netdev - Re: [PATCH] net: netrom: fix memory leak in nr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <17e41b73-3497-4ea0-b91c-4710514f7b14@huawei.com>
Date: Sat, 29 Nov 2025 12:01:20 +0800
From: Wang Liang <wangliang74@...wei.com>
To: Deepanshu Kartikey <kartikey406@...il.com>, <davem@...emloft.net>,
	<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
	<horms@...nel.org>
CC: <linux-hams@...r.kernel.org>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	<syzbot+d7abc36bbbb6d7d40b58@...kaller.appspotmail.com>
Subject: Re: [PATCH] net: netrom: fix memory leak in nr_output()


在 2025/11/29 11:42, Deepanshu Kartikey 写道:
> When nr_output() fragments a large packet, it calls sock_alloc_send_skb()


Hi!

Coincidentally, we both are working on this issue simultaneously.

 From the syz test requests:
https://syzkaller.appspot.com/bug?extid=d7abc36bbbb6d7d40b58

I sended the test patch earlier, only a dozen seconds...

------
Best regards
Wang Liang

> in a loop to allocate skbs for each fragment. If this allocation fails,
> the function returns without freeing the original skb that was passed in,
> causing a memory leak.
>
> Add the missing kfree_skb() call before returning on allocation failure.
>
> Reported-by: syzbot+d7abc36bbbb6d7d40b58@...kaller.appspotmail.com
> Tested-by: syzbot+d7abc36bbbb6d7d40b58@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=d7abc36bbbb6d7d40b58
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Deepanshu Kartikey <kartikey406@...il.com>
> ---
>   net/netrom/nr_out.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/netrom/nr_out.c b/net/netrom/nr_out.c
> index 5e531394a724..2b3cbceb0b52 100644
> --- a/net/netrom/nr_out.c
> +++ b/net/netrom/nr_out.c
> @@ -43,8 +42,11 @@ void nr_output(struct sock *sk, struct sk_buff *skb)
>   		frontlen = skb_headroom(skb);
>   
>   		while (skb->len > 0) {
> -			if ((skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err)) == NULL)
> 			skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err);
> 			if (skbn == NULL) {
> +				kfree_skb(skb);
>   				return;
> +			}
>   
>   			skb_reserve(skbn, frontlen);
>