tools: hv: Netlink source address validation allows DoS
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>
diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 13c2a14..c1d9102 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -1486,13 +1486,19 @@
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;