tools: hv: fix checks for origin of netlink message in hv_vss_daemon

Similar to what commit 95a69adab9acfc3981c504737a2b6578e4d846ef ("tools:
hv: Netlink source address validation allows DoS") does in
hv_kvp_daemon, improve checks for origin of netlink connector message.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 2a03d0b4e213..dc3eb1e44c8a 100644
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -186,13 +186,19 @@ int main(void)
                 len = recvfrom(fd, vss_recv_buffer, sizeof(vss_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 *)vss_recv_buffer;
 
                 if (incoming_msg->nlmsg_type != NLMSG_DONE)