linux-kernel - Re: [PATCH] net: memory leak in nr_rx

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Message-ID: <16a0e7e8-a03a-401e-a25a-a12b07d621a3@gmail.com>
Date:   Sat, 11 Nov 2023 11:46:20 +0530
From:   Bragatheswaran Manickavel <bragathemanick0908@...il.com>
To:     Kuniyuki Iwashima <kuniyu@...zon.com>
Cc:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        linux-hams@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, pabeni@...hat.com, ralf@...ux-mips.org,
        syzbot+0145ea560de205bc09f0@...kaller.appspotmail.com
Subject: Re: [PATCH] net: memory leak in nr_rx_frame


On 11/11/23 03:01, Kuniyuki Iwashima wrote:
> From: Bragatheswaran Manickavel <bragathemanick0908@...il.com>
> Date: Fri, 10 Nov 2023 23:06:32 +0530
>> The condition (make = nr_make_new(sk)) == NULL suggests
>> that nr_make_new allocates memory and returns a pointer.
>> If this allocation fails (returns NULL), it indicates a
>> potential memory leak.
> If make is NULL, nothing is allocated and leaked here, and
> your code will never be executed as "if (make)" is always false.
>
>
>> Added sock_put() for make which can potentially solve
>> this issue
> Sounds like the patch is not tested with kmemleak.

Yes, Had some issue with reproducer. So, haven't tested it

>
>
>> Reported-by: syzbot+0145ea560de205bc09f0@...kaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=0145ea560de205bc09f0
>> Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@...il.com>
>> ---
>>   net/netrom/af_netrom.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
>> index 0eed00184adf..7d7cda4ae300 100644
>> --- a/net/netrom/af_netrom.c
>> +++ b/net/netrom/af_netrom.c
>> @@ -970,6 +970,8 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
>>   		nr_transmit_refusal(skb, 0);
>>   		if (sk)
>>   			sock_put(sk);
>> +		if (make)
>> +			sock_put(make);
> Also, make could be uninitialised here if the first two
> condition is true.
>
>     if (sk == NULL || sk_acceptq_is_full(sk) ||
>
>
>>   		return 0;
>>   	}
>>   
>> -- 
>> 2.34.1


Sorry for the inconvenience, let me check the code and get back properly.

Thanks,
Bragathe