Commit f843ee6d authored Mar 23, 2017 by Andy Whitcroft Committed by Linus Torvalds Mar 29, 2017

xfrm_user: validate XFRM_MSG_NEWAE incoming ESN size harder



Kees Cook has pointed out that xfrm_replay_state_esn_len() is subject to
wrapping issues.  To ensure we are correctly ensuring that the two ESN
structures are the same size compare both the overall size as reported
by xfrm_replay_state_esn_len() and the internal length are the same.

CVE-2017-7184
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 677e806d

net/xfrm/xfrm_user.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -412,7 +412,11 @@ static inline int xfrm_replay_verify_len(struct xfrm_replay_state_esn *replay_es
		up = nla_data(rp);
		ulen = xfrm_replay_state_esn_len(up);

		if (nla_len(rp) < ulen \|\| xfrm_replay_state_esn_len(replay_esn) != ulen)
		/* Check the overall length and the internal bitmap length to avoid
		* potential overflow. */
		if (nla_len(rp) < ulen \|\|
		xfrm_replay_state_esn_len(replay_esn) != ulen \|\|
		replay_esn->bmp_len != up->bmp_len)
		return -EINVAL;

		if (up->replay_window > up->bmp_len * sizeof(__u32) * 8)

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