This is a note to let you know that I've just added the patch titled
net: xfrm: fix shift-out-of-bounds in xfrm_get_default
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-xfrm-fix-shift-out-of-bounds-in-xfrm_get_default.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3c10ffddc61f8a1a59e29a110ba70b47e679206a Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@xxxxxxxxx>
Date: Thu, 2 Sep 2021 22:04:00 +0300
Subject: net: xfrm: fix shift-out-of-bounds in xfrm_get_default
From: Pavel Skripkin <paskripkin@xxxxxxxxx>
commit 3c10ffddc61f8a1a59e29a110ba70b47e679206a upstream.
Syzbot hit shift-out-of-bounds in xfrm_get_default. The problem was in
missing validation check for user data.
up->dirmask comes from user-space, so we need to check if this value
is less than XFRM_USERPOLICY_DIRMASK_MAX to avoid shift-out-of-bounds bugs.
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
Reported-and-tested-by: syzbot+b2be9dd8ca6f6c73ee2d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/xfrm/xfrm_user.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1989,6 +1989,11 @@ static int xfrm_get_default(struct sk_bu
return -EMSGSIZE;
}
+ if (up->dirmask >= XFRM_USERPOLICY_DIRMASK_MAX) {
+ kfree_skb(r_skb);
+ return -EINVAL;
+ }
+
r_up = nlmsg_data(r_nlh);
r_up->in = net->xfrm.policy_default[XFRM_POLICY_IN];
r_up->fwd = net->xfrm.policy_default[XFRM_POLICY_FWD];
Patches currently in stable-queue which might be from paskripkin@xxxxxxxxx are
queue-5.10/net-xfrm-fix-shift-out-of-bounce.patch
queue-5.10/net-xfrm-fix-shift-out-of-bounds-in-xfrm_get_default.patch
