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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-02 03:09:03 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-02 03:09:03 +0300 |
commit | f594e28d805aca2c6e158cc647f133cab58a8bb4 (patch) | |
tree | bbc6044de5bc18185c0de5318fc0d2890f9a32d8 /kernel | |
parent | 01463374c50e4fe75abec927fa231f8f5d701852 (diff) | |
parent | 6425392acf24b6d469932dd1b217dc7b20d6447f (diff) | |
download | linux-f594e28d805aca2c6e158cc647f133cab58a8bb4.tar.xz |
Merge tag 'hardening-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull compiler hardening updates from Kees Cook:
"These are various compiler-related hardening feature updates. Notable
is the addition of an explicit limited rationale for, and deprecation
schedule of, gcc-plugins.
gcc-plugins:
- remove support for GCC 4.9 and older (Ard Biesheuvel)
- remove duplicate include in gcc-common.h (Ye Guojin)
- Explicitly document purpose and deprecation schedule (Kees Cook)
- Remove cyc_complexity (Kees Cook)
instrumentation:
- Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO (Kees Cook)
Clang LTO:
- kallsyms: strip LTO suffixes from static functions (Nick Desaulniers)"
* tag 'hardening-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: remove duplicate include in gcc-common.h
gcc-plugins: Remove cyc_complexity
gcc-plugins: Explicitly document purpose and deprecation schedule
kallsyms: strip LTO suffixes from static functions
gcc-plugins: remove support for GCC 4.9 and older
hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/kallsyms.c | 46 |
1 files changed, 33 insertions, 13 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 0ba87982d017..3011bc33a5ba 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -164,26 +164,46 @@ static unsigned long kallsyms_sym_address(int idx) return kallsyms_relative_base - 1 - kallsyms_offsets[idx]; } -#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_LTO_CLANG_THIN) -/* - * LLVM appends a hash to static function names when ThinLTO and CFI are - * both enabled, i.e. foo() becomes foo$707af9a22804d33c81801f27dcfe489b. - * This causes confusion and potentially breaks user space tools, so we - * strip the suffix from expanded symbol names. - */ -static inline bool cleanup_symbol_name(char *s) +static bool cleanup_symbol_name(char *s) { char *res; + if (!IS_ENABLED(CONFIG_LTO_CLANG)) + return false; + + /* + * LLVM appends various suffixes for local functions and variables that + * must be promoted to global scope as part of LTO. This can break + * hooking of static functions with kprobes. '.' is not a valid + * character in an identifier in C. Suffixes observed: + * - foo.llvm.[0-9a-f]+ + * - foo.[0-9a-f]+ + * - foo.[0-9a-f]+.cfi_jt + */ + res = strchr(s, '.'); + if (res) { + *res = '\0'; + return true; + } + + if (!IS_ENABLED(CONFIG_CFI_CLANG) || + !IS_ENABLED(CONFIG_LTO_CLANG_THIN) || + CONFIG_CLANG_VERSION >= 130000) + return false; + + /* + * Prior to LLVM 13, the following suffixes were observed when thinLTO + * and CFI are both enabled: + * - foo$[0-9]+ + */ res = strrchr(s, '$'); - if (res) + if (res) { *res = '\0'; + return true; + } - return res != NULL; + return false; } -#else -static inline bool cleanup_symbol_name(char *s) { return false; } -#endif /* Lookup the address for this symbol. Returns 0 if not found. */ unsigned long kallsyms_lookup_name(const char *name) |