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Diffstat (limited to 'include/dnsjit/lib/base64url.c')
| -rw-r--r-- | include/dnsjit/lib/base64url.c | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/include/dnsjit/lib/base64url.c b/include/dnsjit/lib/base64url.c new file mode 100644 index 0000000..aacd490 --- /dev/null +++ b/include/dnsjit/lib/base64url.c @@ -0,0 +1,480 @@ +/* Copyright (C) 2020 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include "lib/base64url.h" + +#include <errno.h> +#include <stdlib.h> +#include <stdint.h> + +/*! \brief Maximal length of binary input to Base64url encoding. */ +#define MAX_BIN_DATA_LEN ((INT32_MAX / 4) * 3) + +/*! \brief Base64url padding character. */ +static const uint8_t base64url_pad = '\0'; +/*! \brief Base64 alphabet. */ +static const uint8_t base64url_enc[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"; + +/*! \brief Indicates bad Base64 character. */ +#define KO 255 +/*! \brief Indicates Base64 padding character. */ +#define PD 64 + +/*! \brief Transformation and validation table for decoding Base64. */ +static const uint8_t base64url_dec[256] = { + [0] = PD, + [43] = KO, + ['V'] = 21, + [129] = KO, + [172] = KO, + [215] = KO, + [1] = KO, + [44] = KO, + ['W'] = 22, + [130] = KO, + [173] = KO, + [216] = KO, + [2] = KO, + ['-'] = 62, + ['X'] = 23, + [131] = KO, + [174] = KO, + [217] = KO, + [3] = KO, + [46] = KO, + ['Y'] = 24, + [132] = KO, + [175] = KO, + [218] = KO, + [4] = KO, + [47] = KO, + ['Z'] = 25, + [133] = KO, + [176] = KO, + [219] = KO, + [5] = KO, + ['0'] = 52, + [91] = KO, + [134] = KO, + [177] = KO, + [220] = KO, + [6] = KO, + ['1'] = 53, + [92] = KO, + [135] = KO, + [178] = KO, + [221] = KO, + [7] = KO, + ['2'] = 54, + [93] = KO, + [136] = KO, + [179] = KO, + [222] = KO, + [8] = KO, + ['3'] = 55, + [94] = KO, + [137] = KO, + [180] = KO, + [223] = KO, + [9] = KO, + ['4'] = 56, + ['_'] = 63, + [138] = KO, + [181] = KO, + [224] = KO, + [10] = KO, + ['5'] = 57, + [96] = KO, + [139] = KO, + [182] = KO, + [225] = KO, + [11] = KO, + ['6'] = 58, + ['a'] = 26, + [140] = KO, + [183] = KO, + [226] = KO, + [12] = KO, + ['7'] = 59, + ['b'] = 27, + [141] = KO, + [184] = KO, + [227] = KO, + [13] = KO, + ['8'] = 60, + ['c'] = 28, + [142] = KO, + [185] = KO, + [228] = KO, + [14] = KO, + ['9'] = 61, + ['d'] = 29, + [143] = KO, + [186] = KO, + [229] = KO, + [15] = KO, + [58] = KO, + ['e'] = 30, + [144] = KO, + [187] = KO, + [230] = KO, + [16] = KO, + [59] = KO, + ['f'] = 31, + [145] = KO, + [188] = KO, + [231] = KO, + [17] = KO, + [60] = KO, + ['g'] = 32, + [146] = KO, + [189] = KO, + [232] = KO, + [18] = KO, + [61] = KO, + ['h'] = 33, + [147] = KO, + [190] = KO, + [233] = KO, + [19] = KO, + [62] = KO, + ['i'] = 34, + [148] = KO, + [191] = KO, + [234] = KO, + [20] = KO, + [63] = KO, + ['j'] = 35, + [149] = KO, + [192] = KO, + [235] = KO, + [21] = KO, + [64] = KO, + ['k'] = 36, + [150] = KO, + [193] = KO, + [236] = KO, + [22] = KO, + ['A'] = 0, + ['l'] = 37, + [151] = KO, + [194] = KO, + [237] = KO, + [23] = KO, + ['B'] = 1, + ['m'] = 38, + [152] = KO, + [195] = KO, + [238] = KO, + [24] = KO, + ['C'] = 2, + ['n'] = 39, + [153] = KO, + [196] = KO, + [239] = KO, + [25] = KO, + ['D'] = 3, + ['o'] = 40, + [154] = KO, + [197] = KO, + [240] = KO, + [26] = KO, + ['E'] = 4, + ['p'] = 41, + [155] = KO, + [198] = KO, + [241] = KO, + [27] = KO, + ['F'] = 5, + ['q'] = 42, + [156] = KO, + [199] = KO, + [242] = KO, + [28] = KO, + ['G'] = 6, + ['r'] = 43, + [157] = KO, + [200] = KO, + [243] = KO, + [29] = KO, + ['H'] = 7, + ['s'] = 44, + [158] = KO, + [201] = KO, + [244] = KO, + [30] = KO, + ['I'] = 8, + ['t'] = 45, + [159] = KO, + [202] = KO, + [245] = KO, + [31] = KO, + ['J'] = 9, + ['u'] = 46, + [160] = KO, + [203] = KO, + [246] = KO, + [32] = KO, + ['K'] = 10, + ['v'] = 47, + [161] = KO, + [204] = KO, + [247] = KO, + [33] = KO, + ['L'] = 11, + ['w'] = 48, + [162] = KO, + [205] = KO, + [248] = KO, + [34] = KO, + ['M'] = 12, + ['x'] = 49, + [163] = KO, + [206] = KO, + [249] = KO, + [35] = KO, + ['N'] = 13, + ['y'] = 50, + [164] = KO, + [207] = KO, + [250] = KO, + [36] = KO, + ['O'] = 14, + ['z'] = 51, + [165] = KO, + [208] = KO, + [251] = KO, + [37] = KO, + ['P'] = 