[PATCH 1/2] string: move __compiletime_strlen() to string.h
From: Xie Yuanbin <hidden>
Date: 2026-02-05 10:05:32
Also in:
linux-hardening, lkml
Subsystem:
fortify_source, generic string library, library code, the rest · Maintainers:
Kees Cook, Andrew Morton, Linus Torvalds
Move __compiletime_strlen() to string.h, so that others can use. Signed-off-by: Xie Yuanbin <redacted> --- include/linux/fortify-string.h | 15 --------------- include/linux/string.h | 15 +++++++++++++++ lib/tests/fortify_kunit.c | 3 ++- 3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index 171982e53c9a..c181dac26353 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h@@ -58,21 +58,6 @@ void __read_overflow2_field(size_t avail, size_t wanted) __compiletime_warning(" void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)"); void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("detected write beyond size of field (1st parameter); maybe use struct_group()?"); -#define __compiletime_strlen(p) \ -({ \ - char *__p = (char *)(p); \ - size_t __ret = SIZE_MAX; \ - const size_t __p_size = __member_size(p); \ - if (__p_size != SIZE_MAX && \ - __builtin_constant_p(*__p)) { \ - size_t __p_len = __p_size - 1; \ - if (__builtin_constant_p(__p[__p_len]) && \ - __p[__p_len] == '\0') \ - __ret = __builtin_strlen(__p); \ - } \ - __ret; \ -}) - #if defined(__SANITIZE_ADDRESS__) #if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
diff --git a/include/linux/string.h b/include/linux/string.h
index 1b564c36d721..fbae7d99bb6f 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h@@ -19,6 +19,21 @@ extern void *memdup_user(const void __user *, size_t) __realloc_size(2); extern void *vmemdup_user(const void __user *, size_t) __realloc_size(2); extern void *memdup_user_nul(const void __user *, size_t); +#define __compiletime_strlen(p) \ +({ \ + char *__p = (char *)(p); \ + size_t __ret = SIZE_MAX; \ + const size_t __p_size = __member_size(p); \ + if (__p_size != SIZE_MAX && \ + __builtin_constant_p(*__p)) { \ + size_t __p_len = __p_size - 1; \ + if (__builtin_constant_p(__p[__p_len]) && \ + __p[__p_len] == '\0') \ + __ret = __builtin_strlen(__p); \ + } \ + __ret; \ +}) + /** * memdup_array_user - duplicate array from user space * @src: source address in user space
diff --git a/lib/tests/fortify_kunit.c b/lib/tests/fortify_kunit.c
index fc9c76f026d6..86181e3bd994 100644
--- a/lib/tests/fortify_kunit.c
+++ b/lib/tests/fortify_kunit.c@@ -49,7 +49,8 @@ void fortify_add_kunit_error(int write); #include <linux/vmalloc.h> /* Handle being built without CONFIG_FORTIFY_SOURCE */ -#ifndef __compiletime_strlen +#if defined(__NO_FORTIFY) || !defined(__OPTIMIZE__) || !defined(CONFIG_FORTIFY_SOURCE) +# undef __compiletime_strlen # define __compiletime_strlen __builtin_strlen #endif
--
2.51.0