Don't crash when processing a zero-length, TLS >= 1.1 record.
authorBen Laurie <ben@links.org>
Mon, 28 Jan 2013 17:33:18 +0000 (17:33 +0000)
committerDr. Stephen Henson <steve@openssl.org>
Wed, 6 Feb 2013 14:19:07 +0000 (14:19 +0000)
The previous CBC patch was bugged in that there was a path through enc()
in s3_pkt.c/d1_pkt.c which didn't set orig_len. orig_len would be left
at the previous value which could suggest that the packet was a
sufficient length when it wasn't.
(cherry picked from commit 6cb19b7681f600b2f165e4adc57547b097b475fd)

ssl/d1_enc.c
ssl/d1_pkt.c
ssl/s3_enc.c
ssl/s3_pkt.c
ssl/t1_enc.c

index c13b495..da42348 100644 (file)
@@ -245,7 +245,6 @@ int dtls1_enc(SSL *s, int send)
                 }
 #endif /* KSSL_DEBUG */
 
-               rec->orig_len = rec->length;
                if ((bs != 1) && !send)
                        return tls1_cbc_remove_padding(s, rec, bs, mac_size);
                }
index 5e2c56c..4763d5c 100644 (file)
@@ -414,6 +414,7 @@ dtls1_process_record(SSL *s)
 
        /* decrypt in place in 'rr->input' */
        rr->data=rr->input;
+       rr->orig_len=rr->length;
 
        enc_err = s->method->ssl3_enc->enc(s,0);
        if (enc_err <= 0)
index 13ebfc6..98f3894 100644 (file)
@@ -487,6 +487,15 @@ void ssl3_cleanup_key_block(SSL *s)
        s->s3->tmp.key_block_length=0;
        }
 
+/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ *   0: (in non-constant time) if the record is publically invalid (i.e. too
+ *       short etc).
+ *   1: if the record's padding is valid / the encryption was successful.
+ *   -1: if the record's padding is invalid or, if sending, an internal error
+ *       occured.
+ */
 int ssl3_enc(SSL *s, int send)
        {
        SSL3_RECORD *rec;
@@ -553,8 +562,6 @@ int ssl3_enc(SSL *s, int send)
                
                EVP_Cipher(ds,rec->data,rec->input,l);
 
-               rec->orig_len = rec->length;
-
                if (EVP_MD_CTX_md(s->read_hash) != NULL)
                        mac_size = EVP_MD_CTX_size(s->read_hash);
                if ((bs != 1) && !send)
index b2e5dc1..3e60f50 100644 (file)
@@ -401,8 +401,13 @@ fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
 
        /* decrypt in place in 'rr->input' */
        rr->data=rr->input;
+       rr->orig_len=rr->length;
 
        enc_err = s->method->ssl3_enc->enc(s,0);
+       /* enc_err is:
+        *    0: (in non-constant time) if the record is publically invalid.
+        *    1: if the padding is valid
+        *    -1: if the padding is invalid */
        if (enc_err == 0)
                {
                /* SSLerr() and ssl3_send_alert() have been called */
index 8153b2c..4b31742 100644 (file)
@@ -691,6 +691,15 @@ err:
        return(ret);
        }
 
+/* tls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
+ *
+ * Returns:
+ *   0: (in non-constant time) if the record is publically invalid (i.e. too
+ *       short etc).
+ *   1: if the record's padding is valid / the encryption was successful.
+ *   -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
+ *       an internal error occured.
+ */
 int tls1_enc(SSL *s, int send)
        {
        SSL3_RECORD *rec;
@@ -841,8 +850,6 @@ int tls1_enc(SSL *s, int send)
                        {
                        if (l == 0 || l%bs != 0)
                                {
-                               if (s->version >= TLS1_1_VERSION)
-                                       return -1;
                                SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
                                ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
                                return 0;
@@ -870,8 +877,6 @@ int tls1_enc(SSL *s, int send)
                }
 #endif /* KSSL_DEBUG */
 
-               rec->orig_len = rec->length;
-
                ret = 1;
                if (EVP_MD_CTX_md(s->read_hash) != NULL)
                        mac_size = EVP_MD_CTX_size(s->read_hash);