From: Ben Laurie <ben@links.org>
Date: Mon, 28 Jan 2013 17:33:18 +0000 (+0000)
Subject: Don't crash when processing a zero-length, TLS >= 1.1 record.
X-Git-Tag: OpenSSL_1_0_2-beta1~437
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=e0da2c2ed29a3a66c22e6a8a5072b58399835d71;p=oweals%2Fopenssl.git

Don't crash when processing a zero-length, TLS >= 1.1 record.

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)
---

diff --git a/ssl/d1_enc.c b/ssl/d1_enc.c
index c13b495a08..da42348b3d 100644
--- a/ssl/d1_enc.c
+++ b/ssl/d1_enc.c
@@ -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);
 		}
diff --git a/ssl/d1_pkt.c b/ssl/d1_pkt.c
index 5e2c56c983..4763d5cd1f 100644
--- a/ssl/d1_pkt.c
+++ b/ssl/d1_pkt.c
@@ -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)
diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index 13ebfc6996..98f3894954 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -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)
diff --git a/ssl/s3_pkt.c b/ssl/s3_pkt.c
index b2e5dc1882..3e60f5018c 100644
--- a/ssl/s3_pkt.c
+++ b/ssl/s3_pkt.c
@@ -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 */
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 8153b2ca43..4b31742783 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -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);