Author: asomers
Date: Wed Sep 11 18:54:45 2019
New Revision: 352229
URL: https://svnweb.freebsd.org/changeset/base/352229
Log:
ping: Verify whether a datagram timestamp was actually received.
ping(8) uses SO_TIMESTAMP, which attaches a timestamp to each IP datagram at
the time it's received by the kernel. Except that occasionally it doesn't.
Add a check to see whether such a timestamp was actually set before trying
to read it. This fixes segfaults that can happen when the kernel doesn't
attach a timestamp.
The bug has always existed, but prior to r351461 it manifested as an
implausible round-trip-time, not a segfault.
Reported by: pho
MFC after: 3 days
MFC-With: 351461
Modified:
head/sbin/ping/ping.c
Modified: head/sbin/ping/ping.c
==============================================================================
--- head/sbin/ping/ping.c Wed Sep 11 18:48:26 2019 (r352228)
+++ head/sbin/ping/ping.c Wed Sep 11 18:54:45 2019 (r352229)
@@ -931,7 +931,8 @@ main(int argc, char *const *argv)
continue;
}
#ifdef SO_TIMESTAMP
- if (cmsg->cmsg_level == SOL_SOCKET &&
+ if (cmsg != NULL &&
+ cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_TIMESTAMP &&
cmsg->cmsg_len == CMSG_LEN(sizeof *tv)) {
/* Copy to avoid alignment problems: */
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