diff options
| author | Ben Hutchings <benh@debian.org> | 2022-07-23 17:28:13 +0200 |
|---|---|---|
| committer | Ben Hutchings <benh@debian.org> | 2022-07-23 18:29:42 +0200 |
| commit | 166b4f33b02eb74509b66357e57453b924f15608 (patch) | |
| tree | 423c9c02cd2a998f4e690398423d1e48aee3fd16 /debian/patches | |
| parent | fe75236211051481b79eb3ec1c69f972a49f8001 (diff) | |
| download | linux-debian-166b4f33b02eb74509b66357e57453b924f15608.tar.gz | |
[x86] speculation: Make all RETbleed mitigations depend on X86_64
The mitigations for RETBleed are currently ineffective on i386,
but without this they would wrongly be reported as active.
Diffstat (limited to 'debian/patches')
| -rw-r--r-- | debian/patches/bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch | 56 | ||||
| -rw-r--r-- | debian/patches/series | 1 |
2 files changed, 57 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. diff --git a/debian/patches/series b/debian/patches/series index 550311549..4f48a68d2 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -99,6 +99,7 @@ features/all/db-mok-keyring/KEYS-Make-use-of-platform-keyring-for-module-signatu # Security fixes debian/i386-686-pae-pci-set-pci-nobios-by-default.patch debian/ntfs-mark-it-as-broken.patch +bugfix/x86/x86-speculation-make-all-retbleed-mitigations-depend.patch # Fix exported symbol versions bugfix/all/module-disable-matching-missing-version-crc.patch |