net: xfrm: fix memory leak in xfrm_user_rcv_msg

Syzbot reported memory leak in xfrm_user_rcv_msg(). The
problem was is non-freed skb's frag_list.

In skb_release_all() skb_release_data() will be called only
in case of skb->head != NULL, but netlink_skb_destructor()
sets head to NULL. So, allocated frag_list skb should be
freed manualy, since consume_skb() won't take care of it

Fixes: 5106f4a8ac ("xfrm/compat: Add 32=>64-bit messages translator")
Reported-and-tested-by: syzbot+fb347cf82c73a90efcca@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Pavel Skripkin 2021-06-25 13:23:54 +03:00 committed by Steffen Klassert
parent a118ff6618
commit 7c1a80e80c

View File

@ -2811,6 +2811,16 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
err = link->doit(skb, nlh, attrs);
/* We need to free skb allocated in xfrm_alloc_compat() before
* returning from this function, because consume_skb() won't take
* care of frag_list since netlink destructor sets
* sbk->head to NULL. (see netlink_skb_destructor())
*/
if (skb_has_frag_list(skb)) {
kfree_skb(skb_shinfo(skb)->frag_list);
skb_shinfo(skb)->frag_list = NULL;
}
err:
kvfree(nlh64);
return err;