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authorFlorian Westphal <fw@strlen.de>2018-02-12 14:42:01 +0100
committerSteffen Klassert <steffen.klassert@secunet.com>2018-02-13 09:12:09 +0100
commitd97ca5d714a5334aecadadf696875da40f1fbf3e (patch)
tree6bbb65e655aca87c6fc27289673cd3ffe005147a /net/xfrm
parent2471c98165494173a3cd03231b216b909c063e41 (diff)
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xfrm_user: uncoditionally validate esn replay attribute struct
The sanity test added in ecd7918745234 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: ecd7918745234 ("xfrm_user: ensure user supplied esn replay window is valid") Fixes: d8647b79c3b7e ("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>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_user.c21
1 files changed, 8 insertions, 13 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 7f52b8eb177d..080035f056d9 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -121,22 +121,17 @@ 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;
+ if (!rt)
+ return (p->flags & XFRM_STATE_ESN) ? -EINVAL : 0;
- rs = nla_data(rt);
+ rs = nla_data(rt);
- if (rs->bmp_len > XFRMA_REPLAY_ESN_MAX / sizeof(rs->bmp[0]) / 8)
- return -EINVAL;
-
- if (nla_len(rt) < (int)xfrm_replay_state_esn_len(rs) &&
- nla_len(rt) != sizeof(*rs))
- return -EINVAL;
- }
+ if (rs->bmp_len > XFRMA_REPLAY_ESN_MAX / sizeof(rs->bmp[0]) / 8)
+ return -EINVAL;
- if (!rt)
- return 0;
+ if (nla_len(rt) < (int)xfrm_replay_state_esn_len(rs) &&
+ nla_len(rt) != sizeof(*rs))
+ return -EINVAL;
/* As only ESP and AH support ESN feature. */
if ((p->id.proto != IPPROTO_ESP) && (p->id.proto != IPPROTO_AH))