From: Topi Miettinen <toiwoton@gmail.com>
Date: Sun, 18 Jan 2015 14:01:25 +0000 (+0200)
Subject: timesyncd: consider too long packets as invalid
X-Git-Tag: v219~452
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=43fcd650e5cb0836cfc9f667ed74b3bc0283a81c

timesyncd: consider too long packets as invalid

If the received NTP message from server didn't fit to our buffer, either
it is doing something nasty or we don't know the protocol. Consider the
packet as invalid.

(David: add parantheses around conditional)
---

diff --git a/src/timesync/timesyncd-manager.c b/src/timesync/timesyncd-manager.c
index 117ea8c98..bc3566248 100644
--- a/src/timesync/timesyncd-manager.c
+++ b/src/timesync/timesyncd-manager.c
@@ -525,7 +525,8 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                 return manager_connect(m);
         }
 
-        if (iov.iov_len < sizeof(struct ntp_msg)) {
+        /* Too short or too long packet? */
+        if (iov.iov_len < sizeof(struct ntp_msg) || (msghdr.msg_flags & MSG_TRUNC)) {
                 log_warning("Invalid response from server. Disconnecting.");
                 return manager_connect(m);
         }