From: Eric Sandeen <sandeen@redhat.com>
Subject: Re: [PATCH] mke2fs: don't accept too-high revision levels
Date: Thu, 14 Jan 2016 12:35:37 -0600
Message-ID: <5697EA79.40902@redhat.com>
References: <5362A6A2.7040504@redhat.com>
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To: ext4 development <linux-ext4@vger.kernel.org>
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Sender: linux-ext4-owner@vger.kernel.org

Came across this, still not merged, so ping?

On 5/1/14 2:55 PM, Eric Sandeen wrote:
> It's a bit strange to accept revision levels higher than
> the code creating the filesystem can understand, so don't
> allow it.
> 
> At least the kernel will mount the fs readonly if it's too
> high, but no other utility will touch it, so you can't
> fix the error.
> 
> Just reject anything > EXT2_MAX_SUPP_REV at mkfs time.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/misc/mke2fs.c b/misc/mke2fs.c
> index aecd5d5..82019dc 100644
> --- a/misc/mke2fs.c
> +++ b/misc/mke2fs.c
> @@ -1679,9 +1679,10 @@ profile_error:
>  			break;
>  		case 'r':
>  			r_opt = strtoul(optarg, &tmp, 0);
> -			if (*tmp) {
> +			if (*tmp || (r_opt > EXT2_MAX_SUPP_REV)) {
>  				com_err(program_name, 0,
> -					_("bad revision level - %s"), optarg);
> +					_("bad revision level - %s (max %d)"),
> +					   optarg, EXT2_MAX_SUPP_REV);
>  				exit(1);
>  			}
>  			fs_param.s_rev_level = r_opt;
> 
> --
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