From: Sascha Hauer <s.hauer@pengutronix.de>
To: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH v2 17/19] commands: md: Do not use memmap()
Date: Mon, 4 Feb 2019 14:57:49 +0100 [thread overview]
Message-ID: <20190204135749.f2xoc6vli5od7htl@pengutronix.de> (raw)
In-Reply-To: <20190129065549.29161-18-andrew.smirnov@gmail.com>
On Mon, Jan 28, 2019 at 10:55:47PM -0800, Andrey Smirnov wrote:
> Codepaths using memmap() in md.c don't do any boundary checks, so it
> can be easily made to read past the underlying file's
> boundary. For example on i.MX8MQ based board with 4GiB or RAM we get:
>
> md -b -s /dev/ram0 0xfffffff0
> fffffff0: 00 00 00 00 00 00 08 0c 00 02 20 00 20 00 05 20 .......... . ..
> 100000000: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000010: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000020: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000030: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000040: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000050: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000060: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000070: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000080: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 100000090: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 1000000a0: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 1000000b0: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 1000000c0: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 1000000d0: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
> 1000000e0: xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx ................
>
> Drop the memmap() realted codepath, so we can realy on boundary
> checking done by file I/O layer.
>
> Note that this change has a cosmetic side effect, before:
With this change we can no longer see that the underlying memory cannot
be accessed 'xx'. I find this feature very useful and don't want to
loose it.
If we want to do size checking we can do this, well, by checking the
size. We could add offset/size parameters to memmap().
So, dropped this patch for now.
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox
next prev parent reply other threads:[~2019-02-04 13:57 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 6:55 [PATCH v2 00/19] 32-bit lseek and /dev/mem fixes/improvements Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 01/19] commands: Move mem_parse_options() to lib/misc.c Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 02/19] commands: Get rid of mem_rw_buf Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 03/19] commands: Move /dev/mem driver to drivers/misc Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 04/19] nvmem: Do not use DEVFS_IS_CHARACTER_DEV Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 05/19] common: firmware: Don't use FILE_SIZE_STREAM directly Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 06/19] devfs: Fix incorrect error check for cdev->ops->lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 07/19] fs: Update FILE position in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 08/19] fs: Drop trivial .lseek() implementaitons in FS drivers Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 09/19] devfs: Drop dev_lseek_default() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 10/19] fs: devfs: Change .lseek callbacks to return 'int' Andrey Smirnov
2019-02-04 14:32 ` Sascha Hauer
2019-01-29 6:55 ` [PATCH v2 11/19] fs: Do not use IS_ERR_VALUE() to validate offset in lseek() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 12/19] fs: Simplify new position calculation " Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 13/19] fs: Share code between mem_write()/mem_read() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 14/19] fs: Avoid division in mem_copy() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 15/19] fs: Report actual data processed by mem_copy() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 16/19] fs: Introduce mem_read_nofail() Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 17/19] commands: md: Do not use memmap() Andrey Smirnov
2019-02-04 13:57 ` Sascha Hauer [this message]
2019-02-04 19:35 ` Andrey Smirnov
2019-01-29 6:55 ` [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory Andrey Smirnov
2019-01-29 8:48 ` Sascha Hauer
2019-01-29 20:40 ` Andrey Smirnov
2019-01-29 21:09 ` Sam Ravnborg
2019-01-31 10:54 ` Peter Mamonov
2019-01-31 12:50 ` Peter Mamonov
2019-02-01 7:47 ` Sascha Hauer
2019-02-01 10:25 ` Peter Mamonov
2019-02-02 1:07 ` Andrey Smirnov
2019-02-02 0:35 ` Andrey Smirnov
2019-02-04 7:40 ` Sascha Hauer
2019-01-31 20:17 ` Andrey Smirnov
2019-02-01 10:14 ` Peter Mamonov
2019-01-29 6:55 ` [PATCH v2 19/19] libfile: Fix incorrect lseek check in open_and_lseek() Andrey Smirnov
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=20190204135749.f2xoc6vli5od7htl@pengutronix.de \
--to=s.hauer@pengutronix.de \
--cc=andrew.smirnov@gmail.com \
--cc=barebox@lists.infradead.org \
/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