PING^5 aka New ways to attract attentions Re: [PATCH v2 00/14] Correctionsand customization of the SG_IO command whitelist (CVE-2012-4542)

From: Paolo Bonzini
Date: Sat Apr 27 2013 - 09:32:06 EST


PING^5

So a blatant attempt at getting attention from LWN didn't work. I'm
desperate, so...

... look! I'm top posting!

Paolo

Il 17/04/2013 14:26, Paolo Bonzini ha scritto:
> And a fourth ping comes...
>
> Jon, the next time I read "it seems likely to be picked up fairly soon"
> (http://lwn.net/Articles/535075/), I'll picture the author of the patch
> attempting open-heart surgery on a long-red-haired voodoo doll!
>
> Paolo
>
> Il 04/04/2013 20:18, Paolo Bonzini ha scritto:
>> Il 22/03/2013 23:30, Paolo Bonzini ha scritto:
>>> Il 20/02/2013 17:12, Paolo Bonzini ha scritto:
>>>> Il 06/02/2013 16:15, Paolo Bonzini ha scritto:
>>>>> This series regards the whitelist that is used for the SG_IO ioctl. This
>>>>> whitelist has three problems:
>>>>>
>>>>> * the bitmap of allowed commands is designed for MMC devices (roughly,
>>>>> "play/burn CDs without requiring root") but some opcodes overlap across SCSI
>>>>> device classes and have different meanings for different classes.
>>>>>
>>>>> * also because the bitmap of allowed commands is designed for MMC devices
>>>>> only, some commands are missing even though they are generally useful and
>>>>> not insecure. At least not more insecure than anything else you can
>>>>> do if you have access to /dev/sdX or /dev/stX nodes.
>>>>>
>>>>> * the whitelist can be disabled per-process but not per-disk. In addition,
>>>>> the required capability (CAP_SYS_RAWIO) gives access to a range of other
>>>>> resources, enough to make it insecure.
>>>>>
>>>>> The series corrects these problems. Patches 1-4 solve the first problem,
>>>>> which also has an assigned CVE, by using different bitmaps for the various
>>>>> device classes. Patches 5-11 solve the second by adding more commands
>>>>> to the bitmaps. Patches 12 and 13 solve the third, and were already
>>>>> posted but ignored by the maintainers despite multiple pings.
>>>>>
>>>>> Note: checkpatch hates the formatting of the command table. I know about this,
>>>>> and ensured that there are no errors in the rest of the code. The current
>>>>> formatting is IMHO quite handy, and roughly based on the files available
>>>>> from the SCSI standard body.
>>>>>
>>>>> Ok for the next merge window?
>>>>>
>>>>> Paolo
>>>>>
>>>>> v1->v2: remove 2 MMC commands and 6 SBC commands (see patches 6 and 9
>>>>> for details). Added patch 14 and added a few more scanner
>>>>> commands based on SANE (scanners are not whitelisted by default,
>>>>> also were not in v1, but this makes it possible to opt into the
>>>>> whitelist out of paranoia). Removed C++ comments. Removed the
>>>>> large #if 0'd list of commands that the kernel does not pass
>>>>> though. Marked blk_set_cmd_filter_defaults as __init.
>>>>
>>>> Ping...
>>>>
>>>> Jens/James, is anyone going to pick this up for 3.9?
>>>
>>> Another month has passed, Ping^2...
>>
>> Ping^3, any hope for 3.10?
>>
>> Paolo
>>
>>>
>>> Paolo
>>>
>>>> Paolo
>>>>
>>>>>
>>>>> Paolo Bonzini (14):
>>>>> sg_io: pass request_queue to blk_verify_command
>>>>> sg_io: reorganize list of allowed commands
>>>>> sg_io: use different default filters for each device class
>>>>> sg_io: resolve conflicts between commands assigned to multiple
>>>>> classes (CVE-2012-4542)
>>>>> sg_io: whitelist a few more commands for rare & obsolete device types
>>>>> sg_io: whitelist another command for multimedia devices
>>>>> sg_io: whitelist a few more commands for media changers
>>>>> sg_io: whitelist a few more commands for tapes
>>>>> sg_io: whitelist a few more commands for disks
>>>>> sg_io: whitelist a few obsolete commands
>>>>> sg_io: mark blk_set_cmd_filter_defaults as __init
>>>>> sg_io: remove remnants of sysfs SG_IO filters
>>>>> sg_io: introduce unpriv_sgio queue flag
>>>>> sg_io: use unpriv_sgio to disable whitelisting for scanners
>>>>>
>>>>> Documentation/block/queue-sysfs.txt | 8 +
>>>>> block/blk-sysfs.c | 33 +++
>>>>> block/bsg.c | 2 +-
>>>>> block/scsi_ioctl.c | 369 ++++++++++++++++++++++++++---------
>>>>> drivers/scsi/scsi_scan.c | 14 ++-
>>>>> drivers/scsi/sg.c | 6 +-
>>>>> include/linux/blkdev.h | 8 +-
>>>>> include/linux/genhd.h | 9 -
>>>>> include/scsi/scsi.h | 3 +
>>>>> 9 files changed, 344 insertions(+), 108 deletions(-)
>>>>>
>>>>
>>>
>>
>

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