diff options
Diffstat (limited to 'lib/string.c')
| -rw-r--r-- | lib/string.c | 193 |
1 files changed, 53 insertions, 140 deletions
diff --git a/lib/string.c b/lib/string.c index 485777c9da83..b632c71df1a5 100644 --- a/lib/string.c +++ b/lib/string.c @@ -15,19 +15,20 @@ */ #define __NO_FORTIFY -#include <linux/types.h> -#include <linux/string.h> -#include <linux/ctype.h> -#include <linux/kernel.h> -#include <linux/export.h> +#include <linux/bits.h> #include <linux/bug.h> +#include <linux/ctype.h> #include <linux/errno.h> -#include <linux/slab.h> +#include <linux/limits.h> +#include <linux/linkage.h> +#include <linux/stddef.h> +#include <linux/string.h> +#include <linux/types.h> -#include <asm/unaligned.h> -#include <asm/byteorder.h> -#include <asm/word-at-a-time.h> #include <asm/page.h> +#include <asm/rwonce.h> +#include <linux/unaligned.h> +#include <asm/word-at-a-time.h> #ifndef __HAVE_ARCH_STRNCASECMP /** @@ -76,11 +77,6 @@ EXPORT_SYMBOL(strcasecmp); #endif #ifndef __HAVE_ARCH_STRCPY -/** - * strcpy - Copy a %NUL terminated string - * @dest: Where to copy the string to - * @src: Where to copy the string from - */ char *strcpy(char *dest, const char *src) { char *tmp = dest; @@ -93,19 +89,6 @@ EXPORT_SYMBOL(strcpy); #endif #ifndef __HAVE_ARCH_STRNCPY -/** - * strncpy - Copy a length-limited, C-string - * @dest: Where to copy the string to - * @src: Where to copy the string from - * @count: The maximum number of bytes to copy - * - * The result is not %NUL-terminated if the source exceeds - * @count bytes. - * - * In the case where the length of @src is less than that of - * count, the remainder of @dest will be padded with %NUL. - * - */ char *strncpy(char *dest, const char *src, size_t count) { char *tmp = dest; @@ -121,58 +104,13 @@ char *strncpy(char *dest, const char *src, size_t count) EXPORT_SYMBOL(strncpy); #endif -#ifndef __HAVE_ARCH_STRLCPY -/** - * strlcpy - Copy a C-string into a sized buffer - * @dest: Where to copy the string to - * @src: Where to copy the string from - * @size: size of destination buffer - * - * Compatible with ``*BSD``: the result is always a valid - * NUL-terminated string that fits in the buffer (unless, - * of course, the buffer size is zero). It does not pad - * out the result like strncpy() does. - */ -size_t strlcpy(char *dest, const char *src, size_t size) -{ - size_t ret = strlen(src); - - if (size) { - size_t len = (ret >= size) ? size - 1 : ret; - memcpy(dest, src, len); - dest[len] = '\0'; - } - return ret; -} -EXPORT_SYMBOL(strlcpy); +#ifdef __BIG_ENDIAN +# define ALLBUTLAST_BYTE_MASK (~255ul) +#else +# define ALLBUTLAST_BYTE_MASK (~0ul >> 8) #endif -#ifndef __HAVE_ARCH_STRSCPY -/** - * strscpy - Copy a C-string into a sized buffer - * @dest: Where to copy the string to - * @src: Where to copy the string from - * @count: Size of destination buffer - * - * Copy the string, or as much of it as fits, into the dest buffer. The - * behavior is undefined if the string buffers overlap. The destination - * buffer is always NUL terminated, unless it's zero-sized. - * - * Preferred to strlcpy() since the API doesn't require reading memory - * from the src string beyond the specified "count" bytes, and since - * the return value is easier to error-check than strlcpy()'s. - * In addition, the implementation is robust to the string changing out - * from underneath it, unlike the current strlcpy() implementation. - * - * Preferred to strncpy() since it always returns a valid string, and - * doesn't unnecessarily force the tail of the destination buffer to be - * zeroed. If zeroing is desired please use strscpy_pad(). - * - * Returns: - * * The number of characters copied (not including the trailing %NUL) - * * -E2BIG if count is 0 or @src was truncated. - */ -ssize_t strscpy(char *dest, const char *src, size_t count) +ssize_t sized_strscpy(char *dest, const char *src, size_t count) { const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; size_t max = count; @@ -181,6 +119,7 @@ ssize_t strscpy(char *dest, const char *src, size_t count) if (count == 0 || WARN_ON_ONCE(count > INT_MAX)) return -E2BIG; +#ifndef CONFIG_DCACHE_WORD_ACCESS #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS /* * If src is unaligned, don't cross a page boundary, @@ -196,24 +135,43 @@ ssize_t strscpy(char *dest, const char *src, size_t count) if (((long) dest | (long) src) & (sizeof(long) - 1)) max = 0; #endif +#endif + + /* + * load_unaligned_zeropad() or read_word_at_a_time() below may read + * uninitialized bytes after the trailing zero and use them in + * comparisons. Disable this optimization under KMSAN to prevent + * false positive reports. