| /* $OpenBSD: base64.c,v 1.8 2015/01/16 16:48:51 deraadt Exp $ */ |
| |
| /* |
| * Copyright (c) 1996 by Internet Software Consortium. |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
| * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
| * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
| * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
| * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
| * SOFTWARE. |
| */ |
| |
| /* |
| * Portions Copyright (c) 1995 by International Business Machines, Inc. |
| * |
| * International Business Machines, Inc. (hereinafter called IBM) grants |
| * permission under its copyrights to use, copy, modify, and distribute this |
| * Software with or without fee, provided that the above copyright notice and |
| * all paragraphs of this notice appear in all copies, and that the name of IBM |
| * not be used in connection with the marketing of any product incorporating |
| * the Software or modifications thereof, without specific, written prior |
| * permission. |
| * |
| * To the extent it has a right to do so, IBM grants an immunity from suit |
| * under its patents, if any, for the use, sale or manufacture of products to |
| * the extent that such products are used for performing Domain Name System |
| * dynamic updates in TCP/IP networks by means of the Software. No immunity is |
| * granted for any product per se or for any other function of any product. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES, |
| * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| * PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, |
| * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING |
| * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN |
| * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES. |
| */ |
| |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <netinet/in.h> |
| #include <arpa/inet.h> |
| #include <arpa/nameser.h> |
| |
| #include <ctype.h> |
| #include <resolv.h> |
| #include <stdio.h> |
| |
| #include <stdlib.h> |
| #include <string.h> |
| |
| static const char Base64[] = |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| static const char Pad64 = '='; |
| |
| /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) |
| The following encoding technique is taken from RFC 1521 by Borenstein |
| and Freed. It is reproduced here in a slightly edited form for |
| convenience. |
| |
| A 65-character subset of US-ASCII is used, enabling 6 bits to be |
| represented per printable character. (The extra 65th character, "=", |
| is used to signify a special processing function.) |
| |
| The encoding process represents 24-bit groups of input bits as output |
| strings of 4 encoded characters. Proceeding from left to right, a |
| 24-bit input group is formed by concatenating 3 8-bit input groups. |
| These 24 bits are then treated as 4 concatenated 6-bit groups, each |
| of which is translated into a single digit in the base64 alphabet. |
| |
| Each 6-bit group is used as an index into an array of 64 printable |
| characters. The character referenced by the index is placed in the |
| output string. |
| |
| Table 1: The Base64 Alphabet |
| |
| Value Encoding Value Encoding Value Encoding Value Encoding |
| 0 A 17 R 34 i 51 z |
| 1 B 18 S 35 j 52 0 |
| 2 C 19 T 36 k 53 1 |
| 3 D 20 U 37 l 54 2 |
| 4 E 21 V 38 m 55 3 |
| 5 F 22 W 39 n 56 4 |
| 6 G 23 X 40 o 57 5 |
| 7 H 24 Y 41 p 58 6 |
| 8 I 25 Z 42 q 59 7 |
| 9 J 26 a 43 r 60 8 |
| 10 K 27 b 44 s 61 9 |
| 11 L 28 c 45 t 62 + |
| 12 M 29 d 46 u 63 / |
| 13 N 30 e 47 v |
| 14 O 31 f 48 w (pad) = |
| 15 P 32 g 49 x |
| 16 Q 33 h 50 y |
| |
| Special processing is performed if fewer than 24 bits are available |
| at the end of the data being encoded. A full encoding quantum is |
| always completed at the end of a quantity. When fewer than 24 input |
| bits are available in an input group, zero bits are added (on the |
| right) to form an integral number of 6-bit groups. Padding at the |
| end of the data is performed using the '=' character. |
| |
| Since all base64 input is an integral number of octets, only the |
| ------------------------------------------------- |
| following cases can arise: |
| |
| (1) the final quantum of encoding input is an integral |
| multiple of 24 bits; here, the final unit of encoded |
| output will be an integral multiple of 4 characters |
| with no "=" padding, |
| (2) the final quantum of encoding input is exactly 8 bits; |
| here, the final unit of encoded output will be two |
| characters followed by two "=" padding characters, or |
| (3) the final quantum of encoding input is exactly 16 bits; |
| here, the final unit of encoded output will be three |
| characters followed by one "=" padding character. |
| */ |
| |
| int |
| b64_ntop(src, srclength, target, targsize) |
