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Diffstat (limited to 'src/lib/base64.c')
| -rw-r--r-- | src/lib/base64.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/src/lib/base64.c b/src/lib/base64.c new file mode 100644 index 0000000..6b40866 --- /dev/null +++ b/src/lib/base64.c @@ -0,0 +1,315 @@ +/* + * Copyright (C) 1999, 2000, 2001, 2004, 2005, 2006 Free Software + * Foundation, Inc. + * + * This program is left 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 2, 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, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +/** + * @brief Encode/decode binary data using printable characters. + * @author Simon Josefsson. + * @see RFC 3548 <http://www.ietf.org/rfc/rfc3548.txt>. + */ +RCSID("$Id$") + +#include <freeradius-devel/libradius.h> +#include <freeradius-devel/base64.h> + +#define us(x) (uint8_t) x + +/** Base 64 encode binary data + * + * Base64 encode IN array of size INLEN into OUT array of size OUTLEN. + * + * @param[out] out Where to write Base64 string. + * @param[in] outlen size of buffer including NULL byte. + * @param[in] in Data to encode. + * @param[in] inlen Length of data to encode. + * @return The amount of data we wrote to the buffer or -1 if output buffer + * was too small. + */ +ssize_t fr_base64_encode(char *out, size_t outlen, uint8_t const *in, size_t inlen) +{ + static char const b64str[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; + + char *p = out; + if (outlen < (FR_BASE64_ENC_LENGTH(inlen) + 1)) { + *out = '\0'; + return -1; + } + + while (inlen) { + *p++ = b64str[(in[0] >> 2) & 0x3f]; + *p++ = b64str[((in[0] << 4) + (--inlen ? in[1] >> 4 : 0)) & 0x3f]; + *p++ = (inlen ? b64str[((in[1] << 2) + (--inlen ? in[2] >> 6 : 0)) & 0x3f] : '='); + *p++ = inlen ? b64str[in[2] & 0x3f] : '='; + + if (inlen) inlen--; + if (inlen) in += 3; + } + + p[0] = '\0'; + + return p - out; +} + +/* + * With this approach this file works independent of the charset used + * (think EBCDIC). However, it does assume that the characters in the + * Base64 alphabet (A-Za-z0-9+/) are encoded in 0..255. POSIX + * 1003.1-2001 require that char and unsigned char are 8-bit + * quantities, though, taking care of that problem. But this may be a + * potential problem on non-POSIX C99 platforms. + * + * IBM C V6 for AIX mishandles "#define B64(x) ...'x'...", so use "_" + * as the formal parameter rather than "x". + */ +#define B64(_) \ + ((_) == 'A' ? 0 \ + : (_) == 'B' ? 1 \ + : (_) == 'C' ? 2 \ + : (_) == 'D' ? 3 \ + : (_) == 'E' ? 4 \ + : (_) == 'F' ? 5 \ + : (_) == 'G' ? 6 \ + : (_) == 'H' ? 7 \ + : (_) == 'I' ? 8 \ + : (_) == 'J' ? 9 \ + : (_) == 'K' ? 10 \ + : (_) == 'L' ? 11 \ + : (_) == 'M' ? 12 \ + : (_) == 'N' ? 13 \ + : (_) == 'O' ? 14 \ + : (_) == 'P' ? 15 \ + : (_) == 'Q' ? 16 \ + : (_) == 'R' ? 17 \ + : (_) == 'S' ? 18 \ + : (_) == 'T' ? 19 \ + : (_) == 'U' ? 20 \ + : (_) == 'V' ? 21 \ + : (_) == 'W' ? 22 \ + : (_) == 'X' ? 23 \ + : (_) == 'Y' ? 24 \ + : (_) == 'Z' ? 25 \ + : (_) == 'a' ? 26 \ + : (_) == 'b' ? 27 \ + : (_) == 'c' ? 28 \ + : (_) == 'd' ? 29 \ + : (_) == 'e' ? 30 \ + : (_) == 'f' ? 31 \ + : (_) == 'g' ? 32 \ + : (_) == 'h' ? 33 \ + : (_) == 'i' ? 34 \ + : (_) == 'j' ? 