for single realm 333 334 https://github.com/curl/curl/issues/3267 335 336 6.8 Heimdal memory leaks 337 338 Running test 2077 and 2078 with curl built to do GSS with Heimdal causes 339 valgrind errors (memory leak). 340 341 https://github.com/curl/curl/issues/14446 342 343 6.9 SHA-256 digest not supported in Windows SSPI builds 344 345 Windows builds of curl that have SSPI enabled use the native Windows API calls 346 to create authentication strings. The call to InitializeSecurityContext fails 347 with SEC_E_QOP_NOT_SUPPORTED which causes curl to fail with CURLE_AUTH_ERROR. 348 349 Microsoft does not document supported digest algorithms and that SEC_E error 350 code is not a documented error for InitializeSecurityContext (digest). 351 352 https://github.com/curl/curl/issues/6302 353 354 6.10 curl never completes Negotiate over HTTP 355 356 Apparently it is not working correctly...? 357 358 See https://github.com/curl/curl/issues/5235 359 360 6.11 Negotiate on Windows fails 361 362 When using --negotiate (or NTLM) with curl on Windows, SSL/TLS handshake 363 fails despite having a valid kerberos ticket cached. Works without any issue 364 in Unix/Linux. 365 366 https://github.com/curl/curl/issues/5881 367 368 6.13 Negotiate authentication against Hadoop HDFS 369 370 https://github.com/curl/curl/issues/8264 371 372 7. FTP 373 374 7.4 FTP with ACCT 375 376 When doing an operation over FTP that requires the ACCT command (but not when 377 logging in), the operation fails since libcurl does not detect this and thus 378 fails to issue the correct command: https://curl.se/bug/view.cgi?id=635 379 380 7.12 FTPS server compatibility on Windows with Schannel 381 382 FTPS is not widely used with the Schannel TLS backend and so there may be 383 more bugs compared to other TLS backends such as OpenSSL. In the past users 384 have reported hanging and failed connections. It is likely some changes to 385 curl since then fixed the issues. None of the reported issues can be 386 reproduced any longer. 387 388 If you encounter an issue connecting to your server via FTPS with the latest 389 curl and Schannel then please search for open issues or file a new issue. 390 391 9. SFTP and SCP 392 393 9.1 SFTP does not do CURLOPT_POSTQUOTE correct 394 395 When libcurl sends CURLOPT_POSTQUOTE commands when connected to an SFTP 396 server using the multi interface, the commands are not being sent correctly 397 and instead the connection is "cancelled" (the operation is considered done) 398 prematurely. There is a half-baked (busy-looping) patch provided in the bug 399 report but it cannot be accepted as-is. See 400 https://curl.se/bug/view.cgi?id=748 401 402 9.2 wolfssh: publickey auth does not work 403 404 When building curl to use the wolfSSH backend for SFTP, the publickey 405 authentication does not work. This is simply functionality not written for curl 406 yet, the necessary API for make this work is provided by wolfSSH. 407 408 See https://github.com/curl/curl/issues/4820 409 410 9.3 Remote recursive folder creation with SFTP 411 412 On this servers, the curl fails to create directories on the remote server 413 even when the CURLOPT_FTP_CREATE_MISSING_DIRS option is set. 414 415 See https://github.com/curl/curl/issues/5204 416 417 9.4 libssh blocking and infinite loop problem 418 419 In the SSH_SFTP_INIT state for libssh, the ssh session working mode is set to 420 blocking mode. If the network is suddenly disconnected during sftp 421 transmission, curl is stuck, even if curl is configured with a timeout. 422 423 https://github.com/curl/curl/issues/8632 424 425 9.5 Cygwin: "WARNING: UNPROTECTED PRIVATE KEY FILE!" 426 427 Running SCP and SFTP tests on Cygwin makes this warning message appear. 428 429 https://github.com/curl/curl/issues/11244 430 431 9.6 wolfssh: all tests fail 432 433 Something fundamental stops them all from working properly. 