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| author | Prarit Bhargava <prarit@redhat.com> | 2013-11-12 15:08:33 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-13 12:09:11 +0900 |
| commit | 3d035f580699feba352f8703cced127fc203f0dd (patch) | |
| tree | 9469709ea2eda88e66531edb865ab41757615a0d /Documentation/kernel-parameters.txt | |
| parent | 72403b4a0fbdf433c1fe0127e49864658f6f6468 (diff) | |
| download | lwn-3d035f580699feba352f8703cced127fc203f0dd.tar.gz lwn-3d035f580699feba352f8703cced127fc203f0dd.zip | |
drivers/char/hpet.c: allow user controlled mmap for user processes
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.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Matt Wilson <msw@amazon.com>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 882a40d405c8..9ca3e74a10e1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1070,6 +1070,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. VIA, nVidia) verbose: show contents of HPET registers during setup + hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET + registers. Default set by CONFIG_HPET_MMAP_DEFAULT. + hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. On x86-64 and powerpc, this option can be specified |