* [PATCH 3.1-rc3/3.0.3] sendmmsg/sendmsg: fix unsafe user pointer access
@ 2011-08-25 2:39 Mathieu Desnoyers
2011-08-25 2:45 ` David Miller
0 siblings, 1 reply; 4+ messages in thread
From: Mathieu Desnoyers @ 2011-08-25 2:39 UTC (permalink / raw)
To: Mathieu Desnoyers, linux-kernel
Cc: David Goulet, Tetsuo Handa, Anton Blanchard, David S. Miller,
stable
Dereferencing a user pointer directly from kernel-space without going
through the copy_from_user family of functions is a bad idea. Two of
such usages can be found in the sendmsg code path called from sendmmsg,
added by
commit c71d8ebe7a4496fb7231151cb70a6baa0cb56f9a upstream.
commit 5b47b8038f183b44d2d8ff1c7d11a5c1be706b34 in the 3.0-stable tree.
Usages are performed through memcmp() and memcpy() directly. Fix those
by using the already copied msg_sys structure instead of the __user *msg
structure. Note that msg_sys can be set to NULL by verify_compat_iovec()
or verify_iovec(), which requires additional NULL pointer checks.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@ev0ke.net>
CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
CC: Anton Blanchard <anton@samba.org>
CC: David S. Miller <davem@davemloft.net>
CC: stable <stable@kernel.org>
---
net/socket.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
Index: linux-2.6-lttng/net/socket.c
===================================================================
--- linux-2.6-lttng.orig/net/socket.c
+++ linux-2.6-lttng/net/socket.c
@@ -1965,8 +1965,9 @@ static int __sys_sendmsg(struct socket *
* used_address->name_len is initialized to UINT_MAX so that the first
* destination address never matches.
*/
- if (used_address && used_address->name_len == msg_sys->msg_namelen &&
- !memcmp(&used_address->name, msg->msg_name,
+ if (used_address && msg_sys->msg_name &&
+ used_address->name_len == msg_sys->msg_namelen &&
+ !memcmp(&used_address->name, msg_sys->msg_name,
used_address->name_len)) {
err = sock_sendmsg_nosec(sock, msg_sys, total_len);
goto out_freectl;
@@ -1978,8 +1979,9 @@ static int __sys_sendmsg(struct socket *
*/
if (used_address && err >= 0) {
used_address->name_len = msg_sys->msg_namelen;
- memcpy(&used_address->name, msg->msg_name,
- used_address->name_len);
+ if (msg_sys->msg_name)
+ memcpy(&used_address->name, msg_sys->msg_name,
+ used_address->name_len);
}
out_freectl:
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 3.1-rc3/3.0.3] sendmmsg/sendmsg: fix unsafe user pointer access
2011-08-25 2:39 [PATCH 3.1-rc3/3.0.3] sendmmsg/sendmsg: fix unsafe user pointer access Mathieu Desnoyers
@ 2011-08-25 2:45 ` David Miller
2011-08-25 2:46 ` David Miller
0 siblings, 1 reply; 4+ messages in thread
From: David Miller @ 2011-08-25 2:45 UTC (permalink / raw)
To: mathieu.desnoyers; +Cc: linux-kernel, dgoulet, penguin-kernel, anton, stable
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 24 Aug 2011 22:39:40 -0400
> Dereferencing a user pointer directly from kernel-space without going
> through the copy_from_user family of functions is a bad idea. Two of
> such usages can be found in the sendmsg code path called from sendmmsg,
> added by
>
> commit c71d8ebe7a4496fb7231151cb70a6baa0cb56f9a upstream.
> commit 5b47b8038f183b44d2d8ff1c7d11a5c1be706b34 in the 3.0-stable tree.
>
> Usages are performed through memcmp() and memcpy() directly. Fix those
> by using the already copied msg_sys structure instead of the __user *msg
> structure. Note that msg_sys can be set to NULL by verify_compat_iovec()
> or verify_iovec(), which requires additional NULL pointer checks.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Signed-off-by: David Goulet <dgoulet@ev0ke.net>
> CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> CC: Anton Blanchard <anton@samba.org>
> CC: David S. Miller <davem@davemloft.net>
> CC: stable <stable@kernel.org>
Applied, thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2011-08-25 2:39 [PATCH 3.1-rc3/3.0.3] sendmmsg/sendmsg: fix unsafe user pointer access Mathieu Desnoyers
2011-08-25 2:45 ` David Miller
2011-08-25 2:46 ` David Miller
2011-08-25 2:48 ` Mathieu Desnoyers
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