From edc447f2f3134d81575f16b1701fc802161f153f Mon Sep 17 00:00:00 2001 From: Jiung Date: Mon, 7 Aug 2017 13:56:32 +0900 Subject: ares_parse_naptr_reply: check sufficient data Description: https://github.com/c-ares/c-ares/commit/9478908a490a6bf009ba58d81de8c1d06d50a117 ares_parse_naptr_reply: check sufficient data Check that there is enough data for the required elements of an NAPTR record (2 int16, 3 bytes for string lengths) before processing a record. https://github.com/c-ares/c-ares/commit/18ea99693d63f957ecb670045adbd2c1da8a4641 ares_parse_naptr_reply: make buffer length check more accurate 9478908 introduced a length check for records parsed by `ares_parse_naptr_reply()`. However, that function is designed to parse replies which also contain non-NAPTR records; for A records, the `rr_len > 7` check will fail as there are only 4 bytes of payload. In particular, parsing ANY replies for NAPTR records was broken by that patch. Fix that by moving the check into the case in which it is already known that the record is a NAPTR record. Change-Id: I7ca730c0367ff1cc416e67a3a99021438d237666 --- ares_parse_naptr_reply.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/ares_parse_naptr_reply.c b/ares_parse_naptr_reply.c index 11634df..0e37b02 100644 --- a/ares_parse_naptr_reply.c +++ b/ares_parse_naptr_reply.c @@ -116,6 +116,13 @@ ares_parse_naptr_reply (const unsigned char *abuf, int alen, { /* parse the NAPTR record itself */ + /* RR must contain at least 7 bytes = 2 x int16 + 3 x name */ + if (rr_len < 7) + { + status = ARES_EBADRESP; + break; + } + /* Allocate storage for this NAPTR answer appending it to the list */ naptr_curr = ares_malloc_data(ARES_DATATYPE_NAPTR_REPLY); if (!naptr_curr) -- cgit v1.2.3