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Diffstat (limited to '')
| -rw-r--r-- | src/contrib/base64url.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/src/contrib/base64url.c b/src/contrib/base64url.c new file mode 100644 index 0000000..34e2bbe --- /dev/null +++ b/src/contrib/base64url.c @@ -0,0 +1,287 @@ +/* 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 "contrib/base64url.h" +#include "libknot/errcode.h" + +#include <stdlib.h> +#include <stdint.h> +#include <ctype.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, + ['%'] = 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 knot_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 KNOT_EINVAL; + } + if (in_len > MAX_BIN_DATA_LEN || out_len < ((in_len + 2) / 3) * 4) { + return KNOT_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 knot_base64url_encode_alloc(const uint8_t *in, + const uint32_t in_len, + uint8_t **out) +{ + // Checking inputs. + if (out == NULL) { + return KNOT_EINVAL; + } + if (in_len > MAX_BIN_DATA_LEN) { + return KNOT_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 KNOT_ENOMEM; + } + + // Encode data. + int32_t ret = knot_base64url_encode(in, in_len, *out, out_len); + if (ret < 0) { + free(*out); + *out = NULL; + } + + return ret; +} + +int32_t knot_base64url_decode(const uint8_t *in, + uint32_t in_len, + uint8_t *out, + const uint32_t out_len) +{ + // Checking inputs. + if (in == NULL || out == NULL) { + return KNOT_EINVAL; + } + + // cut up to two "%3d" from the end of input + int pad3d = 0; + const uint8_t *end = in + in_len; + char *perc3d = "d3%d3%", *stop3d = perc3d + 6; + while (end != in && perc3d != stop3d && tolower(*--end) == *perc3d) { + if (*perc3d++ == '%') { + in_len -= 3; + pad3d++; + } + } + + if (in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) { + return KNOT_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 = base64url_dec[in[1]] ; + c3 = (in + 2 < stop) ? base64url_dec[in[2]] : PD; + c4 = (in + 3 < stop) ? base64url_dec[in[3]] : PD; + + // Check 1. and 2. chars if are not padding + if (c1 >= PD || c2 >= PD) { + return KNOT_BASE64_ECHAR; + } + // Check 3. char if is bad or padding. + else if (c3 >= PD) { + if (c3 == PD) { + pad_len = 2; + } else { + return KNOT_BASE64_ECHAR; + } + } + // Check 3. char if is bad or padding. + else if (c4 >= PD) { + if (c4 == PD) { + pad_len = 1; + } else { + return KNOT_BASE64_ECHAR; + } + } + + if (pad_len > 0 && in <= stop - 4) { + return KNOT_BASE64_ECHAR; + } + + // 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; + goto end; + case 2: + bin += 1; + goto end; + } + + in += 4; + } + +end: + if (pad3d > pad_len) { + return KNOT_BASE64_ECHAR; + } + return (bin - out); +} + +int32_t knot_base64url_decode_alloc(const uint8_t *in, + const uint32_t in_len, + uint8_t **out) +{ + // Checking inputs. + if (out == NULL) { + return KNOT_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 KNOT_ENOMEM; + } + + // Decode data. + int32_t ret = knot_base64url_decode(in, in_len, *out, out_len); + if (ret < 0) { + free(*out); + *out = NULL; + } + + return ret; +} |