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): all How reproducible: always 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 3. Actual results: system will oops on a page fault Expected results: system should truncate file to 4096 bytes. Additional info:
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. http://rhn.redhat.com/errata/RHSA-2007-0012.html