Commit cb7380de authored by Kees Cook's avatar Kees Cook
Browse files

compiler.h: Move C string helpers into C-only kernel section 



The C kernel helpers for evaluating C Strings were positioned where they
were visible to assembly inclusion, which was not intended. Move them
into the kernel and C-only area of the header so future changes won't
confuse the assembler.

Fixes: d7a516c6 ("compiler.h: Fix undefined BUILD_BUG_ON_ZERO()")
Fixes: 559048d1 ("string: Check for "nonstring" attribute on strscpy() arguments")
Reviewed-by: default avatarMiguel Ojeda <ojeda@kernel.org>
Signed-off-by: default avatarKees Cook <kees@kernel.org>
parent 78bba609

include/linux/compiler.h

+13 −13
Original line number Diff line number Diff line
@@ -214,6 +214,19 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, 
	__v;								\

})



#ifdef __CHECKER__

#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)

#else /* __CHECKER__ */

#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))

#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")



/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */

#define __must_be_cstr(p) \

	__BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")



#endif /* __KERNEL__ */



/**
@@ -254,19 +267,6 @@ static inline void *offset_to_ptr(const int *off) 


#define __ADDRESSABLE_ASM_STR(sym) __stringify(__ADDRESSABLE_ASM(sym))



#ifdef __CHECKER__

#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)

#else /* __CHECKER__ */

#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))

#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")



/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */

#define __must_be_cstr(p) \

	__BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")



/*

 * This returns a constant expression while determining if an argument is

 * a constant expression, most importantly without evaluating the argument.