diff options
| author | Peter Wu <peter@lekensteyn.nl> | 2018-05-13 00:27:03 +0200 |
|---|---|---|
| committer | Anders Broman <a.broman58@gmail.com> | 2018-05-13 12:02:37 +0000 |
| commit | b1e0cb01b33d1e6798e5f3b2f649b2359874c622 (patch) | |
| tree | 7af369c6d0ff980275fbc4e48492135ee428c0dd | |
| parent | 5b385f3a4dd1a82cae6d62e5563d1d7d9a0a80cf (diff) | |
coap: fix use-after-free of "coinfo->ctype_str"
A use-after-free is possible through the following path:
// returns wmem_packet_scope() memory
coinfo->ctype_str = val_to_str(coinfo->ctype_value, vals_ctype, "Unknown Type %u");
// leaks packet scoped memory into conversation
coap_trans = wmem_new0(wmem_file_scope(), coap_transaction);
coap_trans->req_ctype_str = coinfo->ctype_str; // <-- oops
// next packet: use-after-free of packet scoped memory
coinfo->ctype_str = coap_trans->req_ctype_str;
This could be fixed by duplicating "ctype_str" with wmem_file_scope, but
since all "ctype_str" strings are constant, make the problematic
"ctype_str" assignment also constant for unknown types (the numeric type
is also stored in "ctype_value" if necessary).
Change-Id: I6249e076fa282bbe0982b8c709788e27f6fdf86e
Fixes: v2.9.0rc0-317-g46fcf452ac ("coap: Store ctype values in transaction tracking")
Link: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8196
Reviewed-on: https://code.wireshark.org/review/27477
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
| -rw-r--r-- | epan/dissectors/packet-coap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/epan/dissectors/packet-coap.c b/epan/dissectors/packet-coap.c index aa404ae0b4..ae08aba66c 100644 --- a/epan/dissectors/packet-coap.c +++ b/epan/dissectors/packet-coap.c @@ -574,7 +574,7 @@ dissect_coap_opt_ctype(tvbuff_t *tvb, proto_item *head_item, proto_tree *subtree coinfo->ctype_value = coap_get_opt_uint(tvb, offset, opt_length); } - coinfo->ctype_str = val_to_str(coinfo->ctype_value, vals_ctype, "Unknown Type %u"); + coinfo->ctype_str = val_to_str_const(coinfo->ctype_value, vals_ctype, "Unknown Type"); proto_tree_add_string(subtree, hf, tvb, offset, opt_length, coinfo->ctype_str); |