Re: [PATCH 06/14] Fix CFLAGS for UBSAN_BOUNDS on Clang
From: Kees Cook <hidden>
Date: 2020-09-14 22:13:23
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On Mon, Sep 14, 2020 at 05:27:42PM +0000, George-Aurelian Popescu wrote:
From: George Popescu <redacted> When the kernel is compiled with Clang, UBSAN_BOUNDS inserts a brk after the handler call, preventing it from printing any information processed inside the buffer. For Clang -fsanitize=bounds expands to -fsanitize=array-bounds and -fsanitize=local-bounds, and the latter adds a brk after the handler call
That sounds like a compiler bug?
quoted hunk ↗ jump to hunk
Signed-off-by: George Popescu <redacted> --- scripts/Makefile.ubsan | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index 27348029b2b8..3d15ac346c97 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan@@ -4,7 +4,14 @@ ifdef CONFIG_UBSAN_ALIGNMENT endif ifdef CONFIG_UBSAN_BOUNDS - CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds) + # For Clang -fsanitize=bounds translates to -fsanitize=array-bounds and + # -fsanitize=local-bounds; the latter adds a brk right after the + # handler is called. + ifdef CONFIG_CC_IS_CLANG + CFLAGS_UBSAN += $(call cc-option, -fsanitize=array-bounds)
This would mean losing the local-bounds coverage? Isn't that for locally defined arrays on the stack?
+ else + CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds) + endif endif ifdef CONFIG_UBSAN_MISC -- 2.28.0.618.gf4bc123cb7-goog
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