35 \ + : (_) == 'k' ? 36 \ + : (_) == 'l' ? 37 \ + : (_) == 'm' ? 38 \ + : (_) == 'n' ? 39 \ + : (_) == 'o' ? 40 \ + : (_) == 'p' ? 41 \ + : (_) == 'q' ? 42 \ + : (_) == 'r' ? 43 \ + : (_) == 's' ? 44 \ + : (_) == 't' ? 45 \ + : (_) == 'u' ? 46 \ + : (_) == 'v' ? 47 \ + : (_) == 'w' ? 48 \ + : (_) == 'x' ? 49 \ + : (_) == 'y' ? 50 \ + : (_) == 'z' ? 51 \ + : (_) == '0' ? 52 \ + : (_) == '1' ? 53 \ + : (_) == '2' ? 54 \ + : (_) == '3' ? 55 \ + : (_) == '4' ? 56 \ + : (_) == '5' ? 57 \ + : (_) == '6' ? 58 \ + : (_) == '7' ? 59 \ + : (_) == '8' ? 60 \ + : (_) == '9' ? 61 \ + : (_) == '+' ? 62 \ + : (_) == '/' ? 63 \ + : -1) + +static const signed char b64[0x100] = { + B64 (0), B64 (1), B64 (2), B64 (3), + B64 (4), B64 (5), B64 (6), B64 (7), + B64 (8), B64 (9), B64 (10), B64 (11), + B64 (12), B64 (13), B64 (14), B64 (15), + B64 (16), B64 (17), B64 (18), B64 (19), + B64 (20), B64 (21), B64 (22), B64 (23), + B64 (24), B64 (25), B64 (26), B64 (27), + B64 (28), B64 (29), B64 (30), B64 (31), + B64 (32), B64 (33), B64 (34), B64 (35), + B64 (36), B64 (37), B64 (38), B64 (39), + B64 (40), B64 (41), B64 (42), B64 (43), + B64 (44), B64 (45), B64 (46), B64 (47), + B64 (48), B64 (49), B64 (50), B64 (51), + B64 (52), B64 (53), B64 (54), B64 (55), + B64 (56), B64 (57), B64 (58), B64 (59), + B64 (60), B64 (61), B64 (62), B64 (63), + B64 (64), B64 (65), B64 (66), B64 (67), + B64 (68), B64 (69), B64 (70), B64 (71), + B64 (72), B64 (73), B64 (74), B64 (75), + B64 (76), B64 (77), B64 (78), B64 (79), + B64 (80), B64 (81), B64 (82), B64 (83), + B64 (84), B64 (85), B64 (86), B64 (87), + B64 (88), B64 (89), B64 (90), B64 (91), + B64 (92), B64 (93), B64 (94), B64 (95), + B64 (96), B64 (97), B64 (98), B64 (99), + B64 (100), B64 (101), B64 (102), B64 (103), + B64 (104), B64 (105), B64 (106), B64 (107), + B64 (108), B64 (109), B64 (110), B64 (111), + B64 (112), B64 (113), B64 (114), B64 (115), + B64 (116), B64 (117), B64 (118), B64 (119), + B64 (120), B64 (121), B64 (122), B64 (123), + B64 (124), B64 (125), B64 (126), B64 (127), + B64 (128), B64 (129), B64 (130), B64 (131), + B64 (132), B64 (133), B64 (134), B64 (135), + B64 (136), B64 (137), B64 (138), B64 (139), + B64 (140), B64 (141), B64 (142), B64 (143), + B64 (144), B64 (145), B64 (146), B64 (147), + B64 (148), B64 (149), B64 (150), B64 (151), + B64 (152), B64 (153), B64 (154), B64 (155), + B64 (156), B64 (157), B64 (158), B64 (159), + B64 (160), B64 (161), B64 (162), B64 (163), + B64 (164), B64 (165), B64 (166), B64 (167), + B64 (168), B64 (169), B64 (170), B64 (171), + B64 (172), B64 (173), B64 (174), B64 (175), + B64 (176), B64 (177), B64 (178), B64 (179), + B64 (180), B64 (181), B64 (182), B64 (183), + B64 (184), B64 (185), B64 (186), B64 (187), + B64 (188), B64 (189), B64 (190), B64 (191), + B64 (192), B64 (193), B64 (194), B64 (195), + B64 (196), B64 (197), B64 (198), B64 (199), + B64 (200), B64 (201), B64 (202), B64 (203), + B64 (204), B64 (205), B64 (206), B64 (207), + B64 (208), B64 (209), B64 (210), B64 (211), + B64 (212), B64 (213), B64 (214), B64 (215), + B64 (216), B64 (217), B64 (218), B64 (219), + B64 (220), B64 (221), B64 (222), B64 (223), + B64 (224), B64 (225), B64 (226), B64 (227), + B64 (228), B64 (229), B64 (230), B64 (231), + B64 (232), B64 (233), B64 (234), B64 (235), + B64 (236), B64 (237), B64 (238), B64 (239), + B64 (240), B64 (241), B64 (242), B64 (243), + B64 (244), B64 (245), B64 (246), B64 (247), + B64 (248), B64 (249), B64 (250), B64 (251), + B64 (252), B64 (253), B64 (254), B64 (255) +}; + +/** Check if char is in Base64 alphabet + * + * Note that '=' is padding and not considered to be part of the alphabet. + * + * @param c char to check. + * @return true if CH is a character from the Base64 alphabet, and false + * otherwise. + */ +bool fr_is_base64(char c) +{ + return b64[us(c)] >= 0; +} + +/* Decode base64 encoded input array. + * + * Decode base64 encoded input array IN of length INLEN to output array OUT that + * can hold *OUTLEN bytes. Return true if decoding was successful, i.e. + * if the input was valid base64 data, -1 otherwise. + * + * If *OUTLEN is too small, as many bytes as possible will be written to OUT. + * On return, *OUTLEN holds the length of decoded bytes in OUT. + * + * Note that as soon as any non-alphabet characters are encountered, + * decoding is stopped and -1 is returned. + * + * This means that, when applicable, you must remove any line terminators + * that is part of the data stream before calling this function. + * + * @param[out] out Where to write the decoded data. + * @param[in] outlen The length of the output buffer. + * @param[in] in Base64 string to decode. + * @param[in] inlen length of Base64 string. + * @return -1 on error, else the length of decoded data. + */ +ssize_t fr_base64_decode(uint8_t *out, size_t outlen, char const *in, size_t inlen) +{ + uint8_t *out_p = out; + uint8_t *out_end = out + outlen; + char const *p = in, *q; + char const *end = p + inlen; + + /* + * Process complete 24bit quanta + */ + while ((end - p) >= 4) { + if (!fr_is_base64(p[0]) || !fr_is_base64(p[1]) || !fr_is_base64(p[2]) || !fr_is_base64(p[3])) break; + + /* + * Check we have enough bytes to write out + * the 24bit quantum. + */ + if ((out_end - out_p) <= 3) { + oob: + fr_strerror_printf("Output buffer too small, needed at least %zu bytes", outlen + 1); + return p - end; + } + + *out_p++ = ((b64[us(p[0])] << 2) | (b64[us(p[1])] >> 4)); + *out_p++ = ((b64[us(p[1])] << 4) & 0xf0) | (b64[us(p[2])] >> 2); + *out_p++ = ((b64[us(p[2])] << 6) & 0xc0) | b64[us(p[3])]; + + p += 4; /* 32bit input -> 24bit output */ + } + + q = p; + + /* + * Find the first non-base64 char + */ + while ((q < end) && fr_is_base64(*q)) q++; + + switch (q - p) { + case 0: /* Final quantum is 24 bits */ + break; + + case 2: /* Final quantum is 8 bits */ + if ((out_end - out_p) < 1) goto oob; + *out_p++ = ((b64[us(p[0])] << 2) | (b64[us(p[1])] >> 4)); + p += 2; + break; + + case 3: /* Final quantum is 16 bits */ + if ((out_end - out_p) < 2) goto oob; + *out_p++ = ((b64[us(p[0])] << 2) | (b64[us(p[1])] >> 4)); + *out_p++ = ((b64[us(p[1])] << 4) & 0xf0) | (b64[us(p[2])] >> 2); + p += 3; + break; + + default: + fr_strerror_printf("Invalid base64 padding data"); + return p - end; + } + + while (p < end) { + if (*p != '=') { + fr_strerror_printf("Found non-padding char '%c' at end of base64 string", *p); + return p - end; + } + p++; + } + + return out_p - out; +} |