1
0
mirror of https://github.com/moparisthebest/curl synced 2024-08-13 17:03:50 -04:00
curl/lib/vtls
Johannes Schindelin 5450428491 schannel: add "best effort" revocation check option
- Implement new option CURLSSLOPT_REVOKE_BEST_EFFORT and
  --ssl-revoke-best-effort to allow a "best effort" revocation check.

A best effort revocation check ignores errors that the revocation check
was unable to take place. The reasoning is described in detail below and
discussed further in the PR.

---

When running e.g. with Fiddler, the schannel backend fails with an
unhelpful error message:

	Unknown error (0x80092012) - The revocation function was unable
	to check revocation for the certificate.

Sadly, many enterprise users who are stuck behind MITM proxies suffer
the very same problem.

This has been discussed in plenty of issues:
https://github.com/curl/curl/issues/3727,
https://github.com/curl/curl/issues/264, for example.

In the latter, a Microsoft Edge developer even made the case that the
common behavior is to ignore issues when a certificate has no recorded
distribution point for revocation lists, or when the server is offline.
This is also known as "best effort" strategy and addresses the Fiddler
issue.

Unfortunately, this strategy was not chosen as the default for schannel
(and is therefore a backend-specific behavior: OpenSSL seems to happily
ignore the offline servers and missing distribution points).

To maintain backward-compatibility, we therefore add a new flag
(`CURLSSLOPT_REVOKE_BEST_EFFORT`) and a new option
(`--ssl-revoke-best-effort`) to select the new behavior.

Due to the many related issues Git for Windows and GitHub Desktop, the
plan is to make this behavior the default in these software packages.

The test 2070 was added to verify this behavior, adapted from 310.

Based-on-work-by: georgeok <giorgos.n.oikonomou@gmail.com>
Co-authored-by: Markus Olsson <j.markus.olsson@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Closes https://github.com/curl/curl/pull/4981
2020-03-18 03:23:39 -04:00
..
bearssl.c bearssl: Improve I/O handling 2019-12-31 02:43:47 -05:00
bearssl.h TLS: add BearSSL vtls implementation 2019-11-26 08:32:23 +01:00
gskit.c gskit: update the copyright year range 2020-03-15 23:43:50 +01:00
gskit.h copyrights: fix copyright year range 2019-11-08 14:51:42 +01:00
gtls.c gtls: Fixed compilation when using GnuTLS < 3.5.0 2020-02-27 15:17:57 +00:00
gtls.h vtls: fold the backend ID into the Curl_ssl structure 2017-08-28 14:56:58 +02:00
mbedtls_threadlock.c polarssl: removed 2020-01-16 11:55:56 +01:00
mbedtls_threadlock.h polarssl: removed 2020-01-16 11:55:56 +01:00
mbedtls.c polarssl: removed 2020-01-16 11:55:56 +01:00
mbedtls.h copyrights: fix copyright year range 2019-11-08 14:51:42 +01:00
mesalink.c vtls: fix narrowing conversion warnings 2019-09-23 09:44:35 +02:00
mesalink.h vtls: add a MesaLink vtls backend 2018-09-13 08:26:37 +02:00
nss.c build: Disable Visual Studio warning "conditional expression is constant" 2019-12-01 19:01:02 -05:00
nssg.h vtls: fold the backend ID into the Curl_ssl structure 2017-08-28 14:56:58 +02:00
openssl.c openssl: remove redundant assignment 2020-02-03 14:20:51 +01:00
openssl.h vtls: fold the backend ID into the Curl_ssl structure 2017-08-28 14:56:58 +02:00
schannel_verify.c schannel: add "best effort" revocation check option 2020-03-18 03:23:39 -04:00
schannel.c schannel: add "best effort" revocation check option 2020-03-18 03:23:39 -04:00
schannel.h schannel: use Curl_ prefix for global private symbols 2018-11-01 09:39:45 +01:00
sectransp.c cleanup: fix typos and wording in docs and comments 2020-02-02 18:43:01 +01:00
sectransp.h Secure Transport: no more "darwinssl" 2019-02-28 08:42:59 +01:00
vtls.c vtls: free ssl_config leftovers on out-of-memory 2020-03-16 08:10:30 +01:00
vtls.h version: make curl_version* thread-safe without using global context 2020-03-07 12:10:11 +01:00
wolfssl.c wolfssl: use the wc-prefixed symbol alternatives 2020-01-16 16:02:17 +01:00
wolfssl.h wolfssl: refer to it as wolfSSL only 2019-06-10 09:18:16 +02:00