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TLS13: add length validation for Pre-Shared Key Exchange Modes

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Add length validation for expert info and add a reference.

Change-Id: Id21916b11ca924b517ea45294798692a010e7541
Reviewed-on: https://code.wireshark.org/review/20009
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
This commit is contained in:
Peter Wu 2017-02-08 00:01:13 +01:00
parent 738f4b72cc
commit 0e08518915
1 changed files with 12 additions and 17 deletions
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29
epan/dissectors/packet-ssl-utils.c
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@ -6193,34 +6193,29 @@ ssl_dissect_hnd_hello_ext_cookie(ssl_common_dissect_t *hf, tvbuff_t *tvb,
}
static gint
ssl_dissect_hnd_hello_ext_psk_key_exchange_modes(ssl_common_dissect_t *hf, tvbuff_t *tvb,
ssl_dissect_hnd_hello_ext_psk_key_exchange_modes(ssl_common_dissect_t *hf, tvbuff_t *tvb, packet_info *pinfo,
proto_tree *tree, guint32 offset, guint32 offset_end)
{
/*
/* https://tools.ietf.org/html/draft-ietf-tls-tls13-18#section-4.2.7
* enum { psk_ke(0), psk_dhe_ke(1), (255) } PskKeyExchangeMode;
*
* struct {
* PskKeyExchangeMode ke_modes<1..255>;
* } PskKeyExchangeModes;
*/
guint32 ke_modes_length, i;
guint32 ke_modes_length, next_offset;
if (offset_end - offset < 1) {
/* XXX expert info, there must be at least 1 ke mode */
return offset;
/* PskKeyExchangeMode ke_modes<1..255> */
if (!ssl_add_vector(hf, tvb, pinfo, tree, offset, offset_end, &ke_modes_length,
hf->hf.hs_ext_psk_ke_modes_len, 1, 255)) {
return offset_end;
}
offset++;
next_offset = offset + ke_modes_length;
proto_tree_add_item_ret_uint(tree, hf->hf.hs_ext_psk_ke_modes_len, tvb, offset, 1, ENC_NA, &ke_modes_length);
offset += 1;
if (ke_modes_length > offset_end - offset) {
ke_modes_length = offset_end - offset;
/* XXX expert info: size too large */
}
for (i = 0; i < ke_modes_length; i++) {
while (offset < next_offset) {
proto_tree_add_item(tree, hf->hf.hs_ext_psk_ke_mode, tvb, offset, 1, ENC_NA);
offset += 1;
offset++;
}
return offset;
@ -7517,7 +7512,7 @@ ssl_dissect_hnd_hello_ext(ssl_common_dissect_t *hf, tvbuff_t *tvb, proto_tree *t
offset = ssl_dissect_hnd_hello_ext_cookie(hf, tvb, pinfo, ext_tree, offset, next_offset);
break;
case SSL_HND_HELLO_EXT_PSK_KEY_EXCHANGE_MODES:
offset = ssl_dissect_hnd_hello_ext_psk_key_exchange_modes(hf, tvb, ext_tree, offset, next_offset);
offset = ssl_dissect_hnd_hello_ext_psk_key_exchange_modes(hf, tvb, pinfo, ext_tree, offset, next_offset);
break;
case SSL_HND_HELLO_EXT_DRAFT_VERSION_TLS13:
proto_tree_add_item(ext_tree, hf->hf.hs_ext_draft_version_tls13,