[libvirt] [PATCH] util: fix missing broadcast address in bridge and tap device IP addresses

Laine Stump laine at laine.org
Thu Jun 16 17:29:40 UTC 2016


Commit b3d069872ce53eb added peer address setting to the low level
virNetDevSetIPAddress() function, but ended up causing a segfault in
cases where the caller passed NULL for peer address.

Commit a3510e33d33e52c fixed the segfault, but managed to cause us to
skip setting the broadcast address when setting an interface's IP
address if the peer address was NULL. The result is that the broadcast
address is 0.0.0.0 for all libvirt-created bridges (and for now also
in interfaces in lxc containers with IP addresses set by libvirt).

This was reported on the mailing list:

  https://www.redhat.com/archives/libvir-list/2016-June/msg00027.html

but I was too busy to investigate at the time. I found it by accident
today while refactoring virNetDevSetIPAddress(). Since this regression
is present in the 1.3.5 release, I'm sending the bugfix as a separate
simpler patch from my larger refactoring patchset.
---

 src/util/virnetdev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
index 925b41f..5a4ccc6 100644
--- a/src/util/virnetdev.c
+++ b/src/util/virnetdev.c
@@ -1129,7 +1129,8 @@ int virNetDevSetIPAddress(const char *ifname,
     unsigned int recvbuflen;
 
     /* The caller needs to provide a correct address */
-    if (VIR_SOCKET_ADDR_FAMILY(addr) == AF_INET && peer && !VIR_SOCKET_ADDR_VALID(peer)) {
+    if (VIR_SOCKET_ADDR_FAMILY(addr) == AF_INET &&
+        !(peer && VIR_SOCKET_ADDR_VALID(peer))) {
         /* compute a broadcast address if this is IPv4 */
         if (VIR_ALLOC(broadcast) < 0)
             return -1;
-- 
2.4.11




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