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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-05-15 01:33:54 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-05-15 01:33:54 +0200 |
| commit | fa81511bb0bbb2b1aace3695ce869da9762624ff (patch) | |
| tree | 4feff999a6217471bc23f997ef77bc492b225ffc /arch/x86/kernel/head64.c | |
| parent | x86, mm, hugetlb: Add missing TLB page invalidation for hugetlb_cow() (diff) | |
| download | linux-fa81511bb0bbb2b1aace3695ce869da9762624ff.tar.xz linux-fa81511bb0bbb2b1aace3695ce869da9762624ff.zip | |
x86-64, modify_ldt: Make support for 16-bit segments a runtime option
Checkin:
b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels
disabled 16-bit segments on 64-bit kernels due to an information
leak. However, it does seem that people are genuinely using Wine to
run old 16-bit Windows programs on Linux.
A proper fix for this ("espfix64") is coming in the upcoming merge
window, but as a temporary fix, create a sysctl to allow the
administrator to re-enable support for 16-bit segments.
It adds a "/proc/sys/abi/ldt16" sysctl that defaults to zero (off). If
you hit this issue and care about your old Windows program more than
you care about a kernel stack address information leak, you can do
echo 1 > /proc/sys/abi/ldt16
as root (add it to your startup scripts), and you should be ok.
The sysctl table is only added if you have COMPAT support enabled on
x86-64, but I assume anybody who runs old windows binaries very much
does that ;)
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/CA%2B55aFw9BPoD10U1LfHbOMpHWZkvJTkMcfCs9s3urPr1YyWBxw@mail.gmail.com
Cc: <stable@vger.kernel.org>
Diffstat (limited to 'arch/x86/kernel/head64.c')
0 files changed, 0 insertions, 0 deletions