diff options
| author | Pavel Skripkin <paskripkin@gmail.com> | 2021-07-28 19:38:18 +0300 |
|---|---|---|
| committer | Steffen Klassert <steffen.klassert@secunet.com> | 2021-07-29 08:04:10 +0200 |
| commit | 5d8dbb7fb82b8661c16d496644b931c0e2e3a12e (patch) | |
| tree | 5c572c0adfa04517c87e64c38c570bb0694e3f8e /net/xfrm | |
| parent | 2d151d39073aff498358543801fca0f670fea981 (diff) | |
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.
Also, added XFRM_USERPOLICY_DIRMASK_MAX constant to uapi to inform
user-space that up->dirmask has maximum possible value
Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
Reported-and-tested-by: syzbot+9cd5837a045bbee5b810@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.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 4eafd1130c3e..127c99f71c99 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 >= XFRM_USERPOLICY_DIRMASK_MAX) + return -EINVAL; + + dirmask = (1 << up->dirmask) & XFRM_POL_DEFAULT_MASK; + net->xfrm.policy_default = (old_default & (0xff ^ dirmask)) | (up->action << up->dirmask); |