More carefull parsing of incoming packets.

6 files changed, 50 insertions, 8 deletions

diff --git a/lib/auth_anon.c b/lib/auth_anon.c
index 712da0fbff..dda3c275c6 100644
--- a/lib/auth_anon.c
+++ b/lib/auth_anon.c
@@ -194,18 +194,22 @@ int proc_anon_server_kx( GNUTLS_STATE state, opaque* data, int data_size) {
 
 
 	i = 0;
+	DECR_LEN( data_size, 2);
 	n_p = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_p);
 	data_p = &data[i];
 	i += n_p;
 	if (i > data_size) {
 		gnutls_assert();
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
+	DECR_LEN( data_size, 2);
 	n_g = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_g);
 	data_g = &data[i];
 	i += n_g;
 	if (i > data_size) {
@@ -213,9 +217,11 @@ int proc_anon_server_kx( GNUTLS_STATE state, opaque* data, int data_size) {
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 	
+	DECR_LEN( data_size, 2);
 	n_Y = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_Y);
 	data_Y = &data[i];
 	i += n_Y;
 	if (i > data_size) {
@@ -267,9 +273,11 @@ int proc_anon_client_kx( GNUTLS_STATE state, opaque* data, int data_size) {
 		bits = cred->dh_bits;
 	}
 
+	DECR_LEN( data_size, 2);
 	n_Y = READuint16( &data[0]);
 
 	_n_Y = n_Y;
+	DECR_LEN( data_size, n_Y);
 	if (_gnutls_mpi_scan(&state->gnutls_key->client_Y, &data[2], &_n_Y) !=0 || state->gnutls_key->client_Y==NULL) {
 		gnutls_assert();
 		return GNUTLS_E_MPI_SCAN_FAILED;
diff --git a/lib/auth_dhe_rsa.c b/lib/auth_dhe_rsa.c
index 5ec132032d..66bc530eac 100644
--- a/lib/auth_dhe_rsa.c
+++ b/lib/auth_dhe_rsa.c
@@ -260,9 +260,12 @@ static int proc_dhe_rsa_server_kx(GNUTLS_STATE state, opaque * data,
 	}
 
 	i = 0;
+	
+	DECR_LEN( data_size, 2);
 	n_p = READuint16(&data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_p);
 	data_p = &data[i];
 	i += n_p;
 	if (i > data_size) {
@@ -270,9 +273,11 @@ static int proc_dhe_rsa_server_kx(GNUTLS_STATE state, opaque * data,
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 
+	DECR_LEN( data_size, 2);
 	n_g = READuint16(&data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_g);
 	data_g = &data[i];
 	i += n_g;
 	if (i > data_size) {
@@ -280,9 +285,11 @@ static int proc_dhe_rsa_server_kx(GNUTLS_STATE state, opaque * data,
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 
+	DECR_LEN( data_size, 2);
 	n_Y = READuint16(&data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_Y);
 	data_Y = &data[i];
 	i += n_Y;
 	if (i > data_size) {
@@ -318,7 +325,10 @@ static int proc_dhe_rsa_server_kx(GNUTLS_STATE state, opaque * data,
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 
+	DECR_LEN( data_size, 2);
 	sigsize = READuint16(&data[vparams.size]);
+
+	DECR_LEN( data_size, sigsize);
 	signature.data = &data[vparams.size + 2];
 	signature.size = GMIN(data_size - vparams.size - 2, sigsize);
 
@@ -355,10 +365,11 @@ static int proc_dhe_rsa_client_kx(GNUTLS_STATE state, opaque * data,
 	if (bits < MIN_BITS)
 		bits = DEFAULT_BITS;	/* default */
 
-
+	DECR_LEN( data_size, 2);
 	n_Y = READuint16(&data[0]);
 	_n_Y = n_Y;
 
+	DECR_LEN( data_size, n_Y);
 	if (_gnutls_mpi_scan(&state->gnutls_key->client_Y, &data[2], &_n_Y)) {
 		gnutls_assert();
 		return GNUTLS_E_MPI_SCAN_FAILED;
diff --git a/lib/auth_srp.c b/lib/auth_srp.c
index 6be3f358a5..a2aa05a60b 100644
--- a/lib/auth_srp.c
+++ b/lib/auth_srp.c
@@ -323,12 +323,15 @@ int proc_srp_server_hello(GNUTLS_STATE state, const opaque * data, int data_size
 /* read the algorithm used to generate V */
 	
 	i = 0;
+	DECR_LEN( data_size, 1);
 	memcpy( &pwd_algo, data, 1);
-
 	i++;
+
+	DECR_LEN( data_size, 2);
 	n_g = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_g);
 	data_g = &data[i];
 	i += n_g;
 	if (i > data_size) {
@@ -336,9 +339,11 @@ int proc_srp_server_hello(GNUTLS_STATE state, const opaque * data, int data_size
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 
+	DECR_LEN( data_size, 2);
 	n_n = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_n);
 	data_n = &data[i];
 	i += n_n;
 	if (i > data_size) {
@@ -346,9 +351,11 @@ int proc_srp_server_hello(GNUTLS_STATE state, const opaque * data, int data_size
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
 	
