[PATCH v2 2/3] Mark functions with the __nocapture attribute

Emese Revfy
2016-07-04T23:35:49Z

The nocapture gcc attribute can be on functions only.
The attribute takes one or more unsigned integer constants as parameters
that specify the function argument(s) of const char* type to initify.
If the marked argument is a vararg then the plugin initifies
all vararg arguments.

I couldn't test the arm, arm64 and powerpc architectures.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
---
arch/arm/include/asm/string.h | 4 +--
arch/arm64/include/asm/string.h | 19 ++++++------
arch/powerpc/include/asm/string.h | 19 ++++++------
arch/x86/include/asm/string_32.h | 21 ++++++-------
arch/x86/include/asm/string_64.h | 20 ++++++-------
arch/x86/kernel/hpet.c | 2 +-
include/asm-generic/bug.h | 6 ++--
include/linux/compiler-gcc.h | 10 +++++--
include/linux/compiler.h | 4 +++
include/linux/fs.h | 5 ++--
include/linux/printk.h | 2 +-
include/linux/string.h | 63 ++++++++++++++++++++-------------------
12 files changed, 96 insertions(+), 79 deletions(-)

diff --git a/arch/arm/include/asm/string.h b/arch/arm/include/asm/string.h
index cf4f3aa..ddb9d58 100644
--- a/arch/arm/include/asm/string.h
+++ b/arch/arm/include/asm/string.h
@@ -13,10 +13,10 @@ extern char * strrchr(const char * s, int c);
extern char * strchr(const char * s, int c);

#define __HAVE_ARCH_MEMCPY
-extern void * memcpy(void *, const void *, __kernel_size_t);
+extern void * memcpy(void *, const void *, __kernel_size_t) __nocapture(2);

#define __HAVE_ARCH_MEMMOVE
-extern void * memmove(void *, const void *, __kernel_size_t);
+extern void * memmove(void *, const void *, __kernel_size_t) __nocapture(2);

#define __HAVE_ARCH_MEMCHR
extern void * memchr(const void *, int, __kernel_size_t);
diff --git a/arch/arm64/include/asm/string.h b/arch/arm64/include/asm/string.h
index 2eb714c..4263a27 100644
--- a/arch/arm64/include/asm/string.h
+++ b/arch/arm64/include/asm/string.h
@@ -23,24 +23,25 @@ extern char *strrchr(const char *, int c);
extern char *strchr(const char *, int c);

#define __HAVE_ARCH_STRCMP
-extern int strcmp(const char *, const char *);
+extern int strcmp(const char *, const char *) __nocapture(1, 2);

#define __HAVE_ARCH_STRNCMP
-extern int strncmp(const char *, const char *, __kernel_size_t);
+extern int
+strncmp(const char *, const char *, __kernel_size_t) __nocapture(1, 2);

#define __HAVE_ARCH_STRLEN
-extern __kernel_size_t strlen(const char *);
+extern __kernel_size_t strlen(const char *) __nocapture(1);

#define __HAVE_ARCH_STRNLEN
-extern __kernel_size_t strnlen(const char *, __kernel_size_t);
+extern __kernel_size_t strnlen(const char *, __kernel_size_t) __nocapture(1);

#define __HAVE_ARCH_MEMCPY
-extern void *memcpy(void *, const void *, __kernel_size_t);
-extern void *__memcpy(void *, const void *, __kernel_size_t);
+extern void *memcpy(void *, const void *, __kernel_size_t) __nocapture(2);
+extern void *__memcpy(void *, const void *, __kernel_size_t) __nocapture(2);

#define __HAVE_ARCH_MEMMOVE
-extern void *memmove(void *, const void *, __kernel_size_t);
-extern void *__memmove(void *, const void *, __kernel_size_t);
+extern void *memmove(void *, const void *, __kernel_size_t) __nocapture(2);
+extern void *__memmove(void *, const void *, __kernel_size_t) __nocapture(2);

