From e7cf3838979bf3079a511b6809e971945f50eb25 Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Tue, 27 Jul 2021 17:38:24 +0300 Subject: [PATCH] net: xfrm: fix shift-out-of-bounce We need to check up->dirmask to avoid shift-out-of-bounce bug, since up->dirmask comes from userspace. Signed-off-by: Pavel Skripkin --- net/xfrm/xfrm_user.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index acc3a0dab331..4a7bb169314e 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1966,9 +1966,14 @@ static int xfrm_set_default(struct sk_buff *skb, struct nlmsghdr *nlh, { struct net *net = sock_net(skb->sk); struct xfrm_userpolicy_default *up = nlmsg_data(nlh); - u8 dirmask = (1 << up->dirmask) & XFRM_POL_DEFAULT_MASK; + u8 dirmask; u8 old_default = net->xfrm.policy_default; + if (up->dirmask >= sizeof(up->action) * 8) + return -EINVAL; + + dirmask = (1 << up->dirmask) & XFRM_POL_DEFAULT_MASK; + net->xfrm.policy_default = (old_default & (0xff ^ dirmask)) | (up->action << up->dirmask); -- 2.32.0