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| author |   Pavel Skripkin <paskripkin@gmail.com> | 2021-09-02 22:04:00 +0300 |
|---|---|---|
| committer |   Steffen Klassert <steffen.klassert@secunet.com> | 2021-09-09 12:12:17 +0200 |
| commit | 3c10ffddc61f8a1a59e29a110ba70b47e679206a (patch) | |
| tree | 7af23af0a5764faae0f99988c410e224cbaf44dc /net/xfrm | |
| parent | Merge tag 'net-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net (diff) | |
| download | linux-dev-3c10ffddc61f8a1a59e29a110ba70b47e679206a.tar.xz linux-dev-3c10ffddc61f8a1a59e29a110ba70b47e679206a.zip | |
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.c | 5 |
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); |