From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 25 Aug 2011 02:45:03 +0000 (-0700)
Subject: sendmmsg/sendmsg: fix unsafe user pointer access
X-Git-Tag: v3.1-rc5~12^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc909d9ddbf7778371e36a651d6e4194b1cc7d4c;p=pandora-kernel.git

sendmmsg/sendmsg: fix unsafe user pointer access

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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