/* Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> * SPDX-License-Identifier: GPL-3.0-or-later */ #include "base64.h" #include "libknot/errcode.h" #include <stdlib.h> #include <stdint.h> /*! \brief Maximal length of binary input to Base64 encoding. */ #define MAX_BIN_DATA_LEN ((INT32_MAX / 4) * 3) /*! \brief Base64 padding character. */ static const uint8_t base64_pad = '='; /*! \brief Base64 alphabet. */ static const uint8_t base64_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 base64_dec[256] = { [ 0] = KO, ['+'] = 62, ['V'] = 21, [129] = KO, [172] = KO, [215] = KO, [ 1] = KO, [ 44] = KO, ['W'] = 22, [130] = KO, [173] = KO, [216] = KO, [ 2] = KO, [ 45] = KO, ['X'] = 23, [131] = KO, [174] = KO, [217] = KO, [ 3] = KO, [ 46] = KO, ['Y'] = 24, [132] = KO, [175] = KO, [218] = KO, [ 4] = KO, ['/'] = 63, ['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, [ 95] = KO, [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, ['='] = PD, ['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 kr_base64_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] = base64_enc[in[0] >> 2]; text[1] = base64_enc[(in[0] & 0x03) << 4 | in[1] >> 4]; text[2] = base64_enc[(in[1] & 0x0F) << 2 | in[2] >> 6]; text[3] = base64_enc[in[2] & 0x3F]; text += 4; in += 3; } // Processing of padding, if any. switch (rest_len) { case 2: text[0] = base64_enc[in[0] >> 2]; text[1] = base64_enc[(in[0] & 0x03) << 4 | in[1] >> 4]; text[2] = base64_enc[(in[1] & 0x0F) << 2]; text[3] = base64_pad; text += 4; break; case 1: text[0] = base64_enc[in[0] >> 2]; text[1] = base64_enc[(in[0] & 0x03) << 4]; text[2] = base64_pad; text[3] = base64_pad; text += 4; break; } return (text - out); } int32_t kr_base64_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 = kr_base64_encode(in, in_len, *out, out_len); if (ret < 0) { free(*out); *out = NULL; } return ret; } int32_t kr_base64_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 KNOT_EINVAL; } if (in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) { return KNOT_ERANGE; } if ((in_len % 4) != 0) { return KNOT_BASE64_ESIZE; } 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 = base64_dec[in[0]]; c2 = base64_dec[in[1]]; c3 = base64_dec[in[2]]; c4 = base64_dec[in[3]]; // Check 4. char if is bad or padding. if (c4 >= PD) { if (c4 == PD && pad_len == 0) { pad_len = 1; } else { return KNOT_BASE64_ECHAR; } } // Check 3. char if is bad or padding. if (c3 >= PD) { if (c3 == PD && pad_len == 1) { pad_len = 2; } else { return KNOT_BASE64_ECHAR; } } // Check 1. and 2. chars if are not padding. if (c2 >= PD || c1 >= PD) { 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; break; case 2: bin += 1; break; } in += 4; } return (bin - out); } int32_t kr_base64_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 = kr_base64_decode(in, in_len, *out, out_len); if (ret < 0) { free(*out); *out = NULL; } return ret; }