| /* base32.c -- Encode binary data using printable characters. | |
| Copyright (C) 1999-2001, 2004-2006, 2009-2026 Free Software Foundation, Inc. | |
| This file is free software: you can redistribute it and/or modify | |
| it under the terms of the GNU Lesser General Public License as | |
| published by the Free Software Foundation; either version 2.1 of the | |
| License, or (at your option) any later version. | |
| This file 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 Lesser General Public License for more details. | |
| You should have received a copy of the GNU Lesser General Public License | |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ | |
| /* Adapted from Simon Josefsson's base64 code by Gijs van Tulder. | |
| * | |
| * See also RFC 4648 <https://www.ietf.org/rfc/rfc4648.txt>. | |
| * | |
| * Be careful with error checking. Here is how you would typically | |
| * use these functions: | |
| * | |
| * bool ok = base32_decode_alloc (in, inlen, &out, &outlen); | |
| * if (!ok) | |
| * FAIL: input was not valid base32 | |
| * if (out == NULL) | |
| * FAIL: memory allocation error | |
| * OK: data in OUT/OUTLEN | |
| * | |
| * idx_t outlen = base32_encode_alloc (in, inlen, &out); | |
| * if (out == NULL && outlen == 0 && inlen != 0) | |
| * FAIL: input too long | |
| * if (out == NULL) | |
| * FAIL: memory allocation error | |
| * OK: data in OUT/OUTLEN. | |
| * | |
| */ | |
| #define BASE32_INLINE _GL_EXTERN_INLINE | |
| #include <config.h> | |
| /* Get prototype. */ | |
| #include "base32.h" | |
| /* Get imalloc. */ | |
| #include <ialloc.h> | |
| #include <stdckdint.h> | |
| #include <string.h> | |
| /* Convert 'char' to 'unsigned char' without casting. */ | |
| static unsigned char | |
| to_uchar (char ch) | |
| { | |
| return ch; | |
| } | |
| /* Base32 encode IN array of size INLEN into OUT array of size OUTLEN. | |
| If OUTLEN is less than BASE32_LENGTH(INLEN), write as many bytes as | |
| possible. If OUTLEN is larger than BASE32_LENGTH(INLEN), also zero | |
| terminate the output buffer. */ | |
| void | |
| base32_encode (const char *restrict in, idx_t inlen, | |
| char *restrict out, idx_t outlen) | |
| { | |
| static const char b32str[32] _GL_ATTRIBUTE_NONSTRING = | |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"; | |
| while (inlen && outlen) | |
| { | |
| *out++ = b32str[(to_uchar (in[0]) >> 3) & 0x1f]; | |
| if (!--outlen) | |
| break; | |
| *out++ = b32str[((to_uchar (in[0]) << 2) | |
| + (--inlen ? to_uchar (in[1]) >> 6 : 0)) | |
| & 0x1f]; | |
| if (!--outlen) | |
| break; | |
| *out++ = | |
| (inlen | |
| ? b32str[(to_uchar (in[1]) >> 1) & 0x1f] | |
| : '='); | |
| if (!--outlen) | |
| break; | |
| *out++ = | |
| (inlen | |
| ? b32str[((to_uchar (in[1]) << 4) | |
| + (--inlen ? to_uchar (in[2]) >> 4 : 0)) | |
| & 0x1f] | |
| : '='); | |
| if (!--outlen) | |
| break; | |
| *out++ = | |
| (inlen | |
| ? b32str[((to_uchar (in[2]) << 1) | |
| + (--inlen ? to_uchar (in[3]) >> 7 : 0)) | |
| & 0x1f] | |
| : '='); | |
| if (!--outlen) | |
| break; | |
| *out++ = | |
| (inlen | |
| ? b32str[(to_uchar (in[3]) >> 2) & 0x1f] | |
| : '='); | |
| if (!--outlen) | |
| break; | |
| *out++ = | |
| (inlen | |
| ? b32str[((to_uchar (in[3]) << 3) | |
| + (--inlen ? to_uchar (in[4]) >> 5 : 0)) | |
| & 0x1f] | |
| : '='); | |
| if (!--outlen) | |
| break; | |
| *out++ = inlen ? b32str[to_uchar (in[4]) & 0x1f] : '='; | |
