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authorPavel Skripkin <paskripkin@gmail.com>2021-09-02 22:04:00 +0300
committerSteffen Klassert <steffen.klassert@secunet.com>2021-09-09 12:12:17 +0200
commit3c10ffddc61f8a1a59e29a110ba70b47e679206a (patch)
tree7af23af0a5764faae0f99988c410e224cbaf44dc /net/xfrm
parent626bf91a292e2035af5b9d9cce35c5c138dfe06d (diff)
downloadlinux-3c10ffddc61f8a1a59e29a110ba70b47e679206a.tar.bz2
net: xfrm: fix shift-out-of-bounds in xfrm_get_default
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@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/xfrm')
-rw-r--r--net/xfrm/xfrm_user.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 03b66d154b2b..4719a6d54aa6 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2005,6 +2005,11 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh,
return -EMSGSIZE;
}
+ if (up->dirmask >= XFRM_USERPOLICY_DIRMASK_MAX) {
+ kfree_skb(r_skb);
+ return -EINVAL;
+ }
+
r_up = nlmsg_data(r_nlh);
r_up->action = ((net->xfrm.policy_default & (1 << up->dirmask)) >> up->dirmask);