From dad0334cf1b907252dbd6a7ab54e66292983c889 Mon Sep 17 00:00:00 2001
From: Matthew Jordan <mjordan@digium.com>
Date: Mon, 20 Oct 2014 14:20:15 +0000
Subject: [PATCH] AST-2014-011: Fix POODLE security issues
There are two aspects to the vulnerability:
(1) res_jabber/res_xmpp use SSLv3 only. This patch updates the module to use
TLSv1+. At this time, it does not refactor res_jabber/res_xmpp to use the
TCP/TLS core, which should be done as an improvement at a latter date.
(2) The TCP/TLS core, when tlsclientmethod/sslclientmethod is left unspecified,
will default to the OpenSSL SSLv23_method. This method allows for all
ecnryption methods, including SSLv2/SSLv3. A MITM can exploit this by
forcing a fallback to SSLv3, which leaves the server vulnerable to POODLE.
This patch adds WARNINGS if a user uses SSLv2/SSLv3 in their configuration,
and explicitly disables SSLv2/SSLv3 if using SSLv23_method.
For TLS clients, Asterisk will default to TLSv1+ and WARN if SSLv2 or SSLv3 is
explicitly chosen. For TLS servers, Asterisk will no longer support SSLv2 or
SSLv3.
Much thanks to abelbeck for reporting the vulnerability and providing a patch
for the res_jabber/res_xmpp modules.
Review: https://reviewboard.asterisk.org/r/4096/
ASTERISK-24425 #close
Reported by: abelbeck
Tested by: abelbeck, opsmonitor, gtjoseph
patches:
asterisk-1.8-jabber-tls.patch uploaded by abelbeck (License 5903)
asterisk-11-jabber-xmpp-tls.patch uploaded by abelbeck (License 5903)
AST-2014-011-1.8.diff uploaded by mjordan (License 6283)
AST-2014-011-11.diff uploaded by mjordan (License 6283)
........
Merged revisions 425987 from http://svn.asterisk.org/svn/asterisk/branches/12
........
Merged revisions 425991 from http://svn.asterisk.org/svn/asterisk/branches/13
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@426003 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
main/tcptls.c | 22 +++++++++++++++++-----
res/res_xmpp.c | 6 +++++-
2 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/main/tcptls.c b/main/tcptls.c
index fd6d5016ed..1930d61cf3 100644
--- a/main/tcptls.c
+++ b/main/tcptls.c
@@ -747,6 +747,8 @@ static int __ssl_setup(struct ast_tls_config *cfg, int client)
cfg->enabled = 0;
return 0;
#else
+ int disable_ssl = 0;
+
if (!cfg->enabled) {
return 0;
}
@@ -762,22 +764,21 @@ static int __ssl_setup(struct ast_tls_config *cfg, int client)
if (client) {
#ifndef OPENSSL_NO_SSL2
if (ast_test_flag(&cfg->flags, AST_SSL_SSLV2_CLIENT)) {
+ ast_log(LOG_WARNING, "Usage of SSLv2 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
cfg->ssl_ctx = SSL_CTX_new(SSLv2_client_method());
} else
#endif
if (ast_test_flag(&cfg->flags, AST_SSL_SSLV3_CLIENT)) {
+ ast_log(LOG_WARNING, "Usage of SSLv3 is discouraged due to known vulnerabilities. Please use 'tlsv1' or leave the TLS method unspecified!\n");
cfg->ssl_ctx = SSL_CTX_new(SSLv3_client_method());
} else if (ast_test_flag(&cfg->flags, AST_SSL_TLSV1_CLIENT)) {
cfg->ssl_ctx = SSL_CTX_new(TLSv1_client_method());
} else {
- /* SSLv23_client_method() sends SSLv2, this was the original
- * default for ssl clients before the option was given to
- * pick what protocol a client should use. In order not
- * to break expected behavior it remains the default. */
+ disable_ssl = 1;
cfg->ssl_ctx = SSL_CTX_new(SSLv23_client_method());
}
} else {
- /* SSLv23_server_method() supports TLSv1, SSLv2, and SSLv3 inbound connections. */
+ disable_ssl = 1;
cfg->ssl_ctx = SSL_CTX_new(SSLv23_server_method());
}
@@ -787,6 +788,17 @@ static int __ssl_setup(struct ast_tls_config *cfg, int client)
return 0;
}
+ /* Due to the POODLE vulnerability, completely disable
+ * SSLv2 and SSLv3 if we are not explicitly told to use
+ * them. SSLv23_*_method supports TLSv1+.
+ */
+ if (disable_ssl) {
+ long ssl_opts;
+
+ ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
+ SSL_CTX_set_options(cfg->ssl_ctx, ssl_opts);
+ }
+
SSL_CTX_set_verify(cfg->ssl_ctx,
ast_test_flag(&cfg->flags, AST_SSL_VERIFY_CLIENT) ? SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT : SSL_VERIFY_NONE,
NULL);
diff --git a/res/res_xmpp.c b/res/res_xmpp.c
index b3c374871d..3cb6fc572c 100644
--- a/res/res_xmpp.c
+++ b/res/res_xmpp.c
@@ -2637,6 +2637,7 @@ static int xmpp_client_requested_tls(struct ast_xmpp_client *client, struct ast_
{
#ifdef HAVE_OPENSSL
int sock;
+ long ssl_opts;
#endif
if (!strcmp(iks_name(node), "success")) {
@@ -2655,11 +2656,14 @@ static int xmpp_client_requested_tls(struct ast_xmpp_client *client, struct ast_
ast_log(LOG_ERROR, "Somehow we managed to try to start TLS negotiation on client '%s' without OpenSSL support, disconnecting\n", client->name);
return -1;
#else
- client->ssl_method = SSLv3_method();
+ client->ssl_method = SSLv23_method();
if (!(client->ssl_context = SSL_CTX_new((SSL_METHOD *) client->ssl_method))) {
goto failure;
}
+ ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
+ SSL_CTX_set_options(client->ssl_context, ssl_opts);
+
if (!(client->ssl_session = SSL_new(client->ssl_context))) {
goto failure;
}
--
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