Patchwork [060/150] tools: hv: Netlink source address validation allows DoS

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Submitter Luis Henriques
Date March 26, 2013, 3:19 p.m.
Message ID <1364311249-14454-61-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/231326/
State New
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Luis Henriques - March 26, 2013, 3:19 p.m.
3.5.7.9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomas Hozza <thozza@redhat.com>

commit 95a69adab9acfc3981c504737a2b6578e4d846ef upstream.

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@redhat.com>
Acked-by:  K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 tools/hv/hv_kvp_daemon.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Patch

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 2984ffb..60a8e29 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -727,13 +727,19 @@  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);
 		hv_msg = (struct hv_kvp_msg *)incoming_cn_msg->data;