/*------------------------------------------------------------------ * memcmp16_s.c - Compares memory * * October 2008, Bo Berry * February 2017, Reini Urban * * Copyright (c) 2008-2011 Cisco Systems * Copyright (c) 2017-2018 by Reini Urban * All rights reserved. * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, * copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following * conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. *------------------------------------------------------------------ */ #ifdef FOR_DOXYGEN #include "safe_mem_lib.h" #else #include "safeclib_private.h" #endif /** * @def memcmp16_s(dest,dlen,src,slen,diff) * @brief * Compares memory in uint16_t slices until they differ, and their * difference is returned in diff. If the block of memory is the * same, diff=0. * * @remark EXTENSION TO * ISO/IEC JTC1 SC22 WG14 N1172, Programming languages, environments * and system software interfaces, Extensions to the C Library, * Part I: Bounds-checking interfaces * * @param dest pointer to memory to compare against * @param dlen maximum length of dest, in uint16_t's * @param src pointer to the source memory to compare with dest * @param slen number of uint16_t's from source to be compared * @param *diff pointer to the diff which is an integer greater * than, equal to or less than zero according to * whether the object pointed to by dest is * greater than, equal to or less than the object * pointed to by src. * * @pre Neither dest nor src shall be a null pointer. * @pre Neither dlen nor slen shall be 0. * @pre dlen shall not be greater than RSIZE_MAX_MEM16 and sizeof(dest)/2 * @pre slen shall not be greater than RSIZE_MAX_MEM16 and sizeof(src)/2 * @pre slen shall not be greater than dlen and sizeof(dest)/2 * * @retval EOK when operation is successful * @retval ESNULLP when dest/src is NULL POINTER * @retval ESZEROL when dlen/slen = ZERO * @retval ESLEMAX when dlen/slen > RSIZE_MAX_MEM16 * @retval EOVERFLOW when 2*dlen/slen > size of dest/src (optionally, when * the compiler knows the object_size statically) * @retval ESLEWRNG when 2*dlen/slen != sizeof(dest/src) and * --enable-error-dmax * @retval ESNOSPC when dlen < slen * * @see * memcmp_s(), memcmp32_s() * */ #ifdef FOR_DOXYGEN errno_t memcmp16_s(const uint16_t *dest, rsize_t dlen, const uint16_t *src, rsize_t slen, int *diff) #else EXPORT errno_t _memcmp16_s_chk(const uint16_t *dest, rsize_t dlen, const uint16_t *src, rsize_t slen, int *diff, const size_t destbos, const size_t srcbos) #endif { size_t dmax; /* in bytes */ size_t smax; /* in bytes */ /* must be able to return the diff */ if (unlikely(diff == NULL)) { invoke_safe_mem_constraint_handler("memcmp16_s: diff is null", (void *)dest, ESNULLP); return (RCNEGATE(ESNULLP)); } *diff = -1; /* default diff */ if (unlikely(dest == NULL)) { invoke_safe_mem_constraint_handler("memcmp16_s: dest is null", NULL, ESNULLP); return (RCNEGATE(ESNULLP)); } if (unlikely(src == NULL)) { invoke_safe_mem_constraint_handler("memcmp16_s: src is null", (void *)dest, ESNULLP); return (RCNEGATE(ESNULLP)); } if (unlikely(dlen == 0)) { invoke_safe_mem_constraint_handler("memcmp16_s: dlen is 0", (void *)dest, ESZEROL); return (RCNEGATE(ESZEROL)); } dmax = dlen * 2; smax = slen * 2; if (destbos == BOS_UNKNOWN) { if (unlikely(dmax > RSIZE_MAX_MEM16)) { invoke_safe_mem_constraint_handler("memcmp16_s: dlen exceeds max", (void *)dest, ESLEMAX); return (RCNEGATE(ESLEMAX)); } BND_CHK_PTR_BOUNDS(dest, dmax); BND_CHK_PTR_BOUNDS(dest, smax); } else { if (unlikely(dmax > destbos)) { if (unlikely(dmax > RSIZE_MAX_MEM16)) { invoke_safe_mem_constraint_handler( "memcmp16_s: dlen exceeds max", (void *)dest, ESLEMAX); return (RCNEGATE(ESLEMAX)); } else { invoke_safe_mem_constraint_handler( "memcmp16_s: dlen exceeds dest", (void *)dest, EOVERFLOW); return (RCNEGATE(EOVERFLOW)); } } #ifdef HAVE_WARN_DMAX if (unlikely(dmax != destbos)) { handle_mem_bos_chk_warn("memcmp16_s", (void *)dest, dmax, destbos); RETURN_ESLEWRNG; } #endif } if (unlikely(slen == 0)) { invoke_safe_mem_constraint_handler("memcmp16_s: slen is 0", (void *)dest, ESZEROL); return (RCNEGATE(ESZEROL)); } if (srcbos == BOS_UNKNOWN) { if (unlikely(slen > RSIZE_MAX_MEM16)) { invoke_safe_mem_constraint_handler("memcmp16_s: slen exceeds max", (void *)src, ESLEMAX); return (RCNEGATE(ESLEMAX)); } BND_CHK_PTR_BOUNDS(src, smax); } else { if (unlikely(smax > srcbos)) { if (unlikely(slen > RSIZE_MAX_MEM16)) { invoke_safe_mem_constraint_handler( "memcmp16_s: slen exceeds max", (void *)src, ESLEMAX); return (RCNEGATE(ESLEMAX)); } else { invoke_safe_mem_constraint_handler( "memcmp16_s: slen exceeds src", (void *)src, EOVERFLOW); return (RCNEGATE(EOVERFLOW)); } } } if (unlikely(slen > dlen)) { invoke_safe_mem_constraint_handler("memcmp16_s: slen exceeds dlen", (void *)dest, ESNOSPC); return (RCNEGATE(ESNOSPC)); } /* * no need to compare the same memory */ if (unlikely(dest == src)) { *diff = 0; return (RCNEGATE(EOK)); } /* * now compare sp to dp */ *diff = 0; while (dlen != 0 && slen != 0) { if (*dest != *src) { *diff = *dest - *src; /* in units of int16 */ break; } dlen--; slen--; dest++; src++; } return (RCNEGATE(EOK)); }