Bug 53792

Summary:	Local DoS vulnerabilty in Linux Kernels 2.4 and 2.6
Product:	Gentoo Linux	Reporter:	Marc Ballarin <Ballarin.Marc>
Component:	[OLD] Core system	Assignee:	Gentoo Linux bug wranglers <bug-wranglers>
Status:	RESOLVED DUPLICATE
Severity:	critical
Priority:	High
Version:	unspecified
Hardware:	x86
OS:	Linux
URL:	http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15905
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	Patch from 2.6.7-rc3-bk5

Description Marc Ballarin 2004-06-13 03:53:37 UTC

The code posted by stian@nixia.no at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15905 allows every user with shell access to crash the machine.
Requirements are
- Kernel 2.4 or 2.6
- x86 machine with FPU
- single processor system(?)

The crash is caused by a pending FPU exception from userspace which is triggered as soon as the kernel itself executes an FPU instruction.


Reproducible: Always
Steps to Reproduce:
1. download and compile sample code
2. save your data
3. run sample program

Actual Results:  
System freezes, still responds to network ping and SysReq-Key. 
 

Expected Results:  
 

Original Discussion, including incomplete fixes: 
http://marc.10east.com/?l=linux-kernel&m=108681568931323&w=2 
 
Another fix. Improved but still not perfect: 
http://marc.10east.com/?l=linux-kernel&m=108707205824094&w=2

Comment 1 Marc Ballarin 2004-06-13 09:48:51 UTC

Created attachment 33178 [details, diff]
Patch from 2.6.7-rc3-bk5

This is the patch included in kernel 2.6.7-rc3-bk5.
Tested succesfully on 2.6.5 and 2.6.7-rc3.

The same change should fix kernel 2.4, although this patch won't apply.

Comment 2 Tuan Van (RETIRED) gentoo-dev

2004-06-13 10:51:37 UTC

bug 53804

Comment 3 Seemant Kulleen (RETIRED) gentoo-dev

2004-06-13 11:15:23 UTC


*** This bug has been marked as a duplicate of 53804 ***