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Quentin Casasnovas authored
Commit: f31a9f7c ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area") introduced alternative instructions for XSAVES/XRSTORS and commit: adb9d526 ("x86/xsaves: Add xsaves and xrstors support for booting time") added support for the XSAVES/XRSTORS instructions at boot time. Unfortunately both failed to properly protect them against faulting: The 'xstate_fault' macro will use the closest label named '1' backward and that ends up in the .altinstr_replacement section rather than in .text. This means that the kernel will never find in the __ex_table the .text address where this instruction might fault, leading to serious problems if userspace manages to trigger the fault. Signed-off-by:
Quentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by:
Jamie Iles <jamie.iles@oracle.com> [ Improved the changelog, fixed some whitespace noise. ] Acked-by:
Borislav Petkov <bp@alien8.de> Acked-by:
Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Cc: Allan Xavier <mr.a.xavier@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: adb9d526 ("x86/xsaves: Add xsaves and xrstors support for booting time") Fixes: f31a9f7c ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area") Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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