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| author | Kees Cook <keescook@chromium.org> | 2022-02-08 23:53:50 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-02-14 01:50:07 +0100 |
| commit | 281d0c962752fb40866dd8d4cade68656f34bd1f (patch) | |
| tree | 80e7f2219375ddbf042f9dab52a6e5dea45bcff5 /security | |
| parent | fortify: Make sure strlen() may still be used as a constant expression (diff) | |
| download | linux-281d0c962752fb40866dd8d4cade68656f34bd1f.tar.xz linux-281d0c962752fb40866dd8d4cade68656f34bd1f.zip | |
fortify: Add Clang support
Enable FORTIFY_SOURCE support for Clang:
Use the new __pass_object_size and __overloadable attributes so that
Clang will have appropriate visibility into argument sizes such that
__builtin_object_size(p, 1) will behave correctly. Additional details
available here:
https://github.com/llvm/llvm-project/issues/53516
https://github.com/ClangBuiltLinux/linux/issues/1401
A bug with __builtin_constant_p() of globally defined variables was
fixed in Clang 13 (and backported to 12.0.1), so FORTIFY support must
depend on that version or later. Additional details here:
https://bugs.llvm.org/show_bug.cgi?id=41459
commit a52f8a59aef4 ("fortify: Explicitly disable Clang support")
A bug with Clang's -mregparm=3 and -m32 makes some builtins unusable,
so removing -ffreestanding (to gain the needed libcall optimizations
with Clang) cannot be done. Without the libcall optimizations, Clang
cannot provide appropriate FORTIFY coverage, so it must be disabled
for CONFIG_X86_32. Additional details here;
https://github.com/llvm/llvm-project/issues/53645
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: George Burgess IV <gbiv@google.com>
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20220208225350.1331628-9-keescook@chromium.org
Diffstat (limited to 'security')
| -rw-r--r-- | security/Kconfig | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/security/Kconfig b/security/Kconfig index 0b847f435beb..1d2d71cc1f36 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -177,9 +177,10 @@ config HARDENED_USERCOPY_PAGESPAN config FORTIFY_SOURCE bool "Harden common str/mem functions against buffer overflows" depends on ARCH_HAS_FORTIFY_SOURCE - # https://bugs.llvm.org/show_bug.cgi?id=50322 # https://bugs.llvm.org/show_bug.cgi?id=41459 - depends on !CC_IS_CLANG + depends on !CC_IS_CLANG || CLANG_VERSION >= 120001 + # https://github.com/llvm/llvm-project/issues/53645 + depends on !CC_IS_CLANG || !X86_32 help Detect overflows of buffers in common string and memory functions where the compiler can determine and validate the buffer sizes. |