fortify: Do not cast to "unsigned char"

[ Upstream commit e9a40e1585d792751d3a122392695e5a53032809 ]

Do not cast to "unsigned char", as this needlessly creates type problems
when attempting builds without -Wno-pointer-sign[1]. The intent of the
cast is to drop possible "const" types.

[1] https://lore.kernel.org/lkml/CAHk-=wgz3Uba8w7kdXhsqR1qvfemYL+OFQdefJnkeqXG8qZ_pA@mail.gmail.com/

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 3009f891bb9f ("fortify: Allow strlen() and strnlen() to pass compile-time known lengths")
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index 1067a84..5001a11 100644 (file)
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -18,7 +18,7 @@ void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("
 
 #define __compiletime_strlen(p)                                        \
 ({                                                             \
-       unsigned char *__p = (unsigned char *)(p);              \
+       char *__p = (char *)(p);                                \
        size_t __ret = SIZE_MAX;                                \
        size_t __p_size = __member_size(p);                     \
        if (__p_size != SIZE_MAX &&                             \