1 /* 2 * Copyright (C) Internet Systems Consortium, Inc. ("ISC") 3 * 4 * Permission to use, copy, modify, and/or distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 9 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 10 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 11 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 12 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 13 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 14 * PERFORMANCE OF THIS SOFTWARE. 15 */ 16 17 /* $Id: hex.c,v 1.5 2020/02/26 18:47:59 florian Exp $ */ 18 19 /*! \file */ 20 21 #include <ctype.h> 22 #include <string.h> 23 24 #include <isc/buffer.h> 25 #include <isc/hex.h> 26 #include <isc/region.h> 27 #include <isc/types.h> 28 #include <isc/util.h> 29 30 #define RETERR(x) do { \ 31 isc_result_t _r = (x); \ 32 if (_r != ISC_R_SUCCESS) \ 33 return (_r); \ 34 } while (0) 35 36 static const char hex[] = "0123456789ABCDEF"; 37 38 isc_result_t 39 isc_hex_totext(isc_region_t *source, int wordlength, 40 const char *wordbreak, isc_buffer_t *target) 41 { 42 char buf[3]; 43 unsigned int loops = 0; 44 45 if (wordlength < 2) 46 wordlength = 2; 47 48 memset(buf, 0, sizeof(buf)); 49 while (source->length > 0) { 50 buf[0] = hex[(source->base[0] >> 4) & 0xf]; 51 buf[1] = hex[(source->base[0]) & 0xf]; 52 RETERR(isc_str_tobuffer(buf, target)); 53 isc_region_consume(source, 1); 54 55 loops++; 56 if (source->length != 0 && 57 (int)((loops + 1) * 2) >= wordlength) 58 { 59 loops = 0; 60 RETERR(isc_str_tobuffer(wordbreak, target)); 61 } 62 } 63 return (ISC_R_SUCCESS); 64 } 65 66 /*% 67 * State of a hex decoding process in progress. 68 */ 69 typedef struct { 70 int length; /*%< Desired length of binary data or -1 */ 71 isc_buffer_t *target; /*%< Buffer for resulting binary data */ 72 int digits; /*%< Number of buffered hex digits */ 73 int val[2]; 74 } hex_decode_ctx_t; 75 76 static inline void 77 hex_decode_init(hex_decode_ctx_t *ctx, int length, isc_buffer_t *target) 78 { 79 ctx->digits = 0; 80 ctx->length = length; 81 ctx->target = target; 82 } 83 84 static inline isc_result_t 85 hex_decode_char(hex_decode_ctx_t *ctx, int c) { 86 const char *s; 87 88 if ((s = strchr(hex, toupper(c))) == NULL) 89 return (ISC_R_BADHEX); 90 ctx->val[ctx->digits++] = (int)(s - hex); 91 if (ctx->digits == 2) { 92 unsigned char num; 93 94 num = (ctx->val[0] << 4) + (ctx->val[1]); 95 RETERR(isc_mem_tobuffer(ctx->target, &num, 1)); 96 if (ctx->length >= 0) { 97 if (ctx->length == 0) 98 return (ISC_R_BADHEX); 99 else 100 ctx->length -= 1; 101 } 102 ctx->digits = 0; 103 } 104 return (ISC_R_SUCCESS); 105 } 106 107 static inline isc_result_t 108 hex_decode_finish(hex_decode_ctx_t *ctx) { 109 if (ctx->length > 0) 110 return (ISC_R_UNEXPECTEDEND); 111 if (ctx->digits != 0) 112 return (ISC_R_BADHEX); 113 return (ISC_R_SUCCESS); 114 } 115 116 isc_result_t 117 isc_hex_decodestring(const char *cstr, isc_buffer_t *target) { 118 hex_decode_ctx_t ctx; 119 120 hex_decode_init(&ctx, -1, target); 121 for (;;) { 122 int c = *cstr++; 123 if (c == '\0') 124 break; 125 if (c == ' ' || c == '\t' || c == '\n' || c== '\r') 126 continue; 127 RETERR(hex_decode_char(&ctx, c)); 128 } 129 RETERR(hex_decode_finish(&ctx)); 130 return (ISC_R_SUCCESS); 131 } 132