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ubsan: implement __ubsan_handle_alignment_assumption

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When building ARCH=mips 32r2el_defconfig with CONFIG_UBSAN_ALIGNMENT:

  ld.lld: error: undefined symbol: __ubsan_handle_alignment_assumption
     referenced by slab.h:557 (include/linux/slab.h:557)
                   main.o:(do_initcalls) in archive init/built-in.a
     referenced by slab.h:448 (include/linux/slab.h:448)
                   do_mounts_rd.o:(rd_load_image) in archive init/built-in.a
     referenced by slab.h:448 (include/linux/slab.h:448)
                   do_mounts_rd.o:(identify_ramdisk_image) in archive init/built-in.a
     referenced 1579 more times

Implement this for the kernel based on LLVM's
handleAlignmentAssumptionImpl because the kernel is not linked against
the compiler runtime.

Link: https://github.com/ClangBuiltLinux/linux/issues/1245
Link: https://github.com/llvm/llvm-project/blob/llvmorg-11.0.1/compiler-rt/lib/ubsan/ubsan_handlers.cpp#L151-L190
Link: https://lkml.kernel.org/r/20210127224451.2587372-1-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nathan Chancellor 2021-02-04 18:32:57 -08:00 committed by Linus Torvalds
parent b99acdcbfe
commit 28abcc9631
2 changed files with 37 additions and 0 deletions
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31
lib/ubsan.c
View File

@ -427,3 +427,34 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val)
ubsan_epilogue();
}
EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
unsigned long align,
unsigned long offset);
void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
unsigned long align,
unsigned long offset)
{
struct alignment_assumption_data *data = _data;
unsigned long real_ptr;
if (suppress_report(&data->location))
return;
ubsan_prologue(&data->location, "alignment-assumption");
if (offset)
pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
align, offset, data->type->type_name);
else
pr_err("assumption of %lu byte alignment for pointer of type %s failed",
align, data->type->type_name);
real_ptr = ptr - offset;
pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0),
real_ptr & (align - 1));
ubsan_epilogue();
}
EXPORT_SYMBOL(__ubsan_handle_alignment_assumption);

6
lib/ubsan.h
View File

@ -78,6 +78,12 @@ struct invalid_value_data {
struct type_descriptor *type;
};
struct alignment_assumption_data {
struct source_location location;
struct source_location assumption_location;
struct type_descriptor *type;
};
#if defined(CONFIG_ARCH_SUPPORTS_INT128)
typedef __int128 s_max;
typedef unsigned __int128 u_max;