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Date:   Thu, 16 Nov 2023 15:47:59 +0000 (GMT)
From:   Phillip Lougher <phillip@squashfs.org.uk>
To:     Lizhi Xu <lizhi.xu@windriver.com>,
        syzbot+32d3767580a1ea339a81@syzkaller.appspotmail.com,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        squashfs-devel@lists.sourceforge.net,
        syzkaller-bugs@googlegroups.com
Message-ID: <261429818.1734406.1700149679974@eu1.myprofessionalmail.com>
In-Reply-To: <20231116031352.40853-1-lizhi.xu@windriver.com>
References: <0000000000000526f2060a30a085@google.com>
 <20231116031352.40853-1-lizhi.xu@windriver.com>
Subject: Re: [PATCH] squashfs: squashfs_read_data need to check if the
 length is 0
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> On 16/11/2023 03:13 GMT Lizhi Xu <lizhi.xu@windriver.com> wrote:
> 
>  
> when the length passed in is 0, the subsequent process should be exited.
> 

Reproduced and tested.

Reviewed-by: Phillip Lougher (phillip@squashfs.org.uk)

> Reported-by: syzbot+32d3767580a1ea339a81@syzkaller.appspotmail.com
> Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
> ---
>  fs/squashfs/block.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
> index 581ce9519339..2dc730800f44 100644
> --- a/fs/squashfs/block.c
> +++ b/fs/squashfs/block.c
> @@ -321,7 +321,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
>  		TRACE("Block @ 0x%llx, %scompressed size %d\n", index - 2,
>  		      compressed ? "" : "un", length);
>  	}
> -	if (length < 0 || length > output->length ||
> +	if (length <= 0 || length > output->length ||
>  			(index + length) > msblk->bytes_used) {
>  		res = -EIO;
>  		goto out;
> -- 
> 2.25.1