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From: David Disseldorp <ddiss@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	willy@infradead.org, Martin Wilck <mwilck@suse.com>
Subject: Re: [PATCH v7 4/6] gen_init_cpio: fix short read file handling
Date: Wed, 27 Apr 2022 23:05:22 +0200	[thread overview]
Message-ID: <20220427230522.216c91c8@suse.de> (raw)
In-Reply-To: <20220426134039.4f6f864141577229a01ad8be@linux-foundation.org>

On Tue, 26 Apr 2022 13:40:39 -0700, Andrew Morton wrote:

> On Mon,  4 Apr 2022 11:34:28 +0200 David Disseldorp <ddiss@suse.de> wrote:
> 
> > When processing a "file" entry, gen_init_cpio attempts to allocate a
> > buffer large enough to stage the entire contents of the source file.
> > It then attempts to fill the buffer via a single read() call and
> > subsequently writes out the entire buffer length, without checking that
> > read() returned the full length, potentially writing uninitialized
> > buffer memory.  
> 
> That was rather rude of it.
> 
> > Fix this by breaking up file I/O into 64k chunks and only writing the
> > length returned by the prior read() call.  
> 
> Does this change fix any known or reported problems?

This was found via code inspection. I'm not aware of anyone hitting it
in the wild.

Thanks for the feedback, Andrew.

Cheers, David

  reply	other threads:[~2022-04-27 21:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-04  9:34 [PATCH v7 0/6] initramfs: "crc" cpio format and INITRAMFS_PRESERVE_MTIME David Disseldorp
2022-04-04  9:34 ` [PATCH v7 1/6] initramfs: refactor do_header() cpio magic checks David Disseldorp
2022-04-04  9:34 ` [PATCH v7 2/6] initramfs: make dir_entry.name a flexible array member David Disseldorp
2022-04-04  9:34 ` [PATCH v7 3/6] initramfs: add INITRAMFS_PRESERVE_MTIME Kconfig option David Disseldorp
2022-04-26 20:39   ` Andrew Morton
2022-04-27 21:01     ` David Disseldorp
2022-04-04  9:34 ` [PATCH v7 4/6] gen_init_cpio: fix short read file handling David Disseldorp
2022-04-26 20:40   ` Andrew Morton
2022-04-27 21:05     ` David Disseldorp [this message]
2022-04-04  9:34 ` [PATCH v7 5/6] gen_init_cpio: support file checksum archiving David Disseldorp
2022-04-04  9:34 ` [PATCH v7 6/6] initramfs: support cpio extraction with file checksums David Disseldorp
2022-04-26  9:01 ` [PATCH v7 0/6] initramfs: "crc" cpio format and INITRAMFS_PRESERVE_MTIME David Disseldorp

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