From 6199072f8131056efce208f04e6985d1f9968d8e Mon Sep 17 00:00:00 2001 From: Tomas Hozza Date: Mon, 5 Nov 2012 10:08:16 +0100 Subject: [PATCH] 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. Netlink messages with a non-zero nl_pid source address should just be ignored. --- tools/hv/hv_kvp_daemon.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index 3ea3af2..7d74497 100755 --- a/tools/hv/hv_kvp_daemon.c +++ b/tools/hv/hv_kvp_daemon.c @@ -1478,13 +1478,19 @@ 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; -- 1.7.11.7