Bug 467952 - kernel: reading from /proc/acpi/video/GFX0/DD01/state crashes system [f-9]
Summary: kernel: reading from /proc/acpi/video/GFX0/DD01/state crashes system [f-9]
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 9
Hardware: x86_64
OS: Linux
high
high
Target Milestone: ---
Assignee: John Feeney
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks: 467988
TreeView+ depends on / blocked
 
Reported: 2008-10-21 20:22 UTC by Warren Lewis
Modified: 2013-01-10 07:08 UTC (History)
5 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2009-07-14 13:59:11 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)
Make state file 640 (539 bytes, patch)
2008-10-21 23:20 UTC, Matthew Garrett
no flags Details | Diff

Description Warren Lewis 2008-10-21 20:22:08 UTC
Description of problem:
Reading from /proc/acpi/video/GFX0/DD01/state crashes system. Permissions allow this to be done by a non root user. I have set severity High as this at least allows a DOS attack.
System is a HP DV9334us with NVIDIA G70 [GeForce Go 7600] video.

Version-Release number of selected component (if applicable):
kernel-2.6.26.3-29.fc9.x86_64

How reproducible:
Always

Steps to Reproduce:
1. cat /proc/acpi/video/GFX0/DD01/state
2.
3.
  
Actual results:
System crashes (no panic) with screen display distorted.

Expected results:
No crash.

Additional info:
This also happens under Knoppix so it's not a Fedora specific problem.  I'm reporting it here as I'm running a Fedora kernel and not a vanilla kernel.org one.

Comment 1 Warren Lewis 2008-10-21 20:31:20 UTC
I'm not using the NVIDIA proprietary drivers, only the one that comes with Fedora.

Comment 2 Dave Jones 2008-10-21 20:43:10 UTC
This will probably need a CVE assigned. Adding security-response-team to cc.

When it crashes, does it just lock up, or do you get any stack traces or similar onscreen ? (try from a tty rather than whilst in X)

Comment 3 Warren Lewis 2008-10-21 21:01:48 UTC
tried from console 1 (tty1) same thing happened.  also tried rebooting into runlevel S and again problem happened.  the crash seems to be immediate with no trace info, the info on the screen is the same as before the crash.

Comment 4 Matthew Garrett 2008-10-21 23:20:16 UTC
Created attachment 321103 [details]
Make state file 640

Yeah, letting users read files that trigger execution of quite plausibly entirely broken ACPI methods that probably trip SMI code is probably not the best of ideas. Does this deal with it for now? We can do the same for other nodes, but I'm wary of breaking userspace that might want it for some reason.

Comment 5 Eugene Teo (Security Response) 2008-10-22 05:58:28 UTC
(In reply to comment #4)
> Created an attachment (id=321103) [details]
> Make state file 640
> 
> Yeah, letting users read files that trigger execution of quite plausibly
> entirely broken ACPI methods that probably trip SMI code is probably not the
> best of ideas. Does this deal with it for now? We can do the same for other
> nodes, but I'm wary of breaking userspace that might want it for some reason.

Matthew, are you submitting this to upstream?

RHEL-5 and the real-time kernel have support for the ACPI video driver. Are these kernels affected as well?

(In reply to comment #2)
> This will probably need a CVE assigned. Adding security-response-team to cc.

Thanks Dave. I will file a CVE name request as soon as I have more details about this bug.

Eugene

Comment 6 Eugene Teo (Security Response) 2008-10-22 06:11:24 UTC
(In reply to comment #5)
> (In reply to comment #4)
> > Created an attachment (id=321103) [details] [details]
> > Make state file 640
> > 
> > Yeah, letting users read files that trigger execution of quite plausibly
> > entirely broken ACPI methods that probably trip SMI code is probably not the
> > best of ideas. Does this deal with it for now? We can do the same for other
> > nodes, but I'm wary of breaking userspace that might want it for some reason.
> 
> Matthew, are you submitting this to upstream?

If this is submitted, please paste the link to the email from lkml.org. Thanks!

> RHEL-5 and the real-time kernel have support for the ACPI video driver. Are
> these kernels affected as well?

We should also find out the cause of the problem.

Thanks, Eugene

Comment 7 Eugene Teo (Security Response) 2008-10-22 06:34:40 UTC
Please post your reply to bug #467988 instead of this. Thanks.

Comment 8 Warren Lewis 2008-10-22 18:07:57 UTC
The patch did remove read from other, however it also removed read from user (root).  I added S_IRUSR to the modes to correct this.  

        /* 'state' [R/W] */
        acpi_video_device_state_fops.write = acpi_video_device_write_state;
-       entry = proc_create_data("state", S_IFREG | S_IRUGO | S_IWUSR,
+       entry = proc_create_data("state", S_IFREG | S_IRGRP | S_IRUSR | S_IWUSR,
                                 device_dir,
                                 &acpi_video_device_state_fops,
                                 acpi_driver_data(device));

This seems to work ok.

Comment 9 Bug Zapper 2009-06-10 03:02:45 UTC
This message is a reminder that Fedora 9 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 9.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '9'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version prior to Fedora 9's end of life.

Bug Reporter: Thank you for reporting this issue and we are sorry that 
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The process we are following is described here: 
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Comment 10 Bug Zapper 2009-07-14 13:59:11 UTC
Fedora 9 changed to end-of-life (EOL) status on 2009-07-10. Fedora 9 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.


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