| if (!--outlen) | |
| break; | |
| if (inlen) | |
| inlen--; | |
| if (inlen) | |
| in += 5; | |
| } | |
| if (outlen) | |
| *out = '\0'; | |
| } | |
| /* Allocate a buffer and store zero terminated base32 encoded data | |
| from array IN of size INLEN, returning BASE32_LENGTH(INLEN), i.e., | |
| the length of the encoded data, excluding the terminating zero. On | |
| return, the OUT variable will hold a pointer to newly allocated | |
| memory that must be deallocated by the caller. If output string | |
| length would overflow, 0 is returned and OUT is set to NULL. If | |
| memory allocation failed, OUT is set to NULL, and the return value | |
| indicates length of the requested memory block, i.e., | |
| BASE32_LENGTH(inlen) + 1. */ | |
| idx_t | |
| base32_encode_alloc (const char *in, idx_t inlen, char **out) | |
| { | |
| /* Check for overflow in outlen computation. | |
| Treat negative INLEN as overflow, for better compatibility with | |
| pre-2021-08-27 API, which used size_t. */ | |
| idx_t in_over_5 = inlen / 5 + (inlen % 5 != 0), outlen; | |
| if (ckd_mul (&outlen, in_over_5, 8) || inlen < 0) | |
| { | |
| *out = NULL; | |
| return 0; | |
| } | |
| outlen++; | |
| *out = imalloc (outlen); | |
| if (!*out) | |
| return outlen; | |
| base32_encode (in, inlen, *out, outlen); | |
| return outlen - 1; | |
| } | |
| /* With this approach this file works independent of the charset used | |
| (think EBCDIC). However, it does assume that the characters in the | |
| Base32 alphabet (A-Z2-7) 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 B32(x) ...'x'...", so use "_" | |
| as the formal parameter rather than "x". */ | |
| #define B32(_) \ | |
| ((_) == '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 \ | |
| : (_) == '2' ? 26 \ | |
| : (_) == '3' ? 27 \ | |
| : (_) == '4' ? 28 \ | |
| : (_) == '5' ? 29 \ | |
| : (_) == '6' ? 30 \ | |
| : (_) == '7' ? 31 \ | |
| : -1) | |
| signed char const base32_to_int[256] = { | |
| B32 (0), B32 (1), B32 (2), B32 (3), | |
| B32 (4), B32 (5), B32 (6), B32 (7), | |
| B32 (8), B32 (9), B32 (10), B32 (11), | |
| B32 (12), B32 (13), B32 (14), B32 (15), | |
| B32 (16), B32 (17), B32 (18), B32 (19), | |
| B32 (20), B32 (21), B32 (22), B32 (23), | |
| B32 (24), B32 (25), B32 (26), B32 (27), | |
| B32 (28), B32 (29), B32 (30), B32 (31), | |
| B32 (32), B32 (33), B32 (34), B32 (35), | |
| B32 (36), B32 (37), B32 (38), B32 (39), | |
| B32 (40), B32 (41), B32 (42), B32 (43), | |
| B32 (44), B32 (45), B32 (46), B32 (47), | |
| B32 (48), B32 (49), B32 (50), B32 (51), | |
| B32 (52), B32 (53), B32 (54), B32 (55), | |
| B32 (56), B32 (57), B32 (58), B32 (59), | |
| B32 (60), B32 (61), B32 (62), B32 (63), | |
| B32 (32), B32 (65), B32 (66), B32 (67), | |
| B32 (68), B32 (69), B32 (70), B32 (71), | |
| B32 (72), B32 (73), B32 (74), B32 (75), | |
| B32 (76), B32 (77), B32 (78), B32 (79), | |
| B32 (80), B32 (81), B32 (82), B32 (83), | |
| B32 (84), B32 (85), B32 (86), B32 (87), | |
| B32 (88), B32 (89), B32 (90), B32 (91), | |
| B32 (92), B32 (93), B32 (94), B32 (95), | |
| B32 (96), B32 (97), B32 (98), B32 (99), | |
| B32 (100), B32 (101), B32 (102), B32 (103), | |
| B32 (104), B32 (105), B32 (106), B32 (107), | |
| B32 (108), B32 (109), B32 (110), B32 (111), | |
| B32 (112), B32 (113), B32 (114), B32 (115), | |
| B32 (116), B32 (117), B32 (118), B32 (119), | |
| B32 (120), B32 (121), B32 (122), B32 (123), | |
