Re: + stringh-create-header-for-fortified-string-functions.patch added to -mm tree

[Francis Laniel <laniel_francis@privacyrequired.com>]

Hi.


I am really sorry to mail you but the kernel test robot pointed me two 
problems:
1. When I copied/pasted the code from string.h to the new header my editor 
misindented some code and I did not check properly the compilation warnings...
For example, this code exists in the patch and is then misindented:
+	if (p_size < p_len + copy_len + 1)
+		fortify_panic(__func__);
+		__underlying_memcpy(p + p_len, q, copy_len);
2. It also showed me some warnings when compiling for ARM and related to 
string length:
In function 'strncpy',
       inlined from 'uhid_dev_create2' at drivers/hid/uhid.c:499:2,
       inlined from 'uhid_char_write' at drivers/hid/uhid.c:738:9:
       include/linux/fortify-string.h:27:30: warning: '__builtin_strncpy' 
output may be truncated copying 127 bytes from a string of length 127 [-
Wstringop-truncation]
      27 | #define __underlying_strncpy __builtin_strncpy

So, can you please revert it and I, at least, send a v2 with the code 
correctly indented?
Moreover, I would like to investigate the problem for the ARM compilation to 
see if it is related to the new code I added.


Best regards and sorry for the trouble...

Le vendredi 8 janvier 2021, 00:08:51 CET akpm@linux-foundation.org a écrit :
> The patch titled
>      Subject: string.h: create header for fortified string functions
> has been added to the -mm tree.  Its filename is
>      stringh-create-header-for-fortified-string-functions.patch
> 
> This patch should soon appear at
>    
> https://ozlabs.org/~akpm/mmots/broken-out/stringh-create-header-for-fortifi
> ed-string-functions.patch and later at
>    
> https://ozlabs.org/~akpm/mmotm/broken-out/stringh-create-header-for-fortifi
> ed-string-functions.patch
> 
> Before you just go and hit "reply", please:
>    a) Consider who else should be cc'ed
>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/process/submit-checklist.rst when testing
> your code ***
> 
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
> 
> ------------------------------------------------------
> From: Francis Laniel <laniel_francis@privacyrequired.com>
> Subject: string.h: create header for fortified string functions
> 
> Add fortify-string.h to contain fortified functions definitions.  Thus,
> the code is more separated and compile time is slightly faster for people
> who do not set CONFIG_FORTIFY_SOURCE.
> 
> Link:
> https://lkml.kernel.org/r/20210107145143.7438-2-laniel_francis@privacyrequi
> red.com Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Daniel Axtens <dja@axtens.net>
> Cc: Daniel Micay <danielmicay@gmail.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  include/linux/fortify-string.h |  302 +++++++++++++++++++++++++++++++
>  include/linux/string.h         |  282 ----------------------------
>  2 files changed, 303 insertions(+), 281 deletions(-)
> 
> --- /dev/null
> +++ a/include/linux/fortify-string.h
> @@ -0,0 +1,302 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_FORTIFY_STRING_H_
> +#define _LINUX_FORTIFY_STRING_H_
> +
> +
> +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> +extern void *__underlying_memchr(const void *p, int c, __kernel_size_t
> size) __RENAME(memchr); +extern int __underlying_memcmp(const void *p,
> const void *q, __kernel_size_t size) __RENAME(memcmp); +extern void
> *__underlying_memcpy(void *p, const void *q, __kernel_size_t size)
> __RENAME(memcpy); +extern void *__underlying_memmove(void *p, const void
> *q, __kernel_size_t size) __RENAME(memmove); +extern void
> *__underlying_memset(void *p, int c, __kernel_size_t size)
> __RENAME(memset); +extern char *__underlying_strcat(char *p, const char *q)
> __RENAME(strcat); +extern char *__underlying_strcpy(char *p, const char *q)
> __RENAME(strcpy); +extern __kernel_size_t __underlying_strlen(const char
> *p) __RENAME(strlen); +extern char *__underlying_strncat(char *p, const
> char *q, __kernel_size_t count) __RENAME(strncat); +extern char
> *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
