In preparation for adding stricter type checking to the str/mem*() helpers, provide a way to check that a variable is a character array via __must_be_char_array().
Signed-off-by: Kees Cook <[email protected]> --- include/linux/compiler.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 7af999a131cb..a577fe0b1f8a 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -221,7 +221,13 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, #endif /* __CHECKER__ */ /* &a[0] degrades to a pointer: a different type from an array */ -#define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array") +#define __is_array(a) (!__same_type((a), &(a)[0])) +#define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(!__is_array(a), \ + "must be array") + +#define __is_char_array(a) (__is_array(a) && sizeof((a)[0]) == 1) +#define __must_be_char_array(a) __BUILD_BUG_ON_ZERO_MSG(!__is_char_array(a), \ + "must be byte array") /* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */ #define __must_be_cstr(p) \ -- 2.34.1