| B32 (124), B32 (125), B32 (126), B32 (127), | |
| B32 (128), B32 (129), B32 (130), B32 (131), | |
| B32 (132), B32 (133), B32 (134), B32 (135), | |
| B32 (136), B32 (137), B32 (138), B32 (139), | |
| B32 (140), B32 (141), B32 (142), B32 (143), | |
| B32 (144), B32 (145), B32 (146), B32 (147), | |
| B32 (148), B32 (149), B32 (150), B32 (151), | |
| B32 (152), B32 (153), B32 (154), B32 (155), | |
| B32 (156), B32 (157), B32 (158), B32 (159), | |
| B32 (160), B32 (161), B32 (162), B32 (163), | |
| B32 (132), B32 (165), B32 (166), B32 (167), | |
| B32 (168), B32 (169), B32 (170), B32 (171), | |
| B32 (172), B32 (173), B32 (174), B32 (175), | |
| B32 (176), B32 (177), B32 (178), B32 (179), | |
| B32 (180), B32 (181), B32 (182), B32 (183), | |
| B32 (184), B32 (185), B32 (186), B32 (187), | |
| B32 (188), B32 (189), B32 (190), B32 (191), | |
| B32 (192), B32 (193), B32 (194), B32 (195), | |
| B32 (196), B32 (197), B32 (198), B32 (199), | |
| B32 (200), B32 (201), B32 (202), B32 (203), | |
| B32 (204), B32 (205), B32 (206), B32 (207), | |
| B32 (208), B32 (209), B32 (210), B32 (211), | |
| B32 (212), B32 (213), B32 (214), B32 (215), | |
| B32 (216), B32 (217), B32 (218), B32 (219), | |
| B32 (220), B32 (221), B32 (222), B32 (223), | |
| B32 (224), B32 (225), B32 (226), B32 (227), | |
| B32 (228), B32 (229), B32 (230), B32 (231), | |
| B32 (232), B32 (233), B32 (234), B32 (235), | |
| B32 (236), B32 (237), B32 (238), B32 (239), | |
| B32 (240), B32 (241), B32 (242), B32 (243), | |
| B32 (244), B32 (245), B32 (246), B32 (247), | |
| B32 (248), B32 (249), B32 (250), B32 (251), | |
| B32 (252), B32 (253), B32 (254), B32 (255) | |
| }; | |
| /* If CTX->i is 0 or 8, there are eight or more bytes in [*IN..IN_END), and | |
| none of those eight is a newline, then return *IN. Otherwise, copy up to | |
| 4 - CTX->i non-newline bytes from that range into CTX->buf, starting at | |
| index CTX->i and setting CTX->i to reflect the number of bytes copied, | |
| and return CTX->buf. In either case, advance *IN to point to the byte | |
| after the last one processed, and set *N_NON_NEWLINE to the number of | |
| verified non-newline bytes accessible through the returned pointer. */ | |
| static char * | |
| get_8 (struct base32_decode_context *ctx, | |
| char const *restrict *in, char const *restrict in_end, | |
| idx_t *n_non_newline) | |
| { | |
| if (ctx->i == 8) | |
| ctx->i = 0; | |
| if (ctx->i == 0) | |
| { | |
| char const *t = *in; | |
| if (8 <= in_end - *in && memchr (t, '\n', 8) == NULL) | |
| { | |
| /* This is the common case: no newline. */ | |
| *in += 8; | |
| *n_non_newline = 8; | |
| return (char *) t; | |
| } | |
| } | |
| { | |
| /* Copy non-newline bytes into BUF. */ | |
| char const *p = *in; | |
| while (p < in_end) | |
| { | |
| char c = *p++; | |
| if (c != '\n') | |
| { | |
| ctx->buf[ctx->i++] = c; | |
| if (ctx->i == 8) | |
| break; | |
| } | |
| } | |
| *in = p; | |
| *n_non_newline = ctx->i; | |
| return ctx->buf; | |
| } | |
| } | |
| #define return_false \ | |
| do \ | |
| { \ | |
| *outp = out; \ | |
| return false; \ | |
| } \ | |
| while (false) | |
| /* Decode eight bytes of base32-encoded data, IN, of length INLEN | |
| into the output buffer, *OUT, of size *OUTLEN bytes. Return true if | |
| decoding is successful, false otherwise. If *OUTLEN is too small, | |
| as many bytes as possible are written to *OUT. On return, advance | |
