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315 lines
10 KiB
315 lines
10 KiB
/* $OpenBSD: base64.c,v 1.8 2015/01/16 16:48:51 deraadt Exp $ */ |
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/* |
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* Copyright (c) 1996 by Internet Software Consortium. |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS |
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE |
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL |
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS |
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS |
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* SOFTWARE. |
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*/ |
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/* |
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* Portions Copyright (c) 1995 by International Business Machines, Inc. |
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* |
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* International Business Machines, Inc. (hereinafter called IBM) grants |
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* permission under its copyrights to use, copy, modify, and distribute this |
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* Software with or without fee, provided that the above copyright notice and |
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* all paragraphs of this notice appear in all copies, and that the name of IBM |
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* not be used in connection with the marketing of any product incorporating |
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* the Software or modifications thereof, without specific, written prior |
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* permission. |
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* |
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* To the extent it has a right to do so, IBM grants an immunity from suit |
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* under its patents, if any, for the use, sale or manufacture of products to |
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* the extent that such products are used for performing Domain Name System |
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* dynamic updates in TCP/IP networks by means of the Software. No immunity is |
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* granted for any product per se or for any other function of any product. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES, |
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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* PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL, |
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* DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING |
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* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN |
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* IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES. |
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*/ |
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <arpa/inet.h> |
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#include <arpa/nameser.h> |
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#include <ctype.h> |
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#include <resolv.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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static const char Base64[] = |
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
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static const char Pad64 = '='; |
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/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt) |
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The following encoding technique is taken from RFC 1521 by Borenstein |
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and Freed. It is reproduced here in a slightly edited form for |
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convenience. |
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A 65-character subset of US-ASCII is used, enabling 6 bits to be |
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represented per printable character. (The extra 65th character, "=", |
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is used to signify a special processing function.) |
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The encoding process represents 24-bit groups of input bits as output |
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strings of 4 encoded characters. Proceeding from left to right, a |
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24-bit input group is formed by concatenating 3 8-bit input groups. |
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These 24 bits are then treated as 4 concatenated 6-bit groups, each |
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of which is translated into a single digit in the base64 alphabet. |
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Each 6-bit group is used as an index into an array of 64 printable |
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characters. The character referenced by the index is placed in the |
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output string. |
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Table 1: The Base64 Alphabet |
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Value Encoding Value Encoding Value Encoding Value Encoding |
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0 A 17 R 34 i 51 z |
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1 B 18 S 35 j 52 0 |
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2 C 19 T 36 k 53 1 |
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3 D 20 U 37 l 54 2 |
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4 E 21 V 38 m 55 3 |
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5 F 22 W 39 n 56 4 |
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6 G 23 X 40 o 57 5 |
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7 H 24 Y 41 p 58 6 |
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8 I 25 Z 42 q 59 7 |
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9 J 26 a 43 r 60 8 |
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10 K 27 b 44 s 61 9 |
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11 L 28 c 45 t 62 + |
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12 M 29 d 46 u 63 / |
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13 N 30 e 47 v |
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14 O 31 f 48 w (pad) = |
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15 P 32 g 49 x |
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16 Q 33 h 50 y |
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Special processing is performed if fewer than 24 bits are available |
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at the end of the data being encoded. A full encoding quantum is |
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always completed at the end of a quantity. When fewer than 24 input |
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bits are available in an input group, zero bits are added (on the |
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right) to form an integral number of 6-bit groups. Padding at the |
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end of the data is performed using the '=' character. |
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Since all base64 input is an integral number of octets, only the |
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------------------------------------------------- |
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following cases can arise: |
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(1) the final quantum of encoding input is an integral |
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multiple of 24 bits; here, the final unit of encoded |
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output will be an integral multiple of 4 characters |
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with no "=" padding, |
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(2) the final quantum of encoding input is exactly 8 bits; |
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here, the final unit of encoded output will be two |
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characters followed by two "=" padding characters, or |
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(3) the final quantum of encoding input is exactly 16 bits; |
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here, the final unit of encoded output will be three |
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characters followed by one "=" padding character. |
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*/ |
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int |
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__b64_ntop(src, srclength, target, targsize) |
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u_char const *src; |
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size_t srclength; |
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char *target; |
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size_t targsize; |
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{ |
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size_t datalength = 0; |
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u_char input[3]; |
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u_char output[4]; |
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int i; |
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while (2 < srclength) { |
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input[0] = *src++; |
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input[1] = *src++; |
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input[2] = *src++; |
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srclength -= 3; |
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output[0] = input[0] >> 2; |
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output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
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output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
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output[3] = input[2] & 0x3f; |
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if (datalength + 4 > targsize) |
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return (-1); |
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target[datalength++] = Base64[output[0]]; |
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target[datalength++] = Base64[output[1]]; |
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target[datalength++] = Base64[output[2]]; |
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target[datalength++] = Base64[output[3]]; |
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} |
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/* Now we worry about padding. */ |
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if (0 != srclength) { |
