1 /* $NetBSD: hex.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 2004-2005 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36
37 #include <config.h>
38 #include <krb5/roken.h>
39 #include <ctype.h>
40 #include <krb5/hex.h>
41
42 static const char hexchar[16] = "0123456789ABCDEF";
43
44 static int
pos(char c)45 pos(char c)
46 {
47 const char *p;
48 c = toupper((unsigned char)c);
49 for (p = hexchar; *p; p++)
50 if (*p == c)
51 return p - hexchar;
52 return -1;
53 }
54
55 ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
hex_encode(const void * data,size_t size,char ** str)56 hex_encode(const void *data, size_t size, char **str)
57 {
58 const unsigned char *q = data;
59 size_t i;
60 char *p;
61
62 /* check for overflow */
63 if (size * 2 < size) {
64 *str = NULL;
65 return -1;
66 }
67
68 p = malloc(size * 2 + 1);
69 if (p == NULL) {
70 *str = NULL;
71 return -1;
72 }
73
74 for (i = 0; i < size; i++) {
75 p[i * 2] = hexchar[(*q >> 4) & 0xf];
76 p[i * 2 + 1] = hexchar[*q & 0xf];
77 q++;
78 }
79 p[i * 2] = '\0';
80 *str = p;
81
82 return i * 2;
83 }
84
85 ROKEN_LIB_FUNCTION ssize_t ROKEN_LIB_CALL
hex_decode(const char * str,void * data,size_t len)86 hex_decode(const char *str, void *data, size_t len)
87 {
88 size_t l;
89 unsigned char *p = data;
90 size_t i;
91
92 l = strlen(str);
93
94 /* check for overflow, same as (l+1)/2 but overflow safe */
95 if ((l/2) + (l&1) > len)
96 return -1;
97
98 if (l & 1) {
99 p[0] = pos(str[0]);
100 str++;
101 p++;
102 }
103 for (i = 0; i < l / 2; i++)
104 p[i] = pos(str[i * 2]) << 4 | pos(str[(i * 2) + 1]);
105 return i + (l & 1);
106 }
107