From 48030f9988d803da367af5a3b888549851db2f58 Mon Sep 17 00:00:00 2001 From: Samuel Holland Date: Sun, 14 Jan 2018 23:00:13 -0600 Subject: string: Clean up, fix bugs, implement LSB plus more * Add all checked string functions from LSB, plus those found in use in other applications. Document those functions from LSB as such. * Use a consistent structure and paramater names for all functions. * Fix multiple off-by-one errors. * Use a less hacky and more optimized rawmemchr. * Sort functions by name. Signed-off-by: Samuel Holland --- libgcompat/string.c | 237 +++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 199 insertions(+), 38 deletions(-) diff --git a/libgcompat/string.c b/libgcompat/string.c index 2c05caf..1d387a8 100644 --- a/libgcompat/string.c +++ b/libgcompat/string.c @@ -1,86 +1,247 @@ +#define _GNU_SOURCE /* mempcpy */ #include /* assert */ -#include /* strto[u?]ll */ +#include /* NULL, size_t */ +#include /* SIZE_MAX */ #include /* memcpy, strcpy, strncat, strndup */ #include "alias.h" /* weak_alias */ -/* "Checked" memcpy */ -void *__memcpy_chk(void *dest, const void *src, size_t len, size_t destlen) +/** + * Copy bytes in memory, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---memcpy-chk-1.html + */ +void *__memcpy_chk(void *dest, const void *src, size_t n, size_t destlen) { assert(dest != NULL); assert(src != NULL); - assert(len <= destlen); - if (src < dest) { - assert(!(src + len >= dest)); + assert(destlen >= n); + if (dest < src) { + assert((char *) dest + n <= (char *) src); } else { - assert(!(dest + len >= src)); + assert((char *) src + n <= (char *) dest); } - return memcpy(dest, src, len); + + return memcpy(dest, src, n); } -/* "Checked" strncat */ -char *__strncat_chk(char *dest, const char *src, size_t n, size_t destlen) +/** + * Copy bytes in memory with overlapping areas, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---memmove-chk-1.html + */ +void *__memmove_chk(void *dest, const void *src, size_t n, size_t destlen) { assert(dest != NULL); assert(src != NULL); - assert(n <= destlen); + assert(destlen >= n); - return strncat(dest, src, n); + return memmove(dest, src, n); } -/* "Checked" strcat */ -char *__strcat_chk(char *dest, const char *src, size_t destlen) +/** + * Copy bytes in memory. + * + * LSB 5.0: LSB-Core-generic/baselib---mempcpy.html + */ +void *__mempcpy(void *dest, const void *src, size_t n) { - return strncat(dest, src, destlen - 1); + return mempcpy(dest, src, n); } -/* "Checked" strncpy */ -char *__strncpy_chk(char *dest, const char *src, size_t n, size_t destlen) +/** + * Copy bytes in memory, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---mempcpy-chk-1.html + */ +void *__mempcpy_chk(void *dest, const void *src, size_t n, size_t destlen) { assert(dest != NULL); assert(src != NULL); - assert(strlen(src) < destlen); + assert(destlen >= n); + if (dest < src) { + assert((char *) dest + n <= (char *) src); + } else { + assert((char *) src + n <= (char *) dest); + } - return strncpy(dest, src, n); + return mempcpy(dest, src, n); +} + +/** + * Set bytes in memory, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---memset-chk-1.html + */ +void *__memset_chk(void *s, int c, size_t n, size_t buflen) +{ + assert(s != NULL); + assert(buflen >= n); + + return memset(s, c, n); +} + +/** + * Find byte in memory. + * + * LSB 5.0: LSB-Core-generic/baselib---rawmemchr.html + */ +void *__rawmemchr(const void *s, int c) +{ + return memchr(s, c, SIZE_MAX); +} +weak_alias(__rawmemchr, rawmemchr); + +/** + * Copy a string and return a pointer to the end of the result, with buffer + * overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---stpcpy-chk-1.html + */ +char *__stpcpy_chk(char *dest, const char *src, size_t destlen) +{ + size_t n = strlen(src) + 1; + + assert(dest != NULL); + assert(src != NULL); + assert(destlen >= n); + if (dest < src) { + assert(dest + n <= src); + } else { + assert(src + n <= dest); + } + + return stpcpy(dest, src); +} + +/** + * Copy a fixed-length string, returning a pointer to the array end, with buffer + * overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---stpncpy-chk-1.html + */ +char *__stpncpy_chk(char *dest, const char *src, size_t n, size_t destlen) +{ + assert(dest != NULL); + assert(src != NULL); + assert(destlen >= n); + if (dest < src) { + assert(dest + n <= src); + } else { + assert(src + n <= dest); + } + + return stpncpy(dest, src, n); } -/* "Checked" strcpy */ +/** + * Concatenate two strings, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---strcat-chk-1.html + */ +char *__strcat_chk(char *dest, const char *src, size_t destlen) +{ + size_t n = strlen(src) + 1; + size_t total = strnlen(dest, destlen) + n; + + assert(dest != NULL); + assert(src != NULL); + assert(destlen >= total); + if (dest < src) { + assert(dest + total <= src); + } else { + assert(src + n <= dest); + } + + return strcat(dest, src); +} + +/** + * Copy a string, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---strcpy-chk-1.html + */ char *__strcpy_chk(char *dest, const char *src, size_t destlen) { + size_t n = strlen(src) + 1; + assert(dest != NULL); assert(src != NULL); - assert(strlen(src) < destlen); + assert(destlen >= n); + if (dest < src) { + assert(dest + n <= src); + } else { + assert(src + n <= dest); + } return strcpy(dest, src); } -/* Literally a useless __ alias. */ -char *__strndup(const char *str, size_t count) +/** + * Concatenate a string with part of another, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---strncat-chk-1.html + */ +char *__strncat_chk(char *dest, const char *src, size_t n, size_t destlen) { - return strndup(str, count); + size_t total = strnlen(dest, destlen) + n + 1; + + assert(dest != NULL); + assert(src != NULL); + assert(destlen >= total); + if (dest < src) { + assert(dest + total <= src); + } else { + assert(src + n <= dest); + } + + return strncat(dest, src, n); } -/* The existance of this method, and the fact it is used in real code, gives - * me nightmares. */ -void *__rawmemchr(const void *s, int c) +/** + * Copy a fixed-length string, with buffer overflow checking. + * + * LSB 5.0: LSB-Core-generic/baselib---strncpy-chk-1.html + */ +char *__strncpy_chk(char *dest, const char *src, size_t n, size_t destlen) { - const unsigned char *haystack = s; - unsigned char needle = (unsigned char) c; - while (*haystack++ != needle) - ; - return (void *) haystack; + assert(dest != NULL); + assert(src != NULL); + assert(destlen >= n); + if (dest < src) { + assert(dest + n <= src); + } else { + assert(src + n <= dest); + } + + return strncpy(dest, src, n); } -weak_alias(__rawmemchr, rawmemchr); -/* Another useless __ alias */ -char *__strtok_r(char *str, const char *delim, char **saveptr) +/** + * Duplicate a specific number of bytes from a string. + */ +char *__strndup(const char *s, size_t size) { - return strtok_r(str, delim, saveptr); + return strndup(s, size); } -/* The "global" definition of strsep in glibc, used when architecture dependent - * assembler versions aren't good enough. */ +/** + * Extract token from string. + * + * The "global" definition of strsep in glibc, used when architecture dependent + * assembler versions aren't good enough. + */ char *__strsep_g(char **stringp, const char *delim) { return strsep(stringp, delim); } + +/** + * Split string into tokens. + * + * LSB 5.0: LSB-Core-generic/baselib---strtok-r-1.html + */ +char *__strtok_r(char *s, const char *delim, char **save_ptr) +{ + return strtok_r(s, delim, save_ptr); +} -- cgit v1.2.3-70-g09d2