| *OUT to point to the byte after the last one written, and decrement | |
| *OUTLEN to reflect the number of bytes remaining in *OUT. */ | |
| static bool | |
| decode_8 (char const *restrict in, idx_t inlen, | |
| char *restrict *outp, idx_t *outleft) | |
| { | |
| if (inlen < 8) | |
| return false; | |
| if (!isbase32 (in[0]) || !isbase32 (in[1])) | |
| return false; | |
| char *out = *outp; | |
| if (*outleft) | |
| { | |
| *out++ = ((base32_to_int[to_uchar (in[0])] << 3) | |
| | (base32_to_int[to_uchar (in[1])] >> 2)); | |
| --*outleft; | |
| } | |
| if (in[2] == '=') | |
| { | |
| if (in[3] != '=' || in[4] != '=' || in[5] != '=' | |
| || in[6] != '=' || in[7] != '=') | |
| return_false; | |
| /* Reject non-canonical encodings. */ | |
| if (base32_to_int[to_uchar (in[1])] & 0x03) | |
| return_false; | |
| } | |
| else | |
| { | |
| if (!isbase32 (in[2]) || !isbase32 (in[3])) | |
| return_false; | |
| if (*outleft) | |
| { | |
| *out++ = ((base32_to_int[to_uchar (in[1])] << 6) | |
| | (base32_to_int[to_uchar (in[2])] << 1) | |
| | (base32_to_int[to_uchar (in[3])] >> 4)); | |
| --*outleft; | |
| } | |
| if (in[4] == '=') | |
| { | |
| if (in[5] != '=' || in[6] != '=' || in[7] != '=') | |
| return_false; | |
| /* Reject non-canonical encodings. */ | |
| if (base32_to_int[to_uchar (in[3])] & 0x0f) | |
| return_false; | |
| } | |
| else | |
| { | |
| if (!isbase32 (in[4])) | |
| return_false; | |
| if (*outleft) | |
| { | |
| *out++ = ((base32_to_int[to_uchar (in[3])] << 4) | |
| | (base32_to_int[to_uchar (in[4])] >> 1)); | |
| --*outleft; | |
| } | |
| if (in[5] == '=') | |
| { | |
| if (in[6] != '=' || in[7] != '=') | |
| return_false; | |
| /* Reject non-canonical encodings. */ | |
| if (base32_to_int[to_uchar (in[4])] & 0x01) | |
| return_false; | |
| } | |
| else | |
| { | |
| if (!isbase32 (in[5]) || !isbase32 (in[6])) | |
| return_false; | |
| if (*outleft) | |
| { | |
| *out++ = ((base32_to_int[to_uchar (in[4])] << 7) | |
| | (base32_to_int[to_uchar (in[5])] << 2) | |
| | (base32_to_int[to_uchar (in[6])] >> 3)); | |
| --*outleft; | |
| } | |
| if (in[7] != '=') | |
| { | |
| if (!isbase32 (in[7])) | |
| return_false; | |
| if (*outleft) | |
| { | |
| *out++ = ((base32_to_int[to_uchar (in[6])] << 5) | |
| | (base32_to_int[to_uchar (in[7])])); | |
| --*outleft; | |
| } | |
| } | |
| else | |
| { | |
| /* Reject non-canonical encodings. */ | |
| if (base32_to_int[to_uchar (in[6])] & 0x07) | |
| return_false; | |
| } | |
| } | |
| } | |
| } | |
| *outp = out; | |
| return true; | |
| } | |
| /* Decode base32-encoded input array IN of length INLEN to output array | |
| OUT that can hold *OUTLEN bytes. The input data may be interspersed | |
| with newlines. Return true if decoding was successful, i.e. if the | |
| input was valid base32 data, false 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, non-newline character is encountered, decoding | |
| is stopped and false is returned. If INLEN is zero, then process | |
| only whatever data is stored in CTX. | |
| Initially, CTX must have been initialized via base32_decode_ctx_init. | |
| Subsequent calls to this function must reuse whatever state is recorded | |
| in that buffer. It is necessary for when a octuple of base32 input | |
| bytes spans two input buffers. | |
| If CTX is NULL then newlines are treated as garbage and the input | |
| buffer is processed as a unit. */ | |
