Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 1 | /* |
| 2 | * RFC 1521 base64 encoding/decoding |
| 3 | * |
| 4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved |
| 5 | * |
| 6 | * This file is part of mbed TLS (https://tls.mbed.org) |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; either version 2 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 17 | */ |
| 18 | |
Harald Welte | 292f9e7 | 2021-09-17 08:35:32 +0200 | [diff] [blame] | 19 | #include <osmocom/core/base64.h> |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 20 | |
| 21 | #include <stdint.h> |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 22 | #include <stdio.h> |
Harald Welte | 292f9e7 | 2021-09-17 08:35:32 +0200 | [diff] [blame] | 23 | #include <errno.h> |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 24 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 25 | static const unsigned char base64_enc_map[64] = { |
| 26 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', |
| 27 | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', |
| 28 | 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', |
| 29 | 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', |
| 30 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', |
| 31 | 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', |
| 32 | '8', '9', '+', '/' |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 33 | }; |
| 34 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 35 | static const unsigned char base64_dec_map[128] = { |
| 36 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, |
| 37 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, |
| 38 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, |
| 39 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, |
| 40 | 127, 127, 127, 62, 127, 127, 127, 63, 52, 53, |
| 41 | 54, 55, 56, 57, 58, 59, 60, 61, 127, 127, |
| 42 | 127, 64, 127, 127, 127, 0, 1, 2, 3, 4, |
| 43 | 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, |
| 44 | 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, |
| 45 | 25, 127, 127, 127, 127, 127, 127, 26, 27, 28, |
| 46 | 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, |
| 47 | 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, |
| 48 | 49, 50, 51, 127, 127, 127, 127, 127 |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 49 | }; |
| 50 | |
| 51 | /* |
| 52 | * Encode a buffer into base64 format |
| 53 | */ |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 54 | int osmo_base64_encode(unsigned char *dst, size_t dlen, size_t *olen, |
| 55 | const unsigned char *src, size_t slen) |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 56 | { |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 57 | size_t i, n; |
| 58 | int C1, C2, C3; |
| 59 | unsigned char *p; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 60 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 61 | if (slen == 0) { |
| 62 | *olen = 0; |
| 63 | return 0; |
| 64 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 65 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 66 | n = (slen << 3) / 6; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 67 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 68 | switch ((slen << 3) - (n * 6)) { |
| 69 | case 2: |
| 70 | n += 3; |
| 71 | break; |
| 72 | case 4: |
| 73 | n += 2; |
| 74 | break; |
| 75 | default: |
| 76 | break; |
| 77 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 78 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 79 | if (dlen < n + 1) { |
| 80 | *olen = n + 1; |
| 81 | return -ENOBUFS; |
| 82 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 83 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 84 | n = (slen / 3) * 3; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 85 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 86 | for (i = 0, p = dst; i < n; i += 3) { |
| 87 | C1 = *src++; |
| 88 | C2 = *src++; |
| 89 | C3 = *src++; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 90 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 91 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; |
| 92 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; |
| 93 | *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F]; |
| 94 | *p++ = base64_enc_map[C3 & 0x3F]; |
| 95 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 96 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 97 | if (i < slen) { |
| 98 | C1 = *src++; |
| 99 | C2 = ((i + 1) < slen) ? *src++ : 0; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 100 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 101 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; |
| 102 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 103 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 104 | if ((i + 1) < slen) |
| 105 | *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F]; |
| 106 | else |
| 107 | *p++ = '='; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 108 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 109 | *p++ = '='; |
| 110 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 111 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 112 | *olen = p - dst; |
| 113 | *p = 0; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 114 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 115 | return 0; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 116 | } |
| 117 | |
| 118 | /* |
| 119 | * Decode a base64-formatted buffer |
| 120 | */ |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 121 | int osmo_base64_decode(unsigned char *dst, size_t dlen, size_t *olen, |
| 122 | const unsigned char *src, size_t slen) |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 123 | { |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 124 | size_t i, n; |
| 125 | uint32_t j, x; |
| 126 | unsigned char *p; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 127 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 128 | /* First pass: check for validity and get output length */ |
| 129 | for (i = n = j = 0; i < slen; i++) { |
| 130 | /* Skip spaces before checking for EOL */ |
| 131 | x = 0; |
| 132 | while (i < slen && src[i] == ' ') { |
| 133 | ++i; |
| 134 | ++x; |
| 135 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 136 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 137 | /* Spaces at end of buffer are OK */ |
| 138 | if (i == slen) |
| 139 | break; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 140 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 141 | if ((slen - i) >= 2 && src[i] == '\r' && src[i + 1] == '\n') |
| 142 | continue; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 143 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 144 | if (src[i] == '\n') |
| 145 | continue; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 146 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 147 | /* Space inside a line is an error */ |
| 148 | if (x != 0) |
| 149 | return -EINVAL; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 150 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 151 | if (src[i] == '=' && ++j > 2) |
| 152 | return -EINVAL; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 153 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 154 | if (src[i] > 127 || base64_dec_map[src[i]] == 127) |
| 155 | return -EINVAL; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 156 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 157 | if (base64_dec_map[src[i]] < 64 && j != 0) |
| 158 | return -EINVAL; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 159 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 160 | n++; |
| 161 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 162 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 163 | if (n == 0) |
| 164 | return 0; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 165 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 166 | n = ((n * 6) + 7) >> 3; |
| 167 | n -= j; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 168 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 169 | if (dst == NULL || dlen < n) { |
| 170 | *olen = n; |
| 171 | return -ENOBUFS; |
| 172 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 173 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 174 | for (j = 3, n = x = 0, p = dst; i > 0; i--, src++) { |
| 175 | if (*src == '\r' || *src == '\n' || *src == ' ') |
| 176 | continue; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 177 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 178 | j -= (base64_dec_map[*src] == 64); |
| 179 | x = (x << 6) | (base64_dec_map[*src] & 0x3F); |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 180 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 181 | if (++n == 4) { |
| 182 | n = 0; |
| 183 | if (j > 0) |
| 184 | *p++ = (unsigned char)(x >> 16); |
| 185 | if (j > 1) |
| 186 | *p++ = (unsigned char)(x >> 8); |
| 187 | if (j > 2) |
| 188 | *p++ = (unsigned char)(x); |
| 189 | } |
| 190 | } |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 191 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 192 | *olen = p - dst; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 193 | |
Harald Welte | d075e3a | 2021-09-17 08:45:25 +0200 | [diff] [blame] | 194 | return 0; |
Harald Welte | c757239 | 2021-09-17 08:23:09 +0200 | [diff] [blame] | 195 | } |