xfrm_user: uncoditionally validate esn replay attribute struct

commit d97ca5d714a5334aecadadf696875da40f1fbf3e upstream.

The sanity test added in ecd7918745 can be bypassed, validation
only occurs if XFRM_STATE_ESN flag is set, but rest of code doesn't care
and just checks if the attribute itself is present.

So always validate.  Alternative is to reject if we have the attribute
without the flag but that would change abi.

Reported-by: syzbot+0ab777c27d2bb7588f73@syzkaller.appspotmail.com
Cc: Mathias Krause <minipli@googlemail.com>
Fixes: ecd7918745 ("xfrm_user: ensure user supplied esn replay window is valid")
Fixes: d8647b79c3 ("xfrm: Add user interface for esn and big anti-replay windows")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Florian Westphal 2018-02-12 14:42:01 +01:00 committed by syphyr
parent f70030993f
commit c469a67980
1 changed files with 10 additions and 15 deletions

View File

@ -125,22 +125,17 @@ static inline int verify_replay(struct xfrm_usersa_info *p,
struct nlattr *rt = attrs[XFRMA_REPLAY_ESN_VAL];
struct xfrm_replay_state_esn *rs;
if (p->flags & XFRM_STATE_ESN) {
if (!rt)
return -EINVAL;
rs = nla_data(rt);
if (rs->bmp_len > XFRMA_REPLAY_ESN_MAX / sizeof(rs->bmp[0]) / 8)
return -EINVAL;
if (nla_len(rt) < xfrm_replay_state_esn_len(rs) &&
nla_len(rt) != sizeof(*rs))
return -EINVAL;
}
if (!rt)
return 0;
return (p->flags & XFRM_STATE_ESN) ? -EINVAL : 0;
rs = nla_data(rt);
if (rs->bmp_len > XFRMA_REPLAY_ESN_MAX / sizeof(rs->bmp[0]) / 8)
return -EINVAL;
if (nla_len(rt) < xfrm_replay_state_esn_len(rs) &&
nla_len(rt) != sizeof(*rs))
return -EINVAL;
if (p->id.proto != IPPROTO_ESP)
return -EINVAL;