> __RENAME(strncpy); +#else
> +#define __underlying_memchr	__builtin_memchr
> +#define __underlying_memcmp	__builtin_memcmp
> +#define __underlying_memcpy	__builtin_memcpy
> +#define __underlying_memmove	__builtin_memmove
> +#define __underlying_memset	__builtin_memset
> +#define __underlying_strcat	__builtin_strcat
> +#define __underlying_strcpy	__builtin_strcpy
> +#define __underlying_strlen	__builtin_strlen
> +#define __underlying_strncat	__builtin_strncat
> +#define __underlying_strncpy	__builtin_strncpy
> +#endif
> +
> +__FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t
> size) +{
> +	size_t p_size = __builtin_object_size(p, 1);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__write_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_strncpy(p, q, size);
> +}
> +
> +__FORTIFY_INLINE char *strcat(char *p, const char *q)
> +{
> +	size_t p_size = __builtin_object_size(p, 1);
> +
> +	if (p_size == (size_t)-1)
> +		return __underlying_strcat(p, q);
> +	if (strlcat(p, q, p_size) >= p_size)
> +		fortify_panic(__func__);
> +	return p;
> +}
> +
> +__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
> +{
> +	__kernel_size_t ret;
> +	size_t p_size = __builtin_object_size(p, 1);
> +
> +	/* Work around gcc excess stack consumption issue */
> +	if (p_size == (size_t)-1 ||
> +		(__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
> +		return __underlying_strlen(p);
> +	ret = strnlen(p, p_size);
> +	if (p_size <= ret)
> +		fortify_panic(__func__);
> +	return ret;
> +}
> +
> +extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t)
> __RENAME(strnlen); +__FORTIFY_INLINE __kernel_size_t strnlen(const char *p,
> __kernel_size_t maxlen) +{
> +	size_t p_size = __builtin_object_size(p, 1);
> +	__kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen :
> p_size); +
> +	if (p_size <= ret && maxlen != ret)
> +		fortify_panic(__func__);
> +	return ret;
> +}
> +
> +/* defined after fortified strlen to reuse it */
> +extern size_t __real_strlcpy(char *, const char *, size_t)
> __RENAME(strlcpy); +__FORTIFY_INLINE size_t strlcpy(char *p, const char *q,
> size_t size) +{
> +	size_t ret;
> +	size_t p_size = __builtin_object_size(p, 1);
> +	size_t q_size = __builtin_object_size(q, 1);
> +
> +	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> +		return __real_strlcpy(p, q, size);
> +	ret = strlen(q);
> +	if (size) {
> +		size_t len = (ret >= size) ? size - 1 : ret;
> +
> +		if (__builtin_constant_p(len) && len >= p_size)
> +			__write_overflow();
> +		if (len >= p_size)
> +			fortify_panic(__func__);
> +			__underlying_memcpy(p, q, len);
> +		p[len] = '\0';
> +	}
> +	return ret;
> +}
> +
> +/* defined after fortified strnlen to reuse it */
> +extern ssize_t __real_strscpy(char *, const char *, size_t)
> __RENAME(strscpy); +__FORTIFY_INLINE ssize_t strscpy(char *p, const char
> *q, size_t size) +{
> +	size_t len;
> +	/* Use string size rather than possible enclosing struct size. */
> +	size_t p_size = __builtin_object_size(p, 1);
> +	size_t q_size = __builtin_object_size(q, 1);
> +
> +	/* If we cannot get size of p and q default to call strscpy. */
> +	if (p_size == (size_t) -1 && q_size == (size_t) -1)
> +		return __real_strscpy(p, q, size);
> +
> +	/*
> +	 * If size can be known at compile time and is greater than
> +	 * p_size, generate a compile time write overflow error.
> +	 */
> +	if (__builtin_constant_p(size) && size > p_size)
> +		__write_overflow();
> +
> +	/*
> +	 * This call protects from read overflow, because len will default to q
> +	 * length if it smaller than size.
> +	 */
> +	len = strnlen(q, size);
> +	/*
> +	 * If len equals size, we will copy only size bytes which leads to
> +	 * -E2BIG being returned.
> +	 * Otherwise we will copy len + 1 because of the final '\O'.
> +	 */
> +	len = len == size ? size : len + 1;
> +
> +	/*
> +	 * Generate a runtime write overflow error if len is greater than
> +	 * p_size.
> +	 */
> +	if (len > p_size)
> +		fortify_panic(__func__);
> +
> +	/*
> +	 * We can now safely call vanilla strscpy because we are protected from:
> +	 * 1. Read overflow thanks to call to strnlen().
> +	 * 2. Write overflow thanks to above ifs.
