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SubjectRE: [PATCH] tools: hv: Netlink source address validation allows DoS
Date


> -----Original Message-----
> From: Tomas Hozza [mailto:thozza@redhat.com]
> Sent: Thursday, November 08, 2012 4:53 AM
> To: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com;
> jasowang@redhat.com; KY Srinivasan
> Cc: Tomas Hozza
> Subject: [PATCH] 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>

> ---
> 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 13c2a14..c1d9102 100755
> --- a/tools/hv/hv_kvp_daemon.c
> +++ b/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));
> 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
>
>




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