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(parent: d87e89c) | patch
x86/fpu/xstate: Fix PKRU covert channel
authorJim Mattson <jmattson@google.com>
Thu, 31 Aug 2023 04:32:21 +0000 (21:32 -0700)
committerIngo Molnar <mingo@kernel.org>
Thu, 31 Aug 2023 21:29:49 +0000 (23:29 +0200)
commit18032b47adf1db7b7f5fb2d1344e65aafe6417df
tree7847bbd9a68b4544ebd74c07a5e2f5d7c210c0a0tree | snapshot
parentd87e89c2735772fbed933be0d19e032c1910a51fcommit | diff
x86/fpu/xstate: Fix PKRU covert channel

When XCR0[9] is set, PKRU can be read and written from userspace with
XSAVE and XRSTOR, even when CR4.PKE is clear.

Clear XCR0[9] when protection keys are disabled.

Reported-by: Tavis Ormandy <taviso@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20230831043228.1194256-1-jmattson@google.com
arch/x86/kernel/fpu/xstate.c diff | blob | history
ep93xx device tree rework repo: git://git.maquefel.me/linux.git