Module Name: src
Committed By: riz
Date: Wed Jan 25 18:54:43 UTC 2012
Modified Files:
src/crypto/dist/openssl/ssl [netbsd-5-1]: d1_pkt.c
Log Message:
Apply patch (requested by drochner in ticket #1710):
crypto/dist/openssl/ssl/d1_pkt.c
Address CVS-2012-0050.
To generate a diff of this commit:
cvs rdiff -u -r1.1.1.5.4.1 -r1.1.1.5.4.1.2.1 \
src/crypto/dist/openssl/ssl/d1_pkt.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/crypto/dist/openssl/ssl/d1_pkt.c
diff -u src/crypto/dist/openssl/ssl/d1_pkt.c:1.1.1.5.4.1 src/crypto/dist/openssl/ssl/d1_pkt.c:1.1.1.5.4.1.2.1
--- src/crypto/dist/openssl/ssl/d1_pkt.c:1.1.1.5.4.1 Sun Jul 5 00:34:52 2009
+++ src/crypto/dist/openssl/ssl/d1_pkt.c Wed Jan 25 18:54:43 2012
@@ -375,6 +375,8 @@ dtls1_process_record(SSL *s)
SSL3_RECORD *rr;
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);
@@ -409,12 +411,10 @@ dtls1_process_record(SSL *s)
enc_err = s->method->ssl3_enc->enc(s,0);
if (enc_err <= 0)
{
- if (enc_err == 0)
- /* SSLerr() and ssl3_send_alert() have been called */
- goto err;
-
- /* otherwise enc_err == -1 */
- goto decryption_failed_or_bad_record_mac;
+ /* To minimize information leaked via timing, we will always
+ * perform all computations before discarding the message.
+ */
+ decryption_failed_or_bad_record_mac = 1;
}
#ifdef TLS_DEBUG
@@ -440,28 +440,32 @@ printf("\n");
SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
goto f_err;
#else
- goto decryption_failed_or_bad_record_mac;
+ decryption_failed_or_bad_record_mac = 1;
#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
- goto decryption_failed_or_bad_record_mac;
-#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 (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
+ if (i < 0 || mac == NULL || memcmp(md, mac, mac_size) != 0)
{
- goto decryption_failed_or_bad_record_mac;
+ decryption_failed_or_bad_record_mac = 1;
}
}
+ if (decryption_failed_or_bad_record_mac)
+ {
+ /* decryption failed, silently discard message */
+ rr->length = 0;
+ s->packet_length = 0;
+ goto err;
+ }
+
/* r->length is now just compressed */
if (s->expand != NULL)
{
@@ -500,14 +504,6 @@ printf("\n");
dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
return(1);
-decryption_failed_or_bad_record_mac:
- /* Separate 'decryption_failed' alert was introduced with TLS 1.0,
- * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
- * failure is directly visible from the ciphertext anyway,
- * we should not reveal which kind of error occured -- this
- * might become visible to an attacker (e.g. via logfile) */
- al=SSL_AD_BAD_RECORD_MAC;
- SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