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/* Get what's left. */ |
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input[0] = input[1] = input[2] = '\0'; |
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for (i = 0; i < srclength; i++) |
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input[i] = *src++; |
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output[0] = input[0] >> 2; |
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output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4); |
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output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6); |
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if (datalength + 4 > targsize) |
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return (-1); |
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target[datalength++] = Base64[output[0]]; |
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target[datalength++] = Base64[output[1]]; |
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if (srclength == 1) |
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target[datalength++] = Pad64; |
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else |
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target[datalength++] = Base64[output[2]]; |
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target[datalength++] = Pad64; |
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} |
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if (datalength >= targsize) |
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return (-1); |
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target[datalength] = '\0'; /* Returned value doesn't count \0. */ |
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return (datalength); |
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} |
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/* skips all whitespace anywhere. |
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converts characters, four at a time, starting at (or after) |
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src from base - 64 numbers into three 8 bit bytes in the target area. |
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it returns the number of data bytes stored at the target, or -1 on error. |
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*/ |
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int |
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__b64_pton(src, target, targsize) |
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char const *src; |
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u_char *target; |
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size_t targsize; |
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{ |
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int tarindex, state, ch; |
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u_char nextbyte; |
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char *pos; |
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state = 0; |
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tarindex = 0; |
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while ((ch = (unsigned char)*src++) != '\0') { |
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if (isspace(ch)) /* Skip whitespace anywhere. */ |
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continue; |
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if (ch == Pad64) |
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break; |
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pos = strchr(Base64, ch); |
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if (pos == 0) /* A non-base64 character. */ |
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return (-1); |
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switch (state) { |
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case 0: |
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if (target) { |
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if (tarindex >= targsize) |
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return (-1); |
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target[tarindex] = (pos - Base64) << 2; |
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} |
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state = 1; |
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break; |
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case 1: |
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if (target) { |
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if (tarindex >= targsize) |
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return (-1); |
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target[tarindex] |= (pos - Base64) >> 4; |
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nextbyte = ((pos - Base64) & 0x0f) << 4; |
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if (tarindex + 1 < targsize) |
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target[tarindex+1] = nextbyte; |
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else if (nextbyte) |
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return (-1); |
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} |
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tarindex++; |
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state = 2; |
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break; |
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case 2: |
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if (target) { |
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if (tarindex >= targsize) |
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return (-1); |
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target[tarindex] |= (pos - Base64) >> 2; |
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nextbyte = ((pos - Base64) & 0x03) << 6; |
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if (tarindex + 1 < targsize) |
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target[tarindex+1] = nextbyte; |
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else if (nextbyte) |
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return (-1); |
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} |
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tarindex++; |
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state = 3; |
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break; |
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case 3: |
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if (target) { |
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if (tarindex >= targsize) |
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return (-1); |
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target[tarindex] |= (pos - Base64); |
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} |
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tarindex++; |
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state = 0; |
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break; |
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} |
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} |
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/* |
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* We are done decoding Base-64 chars. Let's see if we ended |
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* on a byte boundary, and/or with erroneous trailing characters. |
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*/ |
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if (ch == Pad64) { /* We got a pad char. */ |
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ch = (unsigned char)*src++; /* Skip it, get next. */ |
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switch (state) { |
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case 0: /* Invalid = in first position */ |
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case 1: /* Invalid = in second position */ |
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return (-1); |
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case 2: /* Valid, means one byte of info */ |
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/* Skip any number of spaces. */ |
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for (; ch != '\0'; ch = (unsigned char)*src++) |
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if (!isspace(ch)) |
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break; |
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/* Make sure there is another trailing = sign. */ |
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if (ch != Pad64) |
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return (-1); |
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ch = (unsigned char)*src++; /* Skip the = */ |
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/* Fall through to "single trailing =" case. */ |
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/* FALLTHROUGH */ |
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case 3: /* Valid, means two bytes of info */ |
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/* |
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* We know this char is an =. Is there anything but |
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* whitespace after it? |
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*/ |
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for (; ch != '\0'; ch = (unsigned char)*src++) |
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if (!isspace(ch)) |
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return (-1); |
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/* |
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* Now make sure for cases 2 and 3 that the "extra" |
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* bits that slopped past the last full byte were |
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* zeros. If we don't check them, they become a |
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* subliminal channel. |
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*/ |
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if (target && tarindex < targsize && |
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target[tarindex] != 0) |
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return (-1); |
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} |
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} else { |
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/* |
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* We ended by seeing the end of the string. Make sure we |
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* have no partial bytes lying around. |
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*/ |
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if (state != 0) |
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return (-1); |
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} |
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return (tarindex); |
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}
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