434 435 https://github.com/curl/curl/issues/16794 436 437 10. Connection 438 439 10.1 --interface with link-scoped IPv6 address 440 441 When you give the `--interface` option telling curl to use a specific 442 interface for its outgoing traffic in combination with an IPv6 address in the 443 URL that uses a link-local scope, curl might pick the wrong address from the 444 named interface and the subsequent transfer fails. 445 446 Example command line: 447 448 curl --interface eth0 'http://[fe80:928d:xxff:fexx:xxxx]/' 449 450 The fact that the given IP address is link-scoped should probably be used as 451 input to somehow make curl make a better choice for this. 452 453 https://github.com/curl/curl/issues/14782 454 455 10.2 Does not acknowledge getaddrinfo sorting policy 456 457 Even if a user edits /etc/gai.conf to prefer IPv4, curl still prefers and 458 tries IPv6 addresses first. 459 460 https://github.com/curl/curl/issues/16718 461 462 11. Internals 463 464 11.1 gssapi library name + version is missing in curl_version_info() 465 466 The struct needs to be expanded and code added to store this info. 467 468 See https://github.com/curl/curl/issues/13492 469 470 11.2 error buffer not set if connection to multiple addresses fails 471 472 If you ask libcurl to resolve a hostname like example.com to IPv6 addresses 473 when you only have IPv4 connectivity. libcurl fails with 474 CURLE_COULDNT_CONNECT, but the error buffer set by CURLOPT_ERRORBUFFER 475 remains empty. Issue: https://github.com/curl/curl/issues/544 476 477 11.4 HTTP test server 'connection-monitor' problems 478 479 The 'connection-monitor' feature of the sws HTTP test server does not work 480 properly if some tests are run in unexpected order. Like 1509 and then 1525. 481 482 See https://github.com/curl/curl/issues/868 483 484 11.5 Connection information when using TCP Fast Open 485 486 CURLINFO_LOCAL_PORT (and possibly a few other) fails when TCP Fast Open is 487 enabled. 488 489 See https://github.com/curl/curl/issues/1332 and 490 https://github.com/curl/curl/issues/4296 491 492 11.6 test cases sometimes timeout 493 494 Occasionally, one of the tests timeouts. Inexplicably. 495 496 See https://github.com/curl/curl/issues/13350 497 498 11.7 CURLOPT_CONNECT_TO does not work for HTTPS proxy 499 500 It is unclear if the same option should even cover the proxy connection or if 501 if requires a separate option. 502 503 See https://github.com/curl/curl/issues/14481 504 505 11.8 WinIDN test failures 506 507 Test 165 disabled when built with WinIDN. 508 509 11.9 setting a disabled option should return CURLE_NOT_BUILT_IN 510 511 When curl has been built with specific features or protocols disabled, 512 setting such options with curl_easy_setopt() should rather return 513 CURLE_NOT_BUILT_IN instead of CURLE_UNKNOWN_OPTION to signal the difference 514 to the application 515 516 See https://github.com/curl/curl/issues/15472 517 518 12. LDAP 519 520 12.1 OpenLDAP hangs after returning results 521 522 By configuration defaults, OpenLDAP automatically chase referrals on 523 secondary socket descriptors. The OpenLDAP backend is asynchronous and thus 524 should monitor all socket descriptors involved. Currently, these secondary 525 descriptors are not monitored, causing OpenLDAP library to never receive 526 data from them. 527 528 As a temporary workaround, disable referrals chasing by configuration. 529 530 The fix is not easy: proper automatic referrals chasing requires a 531 synchronous bind callback and monitoring an arbitrary number of socket 532 descriptors for a single easy handle (currently limited to 5). 533 534 Generic LDAP is synchronous: OK. 535 536 See https://github.com/curl/curl/issues/622 and 537 https://curl.se/mail/lib-2016-01/0101.html 538 539 12.2 LDAP on Windows does authentication wrong? 