#define __HAVE_ARCH_MEMCHR
extern void *memchr(const void *, int, __kernel_size_t);
@@ -50,7 +51,7 @@ extern void *memset(void *, int, __kernel_size_t);
extern void *__memset(void *, int, __kernel_size_t);

#define __HAVE_ARCH_MEMCMP
-extern int memcmp(const void *, const void *, size_t);
+extern int memcmp(const void *, const void *, size_t) __nocapture(1, 2);

#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h
index da3cdff..e67f1eb 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -11,16 +11,17 @@
#define __HAVE_ARCH_MEMCMP
#define __HAVE_ARCH_MEMCHR

-extern char * strcpy(char *,const char *);
-extern char * strncpy(char *,const char *, __kernel_size_t);
-extern __kernel_size_t strlen(const char *);
-extern int strcmp(const char *,const char *);
-extern int strncmp(const char *, const char *, __kernel_size_t);
-extern char * strcat(char *, const char *);
+extern char * strcpy(char *,const char *) __nocapture(2);
+extern char * strncpy(char *,const char *, __kernel_size_t) __nocapture(2);
+extern __kernel_size_t strlen(const char *) __nocapture(1);
+extern int strcmp(const char *,const char *) __nocapture(1, 2);
+extern int
+strncmp(const char *, const char *, __kernel_size_t) __nocapture(1, 2);
+extern char * strcat(char *, const char *) __nocapture(2);
extern void * memset(void *,int,__kernel_size_t);
-extern void * memcpy(void *,const void *,__kernel_size_t);
-extern void * memmove(void *,const void *,__kernel_size_t);
-extern int memcmp(const void *,const void *,__kernel_size_t);
+extern void * memcpy(void *,const void *,__kernel_size_t) __nocapture(2);
+extern void * memmove(void *,const void *,__kernel_size_t) __nocapture(2);
+extern int memcmp(const void *,const void *,__kernel_size_t) __nocapture(1, 2);
extern void * memchr(const void *,int,__kernel_size_t);

#endif /* __KERNEL__ */
diff --git a/arch/x86/include/asm/string_32.h b/arch/x86/include/asm/string_32.h
index 3d3e835..63f29bf 100644
--- a/arch/x86/include/asm/string_32.h
+++ b/arch/x86/include/asm/string_32.h
@@ -6,28 +6,29 @@
/* Let gcc decide whether to inline or use the out of line functions */

#define __HAVE_ARCH_STRCPY
-extern char *strcpy(char *dest, const char *src);
+extern char *strcpy(char *dest, const char *src) __nocapture(2);

#define __HAVE_ARCH_STRNCPY
-extern char *strncpy(char *dest, const char *src, size_t count);
+extern char *strncpy(char *dest, const char *src, size_t count) __nocapture(2);

#define __HAVE_ARCH_STRCAT
-extern char *strcat(char *dest, const char *src);
+extern char *strcat(char *dest, const char *src) __nocapture(2);

#define __HAVE_ARCH_STRNCAT
-extern char *strncat(char *dest, const char *src, size_t count);
+extern char *strncat(char *dest, const char *src, size_t count) __nocapture(2);

#define __HAVE_ARCH_STRCMP
-extern int strcmp(const char *cs, const char *ct);
+extern int strcmp(const char *cs, const char *ct) __nocapture(1, 2);

#define __HAVE_ARCH_STRNCMP
-extern int strncmp(const char *cs, const char *ct, size_t count);
+extern int
+strncmp(const char *cs, const char *ct, size_t count) __nocapture(1, 2);

#define __HAVE_ARCH_STRCHR
extern char *strchr(const char *s, int c);

#define __HAVE_ARCH_STRLEN
-extern size_t strlen(const char *s);
+extern size_t strlen(const char *s) __nocapture(1);

static __always_inline void *__memcpy(void *to, const void *from, size_t n)
{
@@ -197,7 +198,7 @@ static inline void *__memcpy3d(void *to, const void *from, size_t len)
#endif

#define __HAVE_ARCH_MEMMOVE
-void *memmove(void *dest, const void *src, size_t n);
+void *memmove(void *dest, const void *src, size_t n) __nocapture(2);

