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| author | H.J. Lu <hjl.tools@gmail.com> | 2023-12-29 08:43:53 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2024-01-01 05:22:48 -0800 |
| commit | 55d63e731253de82e96ed4ddca2e294076cd0bc5 (patch) | |
| tree | 7bf46a0d70507206c236f946b45d15159687676c | |
| parent | d360dcc001cb12504cd3e8dbddee20df6bebb0f8 (diff) | |
| download | glibc-55d63e731253de82e96ed4ddca2e294076cd0bc5.tar.gz glibc-55d63e731253de82e96ed4ddca2e294076cd0bc5.tar.xz glibc-55d63e731253de82e96ed4ddca2e294076cd0bc5.zip | |
x86/cet: Don't set CET active by default
Not all CET enabled applications and libraries have been properly tested in CET enabled environments. Some CET enabled applications or libraries will crash or misbehave when CET is enabled. Don't set CET active by default so that all applications and libraries will run normally regardless of whether CET is active or not. Shadow stack can be enabled by $ export GLIBC_TUNABLES=glibc.cpu.hwcaps=SHSTK at run-time if shadow stack can be enabled by kernel. NB: This commit can be reverted if it is OK to enable CET by default for all applications and libraries.
| -rw-r--r-- | sysdeps/x86/cpu-features.c | 2 | ||||
| -rw-r--r-- | sysdeps/x86/cpu-tunables.c | 15 |
2 files changed, 15 insertions, 2 deletions
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 097868c1d9..80a07ac589 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -110,7 +110,7 @@ update_active (struct cpu_features *cpu_features) if (!CPU_FEATURES_CPU_P (cpu_features, RTM_ALWAYS_ABORT)) CPU_FEATURE_SET_ACTIVE (cpu_features, RTM); -#if CET_ENABLED +#if CET_ENABLED && 0 CPU_FEATURE_SET_ACTIVE (cpu_features, IBT); CPU_FEATURE_SET_ACTIVE (cpu_features, SHSTK); #endif diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 142c6b9240..1742400525 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -35,6 +35,17 @@ break; \ } +#define CHECK_GLIBC_IFUNC_CPU_BOTH(f, cpu_features, name, len) \ + _Static_assert (sizeof (#name) - 1 == len, #name " != " #len); \ + if (tunable_str_comma_strcmp_cte (&f, #name)) \ + { \ + if (f.disable) \ + CPU_FEATURE_UNSET (cpu_features, name) \ + else \ + CPU_FEATURE_SET_ACTIVE (cpu_features, name) \ + break; \ + } + /* Disable a preferred feature NAME. We don't enable a preferred feature which isn't available. */ #define CHECK_GLIBC_IFUNC_PREFERRED_OFF(f, cpu_features, name, len) \ @@ -131,11 +142,13 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) } break; case 5: + { + CHECK_GLIBC_IFUNC_CPU_BOTH (n, cpu_features, SHSTK, 5); + } if (n.disable) { CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, LZCNT, 5); CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, MOVBE, 5); - CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SHSTK, 5); CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSSE3, 5); CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, XSAVE, 5); } |