+	DECR_LEN( data_size, 2);
 	n_s = READuint16( &data[i]);
 	i += 2;
 
+	DECR_LEN( data_size, n_s);
 	data_s = &data[i];
 	i += n_s;
 	if (i > data_size) {
@@ -390,8 +397,10 @@ int proc_srp_client_kx0(GNUTLS_STATE state, opaque * data, int data_size)
 {
 	size_t _n_A;
 
+	DECR_LEN( data_size, 2);
 	_n_A = READuint16( &data[0]);
 
+	DECR_LEN( data_size, _n_A);
 	if (_gnutls_mpi_scan(&A, &data[2], &_n_A) || A == NULL) {
 		gnutls_assert();
 		return GNUTLS_E_MPI_SCAN_FAILED;
@@ -406,8 +415,10 @@ int proc_srp_server_kx2(GNUTLS_STATE state, opaque * data, int data_size)
 	size_t _n_B;
 	int ret;
 	
+	DECR_LEN( data_size, 2);
 	_n_B = READuint16( &data[0]);
 
+	DECR_LEN( data_size, _n_B);
 	if (_gnutls_mpi_scan(&B, &data[2], &_n_B) || B==NULL) {
 		gnutls_assert();
 		return GNUTLS_E_MPI_SCAN_FAILED;
diff --git a/lib/auth_x509.c b/lib/auth_x509.c
index 05a225c9a6..cbe1b5f96d 100644
--- a/lib/auth_x509.c
+++ b/lib/auth_x509.c
@@ -518,11 +518,12 @@ int _gnutls_proc_x509_server_certificate(GNUTLS_STATE state, opaque * data,
 	}
 	i = dsize;
 
+	DECR_LEN(dsize, 3);
 	len = READuint24(p);
 	p += 3;
 
-	for (; i > 0; len = READuint24(p), p += 3) {
-		DECR_LEN(dsize, (len + 3));
+	for (; i > 0; DECR_LEN(dsize, 3), len = READuint24(p), p += 3) {
+		DECR_LEN(dsize, len);
 		peer_certificate_list_size++;
 		p += len;
 		i -= len + 3;
@@ -532,6 +533,11 @@ int _gnutls_proc_x509_server_certificate(GNUTLS_STATE state, opaque * data,
 		gnutls_assert();
 		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
 	}
+
+	/* Now we start parsing the list (again).
+	 * We don't use DECR_LEN since the list has
+	 * been parsed before.
+	 */
 	dsize = data_size;
 	i = dsize;
 	peer_certificate_list =
@@ -690,6 +696,7 @@ int _gnutls_proc_x509_cert_req(GNUTLS_STATE state, opaque * data,
 		return 0;
 	}
 
+	DECR_LEN(dsize, size);
 	if ((ret =
 	     _gnutls_find_acceptable_client_cert(state, p, size,
 						 &ind)) < 0) {
@@ -772,10 +779,7 @@ int _gnutls_proc_x509_client_cert_vrfy(GNUTLS_STATE state, opaque * data,
 	size = READuint16(pdata);
 	pdata += 2;
 
-	if (size < data_size - 2) {
-		gnutls_assert();
-		return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
-	}
+	DECR_LEN(dsize, size);
 
 	sig.data = pdata;
 	sig.size = size;
diff --git a/lib/gnutls_extensions.c b/lib/gnutls_extensions.c
index 10ab5dc680..52dc1595bc 100644
--- a/lib/gnutls_extensions.c
+++ b/lib/gnutls_extensions.c
@@ -88,21 +88,26 @@ uint16 size;
 
 	if (data_size < 2) return 0;
 
+	DECR_LEN( data_size, 2);
 	next = READuint16( data);
 	pos+=2;
 
 	if (data_size < next) return 0;
+	DECR_LEN( data_size, next);
 	
 	do {
 		next--; if (next < 0) return 0;
+		DECR_LEN( data_size, 1);
 		memcpy( &type, &data[pos], 1);
 		pos++;
 
 		next-=2; if (next < 0) return 0;
 
+		DECR_LEN( data_size, 2);
 		size = READuint16(&data[pos]);
 		pos+=2;
 				
+		DECR_LEN( data_size, size);
 		sdata = &data[pos];
 		pos+=size;
 		next-=size; if (next < 0) return 0;
diff --git a/lib/gnutls_handshake.c b/lib/gnutls_handshake.c
index 1b3465dfa1..1b745664e8 100644
--- a/lib/gnutls_handshake.c
+++ b/lib/gnutls_handshake.c
@@ -791,6 +791,9 @@ static int _gnutls_recv_handshake_header(GNUTLS_STATE state,
 		}
 		*recv_type = dataptr[0];
 
+		/* we do not use DECR_LEN because we know
+		 * that the packet has enough data.
+		 */
 		length32 = READuint24(&dataptr[1]);
 		handshake_header_size = HANDSHAKE_HEADER_SIZE;