Re: [syzbot] KASAN: use-after-free Read in r871xu_dev_remove

[Pavel Skripkin <paskripkin@gmail.com>]

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On Mon, 12 Jul 2021 20:14:24 -0700
syzbot <syzbot+5872a520e0ce0a7c7230@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    92510a7f Add linux-next specific files for 20210709
> git tree:       linux-next
> console output:
> https://syzkaller.appspot.com/x/log.txt?x=16c50180300000 kernel
> config:  https://syzkaller.appspot.com/x/.config?x=505de2716f052686
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=5872a520e0ce0a7c7230 syz
> repro:
> https://syzkaller.appspot.com/x/repro.syz?x=1639a73c300000 C
> reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15fcd5e4300000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit: Reported-by:
> syzbot+5872a520e0ce0a7c7230@syzkaller.appspotmail.com
> 

Hmm, bisection is wrong this time. It should be
e02a3b945816 ("staging: rtl8712: fix memory leak in rtl871x_load_fw_cb")

#syz test:
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master


I guess, this should work


With regards,
Pavel Skripkin

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From 954ffa9067907a5f6d4d6d2b72a98b8773cac11e Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Tue, 13 Jul 2021 11:52:17 +0300
Subject: [PATCH] staging: rtl8712: fix UAF in r871xu_dev_remove

/* .... */

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 drivers/staging/rtl8712/hal_init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/rtl8712/hal_init.c b/drivers/staging/rtl8712/hal_init.c
index 22974277afa0..c06d31784cd4 100644
--- a/drivers/staging/rtl8712/hal_init.c
+++ b/drivers/staging/rtl8712/hal_init.c
@@ -43,6 +43,7 @@ static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
 		r8712_free_drv_sw(adapter);
 		adapter->dvobj_deinit(adapter);
 		complete(&adapter->rtl8712_fw_ready);
+		shedule();				/* to not trigger UAF in wait_for_completion() */
 		free_netdev(adapter->pnetdev);
 		return;
 	}
-- 
2.32.0