diff options
authorRich Felker <>2020-05-19 19:25:42 -0400
committerRich Felker <>2020-05-19 19:25:42 -0400
commit1b4e84c56df0f8ca30f6bc05962a860f869e71df (patch)
parent5cf1ac2443ad0dba263559a3fe043d929e0e5c4c (diff)
fix return value of res_send, res_query on errors from nameserver
the internal __res_msend returns 0 on timeout without having obtained any conclusive answer, but in this case has not filled in meaningful anslen. res_send wrongly treated that as success, but returned a zero answer length. any reasonable caller would eventually end up treating that as an error when attempting to parse/validate it, but it should just be reported as an error. alternatively we could return the last-received inconclusive answer (typically servfail), but doing so would require internal changes in __res_msend. this may be considered later.
1 files changed, 1 insertions, 1 deletions
diff --git a/src/network/res_send.c b/src/network/res_send.c
index b9cea0bf..ee4abf1f 100644
--- a/src/network/res_send.c
+++ b/src/network/res_send.c
@@ -3,7 +3,7 @@
int __res_send(const unsigned char *msg, int msglen, unsigned char *answer, int anslen)
int r = __res_msend(1, &msg, &msglen, &answer, &anslen, anslen);
- return r<0 ? r : anslen;
+ return r<0 || !anslen ? -1 : anslen;
weak_alias(__res_send, res_send);