Date: Fri, 13 Nov 2009 11:57:11 +0100 From: Marcus Meissner <meissner@...e.de> To: oss-security@...ts.openwall.com Cc: "Steven M. Christey" <coley@...us.mitre.org> Subject: Re: CVE request: kernel: bad permissions on megaraid_sas sysfs files On Fri, Nov 13, 2009 at 02:39:24PM +0800, Eugene Teo wrote: > The megaraid_sas driver exposes a number of driver attributes in sysfs. > Many of these are read-only, just export information from the driver and > are world-readable. > > A couple of attributes are writable and may be used to change the > behaviour of the driver (e.g. setting debug logging levels, selecting > poll vs. interrupt I/O mode etc). > > Some of these writable attributes are mistakenly created with > world-writable permissions, e.g. dbg_lvl and poll_mode_io. > > This would allow an unprivileged user to affect kernel driver behaviour > and logging level. > > Upstream made the dbd_lvl permissions more restrictive: > http://git.kernel.org/linus/66dca9b8c50b5e59d3bea8b21cee5c6dae6c9c46 > > The poll_mode_io pseudofile still has world-writable permissions > upstream. I'm getting my colleague to submit a patch. > > https://bugzilla.redhat.com/show_bug.cgi?id=526068 It seems you can set poll_mode_io multiple times to the full integer range, (like to 1 , 2 , 3 etc.) and it will reinitialize its timers everytime via init_timer() and add_timer(). This will corrupt the timer chain (I think) by setting entry.next = NULL in init_timer(). It should only accept a boolean value. :/ Ciao, Marcus
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