Messages in this thread | | | Date | Tue, 16 Feb 2016 22:20:10 -0700 | From | David Brown <> | Subject | Re: [PATCH] ARM: vdso: Mark vDSO code as read-only |
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On Tue, Feb 16, 2016 at 01:52:33PM -0800, Kees Cook wrote: >On Tue, Feb 16, 2016 at 1:36 PM, David Brown <david.brown@linaro.org> wrote: >> Although the arm vDSO is cleanly separated by code/data with the code >> being read-only in userspace mappings, the code page is still writable >> from the kernel. There have been exploits (such as >> http://itszn.com/blog/?p=21) that take advantage of this on x86 to go >> from a bad kernel write to full root. >> >> Prevent this specific exploit on arm by putting the vDSO code page in >> post-init read-only memory as well. > >Is the vdso dynamically built at init time like on x86, or can this >just use .rodata directly?
On ARM, it is patched during init. Arm64's is just plain read-only.
David
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