/* 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_ */