virarptable: End parsing earlier in case of NLMSG_DONE

Check for the last multipart message right as the first thing.  The
presumption probably was that the last message might still contain a
payload we want to parse.  However that cannot be true since that would
have to be a type RTM_NEWNEIGH.  This was not caught because older
kernels were note sending NLMSG_DONE and probably relied on the fact
that the parsing just stops after all the messages are walked through,
which the NLMSG_OK macro successfully did.

Resolves: https://issues.redhat.com/browse/RHEL-52449
Resolves: https://bugzilla.redhat.com/2302245
Fixes: a176d67cdfaf5b8237a7e3a80d8be0e6bdf2d8fd
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Laine Stump <laine@redhat.com>

diff --git a/src/util/virarptable.c b/src/util/virarptable.c
index 45ee76766fe7924e35f2643d234817f01034b19c..20d11f97b0b78b53ea532e8b6bde215810af4436 100644 (file)
--- a/src/util/virarptable.c
+++ b/src/util/virarptable.c
@@ -83,6 +83,9 @@ virArpTableGet(void)
         struct ndmsg *r = NLMSG_DATA(nh);
         void *addr;
 
+        if (nh->nlmsg_type == NLMSG_DONE)
+            break;
+
         if (nh->nlmsg_len < NLMSG_SPACE(sizeof(*r))) {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("wrong nlmsg len"));
@@ -97,9 +100,6 @@ virArpTableGet(void)
             (!(r->ndm_state == NUD_STALE || r->ndm_state == NUD_REACHABLE)))
             continue;
 
-        if (nh->nlmsg_type == NLMSG_DONE)
-            return table;
-
         VIR_WARNINGS_NO_CAST_ALIGN
         parse_rtattr(tb, NDA_MAX, NDA_RTA(r), NLMSG_PAYLOAD(nh, sizeof(*r)));
         VIR_WARNINGS_RESET