From c91b46394b340ed790d6aed76f0044c1c7838de0 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sun, 9 Feb 2020 21:15:29 +0800 Subject: [PATCH] xfrm: fix uctx len check in verify_sec_ctx_len 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 Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman --- net/xfrm/xfrm_user.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 339a070da597..81d96a664afa 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -109,7 +109,8 @@ static inline int verify_sec_ctx_len(struct nlattr **attrs) 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; -- 2.20.1