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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 <>
Acked-by:  K. Y. Srinivasan <>
Signed-off-by: Greg Kroah-Hartman <>
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commit 95a69adab9acfc3981c504737a2b6578e4d846ef 1 parent aeba4a0
@thozza thozza authored gregkh committed
Showing with 7 additions and 1 deletion.
  1. +7 −1 tools/hv/hv_kvp_daemon.c
8 tools/hv/hv_kvp_daemon.c
@@ -1486,13 +1486,19 @@ 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));
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;
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