Re: [syzbot] [PATCH net] netlink: Fix kernel-infoleak in __skb_datagram_iter()

[syzbot <syzbot+34ad5fab48f7bf510349@syzkaller.appspotmail.com>]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [PATCH net] netlink: Fix kernel-infoleak in __skb_datagram_iter()
Author: ryasuoka@redhat.com

#syz test

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 9c962347cf85..ff315351269f 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -167,7 +167,7 @@ static inline u32 netlink_group_mask(u32 group)
 static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
                                           gfp_t gfp_mask)
 {
-       unsigned int len = skb_end_offset(skb);
+       unsigned int len = skb->len;
        struct sk_buff *new;

        new = alloc_skb(len, gfp_mask);