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From: Matthew Wilcox <willy@infradead.org>
To: Egor Chelak <egor.chelak@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>, Arnd Bergmann <arnd@arndb.de>,
	Jan Kara <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] isofs: fix High Sierra dirent flag accesses
Date: Mon, 22 Jun 2020 22:31:02 +0100	[thread overview]
Message-ID: <20200622213102.GD21350@casper.infradead.org> (raw)
In-Reply-To: <20200621040817.3388-1-egor.chelak@gmail.com>

On Sun, Jun 21, 2020 at 07:08:17AM +0300, Egor Chelak wrote:
> The flags byte of the dirent was accessed as de->flags[0] in a couple of
> places, and not as de->flags[-sbi->s_high_sierra], which is how it's
> accessed elsewhere. This caused a bug, where some files on an HSF disc
> could be inaccessible.
> 
> For context, here is the difference between HSF dirents and ISO dirents:
> Offset  | High Sierra | ISO-9660       | struct iso_directory_record
> Byte 24 | Flags       | mtime timezone | de->date[6] (de->flags[-1])
> Byte 25 | Reserved    | Flags          | de->flags[0]

Also, ew.  Why on earth do we do 'de->flags[-sbi->s_high_sierra]'?
I'm surprised we don't have any tools that warn about references outside
an array.  I would do this as ...

static inline u8 de_flags(struct isofs_sb_info *sbi,
		struct iso_directory_record *de)
{
	if (sbi->s_high_sierra)
		return de->date[6];
	return de->flags;
}

      parent reply	other threads:[~2020-06-22 21:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-21  4:08 [PATCH] isofs: fix High Sierra dirent flag accesses Egor Chelak
2020-06-22 21:22 ` Matthew Wilcox
2020-06-23  1:21   ` Egor Chelak
2020-06-22 21:31 ` Matthew Wilcox [this message]

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