#define memcmp __builtin_memcmp

@@ -243,11 +244,11 @@ void *__constant_c_memset(void *s, unsigned long c, size_t count)

/* Added by Gertjan van Wingerde to make minix and sysv module work */
#define __HAVE_ARCH_STRNLEN
-extern size_t strnlen(const char *s, size_t count);
+extern size_t strnlen(const char *s, size_t count) __nocapture(1);
/* end of additional stuff */

#define __HAVE_ARCH_STRSTR
-extern char *strstr(const char *cs, const char *ct);
+extern char *strstr(const char *cs, const char *ct) __nocapture(2);

/*
* This looks horribly ugly, but the compiler can optimize it totally,
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index 90dbbd9..607d3ba 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -27,8 +27,8 @@ static __always_inline void *__inline_memcpy(void *to, const void *from, size_t
function. */

#define __HAVE_ARCH_MEMCPY 1
-extern void *memcpy(void *to, const void *from, size_t len);
-extern void *__memcpy(void *to, const void *from, size_t len);
+extern void *memcpy(void *to, const void *from, size_t len) __nocapture(2);
+extern void *__memcpy(void *to, const void *from, size_t len) __nocapture(2);

#ifndef CONFIG_KMEMCHECK
#if (__GNUC__ == 4 && __GNUC_MINOR__ < 3) || __GNUC__ < 4
@@ -56,14 +56,14 @@ void *memset(void *s, int c, size_t n);
void *__memset(void *s, int c, size_t n);

#define __HAVE_ARCH_MEMMOVE
-void *memmove(void *dest, const void *src, size_t count);
-void *__memmove(void *dest, const void *src, size_t count);
+void *memmove(void *dest, const void *src, size_t count) __nocapture(2);
+void *__memmove(void *dest, const void *src, size_t count) __nocapture(2);

-int memcmp(const void *cs, const void *ct, size_t count);
-size_t strlen(const char *s);
-char *strcpy(char *dest, const char *src);
-char *strcat(char *dest, const char *src);
-int strcmp(const char *cs, const char *ct);
+int memcmp(const void *cs, const void *ct, size_t count) __nocapture(1, 2);
+size_t strlen(const char *s) __nocapture(1);
+char *strcpy(char *dest, const char *src) __nocapture(2);
+char *strcat(char *dest, const char *src) __nocapture(2);
+int strcmp(const char *cs, const char *ct) __nocapture(1, 2);

#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)

@@ -89,7 +89,7 @@ int strcmp(const char *cs, const char *ct);
*
* Return 0 for success, -EFAULT for fail
*/
-int memcpy_mcsafe(void *dst, const void *src, size_t cnt);
+int memcpy_mcsafe(void *dst, const void *src, size_t cnt) __nocapture(2);

#endif /* __KERNEL__ */

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 357900a..c68ab1a 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -136,7 +136,7 @@ int is_hpet_enabled(void)
}
EXPORT_SYMBOL_GPL(is_hpet_enabled);

-static void _hpet_print_config(const char *function, int line)
+static void __nocapture(1) _hpet_print_config(const char *function, int line)
{
u32 i, timers, l, h;
printk(KERN_INFO "hpet: %s(%d):\n", function, line);
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 6f96247..630d0c4 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -62,13 +62,13 @@ struct bug_entry {
* to provide better diagnostics.
*/
#ifndef __WARN_TAINT
-extern __printf(3, 4)
+extern __printf(3, 4) __nocapture(1)
void warn_slowpath_fmt(const char *file, const int line,
const char *fmt, ...);
-extern __printf(4, 5)
+extern __printf(4, 5) __nocapture(1)
void warn_slowpath_fmt_taint(const char *file, const int line, unsigned taint,
const char *fmt, ...);
-extern void warn_slowpath_null(const char *file, const int line);
+extern __nocapture(1) void warn_slowpath_null(const char *file, const int line);
#define WANT_WARN_ON_SLOWPATH
#define __WARN() warn_slowpath_null(__FILE__, __LINE__)
#define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index df88c0a..192cea4 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -116,8 +116,10 @@
*/
#define __pure __attribute__((pure))
#define __aligned(x) __attribute__((aligned(x)))
-#define __printf(a, b) __attribute__((format(printf, a, b)))
-#define __scanf(a, b) __attribute__((format(scanf, a, b)))
+#define __printf(a, b) __attribute__((format(printf, a, b))) \
+ __nocapture(a, b)
+#define __scanf(a, b) __attribute__((format(scanf, a, b))) \
+ __nocapture(a, b)
#define __attribute_const__ __attribute__((__const__))
#define __maybe_unused __attribute__((unused))
#define __always_unused __attribute__((unused))
@@ -193,6 +195,10 @@
# define __latent_entropy __attribute__((latent_entropy))
#endif