> +	 */
> +	return __real_strscpy(p, q, len);
> +}
> +
> +/* defined after fortified strlen and strnlen to reuse them */
> +__FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t
> count) +{
> +	size_t p_len, copy_len;
> +	size_t p_size = __builtin_object_size(p, 1);
> +	size_t q_size = __builtin_object_size(q, 1);
> +
> +	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> +		return __underlying_strncat(p, q, count);
> +	p_len = strlen(p);
> +	copy_len = strnlen(q, count);
> +	if (p_size < p_len + copy_len + 1)
> +		fortify_panic(__func__);
> +		__underlying_memcpy(p + p_len, q, copy_len);
> +	p[p_len + copy_len] = '\0';
> +	return p;
> +}
> +
> +__FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
> +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__write_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_memset(p, c, size);
> +}
> +
> +__FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
> +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +	size_t q_size = __builtin_object_size(q, 0);
> +
> +	if (__builtin_constant_p(size)) {
> +		if (p_size < size)
> +			__write_overflow();
> +		if (q_size < size)
> +			__read_overflow2();
> +	}
> +	if (p_size < size || q_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_memcpy(p, q, size);
> +}
> +
> +__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t
> size) +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +	size_t q_size = __builtin_object_size(q, 0);
> +
> +	if (__builtin_constant_p(size)) {
> +		if (p_size < size)
> +			__write_overflow();
> +		if (q_size < size)
> +			__read_overflow2();
> +	}
> +	if (p_size < size || q_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_memmove(p, q, size);
> +}
> +
> +extern void *__real_memscan(void *, int, __kernel_size_t)
> __RENAME(memscan); +__FORTIFY_INLINE void *memscan(void *p, int c,
> __kernel_size_t size) +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__read_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __real_memscan(p, c, size);
> +}
> +
> +__FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t
> size) +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +	size_t q_size = __builtin_object_size(q, 0);
> +
> +	if (__builtin_constant_p(size)) {
> +		if (p_size < size)
> +			__read_overflow();
> +		if (q_size < size)
> +			__read_overflow2();
> +	}
> +	if (p_size < size || q_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_memcmp(p, q, size);
> +}
> +
> +__FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
> +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__read_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __underlying_memchr(p, c, size);
> +}
> +
> +void *__real_memchr_inv(const void *s, int c, size_t n)
> __RENAME(memchr_inv); +__FORTIFY_INLINE void *memchr_inv(const void *p, int
> c, size_t size) +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__read_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __real_memchr_inv(p, c, size);
> +}
> +
> +extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp)
> __RENAME(kmemdup); +__FORTIFY_INLINE void *kmemdup(const void *p, size_t
> size, gfp_t gfp) +{
> +	size_t p_size = __builtin_object_size(p, 0);
> +
> +	if (__builtin_constant_p(size) && p_size < size)
> +		__read_overflow();
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	return __real_kmemdup(p, size, gfp);
> +}
> +
> +/* defined after fortified strlen and memcpy to reuse them */
> +__FORTIFY_INLINE char *strcpy(char *p, const char *q)
> +{
> +	size_t p_size = __builtin_object_size(p, 1);
> +	size_t q_size = __builtin_object_size(q, 1);
> +	size_t size;
> +
> +	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> +		return __underlying_strcpy(p, q);
> +	size = strlen(q) + 1;
> +	/* test here to use the more stringent object size */
> +	if (p_size < size)
> +		fortify_panic(__func__);
> +	memcpy(p, q, size);
> +	return p;
> +}
> +
> +/* Don't use these outside the FORITFY_SOURCE implementation */
> +#undef __underlying_memchr
> +#undef __underlying_memcmp
> +#undef __underlying_memcpy
> +#undef __underlying_memmove
> +#undef __underlying_memset
> +#undef __underlying_strcat
> +#undef __underlying_strcpy
> +#undef __underlying_strlen
> +#undef __underlying_strncat
> +#undef __underlying_strncpy
> +
> +#endif /* _LINUX_FORTIFY_STRING_H_ */
> ---
> a/include/linux/string.h~stringh-create-header-for-fortified-string-functio
> ns +++ a/include/linux/string.h
> @@ -266,287 +266,7 @@ void __read_overflow3(void) __compiletim
>  void __write_overflow(void) __compiletime_error("detected write beyond size
> of object passed as 1st parameter");
> 
>  #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) &&
> defined(CONFIG_FORTIFY_SOURCE) -
