Hi.
After discussion with KY Srinivasan and Olaf Hering I'm sending you
a patch for the HyperV KVP daemon distributed in linux kernel
"tools/hv/hv_kvp_daemon.c".
There is an issue in the current daemon source causing hyperv kvp daemon
to exit when it processes a spoofed Netlink packet which has been sent
from an untrusted local user.
This patch is fixing this, so now the Netlink messages with a non-zero
nl_pid source address are just ignored.
Regards,
Tomas Hozza
Associate Software Engineer
BaseOS - Brno, CZ
> -----Original Message-----
> From: Tomas Hozza [mailto:[email protected]]
> Sent: Tuesday, November 06, 2012 10:21 AM
> To: [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]
> Cc: Olaf Hering; KY Srinivasan
> Subject: [PATCH] tools/hv/hv_kvp_daemon.c: Netlink source address validation
> allows DoS
>
> Hi.
>
> After discussion with KY Srinivasan and Olaf Hering I'm sending you
> a patch for the HyperV KVP daemon distributed in linux kernel
> "tools/hv/hv_kvp_daemon.c".
>
> There is an issue in the current daemon source causing hyperv kvp daemon
> to exit when it processes a spoofed Netlink packet which has been sent
> from an untrusted local user.
>
> This patch is fixing this, so now the Netlink messages with a non-zero
> nl_pid source address are just ignored.
You don't want to send the patch as an attachment. Please send the patch
as part of the mail.
Regards,
K. Y
>
>
> Regards,
>
> Tomas Hozza
> Associate Software Engineer
> BaseOS - Brno, CZ
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>From 6199072f8131056efce208f04e6985d1f9968d8e Mon Sep 17 00:00:00 2001
From: Tomas Hozza <[email protected]>
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
----- Original Message -----
>
>
> > -----Original Message-----
> > From: Tomas Hozza [mailto:[email protected]]
> > Sent: Tuesday, November 06, 2012 10:21 AM
> > To: [email protected]; [email protected];
> > [email protected]; [email protected];
> > [email protected]
> > Cc: Olaf Hering; KY Srinivasan
> > Subject: [PATCH] tools/hv/hv_kvp_daemon.c: Netlink source address
> > validation
> > allows DoS
> >
> > Hi.
> >
> > After discussion with KY Srinivasan and Olaf Hering I'm sending you
> > a patch for the HyperV KVP daemon distributed in linux kernel
> > "tools/hv/hv_kvp_daemon.c".
> >
> > There is an issue in the current daemon source causing hyperv kvp
> > daemon
> > to exit when it processes a spoofed Netlink packet which has been
> > sent
> > from an untrusted local user.
> >
> > This patch is fixing this, so now the Netlink messages with a
> > non-zero
> > nl_pid source address are just ignored.
>
> You don't want to send the patch as an attachment. Please send the
> patch
> as part of the mail.
>
> Regards,
>
> K. Y
> >
> >
> > Regards,
> >
> > Tomas Hozza
> > Associate Software Engineer
> > BaseOS - Brno, CZ
>
> -----Original Message-----
> From: Tomas Hozza [mailto:[email protected]]
> Sent: Tuesday, November 06, 2012 2:55 PM
> To: KY Srinivasan
> Cc: Olaf Hering; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH] tools/hv/hv_kvp_daemon.c: Netlink source address
> validation allows DoS
>
> From 6199072f8131056efce208f04e6985d1f9968d8e Mon Sep 17 00:00:00 2001
> From: Tomas Hozza <[email protected]>
> 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.
Thomas,
You need a Signed-off-by line. Please refer to the documentation on how to submit a patch.
Regards,
K. Y
> ---
> 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
>
> ----- Original Message -----
> >
> >
> > > -----Original Message-----
> > > From: Tomas Hozza [mailto:[email protected]]
> > > Sent: Tuesday, November 06, 2012 10:21 AM
> > > To: [email protected]; [email protected];
> > > [email protected]; [email protected];
> > > [email protected]
> > > Cc: Olaf Hering; KY Srinivasan
> > > Subject: [PATCH] tools/hv/hv_kvp_daemon.c: Netlink source address
> > > validation
> > > allows DoS
> > >
> > > Hi.
> > >
> > > After discussion with KY Srinivasan and Olaf Hering I'm sending you
> > > a patch for the HyperV KVP daemon distributed in linux kernel
> > > "tools/hv/hv_kvp_daemon.c".
> > >
> > > There is an issue in the current daemon source causing hyperv kvp
> > > daemon
> > > to exit when it processes a spoofed Netlink packet which has been
> > > sent
> > > from an untrusted local user.
> > >
> > > This patch is fixing this, so now the Netlink messages with a
> > > non-zero
> > > nl_pid source address are just ignored.
> >
> > You don't want to send the patch as an attachment. Please send the
> > patch
> > as part of the mail.
> >
> > Regards,
> >
> > K. Y
> > >
> > >
> > > Regards,
> > >
> > > Tomas Hozza
> > > Associate Software Engineer
> > > BaseOS - Brno, CZ
> >
>
????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay? ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?