linux-kernel - Re: [PATCH 2/3] e1000e: Useset_memory_ro()/set_memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 23 Sep 2008 16:29:57 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	jeffrey.t.kirsher@...el.com
Cc:	jeff@...zik.org, mingo@...e.hu, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, jesse.brandeburg@...el.com,
	john.ronciak@...el.com, bruce.w.allan@...el.com
Subject: Re: [PATCH 2/3] e1000e: Useset_memory_ro()/set_memory_rw() to
 protect flash memory

From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Date: Tue, 23 Sep 2008 15:45:54 -0700

> From: Bruce Allan <bruce.w.allan@...el.com>
> 
> A number of users have reported NVM corruption on various ICHx platform
> LOMs.  One possible reasons for this could be unexpected and/or malicious
> writes to the flash memory area mapped into kernel memory.  Once the
> interface is up, there should be very few reads/writes of the mapped flash
> memory.  This patch makes use of the x86 set_memory_*() functions to set
> the mapped memory read-only and temporarily set it writable only when the
> driver needs to write to it.  With the memory set read-only, any unexpected
> write will be logged with a stack dump indicating the offending code.
> 
> Since these LOMs are only on x86 ICHx platforms, it does not matter that
> this API is not yet available on other architectures, however it is
> dependent on a previous patch that exports these function name symbols.
> 
> Signed-off-by: Bruce Allan <bruce.w.allan@...el.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>

If the X server or similar is causing this problem, this patch won't help.

The X server maps MMIO space using mmap() in userspace, and you're only
protecting the kernel side mapping.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/