linux/lib/ubsan.h
Kees Cook 557f8c582a ubsan: Reintroduce signed overflow sanitizer
In order to mitigate unexpected signed wrap-around[1], bring back the
signed integer overflow sanitizer. It was removed in commit 6aaa31aeb9
("ubsan: remove overflow checks") because it was effectively a no-op
when combined with -fno-strict-overflow (which correctly changes signed
overflow from being "undefined" to being explicitly "wrap around").

Compilers are adjusting their sanitizers to trap wrap-around and to
detecting common code patterns that should not be instrumented
(e.g. "var + offset < var"). Prepare for this and explicitly rename
the option from "OVERFLOW" to "WRAP" to more accurately describe the
behavior.

To annotate intentional wrap-around arithmetic, the helpers
wrapping_add/sub/mul_wrap() can be used for individual statements. At
the function level, the __signed_wrap attribute can be used to mark an
entire function as expecting its signed arithmetic to wrap around. For a
single object file the Makefile can use "UBSAN_SIGNED_WRAP_target.o := n"
to mark it as wrapping, and for an entire directory, "UBSAN_SIGNED_WRAP :=
n" can be used.

Additionally keep these disabled under CONFIG_COMPILE_TEST for now.

Link: https://github.com/KSPP/linux/issues/26 [1]
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hao Luo <haoluo@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2024-02-20 20:44:49 -08:00

143 lines
3.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LIB_UBSAN_H
#define _LIB_UBSAN_H
/*
* ABI defined by Clang's UBSAN enum SanitizerHandler:
* https://github.com/llvm/llvm-project/blob/release/16.x/clang/lib/CodeGen/CodeGenFunction.h#L113
*/
enum ubsan_checks {
ubsan_add_overflow,
ubsan_builtin_unreachable,
ubsan_cfi_check_fail,
ubsan_divrem_overflow,
ubsan_dynamic_type_cache_miss,
ubsan_float_cast_overflow,
ubsan_function_type_mismatch,
ubsan_implicit_conversion,
ubsan_invalid_builtin,
ubsan_invalid_objc_cast,
ubsan_load_invalid_value,
ubsan_missing_return,
ubsan_mul_overflow,
ubsan_negate_overflow,
ubsan_nullability_arg,
ubsan_nullability_return,
ubsan_nonnull_arg,
ubsan_nonnull_return,
ubsan_out_of_bounds,
ubsan_pointer_overflow,
ubsan_shift_out_of_bounds,
ubsan_sub_overflow,
ubsan_type_mismatch,
ubsan_alignment_assumption,
ubsan_vla_bound_not_positive,
};
enum {
type_kind_int = 0,
type_kind_float = 1,
type_unknown = 0xffff
};
struct type_descriptor {
u16 type_kind;
u16 type_info;
char type_name[1];
};
struct source_location {
const char *file_name;
union {
unsigned long reported;
struct {
u32 line;
u32 column;
};
};
};
struct overflow_data {
struct source_location location;
struct type_descriptor *type;
};
struct type_mismatch_data {
struct source_location location;
struct type_descriptor *type;
unsigned long alignment;
unsigned char type_check_kind;
};
struct type_mismatch_data_v1 {
struct source_location location;
struct type_descriptor *type;
unsigned char log_alignment;
unsigned char type_check_kind;
};
struct type_mismatch_data_common {
struct source_location *location;
struct type_descriptor *type;
unsigned long alignment;
unsigned char type_check_kind;
};
struct nonnull_arg_data {
struct source_location location;
struct source_location attr_location;
int arg_index;
};
struct out_of_bounds_data {
struct source_location location;
struct type_descriptor *array_type;
struct type_descriptor *index_type;
};
struct shift_out_of_bounds_data {
struct source_location location;
struct type_descriptor *lhs_type;
struct type_descriptor *rhs_type;
};
struct unreachable_data {
struct source_location location;
};
struct invalid_value_data {
struct source_location location;
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;
#else
typedef s64 s_max;
typedef u64 u_max;
#endif
void __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
void __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
void __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
void __ubsan_handle_negate_overflow(void *_data, void *old_val);
void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
void __ubsan_handle_out_of_bounds(void *_data, void *index);
void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
void __ubsan_handle_builtin_unreachable(void *_data);
void __ubsan_handle_load_invalid_value(void *_data, void *val);
void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
unsigned long align,
unsigned long offset);
#endif