diff options
| author | Andi Kleen <ak@linux.intel.com> | 2018-01-26 00:50:28 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-26 15:03:56 +0100 |
| commit | caf7501a1b4ec964190f31f9c3f163de252273b8 (patch) | |
| tree | f626e796eb8f30eca268595ca07dc90e00b06ec3 /arch/x86 | |
| parent | KVM: VMX: Make indirect call speculation safe (diff) | |
| download | linux-caf7501a1b4ec964190f31f9c3f163de252273b8.tar.xz linux-caf7501a1b4ec964190f31f9c3f163de252273b8.zip | |
module/retpoline: Warn about missing retpoline in module
There's a risk that a kernel which has full retpoline mitigations becomes
vulnerable when a module gets loaded that hasn't been compiled with the
right compiler or the right option.
To enable detection of that mismatch at module load time, add a module info
string "retpoline" at build time when the module was compiled with
retpoline support. This only covers compiled C source, but assembler source
or prebuilt object files are not checked.
If a retpoline enabled kernel detects a non retpoline protected module at
load time, print a warning and report it in the sysfs vulnerability file.
[ tglx: Massaged changelog ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: gregkh@linuxfoundation.org
Cc: torvalds@linux-foundation.org
Cc: jeyu@kernel.org
Cc: arjan@linux.intel.com
Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 390b3dc3d438..4a39d7bb4bd8 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -11,6 +11,7 @@ #include <linux/init.h> #include <linux/utsname.h> #include <linux/cpu.h> +#include <linux/module.h> #include <asm/nospec-branch.h> #include <asm/cmdline.h> @@ -93,6 +94,19 @@ static const char *spectre_v2_strings[] = { #define pr_fmt(fmt) "Spectre V2 mitigation: " fmt static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE; +static bool spectre_v2_bad_module; + +#ifdef RETPOLINE +bool retpoline_module_ok(bool has_retpoline) +{ + if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline) + return true; + + pr_err("System may be vunerable to spectre v2\n"); + spectre_v2_bad_module = true; + return false; +} +#endif static void __init spec2_print_if_insecure(const char *reason) { @@ -278,6 +292,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev, if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n"); - return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]); + return sprintf(buf, "%s%s\n", spectre_v2_strings[spectre_v2_enabled], + spectre_v2_bad_module ? " - vulnerable module loaded" : ""); } #endif |