From c566dd90401a8b20b873644e3cdab175f1e86ede Mon Sep 17 00:00:00 2001 From: Phil Pennock Date: Sat, 24 Sep 2011 01:30:34 -0400 Subject: [PATCH] TLS1.2 and TLS1.1 support with GnuTLS --- doc/doc-docbook/spec.xfpt | 10 ++++++++-- doc/doc-txt/ChangeLog | 3 +++ src/README.UPDATING | 10 ++++++++++ src/src/tls-gnu.c | 34 ++++++++++++++++++++++++++++++++-- 4 files changed, 53 insertions(+), 4 deletions(-) diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt index d18b09dfe..51c9b8bab 100644 --- a/doc/doc-docbook/spec.xfpt +++ b/doc/doc-docbook/spec.xfpt @@ -24595,8 +24595,14 @@ DHE_DSS). The default list contains RSA, DHE_DSS, DHE_RSA. For &%gnutls_require_mac%&, the recognized names are SHA (synonym SHA1), and MD5. The default list contains SHA, MD5. -For &%gnutls_require_protocols%&, the recognized names are TLS1 and SSL3. -The default list contains TLS1, SSL3. +.new +For &%gnutls_require_protocols%&, the recognized names are TLS1.2, TLS1.1, +TLS1.0, (TLS1) and SSL3. +The default list contains TLS1.2, TLS1.1, TLS1.0, SSL3. +TLS1 is an alias for TLS1.0, for backwards compatibility. +For sufficiently old versions of the GnuTLS library, TLS1.2 or TLS1.1 might +not be supported and will not be recognised by Exim. +.wen In a server, the order of items in these lists is unimportant. The server advertises the availability of all the relevant cipher suites. However, in a diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index b0d6b06af..c1362b1bd 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -112,6 +112,9 @@ PP/08 Handle ${run} returning more data than OS pipe buffer size. PP/09 Handle IPv6 addresses with SPF. Bugzilla 860. Patch from Wolfgang Breyha. +PP/10 GnuTLS: support TLS 1.2 & 1.1. + Bugzilla 1156. + Exim version 4.76 ----------------- diff --git a/src/README.UPDATING b/src/README.UPDATING index 2f6e57629..fadf59aa9 100644 --- a/src/README.UPDATING +++ b/src/README.UPDATING @@ -26,6 +26,16 @@ The rest of this document contains information about changes in 4.xx releases that might affect a running system. +Exim version 4.77 +----------------- + + * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3, + if supported by your GnuTLS library. Use the existing + "gnutls_require_protocols" option to downgrade this if that will be a + problem. Prior to this release, supported values were "TLS1" and "SSL3", + so you should be able to update configuration prior to update. + + Exim version 4.74 ----------------- diff --git a/src/src/tls-gnu.c b/src/src/tls-gnu.c index bf10526e9..4de9d4f68 100644 --- a/src/src/tls-gnu.c +++ b/src/src/tls-gnu.c @@ -12,6 +12,13 @@ is based on a patch that was contributed by Nikos Mavroyanopoulos. No cryptographic code is included in Exim. All this module does is to call functions from the GnuTLS library. */ +/* Note: This appears to be using an old API from compat.h; it is likely that +someone familiary with GnuTLS programming could rework a lot of this to a +modern API and perhaps remove the explicit knowledge of crypto algorithms from +Exim. Such a re-work would be most welcome and we'd sacrifice support for +older GnuTLS releases without too many qualms -- maturity and experience +in crypto libraries tends to improve their robustness against attack. +Frankly, if you maintain it, you decide what's supported and what isn't. */ /* Heading stuff for GnuTLS */ @@ -46,6 +53,13 @@ static int verify_requirement; and space into which it can be copied and altered. */ static const int default_proto_priority[16] = { + /* These are gnutls_protocol_t enum values */ +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 + GNUTLS_TLS1_2, +#endif +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 + GNUTLS_TLS1_1, +#endif GNUTLS_TLS1, GNUTLS_SSL3, 0 }; @@ -89,11 +103,27 @@ typedef struct pri_item { } pri_item; -static int tls1_codes[] = { GNUTLS_TLS1, 0 }; +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 +static int tls1_2_codes[] = { GNUTLS_TLS1_2, 0 }; +#endif +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 +static int tls1_1_codes[] = { GNUTLS_TLS1_1, 0 }; +#endif +/* more recent libraries define this as an equivalent value to the +canonical GNUTLS_TLS1_0; since they're the same, we stick to the +older name. */ +static int tls1_0_codes[] = { GNUTLS_TLS1, 0 }; static int ssl3_codes[] = { GNUTLS_SSL3, 0 }; static pri_item proto_index[] = { - { US"TLS1", tls1_codes }, +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 7 + { US"TLS1.2", tls1_2_codes }, +#endif +#if GNUTLS_VERSION_MAJOR > 1 || GNUTLS_VERSION_MINOR >= 2 + { US"TLS1.1", tls1_1_codes }, +#endif + { US"TLS1.0", tls1_0_codes }, + { US"TLS1", tls1_0_codes }, { US"SSL3", ssl3_codes } }; -- 2.30.2