diff options
| author |   eric <eric@openbsd.org> | 2017-02-18 22:25:13 +0000 |
|---|---|---|
| committer | eric <eric@openbsd.org> | 2017-02-18 22:25:13 +0000 |
| commit | 193137085330df8d6effbb7aaf3b463669d97084 (patch) | |
| tree | 32ed8fd3a400ec14441288ba5d0a429cb2452206 | |
| parent | Add NULL tests to wrterror() to avoid a NULL deref when called from (diff) | |
| download | wireguard-openbsd-193137085330df8d6effbb7aaf3b463669d97084.tar.xz wireguard-openbsd-193137085330df8d6effbb7aaf3b463669d97084.zip | |
Use more specific error codes for invalid packets.
In particular, truncated packets without the TC flag set (non-compliant
server sending too large packets) now fail with EOVERFLOW instead of EINVAL,
so the TCP fallback mechanism can work.
feedback and ok krw@ jca@ benno@
| -rw-r--r-- | lib/libc/asr/res_send_async.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/libc/asr/res_send_async.c b/lib/libc/asr/res_send_async.c index b75253c101e..4be5731c8e0 100644 --- a/lib/libc/asr/res_send_async.c +++ b/lib/libc/asr/res_send_async.c @@ -1,4 +1,4 @@ -/* $OpenBSD: res_send_async.c,v 1.31 2017/02/18 19:23:05 jca Exp $ */ +/* $OpenBSD: res_send_async.c,v 1.32 2017/02/18 22:25:13 eric Exp $ */ /* * Copyright (c) 2012 Eric Faurot <eric@openbsd.org> * @@ -715,7 +715,8 @@ validate_packet(struct asr_query *as) } /* Check for truncation */ - if (h.flags & TC_MASK) { + if (h.flags & TC_MASK && !(as->as_ctx->ac_options & RES_IGNTC)) { + DPRINT("truncated\n"); errno = EOVERFLOW; return (-1); } @@ -724,8 +725,18 @@ validate_packet(struct asr_query *as) for (r = h.ancount + h.nscount + h.arcount; r; r--) _asr_unpack_rr(&p, &rr); - if (p.err || (p.offset != as->as.dns.ibuflen)) - goto inval; + /* Report any error found when unpacking the RRs. */ + if (p.err) { + DPRINT("unpack: %s\n", strerror(p.err)); + errno = p.err; + return (-1); + } + + if (p.offset != as->as.dns.ibuflen) { + DPRINT("trailing garbage\n"); + errno = EMSGSIZE; + return (-1); + } return (0); |