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authorDr. Stephen Henson <steve@openssl.org>2013-12-20 15:26:50 +0000
committerDr. Stephen Henson <steve@openssl.org>2013-12-20 23:46:16 +0000
commit20b82b514d81a64f5b240788e5051167456af379 (patch)
treeb0b77dd1f987e0930e9ac2980d474198fce2c3f9
parent560b34f2b016038209c7a67791613d0eb0381536 (diff)
downloadopenssl-20b82b514d81a64f5b240788e5051167456af379.tar.gz
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. (cherry picked from commit 34628967f1e65dc8f34e000f0f5518e21afbfc7b)
-rw-r--r--CHANGES5
-rw-r--r--ssl/d1_both.c6
-rw-r--r--ssl/t1_enc.c17
3 files changed, 22 insertions, 6 deletions
diff --git a/CHANGES b/CHANGES
index 2602cfac96..111db939f9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -273,6 +273,11 @@
Changes between 1.0.1e and 1.0.2 [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]
+
*) TLS pad extension: draft-agl-tls-padding-02
Workaround for the "TLS hang bug" (see FAQ and PR#2771): if the
diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index f7947bd988..f0c5962949 100644
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -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);
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index acc5f21363..0432801b16 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -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)
{