540 541 https://github.com/curl/curl/issues/3116 542 543 12.3 LDAP on Windows does not work 544 545 A simple curl command line getting "ldap://ldap.forumsys.com" returns an 546 error that says "no memory" ! 547 548 https://github.com/curl/curl/issues/4261 549 550 12.4 LDAPS requests to ActiveDirectory server hang 551 552 https://github.com/curl/curl/issues/9580 553 554 13. TCP/IP 555 556 13.2 Trying local ports fails on Windows 557 558 This makes '--local-port [range]' to not work since curl cannot properly 559 detect if a port is already in use, so it tries the first port, uses that and 560 then subsequently fails anyway if that was actually in use. 561 562 https://github.com/curl/curl/issues/8112 563 564 15. CMake 565 566 15.1 cmake outputs: no version information available 567 568 Something in the SONAME generation seems to be wrong in the cmake build. 569 570 https://github.com/curl/curl/issues/11158 571 572 15.6 uses -lpthread instead of Threads::Threads 573 574 See https://github.com/curl/curl/issues/6166 575 576 15.7 generated .pc file contains strange entries 577 578 The Libs.private field of the generated .pc file contains -lgcc -lgcc_s -lc 579 -lgcc -lgcc_s 580 581 See https://github.com/curl/curl/issues/6167 582 583 15.13 CMake build with MIT Kerberos does not work 584 585 Minimum CMake version was bumped in curl 7.71.0 (#5358) Since CMake 3.2 586 try_compile started respecting the CMAKE_EXE_FLAGS. The code dealing with 587 MIT Kerberos detection sets few variables to potentially weird mix of space, 588 and ;-separated flags. It had to blow up at some point. All the CMake checks 589 that involve compilation are doomed from that point, the configured tree 590 cannot be built. 591 592 https://github.com/curl/curl/issues/6904 593 594 16. aws-sigv4 595 596 16.2 aws-sigv4 does not handle multipart/form-data correctly 597 598 https://github.com/curl/curl/issues/13351 599 600 17. HTTP/2 601 602 17.1 HTTP/2 prior knowledge over proxy 603 604 https://github.com/curl/curl/issues/12641 605 606 17.2 HTTP/2 frames while in the connection pool kill reuse 607 608 If the server sends HTTP/2 frames (like for example an HTTP/2 PING frame) to 609 curl while the connection is held in curl's connection pool, the socket is 610 found readable when considered for reuse and that makes curl think it is dead 611 and then it is closed and a new connection gets created instead. 612 613 This is *best* fixed by adding monitoring to connections while they are kept 614 in the pool so that pings can be responded to appropriately. 615 616 17.3 ENHANCE_YOUR_CALM causes infinite retries 617 618 Infinite retries with 2 parallel requests on one connection receiving GOAWAY 619 with ENHANCE_YOUR_CALM error code. 620 621 See https://github.com/curl/curl/issues/5119 622 623 17.4 HTTP/2 + TLS spends a lot of time in recv 624 625 It has been observed that by making the speed limit less accurate we could 626 improve this performance. (by reverting 627 https://github.com/curl/curl/commit/db5c9f4f9e0779b49624752b135281a0717b277b) 628 Can we find a golden middle ground? 629 630 See https://curl.se/mail/lib-2024-05/0026.html and 631 https://github.com/curl/curl/issues/13416 632 633 18. HTTP/3 634 635 18.1 connection migration does not work 636 637 https://github.com/curl/curl/issues/7695 638 639 18.2 quiche: QUIC connection is draining 640 641 The transfer ends with error "QUIC connection is draining". 642 643 https://github.com/curl/curl/issues/12037 644 645 19. RTSP 646 647 19.1 Some methods do not support response bodies 648 649 The RTSP implementation is written to assume that a number of RTSP methods 650 always get responses without bodies, even though there seems to be no 651 indication in the RFC that this is always the case. 652 653 https://github.com/curl/curl/issues/12414