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authorFlorian Westphal <fw@strlen.de>2018-02-12 14:42:01 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-08 11:49:45 +0200
commit5520490d27f410f73014aee6052d44130e2db42c (patch)
tree37cfbb2d91d55e80baa44df05c83cb4cfa08af32
parent502990185f76a3f3816e3c1e2c130001dc9923cb (diff)
xfrm_user: uncoditionally validate esn replay attribute struct
commit d97ca5d714a5334aecadadf696875da40f1fbf3e upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 255530dde7df..0608819ba2b6 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -120,22 +120,17 @@ 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) < 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) < 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))