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| author | Kees Cook <keescook@chromium.org> | 2024-01-29 10:21:58 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-02-29 13:38:01 -0800 |
| commit | 3e19086fb5a9079611de426e8cb2f4503e28757e (patch) | |
| tree | cd6e2d20f3e76522542aee1f9b8799362d30c27e /include/linux/overflow.h | |
| parent | adeb04362d74188c1e22ccb824b15a0a7b3de2f4 (diff) | |
| download | linux-3e19086fb5a9079611de426e8cb2f4503e28757e.tar.gz linux-3e19086fb5a9079611de426e8cb2f4503e28757e.tar.bz2 linux-3e19086fb5a9079611de426e8cb2f4503e28757e.zip | |
overflow: Adjust check_*_overflow() kern-doc to reflect results
The check_*_overflow() helpers will return results with potentially
wrapped-around values. These values have always been checked by the
selftests, so avoid the confusing language in the kern-doc. The idea of
"safe for use" was relative to the expectation of whether or not the
caller wants a wrapped value -- the calculation itself will always follow
arithmetic wrapping rules.
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'include/linux/overflow.h')
| -rw-r--r-- | include/linux/overflow.h | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index 7b5cf4a5cd19..ad64d810c8aa 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -57,11 +57,10 @@ static inline bool __must_check __must_check_overflow(bool overflow) * @b: second addend * @d: pointer to store sum * - * Returns 0 on success. + * Returns true on wrap-around, false otherwise. * - * *@d holds the results of the attempted addition, but is not considered - * "safe for use" on a non-zero return value, which indicates that the - * sum has overflowed or been truncated. + * *@d holds the results of the attempted addition, regardless of whether + * wrap-around occurred. */ #define check_add_overflow(a, b, d) \ __must_check_overflow(__builtin_add_overflow(a, b, d)) @@ -72,11 +71,10 @@ static inline bool __must_check __must_check_overflow(bool overflow) * @b: subtrahend; value to subtract from @a * @d: pointer to store difference * - * Returns 0 on success. + * Returns true on wrap-around, false otherwise. * - * *@d holds the results of the attempted subtraction, but is not considered - * "safe for use" on a non-zero return value, which indicates that the - * difference has underflowed or been truncated. + * *@d holds the results of the attempted subtraction, regardless of whether + * wrap-around occurred. */ #define check_sub_overflow(a, b, d) \ __must_check_overflow(__builtin_sub_overflow(a, b, d)) @@ -87,11 +85,10 @@ static inline bool __must_check __must_check_overflow(bool overflow) * @b: second factor * @d: pointer to store product * - * Returns 0 on success. + * Returns true on wrap-around, false otherwise. * - * *@d holds the results of the attempted multiplication, but is not - * considered "safe for use" on a non-zero return value, which indicates - * that the product has overflowed or been truncated. + * *@d holds the results of the attempted multiplication, regardless of whether + * wrap-around occurred. */ #define check_mul_overflow(a, b, d) \ __must_check_overflow(__builtin_mul_overflow(a, b, d)) |