[Oneiric CVE PATCH 1/1] tools: hv: Netlink source address validation allows DoS

[Luis Henriques]

From: Tomas Hozza <thozza at redhat.com>

CVE-2012-5532

BugLink: http://bugs.launchpad.net/bugs/1084777

The source code without this patch caused hypervkvpd to exit when it processed
a spoofed Netlink packet which has been sent from an untrusted local user.
Now Netlink messages with a non-zero nl_pid source address are ignored
and a warning is printed into the syslog.

Signed-off-by: Tomas Hozza <thozza at redhat.com>
Acked-by:  K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(backported from commit 95a69adab9acfc3981c504737a2b6578e4d846ef)

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>

Conflicts:
	tools/hv/hv_kvp_daemon.c
---
 drivers/staging/hv/tools/hv_kvp_daemon.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/hv/tools/hv_kvp_daemon.c b/drivers/staging/hv/tools/hv_kvp_daemon.c
index 1468a01..6399451 100644
--- a/drivers/staging/hv/tools/hv_kvp_daemon.c
+++ b/drivers/staging/hv/tools/hv_kvp_daemon.c
@@ -387,13 +387,19 @@ int main(void)
 		len = recvfrom(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0,
 				addr_p, &addr_l);
 
-		if (len < 0 || addr.nl_pid) {
+		if (len < 0) {
 			syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
 					addr.nl_pid, errno, strerror(errno));
 			close(fd);
 			return -1;
 		}
 
+		if (addr.nl_pid) {
+			syslog(LOG_WARNING, "Received packet from untrusted pid:%u",
+					addr.nl_pid);
+			continue;
+		}
+
 		incoming_msg = (struct nlmsghdr *)kvp_recv_buffer;
 		incoming_cn_msg = (struct cn_msg *)NLMSG_DATA(incoming_msg);
 
-- 
1.8.0