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| author | Kees Cook <keescook@chromium.org> | 2024-03-06 15:51:36 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-03-22 16:25:31 -0700 |
| commit | d8e45f2929b94099913eb66c3ebb18b5063e9421 (patch) | |
| tree | 236c22e5ae9d2d4b3066a6982369edd73d66a7c5 /include | |
| parent | acd80cdcee17eb770fcb2b0dc659b78f369d8c01 (diff) | |
| download | lwn-d8e45f2929b94099913eb66c3ebb18b5063e9421.tar.gz lwn-d8e45f2929b94099913eb66c3ebb18b5063e9421.zip | |
overflow: Change DEFINE_FLEX to take __counted_by member
The norm should be flexible array structures with __counted_by
annotations, so DEFINE_FLEX() is updated to expect that. Rename
the non-annotated version to DEFINE_RAW_FLEX(), and update the
few existing users. Additionally add selftests for the macros.
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20240306235128.it.933-kees@kernel.org
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/overflow.h | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/include/linux/overflow.h b/include/linux/overflow.h index aa691f2119b0..0c7e3dcfe867 100644 --- a/include/linux/overflow.h +++ b/include/linux/overflow.h @@ -398,7 +398,7 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * @count: Number of elements in the array; must be compile-time const. * @initializer: initializer expression (could be empty for no init). */ -#define _DEFINE_FLEX(type, name, member, count, initializer) \ +#define _DEFINE_FLEX(type, name, member, count, initializer...) \ _Static_assert(__builtin_constant_p(count), \ "onstack flex array members require compile-time const count"); \ union { \ @@ -408,8 +408,8 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) type *name = (type *)&name##_u /** - * DEFINE_FLEX() - Define an on-stack instance of structure with a trailing - * flexible array member. + * DEFINE_RAW_FLEX() - Define an on-stack instance of structure with a trailing + * flexible array member, when it does not have a __counted_by annotation. * * @type: structure type name, including "struct" keyword. * @name: Name for a variable to define. @@ -420,7 +420,24 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend) * flexible array member. * Use __struct_size(@name) to get compile-time size of it afterwards. */ -#define DEFINE_FLEX(type, name, member, count) \ +#define DEFINE_RAW_FLEX(type, name, member, count) \ _DEFINE_FLEX(type, name, member, count, = {}) +/** + * DEFINE_FLEX() - Define an on-stack instance of structure with a trailing + * flexible array member. + * + * @TYPE: structure type name, including "struct" keyword. + * @NAME: Name for a variable to define. + * @MEMBER: Name of the array member. + * @COUNTER: Name of the __counted_by member. + * @COUNT: Number of elements in the array; must be compile-time const. + * + * Define a zeroed, on-stack, instance of @TYPE structure with a trailing + * flexible array member. + * Use __struct_size(@NAME) to get compile-time size of it afterwards. + */ +#define DEFINE_FLEX(TYPE, NAME, MEMBER, COUNTER, COUNT) \ + _DEFINE_FLEX(TYPE, NAME, MEMBER, COUNT, = { .obj.COUNTER = COUNT, }) + #endif /* __LINUX_OVERFLOW_H */ |