The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 18032b47adf1db7b7f5fb2d1344e65aafe6417df
Gitweb: https://git.kernel.org/tip/18032b47adf1db7b7f5fb2d1344e65aafe6417df
Author: Jim Mattson <jmattson@xxxxxxxxxx>
AuthorDate: Wed, 30 Aug 2023 21:32:21 -07:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 31 Aug 2023 23:29:49 +02:00
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@xxxxxxxxxx>
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230831043228.1194256-1-jmattson@xxxxxxxxxx
---
arch/x86/kernel/fpu/xstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 1afbc48..a27b4f7 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -71,7 +71,7 @@ static unsigned short xsave_cpuid_features[] __initdata = {
[XFEATURE_ZMM_Hi256] = X86_FEATURE_AVX512F,
[XFEATURE_Hi16_ZMM] = X86_FEATURE_AVX512F,
[XFEATURE_PT_UNIMPLEMENTED_SO_FAR] = X86_FEATURE_INTEL_PT,
- [XFEATURE_PKRU] = X86_FEATURE_PKU,
+ [XFEATURE_PKRU] = X86_FEATURE_OSPKE,
[XFEATURE_PASID] = X86_FEATURE_ENQCMD,
[XFEATURE_XTILE_CFG] = X86_FEATURE_AMX_TILE,
[XFEATURE_XTILE_DATA] = X86_FEATURE_AMX_TILE,
|