+#ifdef INITIFY_PLUGIN
+#define __nocapture(...) __attribute__((nocapture(__VA_ARGS__)))
+#endif
+
/*
* Mark a position in code as unreachable. This can be used to
* suppress control flow warnings after asm blocks that transfer
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 0adcfc2..391b48b 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -412,6 +412,10 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
# define __latent_entropy
#endif

+#ifndef __nocapture
+# define __nocapture(...)
+#endif
+
/*
* Tell gcc if a function is cold. The compiler will assume any path
* directly leading to the call is unlikely.
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c4ab2cf..048a0d9 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2476,8 +2476,9 @@ extern int register_chrdev_region(dev_t, unsigned, const char *);
extern int __register_chrdev(unsigned int major, unsigned int baseminor,
unsigned int count, const char *name,
const struct file_operations *fops);
-extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
- unsigned int count, const char *name);
+extern __nocapture(4) void __unregister_chrdev(unsigned int major,
+ unsigned int baseminor, unsigned int count,
+ const char *name);
extern void unregister_chrdev_region(dev_t, unsigned);
extern void chrdev_show(struct seq_file *,off_t);

diff --git a/include/linux/printk.h b/include/linux/printk.h
index e6ff22e..ca137fa 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -163,7 +163,7 @@ __printf(1, 2) __cold int printk_deferred(const char *fmt, ...);
* with all other unrelated printk_ratelimit() callsites. Instead use
* printk_ratelimited() or plain old __ratelimit().
*/
-extern int __printk_ratelimit(const char *func);
+extern int __printk_ratelimit(const char *func) __nocapture(1);
#define printk_ratelimit() __printk_ratelimit(__func__)
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
unsigned int interval_msec);
diff --git a/include/linux/string.h b/include/linux/string.h
index 26b6f6a..0a56912 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -18,37 +18,38 @@ extern void *memdup_user_nul(const void __user *, size_t);
#include <asm/string.h>

#ifndef __HAVE_ARCH_STRCPY
-extern char * strcpy(char *,const char *);
+extern char * strcpy(char *,const char *) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRNCPY
-extern char * strncpy(char *,const char *, __kernel_size_t);
+extern char * strncpy(char *,const char *, __kernel_size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRLCPY
-size_t strlcpy(char *, const char *, size_t);
+size_t strlcpy(char *, const char *, size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRSCPY
-ssize_t __must_check strscpy(char *, const char *, size_t);
+ssize_t __must_check strscpy(char *, const char *, size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRCAT
-extern char * strcat(char *, const char *);
+extern char * strcat(char *, const char *) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRNCAT
-extern char * strncat(char *, const char *, __kernel_size_t);
+extern char * strncat(char *, const char *, __kernel_size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRLCAT
-extern size_t strlcat(char *, const char *, __kernel_size_t);
+extern size_t strlcat(char *, const char *, __kernel_size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRCMP
-extern int strcmp(const char *,const char *);
+extern int strcmp(const char *,const char *) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_STRNCMP
-extern int strncmp(const char *,const char *,__kernel_size_t);
+extern int strncmp(const char *,const char *,__kernel_size_t) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_STRCASECMP
-extern int strcasecmp(const char *s1, const char *s2);
+extern int strcasecmp(const char *s1, const char *s2) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_STRNCASECMP
-extern int strncasecmp(const char *s1, const char *s2, size_t n);
+extern int
+strncasecmp(const char *s1, const char *s2, size_t n) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_STRCHR
extern char * strchr(const char *,int);
@@ -72,44 +73,44 @@ static inline __must_check char *strstrip(char *str)
}

