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Fix for DTLS DoS issue introduced by fix for CVE-2011-4109.

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Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
This commit is contained in:
Dr. Stephen Henson 2012-01-18 18:14:56 +00:00
parent 7b23c126e6
commit 2dc4b0dbe8
2 changed files with 23 additions and 10 deletions
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16
CHANGES
View File

@ -267,6 +267,14 @@
Add command line options to s_client/s_server.
[Steve Henson]
Changes between 1.0.0f and 1.0.0g [18 Jan 2012]
*) Fix for DTLS DoS issue introduced by fix for CVE-2011-4109.
Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
[Antonio Martin]
Changes between 1.0.0e and 1.0.0f [4 Jan 2012]
*) Nadhem Alfardan and Kenny Paterson have discovered an extension
@ -1230,6 +1238,14 @@
*) Change 'Configure' script to enable Camellia by default.
[NTT]
Changes between 0.9.8s and 0.9.8t [18 Jan 2012]
*) Fix for DTLS DoS issue introduced by fix for CVE-2011-4109.
Thanks to Antonio Martin, Enterprise Secure Access Research and
Development, Cisco Systems, Inc. for discovering this bug and
preparing a fix. (CVE-2012-0050)
[Antonio Martin]
Changes between 0.9.8r and 0.9.8s [4 Jan 2012]

17
ssl/d1_pkt.c
View File

@ -384,6 +384,7 @@ dtls1_process_record(SSL *s)
unsigned int mac_size;
unsigned char md[EVP_MAX_MD_SIZE];
int decryption_failed_or_bad_record_mac = 0;
unsigned char *mac = NULL;
rr= &(s->s3->rrec);
@ -455,19 +456,15 @@ printf("\n");
#endif
}
/* check the MAC for rr->input (it's in mac_size bytes at the tail) */
if (rr->length < mac_size)
if (rr->length >= mac_size)
{
#if 0 /* OK only for stream ciphers */
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
#else
decryption_failed_or_bad_record_mac = 1;
#endif
rr->length -= mac_size;
mac = &rr->data[rr->length];
}
rr->length-=mac_size;
else
rr->length = 0;
i=s->method->ssl3_enc->mac(s,md,0);
if (i < 0 || memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
if (i < 0 || mac == NULL || memcmp(md, mac, mac_size) != 0)
{
decryption_failed_or_bad_record_mac = 1;
}