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authorKees Cook <keescook@chromium.org>2022-02-08 14:53:50 -0800
committerKees Cook <keescook@chromium.org>2022-02-13 16:50:07 -0800
commit281d0c962752fb40866dd8d4cade68656f34bd1f (patch)
tree80e7f2219375ddbf042f9dab52a6e5dea45bcff5 /security
parent67ebc3ab446230c77fe3b545a9d8a11cac1cfb6e (diff)
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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/Kconfig5
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.