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 <[email protected]>
---
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
> -----Original Message-----
> From: Tomas Hozza [mailto:[email protected]]
> Sent: Thursday, November 08, 2012 4:53 AM
> To: [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; 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 <[email protected]>
Acked-by: K. Y. Srinivasan <[email protected]>
> ---
> 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
>
>
On Thu, Nov 08, 2012 at 10:53:29AM +0100, Tomas Hozza wrote:
> 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 <[email protected]>
> Acked-by: K. Y. Srinivasan <[email protected]>
> ---
> 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
Why are you setting a .c file to executable permissions? Something is
really wrong here...
greg k-h
----- Original Message -----
> On Thu, Nov 08, 2012 at 10:53:29AM +0100, Tomas Hozza wrote:
> > 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 <[email protected]>
> > Acked-by: K. Y. Srinivasan <[email protected]>
> > ---
> > 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
>
> Why are you setting a .c file to executable permissions? Something
> is really wrong here...
I'm sorry, this is a mistake and unfortunately I missed it.
Permissions should be 0644. Will check more carefully next time.
Regards,
Tomas Hozza
Hello.
Just FYI there is already a CVE name CVE-2012-5532 for this issue.
Regards,
Tomas Hozza
----- Original Message -----
> On Thu, Nov 08, 2012 at 10:53:29AM +0100, Tomas Hozza wrote:
> > 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 <[email protected]>
> > Acked-by: K. Y. Srinivasan <[email protected]>
> > ---
> > 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
>
> Why are you setting a .c file to executable permissions? Something
> is
> really wrong here...
>
> greg k-h
>