#include <stdio.h>
#include <errno.h>
#define USE_SOCKETS
+#include "ssl_locl.h"
#include <openssl/evp.h>
#include <openssl/buffer.h>
-#include "ssl_locl.h"
static int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
unsigned int len, int create_empty_fragment);
unsigned int mac_size;
int clear=0;
size_t extra;
+ int decryption_failed_or_bad_record_mac = 0;
+ unsigned char *mac = NULL;
rr= &(s->s3->rrec);
sess=s->session;
/* SSLerr() and ssl3_send_alert() have been called */
goto err;
- /* otherwise enc_err == -1 */
- goto decryption_failed_or_bad_record_mac;
+ /* Otherwise enc_err == -1, which indicates bad padding
+ * (rec->length has not been changed in this case).
+ * To minimize information leaked via timing, we will perform
+ * the MAC computation anyway. */
+ decryption_failed_or_bad_record_mac = 1;
}
#ifdef TLS_DEBUG
SSLerr(SSL_F_SSL3_GET_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)
+ {
+ rr->length -= mac_size;
+ mac = &rr->data[rr->length];
+ }
+ else
{
+ /* record (minus padding) is too short to contain a MAC */
#if 0 /* OK only for stream ciphers */
al=SSL_AD_DECODE_ERROR;
SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT);
goto f_err;
#else
- goto decryption_failed_or_bad_record_mac;
+ decryption_failed_or_bad_record_mac = 1;
+ rr->length = 0;
#endif
}
- rr->length-=mac_size;
i=s->method->ssl3_enc->mac(s,md,0);
- if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
+ if (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)
+ {
+ /* A 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 a logfile) */
+ al=SSL_AD_BAD_RECORD_MAC;
+ SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
+ goto f_err;
+ }
+
/* r->length is now just compressed */
if (s->expand != NULL)
{
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_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
f_err:
ssl3_send_alert(s,SSL3_AL_FATAL,al);
err:
if (prefix_len <= 0)
goto err;
- if (s->s3->wbuf.len < prefix_len + SSL3_RT_MAX_PACKET_SIZE)
+ if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
{
/* insufficient space */
SSLerr(SSL_F_DO_SSL3_WRITE, ERR_R_INTERNAL_ERROR);