linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Namjae Jeon" <namjae.jeon@samsung.com>
To: "'Valdis Klētnieks'" <valdis.kletnieks@vt.edu>
Cc: <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<gregkh@linuxfoundation.org>, <hch@lst.de>,
	<sj1557.seo@samsung.com>, <pali.rohar@gmail.com>, <arnd@arndb.de>,
	<viro@zeniv.linux.org.uk>, "'Namjae Jeon'" <linkinjeon@gmail.com>,
	"'Sasha Levin'" <sashal@kernel.org>
Subject: RE: [PATCH] exfat: tighten down num_fats check
Date: Mon, 17 Feb 2020 09:37:55 +0900	[thread overview]
Message-ID: <001b01d5e52a$7f029340$7d07b9c0$@samsung.com> (raw)
In-Reply-To: <89603.1581722921@turing-police>

> Change the test for num_fats from != 0 to a check for specifically 1.
> 
> Although it's theoretically possible that num_fats == 2 for a TexFAT
> volume (or an implementation that doesn't do the full TexFAT but does
> support 2 FAT tables), the rest of the code doesn't currently DTRT if it's
> 2 (in particular, not handling the case of ActiveFat pointing at the
> second FAT area), so we'll disallow that as well, as well as dealing with
> corrupted images that have a trash non-zero value.
> 
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
> 
> --- a/fs/exfat/super.c	2020-02-14 17:45:02.262274632 -0500
> +++ b/fs/exfat/super.c	2020-02-14 17:46:37.200343723 -0500
> @@ -450,7 +450,7 @@ static int __exfat_fill_super(struct sup
>  	}
> 
>  	p_bpb = (struct pbr64 *)p_pbr;
> -	if (!p_bpb->bsx.num_fats) {
> +	if (p_bpb->bsx.num_fats  != 1) {
>  		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
Could you please update error message for the reason why num_fats is allowed
only 1?
>  		ret = -EINVAL;
>  		goto free_bh;
Let's remove exfat_mirror_bh(), FAT2_start_sector variable and the below
related codes together.

sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
                sbi->FAT1_start_sector :
                        sbi->FAT1_start_sector + sbi->num_FAT_sectors;

Thanks for your patch!
> 
> 
> 
> 



  reply	other threads:[~2020-02-17  0:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200214232853epcas1p241e47cdc4e0b9b5c603cc6eaa6182360@epcas1p2.samsung.com>
2020-02-14 23:28 ` [PATCH] exfat: tighten down num_fats check Valdis Klētnieks
2020-02-17  0:37   ` Namjae Jeon [this message]
2020-02-17  1:41     ` Valdis Klētnieks

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='001b01d5e52a$7f029340$7d07b9c0$@samsung.com' \
    --to=namjae.jeon@samsung.com \
    --cc=arnd@arndb.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=hch@lst.de \
    --cc=linkinjeon@gmail.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pali.rohar@gmail.com \
    --cc=sashal@kernel.org \
    --cc=sj1557.seo@samsung.com \
    --cc=valdis.kletnieks@vt.edu \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).