> -#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
> -extern void *__underlying_memchr(const void *p, int c, __kernel_size_t
> size) __RENAME(memchr); -extern int __underlying_memcmp(const void *p,
> const void *q, __kernel_size_t size) __RENAME(memcmp); -extern void
> *__underlying_memcpy(void *p, const void *q, __kernel_size_t size)
> __RENAME(memcpy); -extern void *__underlying_memmove(void *p, const void
> *q, __kernel_size_t size) __RENAME(memmove); -extern void
> *__underlying_memset(void *p, int c, __kernel_size_t size)
> __RENAME(memset); -extern char *__underlying_strcat(char *p, const char *q)
> __RENAME(strcat); -extern char *__underlying_strcpy(char *p, const char *q)
> __RENAME(strcpy); -extern __kernel_size_t __underlying_strlen(const char
> *p) __RENAME(strlen); -extern char *__underlying_strncat(char *p, const
> char *q, __kernel_size_t count) __RENAME(strncat); -extern char
> *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
> __RENAME(strncpy); -#else
> -#define __underlying_memchr	__builtin_memchr
> -#define __underlying_memcmp	__builtin_memcmp
> -#define __underlying_memcpy	__builtin_memcpy
> -#define __underlying_memmove	__builtin_memmove
> -#define __underlying_memset	__builtin_memset
> -#define __underlying_strcat	__builtin_strcat
> -#define __underlying_strcpy	__builtin_strcpy
> -#define __underlying_strlen	__builtin_strlen
> -#define __underlying_strncat	__builtin_strncat
> -#define __underlying_strncpy	__builtin_strncpy
> -#endif
> -
> -__FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t
> size) -{
> -	size_t p_size = __builtin_object_size(p, 1);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__write_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_strncpy(p, q, size);
> -}
> -
> -__FORTIFY_INLINE char *strcat(char *p, const char *q)
> -{
> -	size_t p_size = __builtin_object_size(p, 1);
> -	if (p_size == (size_t)-1)
> -		return __underlying_strcat(p, q);
> -	if (strlcat(p, q, p_size) >= p_size)
> -		fortify_panic(__func__);
> -	return p;
> -}
> -
> -__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
> -{
> -	__kernel_size_t ret;
> -	size_t p_size = __builtin_object_size(p, 1);
> -
> -	/* Work around gcc excess stack consumption issue */
> -	if (p_size == (size_t)-1 ||
> -	    (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
> -		return __underlying_strlen(p);
> -	ret = strnlen(p, p_size);
> -	if (p_size <= ret)
> -		fortify_panic(__func__);
> -	return ret;
> -}
> -
> -extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t)
> __RENAME(strnlen); -__FORTIFY_INLINE __kernel_size_t strnlen(const char *p,
> __kernel_size_t maxlen) -{
> -	size_t p_size = __builtin_object_size(p, 1);
> -	__kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen :
> p_size); -	if (p_size <= ret && maxlen != ret)
> -		fortify_panic(__func__);
> -	return ret;
> -}
> -
> -/* defined after fortified strlen to reuse it */
> -extern size_t __real_strlcpy(char *, const char *, size_t)
> __RENAME(strlcpy); -__FORTIFY_INLINE size_t strlcpy(char *p, const char *q,
> size_t size) -{
> -	size_t ret;
> -	size_t p_size = __builtin_object_size(p, 1);
> -	size_t q_size = __builtin_object_size(q, 1);
> -	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> -		return __real_strlcpy(p, q, size);
> -	ret = strlen(q);
> -	if (size) {
> -		size_t len = (ret >= size) ? size - 1 : ret;
> -		if (__builtin_constant_p(len) && len >= p_size)
> -			__write_overflow();
> -		if (len >= p_size)
> -			fortify_panic(__func__);
> -		__underlying_memcpy(p, q, len);
> -		p[len] = '\0';
> -	}
> -	return ret;
> -}
> -
> -/* defined after fortified strnlen to reuse it */
> -extern ssize_t __real_strscpy(char *, const char *, size_t)
> __RENAME(strscpy); -__FORTIFY_INLINE ssize_t strscpy(char *p, const char
> *q, size_t size) -{
> -	size_t len;
> -	/* Use string size rather than possible enclosing struct size. */
> -	size_t p_size = __builtin_object_size(p, 1);
> -	size_t q_size = __builtin_object_size(q, 1);
> -
> -	/* If we cannot get size of p and q default to call strscpy. */
> -	if (p_size == (size_t) -1 && q_size == (size_t) -1)
> -		return __real_strscpy(p, q, size);
> -
> -	/*
> -	 * If size can be known at compile time and is greater than
> -	 * p_size, generate a compile time write overflow error.
> -	 */
> -	if (__builtin_constant_p(size) && size > p_size)
> -		__write_overflow();
> -
> -	/*
> -	 * This call protects from read overflow, because len will default to q
> -	 * length if it smaller than size.
> -	 */
> -	len = strnlen(q, size);
> -	/*
> -	 * If len equals size, we will copy only size bytes which leads to
> -	 * -E2BIG being returned.
> -	 * Otherwise we will copy len + 1 because of the final '\O'.