#ifndef __HAVE_ARCH_STRSTR
-extern char * strstr(const char *, const char *);
+extern char * strstr(const char *, const char *) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRNSTR
-extern char * strnstr(const char *, const char *, size_t);
+extern char * strnstr(const char *, const char *, size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRLEN
-extern __kernel_size_t strlen(const char *);
+extern __kernel_size_t strlen(const char *) __nocapture(1);
#endif
#ifndef __HAVE_ARCH_STRNLEN
-extern __kernel_size_t strnlen(const char *,__kernel_size_t);
+extern __kernel_size_t strnlen(const char *,__kernel_size_t) __nocapture(1);
#endif
#ifndef __HAVE_ARCH_STRPBRK
-extern char * strpbrk(const char *,const char *);
+extern char * strpbrk(const char *,const char *) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRSEP
-extern char * strsep(char **,const char *);
+extern char * strsep(char **,const char *) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_STRSPN
-extern __kernel_size_t strspn(const char *,const char *);
+extern __kernel_size_t strspn(const char *,const char *) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_STRCSPN
-extern __kernel_size_t strcspn(const char *,const char *);
+extern __kernel_size_t strcspn(const char *,const char *) __nocapture(1, 2);
#endif

#ifndef __HAVE_ARCH_MEMSET
extern void * memset(void *,int,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMCPY
-extern void * memcpy(void *,const void *,__kernel_size_t);
+extern void * memcpy(void *,const void *,__kernel_size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_MEMMOVE
-extern void * memmove(void *,const void *,__kernel_size_t);
+extern void * memmove(void *,const void *,__kernel_size_t) __nocapture(2);
#endif
#ifndef __HAVE_ARCH_MEMSCAN
extern void * memscan(void *,int,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMCMP
-extern int memcmp(const void *,const void *,__kernel_size_t);
+extern int memcmp(const void *,const void *,__kernel_size_t) __nocapture(1, 2);
#endif
#ifndef __HAVE_ARCH_MEMCHR
extern void * memchr(const void *,int,__kernel_size_t);
@@ -119,16 +120,16 @@ char *strreplace(char *s, char old, char new);

extern void kfree_const(const void *x);

-extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
-extern const char *kstrdup_const(const char *s, gfp_t gfp);
-extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
-extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
+extern char *kstrdup(const char *s, gfp_t gfp) __malloc __nocapture(1);
+extern const char *kstrdup_const(const char *s, gfp_t gfp) __nocapture(1);
+extern char *kstrndup(const char *s, size_t len, gfp_t gfp) __nocapture(1);
+extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __nocapture(1);

extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
extern void argv_free(char **argv);

-extern bool sysfs_streq(const char *s1, const char *s2);
-extern int kstrtobool(const char *s, bool *res);
+extern bool sysfs_streq(const char *s1, const char *s2) __nocapture(1, 2);
+extern int kstrtobool(const char *s, bool *res) __nocapture(1);
static inline int strtobool(const char *s, bool *res)
{
return kstrtobool(s, res);
@@ -137,8 +138,10 @@ static inline int strtobool(const char *s, bool *res)
int match_string(const char * const *array, size_t n, const char *string);

#ifdef CONFIG_BINARY_PRINTF
-int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
-int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
+int vbin_printf(u32 *bin_buf, size_t size, const char *fmt,
+ va_list args) __nocapture(3);
+int bstr_printf(char *buf, size_t size, const char *fmt,
+ const u32 *bin_buf) __nocapture(3);
int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
#endif

--
2.8.1