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Fix DTLS retransmission from previous session.

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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.
This commit is contained in:
Dr. Stephen Henson 2013-12-20 15:26:50 +00:00
parent a6c62f0c25
commit 34628967f1
4 changed files with 24 additions and 6 deletions
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5
CHANGES
View file

@ -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

6
ssl/d1_both.c
View file

@ -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);

2
ssl/ssl_locl.h
View file

@ -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) \

17
ssl/t1_enc.c
View file

@ -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)
{