Permalink
Browse files

Fix DTLS retransmission from previous session.

For DTLS we might need to retransmit messages from the previous session
so keep a copy of write context in DTLS retransmission buffers instead
of replacing it after sending CCS. CVE-2013-6450.
  • Loading branch information...
snhenson committed Dec 20, 2013
1 parent a6c62f0 commit 34628967f1e65dc8f34e000f0f5518e21afbfc7b
Showing with 24 additions and 6 deletions.
  1. +5 −0 CHANGES
  2. +6 −0 ssl/d1_both.c
  3. +2 −0 ssl/ssl_locl.h
  4. +11 −6 ssl/t1_enc.c
View
@@ -4,6 +4,11 @@
Changes between 1.0.1e and 1.0.1f [xx XXX xxxx]
+ *) Keep original DTLS digest and encryption contexts in retransmission
+ structures so we can use the previous session parameters if they need
+ to be resent. (CVE-2013-6450)
+ [Steve Henson]
+
*) Add option SSL_OP_SAFARI_ECDHE_ECDSA_BUG (part of SSL_OP_ALL) which
avoids preferring ECDHE-ECDSA ciphers when the client appears to be
Safari on OS X. Safari on OS X 10.8..10.8.3 advertises support for
View
@@ -214,6 +214,12 @@ dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
static void
dtls1_hm_fragment_free(hm_fragment *frag)
{
+
+ if (frag->msg_header.is_ccs)
+ {
+ EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
+ EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
+ }
if (frag->fragment) OPENSSL_free(frag->fragment);
if (frag->reassembly) OPENSSL_free(frag->reassembly);
OPENSSL_free(frag);
View
@@ -621,6 +621,8 @@ extern SSL3_ENC_METHOD TLSv1_enc_data;
extern SSL3_ENC_METHOD SSLv3_enc_data;
extern SSL3_ENC_METHOD DTLSv1_enc_data;
+#define SSL_IS_DTLS(s) (s->method->version == DTLS1_VERSION)
+
#define IMPLEMENT_tls_meth_func(version, func_name, s_accept, s_connect, \
s_get_meth) \
const SSL_METHOD *func_name(void) \
View
@@ -414,15 +414,20 @@ int tls1_change_cipher_state(SSL *s, int which)
s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
else
s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
- if (s->enc_write_ctx != NULL)
+ if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s))
reuse_dd = 1;
- else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
+ else if ((s->enc_write_ctx=EVP_CIPHER_CTX_new()) == NULL)
goto err;
- else
- /* make sure it's intialized in case we exit later with an error */
- EVP_CIPHER_CTX_init(s->enc_write_ctx);
dd= s->enc_write_ctx;
- mac_ctx = ssl_replace_hash(&s->write_hash,NULL);
+ if (SSL_IS_DTLS(s))
+ {
+ mac_ctx = EVP_MD_CTX_create();
+ if (!mac_ctx)
+ goto err;
+ s->write_hash = mac_ctx;
+ }
+ else
+ mac_ctx = ssl_replace_hash(&s->write_hash,NULL);
#ifndef OPENSSL_NO_COMP
if (s->compress != NULL)
{

0 comments on commit 3462896

Please sign in to comment.