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + max = 0; while (max >= sizeof(unsigned long)) { unsigned long c, data; +#ifdef CONFIG_DCACHE_WORD_ACCESS + c = load_unaligned_zeropad(src+res); +#else c = read_word_at_a_time(src+res); +#endif if (has_zero(c, &data, &constants)) { data = prep_zero_mask(c, data, &constants); data = create_zero_mask(data); *(unsigned long *)(dest+res) = c & zero_bytemask(data); return res + find_zero(data); } + count -= sizeof(unsigned long); + if (unlikely(!count)) { + c &= ALLBUTLAST_BYTE_MASK; + *(unsigned long *)(dest+res) = c; + return -E2BIG; + } *(unsigned long *)(dest+res) = c; res += sizeof(unsigned long); - count -= sizeof(unsigned long); max -= sizeof(unsigned long); } - while (count) { + while (count > 1) { char c; c = src[res]; @@ -224,14 +182,13 @@ ssize_t strscpy(char *dest, const char *src, size_t count) count--; } - /* Hit buffer length without finding a NUL; force NUL-termination. */ - if (res) - dest[res-1] = '\0'; + /* Force NUL-termination. */ + dest[res] = '\0'; - return -E2BIG; + /* Return E2BIG if the source didn't stop */ + return src[res] ? -E2BIG : res; } -EXPORT_SYMBOL(strscpy); -#endif +EXPORT_SYMBOL(sized_strscpy); /** * stpcpy - copy a string from src to dest returning a pointer to the new end @@ -258,11 +215,6 @@ char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) EXPORT_SYMBOL(stpcpy); #ifndef __HAVE_ARCH_STRCAT -/** - * strcat - Append one %NUL-terminated string to another - * @dest: The string to be appended to - * @src: The string to append to it - */ char *strcat(char *dest, const char *src) { char *tmp = dest; @@ -277,15 +229,6 @@ EXPORT_SYMBOL(strcat); #endif #ifndef __HAVE_ARCH_STRNCAT -/** - * strncat - Append a length-limited, C-string to another - * @dest: The string to be appended to - * @src: The string to append to it - * @count: The maximum numbers of bytes to copy - * - * Note that in contrast to strncpy(), strncat() ensures the result is - * terminated. - */ char *strncat(char *dest, const char *src, size_t count) { char *tmp = dest; @@ -306,12 +249,6 @@ EXPORT_SYMBOL(strncat); #endif #ifndef __HAVE_ARCH_STRLCAT -/** - * strlcat - Append a length-limited, C-string to another - * @dest: The string to be appended to - * @src: The string to append to it - * @count: The size of the destination buffer. - */ size_t strlcat(char *dest, const char *src, size_t count) { size_t dsize = strlen(dest); @@ -325,7 +262,7 @@ size_t strlcat(char *dest, const char *src, size_t count) count -= dsize; if (len >= count) len = count-1; - memcpy(dest, src, len); + __builtin_memcpy(dest, src, len); dest[len] = 0; return res; } @@ -476,10 +413,6 @@ EXPORT_SYMBOL(strnchr); #endif #ifndef __HAVE_ARCH_STRLEN -/** - * strlen - Find the length of a string - * @s: The string to be sized - */ size_t strlen(const char *s) { const char *sc; @@ -492,11 +425,6 @@ EXPORT_SYMBOL(strlen); #endif #ifndef __HAVE_ARCH_STRNLEN -/** - * strnlen - Find the length of a length-limited string - * @s: The string to be sized - * @count: The maximum number of bytes to search - */ size_t strnlen(const char *s, size_t count) { const char *sc; @@ -517,21 +445,13 @@ EXPORT_SYMBOL(strnlen); size_t strspn(const char *s, const char *accept) { const char *p; - const char *a; - size_t count = 0; for (p = s; *p != '\0'; ++p) { - for (a = accept; *a != '\0'; ++a) { - if (*p == *a) - break; - } - if (*a == '\0') - return count; - ++count; + if (!strchr(accept, *p)) + break; } - return count; + return p - s; } - EXPORT_SYMBOL(strspn); #endif @@ -544,17 +464,12 @@ EXPORT_SYMBOL(strspn); size_t strcspn(const char *s, const char *reject) { const char *p; - const char *r; - size_t count = 0; for (p = s; *p != '\0'; ++p) { - for (r = reject; *r != '\0'; ++r) { - if (*p == *r) - return count; - } - ++count; + if (strchr(reject, *p)) + break; } - return count; + return p - s; } EXPORT_SYMBOL(strcspn); #endif @@ -567,13 +482,11 @@ EXPORT_SYMBOL(strcspn); */ char *strpbrk(const char *cs, const char *ct) { - const char *sc1, *sc2; + const char *sc; - for (sc1 = cs; *sc1 != '\0'; ++sc1) { - for (sc2 = ct; *sc2 != '\0'; ++sc2) { - if (*sc1 == *sc2) - return (char *)sc1; - } + for (sc = cs; *sc != '\0'; ++sc) { + if (strchr(ct, *sc)) + return (char *)sc; } return NULL; } |