| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 62/91] xfrm: fix uctx len check in verify_sec_ctx_len | Date | Wed, 1 Apr 2020 18:17:58 +0200 |
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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(-)
--- 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;
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