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ALPN and SNI Extension parsing improvements

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SNI will not have more than one type, only one entry in the list per
type and therefore no need to loop.
ALPN error checks improved.
This commit is contained in:
Sean Parkinson
2019-06-28 15:52:51 +10:00
parent f51a8fffde
commit 1592d6f856
1 changed files with 55 additions and 57 deletions
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112
src/tls.c
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@ -1530,6 +1530,9 @@ static int TLSX_ALPN_ParseAndSet(WOLFSSL *ssl, byte *input, word16 length,
ato16(input, &size);
offset += OPAQUE16_LEN;
if (size == 0)
return BUFFER_ERROR;
extension = TLSX_Find(ssl->extensions, TLSX_APPLICATION_LAYER_PROTOCOL);
if (extension == NULL)
extension = TLSX_Find(ssl->ctx->extensions,
@ -1579,7 +1582,7 @@ static int TLSX_ALPN_ParseAndSet(WOLFSSL *ssl, byte *input, word16 length,
for (size = 0; offset < length; offset += size) {
size = input[offset++];
if (offset + size > length)
if (offset + size > length || size == 0)
return BUFFER_ERROR;
if (isRequest) {
@ -1898,6 +1901,10 @@ static int TLSX_SNI_Parse(WOLFSSL* ssl, byte* input, word16 length,
word16 size = 0;
word16 offset = 0;
int cacheOnly = 0;
SNI *sni = NULL;
byte type;
int matchStat;
byte matched;
#endif
TLSX *extension = TLSX_Find(ssl->extensions, TLSX_SERVER_NAME);
@ -1951,73 +1958,64 @@ static int TLSX_SNI_Parse(WOLFSSL* ssl, byte* input, word16 length,
offset += OPAQUE16_LEN;
/* validating sni list length */
if (length != OPAQUE16_LEN + size)
if (length != OPAQUE16_LEN + size || size == 0)
return BUFFER_ERROR;
for (size = 0; offset < length; offset += size) {
SNI *sni = NULL;
byte type = input[offset++];
/* SNI was badly specified and only one type is now recognized and allowed.
* Only one SNI value per type (RFC6066), so, no loop. */
type = input[offset++];
if (type != WOLFSSL_SNI_HOST_NAME)
return BUFFER_ERROR;
if (offset + OPAQUE16_LEN > length)
return BUFFER_ERROR;
if (offset + OPAQUE16_LEN > length)
return BUFFER_ERROR;
ato16(input + offset, &size);
offset += OPAQUE16_LEN;
ato16(input + offset, &size);
offset += OPAQUE16_LEN;
if (offset + size != length || size == 0)
return BUFFER_ERROR;
if (offset + size > length)
return BUFFER_ERROR;
if (!cacheOnly && !(sni = TLSX_SNI_Find((SNI*)extension->data, type)))
continue; /* not using this type of SNI. */
switch(type) {
case WOLFSSL_SNI_HOST_NAME: {
int matchStat;
byte matched;
if (!cacheOnly && !(sni = TLSX_SNI_Find((SNI*)extension->data, type)))
return 0; /* not using this type of SNI. */
#ifdef WOLFSSL_TLS13
/* Don't process the second ClientHello SNI extension if there
* was problems with the first.
*/
if (!cacheOnly && sni->status != 0)
break;
/* Don't process the second ClientHello SNI extension if there
* was problems with the first.
*/
if (!cacheOnly && sni->status != 0)
return 0;
#endif
matched = cacheOnly ||
((XSTRLEN(sni->data.host_name) == size) &&
(XSTRNCMP(sni->data.host_name,
(const char*)input + offset, size) == 0));
matched = cacheOnly || (XSTRLEN(sni->data.host_name) == size &&
XSTRNCMP(sni->data.host_name, (const char*)input + offset, size) == 0);
if (matched || sni->options & WOLFSSL_SNI_ANSWER_ON_MISMATCH) {
int r = TLSX_UseSNI(&ssl->extensions,
type, input + offset, size, ssl->heap);
if (matched || sni->options & WOLFSSL_SNI_ANSWER_ON_MISMATCH) {
int r = TLSX_UseSNI(&ssl->extensions, type, input + offset, size,
ssl->heap);
if (r != WOLFSSL_SUCCESS)
return r; /* throws error. */
if (r != WOLFSSL_SUCCESS)
return r; /* throws error. */
if(cacheOnly) {
WOLFSSL_MSG("Forcing storage of SNI, Fake match");
matchStat = WOLFSSL_SNI_FORCE_KEEP;
} else if(matched) {
WOLFSSL_MSG("SNI did match!");
matchStat = WOLFSSL_SNI_REAL_MATCH;
} else {
WOLFSSL_MSG("fake SNI match from ANSWER_ON_MISMATCH");
matchStat = WOLFSSL_SNI_FAKE_MATCH;
}
TLSX_SNI_SetStatus(ssl->extensions, type, (byte)matchStat);
if(!cacheOnly)
TLSX_SetResponse(ssl, TLSX_SERVER_NAME);
} else if (!(sni->options & WOLFSSL_SNI_CONTINUE_ON_MISMATCH)) {
SendAlert(ssl, alert_fatal, unrecognized_name);
return UNKNOWN_SNI_HOST_NAME_E;
}
break;
}
if (cacheOnly) {
WOLFSSL_MSG("Forcing storage of SNI, Fake match");
matchStat = WOLFSSL_SNI_FORCE_KEEP;
}
else if (matched) {
WOLFSSL_MSG("SNI did match!");
matchStat = WOLFSSL_SNI_REAL_MATCH;
}
else {
WOLFSSL_MSG("fake SNI match from ANSWER_ON_MISMATCH");
matchStat = WOLFSSL_SNI_FAKE_MATCH;
}
TLSX_SNI_SetStatus(ssl->extensions, type, (byte)matchStat);
if(!cacheOnly)
TLSX_SetResponse(ssl, TLSX_SERVER_NAME);
}
else if (!(sni->options & WOLFSSL_SNI_CONTINUE_ON_MISMATCH)) {
SendAlert(ssl, alert_fatal, unrecognized_name);
return UNKNOWN_SNI_HOST_NAME_E;
}
#else
(void)input;