Red Hat Bugzilla – Bug 217621
kernel may oops if more than 4k worth of string data returned in /proc/devices
Last modified: 2007-11-30 17:06:55 EST
+++ This bug was initially created as a clone of Bug #156029 +++
Description of problem:
the read routine for /proc/devices is missing a length check routine.
Consequently, if the number of block and char devices in a system totals more
than 4096 bytes of string data between their names and major/minor numbers, the
read routine will sprintf the data off the end of the page and oops the kernel.
other proc files that are part of proc_misc.c protect against this with a length
check that truncates the file if it goes over a page, but this check is missing
from get_device_list and get_blkdev_list.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. register sufficient char/block devices in a system to create > 4096 bytes of
string data for /proc/devices
2. cat /proc/devices
system will oops on a page fault
system should truncate file to 4096 bytes.
I was unable to reproduce the problem with the test module from bz 156029,
however I have verified that the fix is being applied in the 2.4.18-e.64 kernel.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.