From caf7501a1b4ec964190f31f9c3f163de252273b8 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 25 Jan 2018 15:50:28 -0800 Subject: 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 Signed-off-by: Thomas Gleixner Cc: David Woodhouse 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 --- include/linux/module.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index fe5aa3736707..b1cc541f2ddf 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -794,6 +794,15 @@ static inline void module_bug_finalize(const Elf_Ehdr *hdr, static inline void module_bug_cleanup(struct module *mod) {} #endif /* CONFIG_GENERIC_BUG */ +#ifdef RETPOLINE +extern bool retpoline_module_ok(bool has_retpoline); +#else +static inline bool retpoline_module_ok(bool has_retpoline) +{ + return true; +} +#endif + #ifdef CONFIG_MODULE_SIG static inline bool module_sig_ok(struct module *module) { -- cgit v1.2.3