This is a note to let you know that I've just added the patch titled
xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL replay_window
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfrm_user-validate-xfrm_msg_newae-xfrma_replay_esn_val-replay_window.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 677e806da4d916052585301785d847c3b3e6186a Mon Sep 17 00:00:00 2001
From: Andy Whitcroft <apw@xxxxxxxxxxxxx>
Date: Wed, 22 Mar 2017 07:29:31 +0000
Subject: xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL replay_window
From: Andy Whitcroft <apw@xxxxxxxxxxxxx>
commit 677e806da4d916052585301785d847c3b3e6186a upstream.
When a new xfrm state is created during an XFRM_MSG_NEWSA call we
validate the user supplied replay_esn to ensure that the size is valid
and to ensure that the replay_window size is within the allocated
buffer. However later it is possible to update this replay_esn via a
XFRM_MSG_NEWAE call. There we again validate the size of the supplied
buffer matches the existing state and if so inject the contents. We do
not at this point check that the replay_window is within the allocated
memory. This leads to out-of-bounds reads and writes triggered by
netlink packets. This leads to memory corruption and the potential for
priviledge escalation.
We already attempt to validate the incoming replay information in
xfrm_new_ae() via xfrm_replay_verify_len(). This confirms that the user
is not trying to change the size of the replay state buffer which
includes the replay_esn. It however does not check the replay_window
remains within that buffer. Add validation of the contained
replay_window.
CVE-2017-7184
Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxxx>
Acked-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/xfrm/xfrm_user.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -415,6 +415,9 @@ static inline int xfrm_replay_verify_len
if (nla_len(rp) < ulen || xfrm_replay_state_esn_len(replay_esn) != ulen)
return -EINVAL;
+ if (up->replay_window > up->bmp_len * sizeof(__u32) * 8)
+ return -EINVAL;
+
return 0;
}
Patches currently in stable-queue which might be from apw@xxxxxxxxxxxxx are
queue-4.9/xfrm_user-validate-xfrm_msg_newae-incoming-esn-size-harder.patch
queue-4.9/xfrm_user-validate-xfrm_msg_newae-xfrma_replay_esn_val-replay_window.patch