linux-kernel - Re: m(un)map kmalloc buffers to userspace

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 for Android: free password hash cracker in your pocket

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

Date:	Wed, 9 Dec 2015 14:55:44 +0100
From:	Michal Hocko <mhocko@...nel.org>
To:	Sebastian Frias <sebastian_frias@...madesigns.com>
Cc:	linux-mm@...ck.org, Marc Gonzalez <marc_gonzalez@...madesigns.com>,
	linux-kernel@...r.kernel.org
Subject: Re: m(un)map kmalloc buffers to userspace

On Tue 08-12-15 18:25:31, Sebastian Frias wrote:
> Hi,
> 
> We are porting a driver from Linux 3.4.39+ to 4.1.13+, CPU is Cortex-A9.
> 
> The driver maps kmalloc'ed memory to user space.

This sounds like a terrible idea to me. Why don't you simply use the
page allocator directly? Try to imagine what would happen if you mmaped
a kmalloc with a size which is not page aligned? mmaped memory uses
whole page granularity.
-- 
Michal Hocko
SUSE Labs
--
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/