| From | Ben Hutchings <> | Date | Thu, 01 Jun 2017 16:43:16 +0100 | Subject | [PATCH 3.16 187/212] xfrm_user: validate XFRM_MSG_NEWAE incoming ESN size harder |
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3.16.44-rc1 review patch. If anyone has any objections, please let me know.
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From: Andy Whitcroft <apw@canonical.com>
commit f843ee6dd019bcece3e74e76ad9df0155655d0df upstream.
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> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/xfrm/xfrm_user.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -387,7 +387,11 @@ static inline int xfrm_replay_verify_len 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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