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Message-Id: <20200331085431.490001424@linuxfoundation.org>
Date: Tue, 31 Mar 2020 10:59:16 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Xin Long <lucien.xin@...il.com>,
Steffen Klassert <steffen.klassert@...unet.com>
Subject: [PATCH 5.4 116/155] xfrm: fix uctx len check in verify_sec_ctx_len
From: Xin Long <lucien.xin@...il.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@...il.com>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
net/xfrm/xfrm_user.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -110,7 +110,8 @@ 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;
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