15, + [123] = KO, + [166] = KO, + [209] = KO, + [252] = KO, + [38] = KO, + ['Q'] = 16, + [124] = KO, + [167] = KO, + [210] = KO, + [253] = KO, + [39] = KO, + ['R'] = 17, + [125] = KO, + [168] = KO, + [211] = KO, + [254] = KO, + [40] = KO, + ['S'] = 18, + [126] = KO, + [169] = KO, + [212] = KO, + [255] = KO, + [41] = KO, + ['T'] = 19, + [127] = KO, + [170] = KO, + [213] = KO, + [42] = KO, + ['U'] = 20, + [128] = KO, + [171] = KO, + [214] = KO, +}; + +int32_t base64url_encode(const uint8_t* in, + const uint32_t in_len, + uint8_t* out, + const uint32_t out_len) +{ + // Checking inputs. + if (in == NULL || out == NULL) { + return -EINVAL; + } + if (in_len > MAX_BIN_DATA_LEN || out_len < ((in_len + 2) / 3) * 4) { + return -ERANGE; + } + + uint8_t rest_len = in_len % 3; + const uint8_t* stop = in + in_len - rest_len; + uint8_t* text = out; + + // Encoding loop takes 3 bytes and creates 4 characters. + while (in < stop) { + text[0] = base64url_enc[in[0] >> 2]; + text[1] = base64url_enc[(in[0] & 0x03) << 4 | in[1] >> 4]; + text[2] = base64url_enc[(in[1] & 0x0F) << 2 | in[2] >> 6]; + text[3] = base64url_enc[in[2] & 0x3F]; + text += 4; + in += 3; + } + + // Processing of padding, if any. + switch (rest_len) { + case 2: + text[0] = base64url_enc[in[0] >> 2]; + text[1] = base64url_enc[(in[0] & 0x03) << 4 | in[1] >> 4]; + text[2] = base64url_enc[(in[1] & 0x0F) << 2]; + text[3] = base64url_pad; + text += 3; + break; + case 1: + text[0] = base64url_enc[in[0] >> 2]; + text[1] = base64url_enc[(in[0] & 0x03) << 4]; + text[2] = base64url_pad; + text[3] = base64url_pad; + text += 2; + break; + } + return (text - out); +} + +int32_t base64url_encode_alloc(const uint8_t* in, + const uint32_t in_len, + uint8_t** out) +{ + // Checking inputs. + if (out == NULL) { + return -EINVAL; + } + if (in_len > MAX_BIN_DATA_LEN) { + return -ERANGE; + } + + // Compute output buffer length. + uint32_t out_len = ((in_len + 2) / 3) * 4; + + // Allocate output buffer. + *out = malloc(out_len); + if (*out == NULL) { + return -ENOMEM; + } + + // Encode data. + int32_t ret = base64url_encode(in, in_len, *out, out_len); + if (ret < 0) { + free(*out); + *out = NULL; + } + + return ret; +} + +int32_t base64url_decode(const uint8_t* in, + const uint32_t in_len, + uint8_t* out, + const uint32_t out_len) +{ + // Checking inputs. + if (in == NULL || out == NULL) { + return -EINVAL; + } + if (in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) { + return -ERANGE; + } + + const uint8_t* stop = in + in_len; + uint8_t* bin = out; + uint8_t pad_len = 0; + uint8_t c1, c2, c3, c4; + + // Decoding loop takes 4 characters and creates 3 bytes. + while (in < stop) { + // Filling and transforming 4 Base64 chars. + c1 = base64url_dec[in[0]]; + c2 = (in + 1 < stop) ? base64url_dec[in[1]] : PD; + c3 = (in + 2 < stop) ? base64url_dec[in[2]] : PD; + c4 = (in + 3 < stop) ? base64url_dec[in[3]] : PD; + + // Check 4. char if is bad or padding. + if (c4 >= PD) { + if (c4 == PD && pad_len == 0) { + pad_len = 1; + } else { + return -1; + } + } + + // Check 3. char if is bad or padding. + if (c3 >= PD) { + if (c3 == PD && pad_len == 1) { + pad_len = 2; + } else { + return -1; + } + } + + // Check 1. and 2. chars if are not padding. + if (c2 >= PD || c1 >= PD) { + return -1; + } + + // Computing of output data based on padding length. + switch (pad_len) { + case 0: + bin[2] = (c3 << 6) + c4; + // FALLTHROUGH + case 1: + bin[1] = (c2 << 4) + (c3 >> 2); + // FALLTHROUGH + case 2: + bin[0] = (c1 << 2) + (c2 >> 4); + } + + // Update output end. + switch (pad_len) { + case 0: + bin += 3; + break; + case 1: + bin += 2; + break; + case 2: + bin += 1; + break; + } + + in += 4; + } + + return (bin - out); +} + +int32_t base64url_decode_alloc(const uint8_t* in, + const uint32_t in_len, + uint8_t** out) +{ + // Checking inputs. + if (out == NULL) { + return -EINVAL; + } + + // Compute output buffer length. + uint32_t out_len = ((in_len + 3) / 4) * 3; + + // Allocate output buffer. + *out = malloc(out_len); + if (*out == NULL) { + return -ENOMEM; + } + + // Decode data. + int32_t ret = base64url_decode(in, in_len, *out, out_len); + if (ret < 0) { + free(*out); + *out = NULL; + } + + return ret; +} |