> -	 */
> -	len = len == size ? size : len + 1;
> -
> -	/*
> -	 * Generate a runtime write overflow error if len is greater than
> -	 * p_size.
> -	 */
> -	if (len > p_size)
> -		fortify_panic(__func__);
> -
> -	/*
> -	 * We can now safely call vanilla strscpy because we are protected from:
> -	 * 1. Read overflow thanks to call to strnlen().
> -	 * 2. Write overflow thanks to above ifs.
> -	 */
> -	return __real_strscpy(p, q, len);
> -}
> -
> -/* defined after fortified strlen and strnlen to reuse them */
> -__FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t
> count) -{
> -	size_t p_len, copy_len;
> -	size_t p_size = __builtin_object_size(p, 1);
> -	size_t q_size = __builtin_object_size(q, 1);
> -	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> -		return __underlying_strncat(p, q, count);
> -	p_len = strlen(p);
> -	copy_len = strnlen(q, count);
> -	if (p_size < p_len + copy_len + 1)
> -		fortify_panic(__func__);
> -	__underlying_memcpy(p + p_len, q, copy_len);
> -	p[p_len + copy_len] = '\0';
> -	return p;
> -}
> -
> -__FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
> -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__write_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_memset(p, c, size);
> -}
> -
> -__FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
> -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	size_t q_size = __builtin_object_size(q, 0);
> -	if (__builtin_constant_p(size)) {
> -		if (p_size < size)
> -			__write_overflow();
> -		if (q_size < size)
> -			__read_overflow2();
> -	}
> -	if (p_size < size || q_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_memcpy(p, q, size);
> -}
> -
> -__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t
> size) -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	size_t q_size = __builtin_object_size(q, 0);
> -	if (__builtin_constant_p(size)) {
> -		if (p_size < size)
> -			__write_overflow();
> -		if (q_size < size)
> -			__read_overflow2();
> -	}
> -	if (p_size < size || q_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_memmove(p, q, size);
> -}
> -
> -extern void *__real_memscan(void *, int, __kernel_size_t)
> __RENAME(memscan); -__FORTIFY_INLINE void *memscan(void *p, int c,
> __kernel_size_t size) -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__read_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __real_memscan(p, c, size);
> -}
> -
> -__FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t
> size) -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	size_t q_size = __builtin_object_size(q, 0);
> -	if (__builtin_constant_p(size)) {
> -		if (p_size < size)
> -			__read_overflow();
> -		if (q_size < size)
> -			__read_overflow2();
> -	}
> -	if (p_size < size || q_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_memcmp(p, q, size);
> -}
> -
> -__FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
> -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__read_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __underlying_memchr(p, c, size);
> -}
> -
> -void *__real_memchr_inv(const void *s, int c, size_t n)
> __RENAME(memchr_inv); -__FORTIFY_INLINE void *memchr_inv(const void *p, int
> c, size_t size) -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__read_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __real_memchr_inv(p, c, size);
> -}
> -
> -extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp)
> __RENAME(kmemdup); -__FORTIFY_INLINE void *kmemdup(const void *p, size_t
> size, gfp_t gfp) -{
> -	size_t p_size = __builtin_object_size(p, 0);
> -	if (__builtin_constant_p(size) && p_size < size)
> -		__read_overflow();
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	return __real_kmemdup(p, size, gfp);
> -}
> -
> -/* defined after fortified strlen and memcpy to reuse them */
> -__FORTIFY_INLINE char *strcpy(char *p, const char *q)
> -{
> -	size_t p_size = __builtin_object_size(p, 1);
> -	size_t q_size = __builtin_object_size(q, 1);
> -	size_t size;
> -	if (p_size == (size_t)-1 && q_size == (size_t)-1)
> -		return __underlying_strcpy(p, q);
> -	size = strlen(q) + 1;
> -	/* test here to use the more stringent object size */
> -	if (p_size < size)
> -		fortify_panic(__func__);
> -	memcpy(p, q, size);
> -	return p;
> -}
> -
> -/* Don't use these outside the FORITFY_SOURCE implementation */
> -#undef __underlying_memchr
> -#undef __underlying_memcmp
> -#undef __underlying_memcpy
> -#undef __underlying_memmove
> -#undef __underlying_memset
> -#undef __underlying_strcat
> -#undef __underlying_strcpy
> -#undef __underlying_strlen
> -#undef __underlying_strncat
> -#undef __underlying_strncpy
> +#include <linux/fortify-string.h>
>  #endif
> 
>  /**
> _
> 
> Patches currently in -mm which might be from
> laniel_francis@privacyrequired.com are
> 
> stringh-create-header-for-fortified-string-functions.patch