diff options
| author | Matt Caswell <matt@openssl.org> | 2018-08-20 20:05:28 +0300 |
|---|---|---|
| committer | Matt Caswell <matt@openssl.org> | 2018-08-22 17:15:19 +0300 |
| commit | 5627f9f21764af7eac2af2fb8ec867cd65ca8949 (patch) | |
| tree | 4313d7650ce6a132ba00feab55b02cc7fa87b536 /ssl | |
| parent | 3e7cb13dff37795f022a1bedc5951130099a0fc6 (diff) | |
Don't detect a downgrade where the server has a protocol version hole
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7013)
Diffstat (limited to 'ssl')
| -rw-r--r-- | ssl/statem/statem_lib.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c index 795202aadc..3961c14719 100644 --- a/ssl/statem/statem_lib.c +++ b/ssl/statem/statem_lib.c @@ -1665,9 +1665,16 @@ static void check_for_downgrade(SSL *s, int vers, DOWNGRADE *dgrd) if (vers == TLS1_2_VERSION && ssl_version_supported(s, TLS1_3_VERSION, NULL)) { *dgrd = DOWNGRADE_TO_1_2; - } else if (!SSL_IS_DTLS(s) && vers < TLS1_2_VERSION - && (ssl_version_supported(s, TLS1_2_VERSION, NULL) - || ssl_version_supported(s, TLS1_3_VERSION, NULL))) { + } else if (!SSL_IS_DTLS(s) + && vers < TLS1_2_VERSION + /* + * We need to ensure that a server that disables TLSv1.2 + * (creating a hole between TLSv1.3 and TLSv1.1) can still + * complete handshakes with clients that support TLSv1.2 and + * below. Therefore we do not enable the sentinel if TLSv1.3 is + * enabled and TLSv1.2 is not. + */ + && ssl_version_supported(s, TLS1_2_VERSION, NULL)) { *dgrd = DOWNGRADE_TO_1_1; } else { *dgrd = DOWNGRADE_NONE; |