diff options
Diffstat (limited to 'debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch')
| -rw-r--r-- | debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch b/debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch new file mode 100644 index 000000000..a6d04fca8 --- /dev/null +++ b/debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch @@ -0,0 +1,56 @@ +From: Ben Hutchings <ben@decadent.org.uk> +Date: Sat, 23 Jul 2022 16:20:34 +0200 +Subject: x86/speculation: Make all RETbleed mitigations depend on X86_64 +Forwarded: https://lore.kernel.org/lkml/YtwSR3NNsWp1ohfV@decadent.org.uk/T/ + +The mitigations for RETBleed are currently ineffective on x86_32 since +entry_32.S does not use the required macros. However, for an x86_32 +target, the kconfig symbols for them are still enabled by default and +/sys/devices/system/cpu/vulnerabilities/retbleed will wrongly report +that mitigations are in place. + +Make all of these symbols depend on X86_64, and only enable RETHUNK by +default on X86_64. + +Cc: stable@vger.kernel.org +Signed-off-by: Ben Hutchings <ben@decadent.org.uk> +--- + arch/x86/Kconfig | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -2469,7 +2469,7 @@ config RETPOLINE + config RETHUNK + bool "Enable return-thunks" + depends on RETPOLINE && CC_HAS_RETURN_THUNK +- default y ++ default y if X86_64 + help + Compile the kernel with the return-thunks compiler option to guard + against kernel-to-user data leaks by avoiding return speculation. +@@ -2478,21 +2478,21 @@ config RETHUNK + + config CPU_UNRET_ENTRY + bool "Enable UNRET on kernel entry" +- depends on CPU_SUP_AMD && RETHUNK ++ depends on CPU_SUP_AMD && RETHUNK && X86_64 + default y + help + Compile the kernel with support for the retbleed=unret mitigation. + + config CPU_IBPB_ENTRY + bool "Enable IBPB on kernel entry" +- depends on CPU_SUP_AMD ++ depends on CPU_SUP_AMD && X86_64 + default y + help + Compile the kernel with support for the retbleed=ibpb mitigation. + + config CPU_IBRS_ENTRY + bool "Enable IBRS on kernel entry" +- depends on CPU_SUP_INTEL ++ depends on CPU_SUP_INTEL && X86_64 + default y + help + Compile the kernel with support for the spectre_v2=ibrs mitigation. |