diff mbox

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

Message ID 20160705014209.caca7667ac0984c2975b4f41@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Emese Revfy July 4, 2016, 11:42 p.m. UTC 
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(-)

Comments

Kees Cook July 12, 2016, 7:08 p.m. UTC | #1 
On Mon, Jul 4, 2016 at 7:42 PM, Emese Revfy <re.emese@gmail.com> wrote:
> 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.

Why is this called "nocapture"? Not captured by what? It seems like it
means "initify this if possible". Am I misunderstanding its purpose?

-Kees

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

Has anyone had a chance to try this out on these architectures? I'll
be testing arm shortly...

-Kees

>
> 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
>
Daniel Micay July 12, 2016, 7:23 p.m. UTC | #2 
On Tue, 2016-07-12 at 15:08 -0400, Kees Cook wrote:
> On Mon, Jul 4, 2016 at 7:42 PM, Emese Revfy <re.emese@gmail.com>
> wrote:
> > 
> > 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.
> 
> Why is this called "nocapture"? Not captured by what? It seems like
> it
> means "initify this if possible". Am I misunderstanding its purpose?

It means they don't escape via that function, i.e. they aren't stored
anywhere to be used in any way after the call.
Kees Cook July 12, 2016, 7:47 p.m. UTC | #3 
On Tue, Jul 12, 2016 at 3:23 PM, Daniel Micay <danielmicay@gmail.com> wrote:
> On Tue, 2016-07-12 at 15:08 -0400, Kees Cook wrote:
>> On Mon, Jul 4, 2016 at 7:42 PM, Emese Revfy <re.emese@gmail.com>
>> wrote:
>> >
>> > 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.
>>
>> Why is this called "nocapture"? Not captured by what? It seems like
>> it
>> means "initify this if possible". Am I misunderstanding its purpose?
>
> It means they don't escape via that function, i.e. they aren't stored
> anywhere to be used in any way after the call.

Ah, those arguments are confirmed to not be "captured" by that
function, leaving them available to be moved to .init. Got it, thanks!

-Kees
diff mbox

Patch

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