Re: [syzbot] [PATCH] Test for aea6bf908d73

[syzbot <syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com>]

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

***

Subject: [PATCH] Test for aea6bf908d73
Author: eadavis@qq.com

please test uaf in nfc_alloc_send_skb

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git aea6bf908d73


From d6bab181339771591ed9519dced29a8eb20ddadc Mon Sep 17 00:00:00 2001
From: Lizhi Xu <lizhi.xu@windriver.com>
Date: Thu, 9 Nov 2023 21:31:26 +0800
Subject: [PATCH] nfc/nci: fix uaf in nfc_alloc_send_skb

After releasing the nfc/nci device, nfc_llcp_sock->local should be set to null
to avoid referencing expired devices.

Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
---
 net/nfc/llcp_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
index 1dac28136e6a..024cbba26fc8 100644
--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -102,6 +102,7 @@ static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device,
 				accept_sk->sk_state_change(sk);
 
 				bh_unlock_sock(accept_sk);
+				lsk->local = NULL;
 			}
 		}
 
@@ -113,6 +114,7 @@ static void nfc_llcp_socket_release(struct nfc_llcp_local *local, bool device,
 		bh_unlock_sock(sk);
 
 		sk_del_node_init(sk);
+		llcp_sock->local = NULL;
 	}
 
 	write_unlock(&local->sockets.lock);
-- 
2.25.1