| bool | |
| base32_decode_ctx (struct base32_decode_context *ctx, | |
| const char *restrict in, idx_t inlen, | |
| char *restrict out, idx_t *outlen) | |
| { | |
| bool ignore_newlines = ctx != NULL; | |
| bool flush_ctx = false; | |
| unsigned int ctx_i = 0; | |
| if (ignore_newlines) | |
| { | |
| ctx_i = ctx->i; | |
| flush_ctx = inlen == 0; | |
| } | |
| idx_t outleft = *outlen; | |
| while (true) | |
| { | |
| idx_t outleft_save = outleft; | |
| if (ctx_i == 0 && !flush_ctx) | |
| { | |
| while (true) | |
| { | |
| /* Save a copy of outleft, in case we need to re-parse this | |
| block of four bytes. */ | |
| outleft_save = outleft; | |
| if (!decode_8 (in, inlen, &out, &outleft)) | |
| break; | |
| in += 8; | |
| inlen -= 8; | |
| } | |
| } | |
| if (inlen == 0 && !flush_ctx) | |
| break; | |
| /* Handle the common case of 72-byte wrapped lines. | |
| This also handles any other multiple-of-8-byte wrapping. */ | |
| if (inlen && *in == '\n' && ignore_newlines) | |
| { | |
| ++in; | |
| --inlen; | |
| } | |
| else | |
| { | |
| /* Restore OUT and OUTLEFT. */ | |
| out -= outleft_save - outleft; | |
| outleft = outleft_save; | |
| { | |
| char const *in_end = in + inlen; | |
| char const *non_nl; | |
| if (ignore_newlines) | |
| non_nl = get_8 (ctx, &in, in_end, &inlen); | |
| else | |
| non_nl = in; /* Might have nl in this case. */ | |
| /* If the input is empty or consists solely of newlines (0 non-newlines), | |
| then we're done. Likewise if there are fewer than 8 bytes when not | |
| flushing context and not treating newlines as garbage. */ | |
| if (inlen == 0 || (inlen < 8 && !flush_ctx && ignore_newlines)) | |
| { | |
| inlen = 0; | |
| break; | |
| } | |
| if (!decode_8 (non_nl, inlen, &out, &outleft)) | |
| break; | |
| inlen = in_end - in; | |
| } | |
| } | |
| } | |
| *outlen -= outleft; | |
| return inlen == 0; | |
| } | |
| /* Allocate an output buffer in *OUT, and decode the base32 encoded | |
| data stored in IN of size INLEN to the *OUT buffer. On return, the | |
| size of the decoded data is stored in *OUTLEN. OUTLEN may be NULL, | |
| if the caller is not interested in the decoded length. *OUT may be | |
| NULL to indicate an out of memory error, in which case *OUTLEN | |
| contains the size of the memory block needed. The function returns | |
| true on successful decoding and memory allocation errors. (Use the | |
| *OUT and *OUTLEN parameters to differentiate between successful | |
| decoding and memory error.) The function returns false if the | |
| input was invalid, in which case *OUT is NULL and *OUTLEN is | |
| undefined. */ | |
| bool | |
| base32_decode_alloc_ctx (struct base32_decode_context *ctx, | |
| const char *in, idx_t inlen, char **out, | |
| idx_t *outlen) | |
| { | |
| /* This may allocate a few bytes too many, depending on input, | |
| but it's not worth the extra CPU time to compute the exact size. | |
| The exact size is 5 * inlen / 8, minus one or more bytes if the | |
| input is padded with one or more "=". | |
| Shifting before multiplying avoids the possibility of overflow. */ | |
| idx_t needlen = 5 * ((inlen >> 3) + 1); | |
| *out = imalloc (needlen); | |
| if (!*out) | |
| return true; | |
| if (!base32_decode_ctx (ctx, in, inlen, *out, &needlen)) | |
| { | |
| free (*out); | |
| *out = NULL; | |
| return false; | |
| } | |
| if (outlen) | |
| *outlen = needlen; | |
| return true; | |
| } |