Messages in this thread | | | Date | Tue, 19 Mar 2013 08:43:25 +0100 | From | Clemens Ladisch <> | Subject | Re: [PATCH] hpet, allow user controlled mmap for user processes |
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Prarit Bhargava wrote: > The CONFIG_HPET_MMAP Kconfig option exposes the memory map of the HPET > registers to userspace. The Kconfig help points out that in some cases this > can be a security risk as some systems may erroneously configure the map such > that additional data is exposed to userspace. > > This is a problem for distributions -- some users want the MMAP functionality > but it comes with a significant security risk. In an effort to mitigate this > risk, and due to the low number of users of the MMAP functionality, I've > introduced a kernel parameter, hpet_mmap_enable, that is required in order > to actually have the HPET MMAP exposed. > > [v2]: Clemens suggested modifying the Kconfig help text and making the > default setting configurable. > > Signed-off-by: Prarit Bhargava <prarit@redhat.com> > Cc: Clemens Ladisch <clemens@ladisch.de>
> +++ b/Documentation/kernel-parameters.txt > + hpet_mmap_enable [X86, HPET_MMAP] option to expose HPET MMAP to > + userspace. By default this is disabled.
This now takes a value.
> + int "Enable HPET MMAP access by default" > + range 0 1
Shouldn't this be bool?
> + default 0
This breaks backwards compatibility.
Regards, Clemens
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