diff mbox series

[4.4,62/91] xfrm: fix uctx len check in verify_sec_ctx_len

Message ID 20200401161534.360943180@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH April 1, 2020, 4:17 p.m. UTC 
From: Xin Long <lucien.xin@gmail.com>

commit 171d449a028573b2f0acdc7f31ecbb045391b320 upstream.

It's not sufficient to do 'uctx->len != (sizeof(struct xfrm_user_sec_ctx) +
uctx->ctx_len)' check only, as uctx->len may be greater than nla_len(rt),
in which case it will cause slab-out-of-bounds when accessing uctx->ctx_str
later.

This patch is to fix it by return -EINVAL when uctx->len > nla_len(rt).

Fixes: df71837d5024 ("[LSM-IPSec]: Security association restriction.")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/xfrm/xfrm_user.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -109,7 +109,8 @@  static inline int verify_sec_ctx_len(str
 		return 0;
 
 	uctx = nla_data(rt);
-	if (uctx->len != (sizeof(struct xfrm_user_sec_ctx) + uctx->ctx_len))
+	if (uctx->len > nla_len(rt) ||
+	    uctx->len != (sizeof(struct xfrm_user_sec_ctx) + uctx->ctx_len))
 		return -EINVAL;
 
 	return 0;