linux-kernel - Re: [PATCH] f2fs: file: add checks to f2fs_ioc_flush

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 for Android: free password hash cracker in your pocket

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

Message-ID: <e82ab6dd-f4a6-4648-a4b4-b092f2eaf2be@kernel.org>
Date: Tue, 13 Aug 2024 11:50:27 +0800
From: Chao Yu <chao@...nel.org>
To: Roman Smirnov <r.smirnov@....ru>, Jaegeuk Kim <jaegeuk@...nel.org>
Cc: linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
 Sergey Shtylyov <s.shtylyov@....ru>, Karina Yankevich <k.yankevich@....ru>,
 lvc-project@...uxtesting.org
Subject: Re: [PATCH] f2fs: file: add checks to f2fs_ioc_flush_device()

On 2024/8/1 15:17, Roman Smirnov wrote:
> If invalid data is copied from user space and if GET_SEGNO()
> returns NULL_SEGNO an overflow is possible.

Can you explain in which condition that FDEV(range.dev_num).start_blk or
FDEV(range.dev_num).end_blk will be invalid?

 > > Add checks for invalid values.
> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> Signed-off-by: Roman Smirnov <r.smirnov@....ru>
> ---
>   fs/f2fs/file.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 168f08507004..1b9c4fee9db1 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -3093,6 +3093,9 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
>   		start_segno = dev_start_segno;
>   	end_segno = min(start_segno + range.segments, dev_end_segno);
>   
> +	if (start_segno > F2FS_MAX_SEGMENT - range.segments || end_segno == NULL_SEGNO)
> +		return -EINVAL;

It missed to call mnt_drop_write_file() before return.

Thanks,

> +
>   	while (start_segno < end_segno) {
>   		if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
>   			ret = -EBUSY;