Ensure that there is no remainders in the TLS handshake packets.

The issue was discovered using the codenomicon TLS suite.

diff --git a/lib/auth/cert.c b/lib/auth/cert.c
index e89d618e2896d3c225d150c5ee2778be0baa52b3..38debd052d1d2b871b88870580df03cbd9bce562 100644 (file)
--- a/lib/auth/cert.c
+++ b/lib/auth/cert.c
@@ -1073,6 +1073,9 @@ _gnutls_proc_x509_server_crt(gnutls_session_t session,
                i -= len + 3;
        }
 
+       if (dsize != 0)
+               return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
+
        if (peer_certificate_list_size == 0) {
                gnutls_assert();
                return GNUTLS_E_NO_CERTIFICATE_FOUND;
@@ -1284,6 +1287,9 @@ _gnutls_proc_openpgp_server_crt(gnutls_session_t session,
                return GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE;
        }
 
+       if (dsize != 0)
+               return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
+
        /* ok we now have the peer's key in tmp datum
         */
        peer_certificate_list = gnutls_calloc(1, sizeof(gnutls_pcert_st));
@@ -1476,7 +1482,7 @@ _gnutls_proc_cert_cert_req(gnutls_session_t session, uint8_t * data,
                return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
        }
 
-       DECR_LEN(dsize, size);
+       DECR_LEN_FINAL(dsize, size);
 
        /* now we ask the user to tell which one
         * he wants to use.
@@ -1600,16 +1606,14 @@ _gnutls_proc_cert_client_crt_vrfy(gnutls_session_t session,
        }
 
        ret = _gnutls_session_sign_algo_enabled(session, sign_algo);
-       if (ret < 0) {
-               gnutls_assert();
-               return GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM;
-       }
+       if (ret < 0)
+               return gnutls_assert_val(GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM);
 
        DECR_LEN(dsize, 2);
        size = _gnutls_read_uint16(pdata);
        pdata += 2;
 
-       DECR_LEN(dsize, size);
+       DECR_LEN_FINAL(dsize, size);
 
        sig.data = pdata;
        sig.size = size;
@@ -2240,7 +2244,7 @@ _gnutls_proc_dhe_signature(gnutls_session_t session, uint8_t * data,
        sigsize = _gnutls_read_uint16(data);
        data += 2;
 
-       DECR_LEN(data_size, sigsize);
+       DECR_LEN_FINAL(data_size, sigsize);
        signature.data = data;
        signature.size = sigsize;
 

diff --git a/lib/gnutls_int.h b/lib/gnutls_int.h
index 785f9e6e20eb87bd5df6c177a02738b647e25ff9..c5d238d7313f0c2f61de439ac4e79a358039159d 100644 (file)
--- a/lib/gnutls_int.h
+++ b/lib/gnutls_int.h
@@ -225,6 +225,11 @@ typedef enum record_flush_t {
 #define MEMSUB(x,y) ((ssize_t)((ptrdiff_t)x-(ptrdiff_t)y))
 
 #define DECR_LEN(len, x) do { len-=x; if (len<0) {gnutls_assert(); return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;} } while (0)
+#define DECR_LEN_FINAL(len, x) do { \
+       len-=x; \
+       if (len != 0) \
+               return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH); \
+       } while (0)
 #define DECR_LENGTH_RET(len, x, RET) do { len-=x; if (len<0) {gnutls_assert(); return RET;} } while (0)
 #define DECR_LENGTH_COM(len, x, COM) do { len-=x; if (len<0) {gnutls_assert(); COM;} } while (0)