Messages in this thread | | | Date | Thu, 20 Jan 2005 09:35:59 +0100 | From | Ingo Molnar <> | Subject | Re: thoughts on kernel security issues |
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* John Richard Moser <nigelenki@comcast.net> wrote:
> On a final note, isn't PaX the only technology trying to apply NX > protections to kernel space? [...]
NX protection for kernel-space overflows on x86 has been part of the mainline kernel as of June 2004 (released in 2.6.8), on CPUs that support the NX bit - i.e. latest AMD and Intel CPUs. Let me quote from the commit log:
http://linux.bkbits.net:8080/linux-2.5/cset@1.1757.49.12
[...] furthermore, the patch also implements 'NX protection' for kernelspace code: only the kernel code and modules are executable - so even kernel-space overflows are harder (in some cases, impossible) to exploit. Here is how kernel code that tries to execute off the stack is stopped:
kernel tried to access NX-protected page - exploit attempt? (uid: 500) Unable to handle kernel paging request at virtual address f78d0f40 printing eip: ...
implemented, split out and brought to you by yours truly, as part of the exec-shield project. (You know, the one not developed by that 'scheduler developer' ;-)
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