| u_char const *src; |
| size_t srclength; |
| char *target; |
| size_t targsize; |
| { |
| size_t datalength = 0; |
| u_char input[3]; |
| u_char output[4]; |
| int i; |
| |
| while (2 < srclength) { |
| input[0] = *src++; |
| input[1] = *src++; |
| input[2] = *src++; |
| srclength -= 3; |
| |
| output[0] = input[0] >> 2; |
| output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
| output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
| output[3] = input[2] & 0x3f; |
| |
| if (datalength + 4 > targsize) |
| return (-1); |
| target[datalength++] = Base64[output[0]]; |
| target[datalength++] = Base64[output[1]]; |
| target[datalength++] = Base64[output[2]]; |
| target[datalength++] = Base64[output[3]]; |
| } |
| |
| /* Now we worry about padding. */ |
| if (0 != srclength) { |
| /* Get what's left. */ |
| input[0] = input[1] = input[2] = '\0'; |
| for (i = 0; i < srclength; i++) |
| input[i] = *src++; |
| |
| output[0] = input[0] >> 2; |
| output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
| output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
| |
| if (datalength + 4 > targsize) |
| return (-1); |
| target[datalength++] = Base64[output[0]]; |
| target[datalength++] = Base64[output[1]]; |
| if (srclength == 1) |
| target[datalength++] = Pad64; |
| else |
| target[datalength++] = Base64[output[2]]; |
| target[datalength++] = Pad64; |
| } |
| if (datalength >= targsize) |
| return (-1); |
| target[datalength] = '\0'; /* Returned value doesn't count \0. */ |
| return (datalength); |
| } |
| |
| /* skips all whitespace anywhere. |
| converts characters, four at a time, starting at (or after) |
| src from base - 64 numbers into three 8 bit bytes in the target area. |
| it returns the number of data bytes stored at the target, or -1 on error. |
| */ |
| |
| int |
| b64_pton(src, target, targsize) |
| char const *src; |
| u_char *target; |
| size_t targsize; |
| { |
| int tarindex, state, ch; |
| u_char nextbyte; |
| char *pos; |
| |
| state = 0; |
| tarindex = 0; |
| |
| while ((ch = (unsigned char)*src++) != '\0') { |
| if (isspace(ch)) /* Skip whitespace anywhere. */ |
| continue; |
| |
| if (ch == Pad64) |
| break; |
| |
| pos = strchr(Base64, ch); |
| if (pos == 0) /* A non-base64 character. */ |
| return (-1); |
| |
| switch (state) { |
| case 0: |
| if (target) { |
| if (tarindex >= targsize) |
| return (-1); |
| target[tarindex] = (pos - Base64) << 2; |
| } |
| state = 1; |
| break; |
| case 1: |
| if (target) { |
| if (tarindex >= targsize) |
| return (-1); |
| target[tarindex] |= (pos - Base64) >> 4; |
| nextbyte = ((pos - Base64) & 0x0f) << 4; |
| if (tarindex + 1 < targsize) |
| target[tarindex+1] = nextbyte; |
| else if (nextbyte) |
| return (-1); |
| } |
| tarindex++; |
| state = 2; |
| break; |
| case 2: |
| if (target) { |
| if (tarindex >= targsize) |
| return (-1); |
| target[tarindex] |= (pos - Base64) >> 2; |
| nextbyte = ((pos - Base64) & 0x03) << 6; |
| if (tarindex + 1 < targsize) |
| target[tarindex+1] = nextbyte; |
| else if (nextbyte) |
| return (-1); |
| } |
| tarindex++; |
| state = 3; |
| break; |
| case 3: |
| if (target) { |
| if (tarindex >= targsize) |
| return (-1); |
| target[tarindex] |= (pos - Base64); |
| } |
| tarindex++; |
| state = 0; |
| break; |
| } |
| } |
| |
| /* |
| * We are done decoding Base-64 chars. Let's see if we ended |
| * on a byte boundary, and/or with erroneous trailing characters. |
| */ |
| |
| if (ch == Pad64) { /* We got a pad char. */ |
| ch = (unsigned char)*src++; /* Skip it, get next. */ |
| switch (state) { |
| case 0: /* Invalid = in first position */ |
| case 1: /* Invalid = in second position */ |
| return (-1); |
| |
| case 2: /* Valid, means one byte of info */ |
| /* Skip any number of spaces. */ |
| for (; ch != '\0'; ch = (unsigned char)*src++) |
| if (!isspace(ch)) |
| break; |
| /* Make sure there is another trailing = sign. */ |
| if (ch != Pad64) |
| return (-1); |
| ch = (unsigned char)*src++; /* Skip the = */ |
| /* Fall through to "single trailing =" case. */ |
| /* FALLTHROUGH */ |
| |
| case 3: /* Valid, means two bytes of info */ |
| /* |
| * We know this char is an =. Is there anything but |
| * whitespace after it? |
| */ |
| for (; ch != '\0'; ch = (unsigned char)*src++) |
| if (!isspace(ch)) |
| return (-1); |
| |
| /* |
| * Now make sure for cases 2 and 3 that the "extra" |
| * bits that slopped past the last full byte were |
| * zeros. If we don't check them, they become a |
| * subliminal channel. |
| */ |
| if (target && tarindex < targsize && |
| target[tarindex] != 0) |
| return (-1); |
| } |
| } else { |
| /* |
| * We ended by seeing the end of the string. Make sure we |
| * have no partial bytes lying around. |
| */ |
| if (state != 0) |
| return (-1); |
| } |
| |
| return (tarindex); |
| } |