On 11/11/23 03:01, Kuniyuki Iwashima wrote:

From: Bragatheswaran Manickavel <redacted>
Date: Fri, 10 Nov 2023 23:06:32 +0530

quoted

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.

quoted

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

quoted

Reported-by: syzbot+0145ea560de205bc09f0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0145ea560de205bc09f0
Signed-off-by: Bragatheswaran Manickavel <redacted>
---
  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) ||

quoted

  		return 0;
  	}
  
-- 
2.34.1

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

Thanks,
Bragathe