deps: cherry-pick 18ea996 from c-ares upstream

Original commit message:

    ares_parse_naptr_reply: make buffer length check more accurate

    9478908a490a6bf009ba58d81de8c1d06d50a117 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.

Ref: https://github.com/c-ares/c-ares/commit/18ea99693d63f957ecb670045adbd2c1da8a4641
PR-URL: https://github.com/nodejs/node/pull/13883
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/deps/cares/src/ares_parse_naptr_reply.c b/deps/cares/src/ares_parse_naptr_reply.c
index 717d355778..a14c226a9e 100644
--- a/deps/cares/src/ares_parse_naptr_reply.c
+++ b/deps/cares/src/ares_parse_naptr_reply.c
@@ -110,18 +110,19 @@ ares_parse_naptr_reply (const unsigned char *abuf, int alen,
           status = ARES_EBADRESP;
           break;
         }
-      /* RR must contain at least 7 bytes = 2 x int16 + 3 x name */
-      if (rr_len < 7)
-        {
-          status = ARES_EBADRESP;
-          break;
-        }
 
       /* Check if we are really looking at a NAPTR record */
       if (rr_class == C_IN && rr_type == T_NAPTR)
         {
           /* 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)