From f843ee6dd019bcece3e74e76ad9df0155655d0df Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Thu, 23 Mar 2017 07:45:44 +0000 Subject: [PATCH] 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 Acked-by: Steffen Klassert Signed-off-by: Linus Torvalds --- net/xfrm/xfrm_user.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index cdf887fa61d5..40a8aa39220d 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -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) -- 2.20.1