206 lines
6.5 KiB
C
206 lines
6.5 KiB
C
/*-
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* Copyright (c) 2013-2014 The University of Oslo
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id$
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <sys/types.h>
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#include <errno.h>
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#include <stdint.h>
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#include <security/oath.h>
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#include "oath_impl.h"
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static const char b32enc[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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static const char b32dec[256] = {
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
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0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
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0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
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0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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};
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/*
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* Encode data in RFC 4648 base 32 representation. The target buffer must
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* have room for base32_enclen(len) characters and a terminating NUL.
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*/
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int
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base32_enc(const char *cin, size_t ilen, char *out, size_t *olen)
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{
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const uint8_t *in = (const uint8_t *)cin;
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uint64_t bits;
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if (*olen <= base32_enclen(ilen)) {
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*olen = base32_enclen(ilen) + 1;
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errno = ENOSPC;
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return (-1);
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}
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*olen = 0;
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while (ilen >= 5) {
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bits = 0;
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bits |= (uint64_t)in[0] << 32;
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bits |= (uint64_t)in[1] << 24;
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bits |= (uint64_t)in[2] << 16;
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bits |= (uint64_t)in[3] << 8;
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bits |= (uint64_t)in[4];
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ilen -= 5;
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in += 5;
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out[0] = b32enc[bits >> 35 & 0x1f];
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out[1] = b32enc[bits >> 30 & 0x1f];
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out[2] = b32enc[bits >> 25 & 0x1f];
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out[3] = b32enc[bits >> 20 & 0x1f];
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out[4] = b32enc[bits >> 15 & 0x1f];
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out[5] = b32enc[bits >> 10 & 0x1f];
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out[6] = b32enc[bits >> 5 & 0x1f];
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out[7] = b32enc[bits & 0x1f];
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*olen += 8;
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out += 8;
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}
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if (ilen > 0) {
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bits = 0;
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switch (ilen) {
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case 4:
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bits |= (uint64_t)in[3] << 8;
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case 3:
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bits |= (uint64_t)in[2] << 16;
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case 2:
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bits |= (uint64_t)in[1] << 24;
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case 1:
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bits |= (uint64_t)in[0] << 32;
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COVERAGE_NO_DEFAULT_CASE
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}
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out[0] = b32enc[bits >> 35 & 0x1f];
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out[1] = b32enc[bits >> 30 & 0x1f];
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out[2] = ilen > 1 ? b32enc[bits >> 25 & 0x1f] : '=';
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out[3] = ilen > 1 ? b32enc[bits >> 20 & 0x1f] : '=';
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out[4] = ilen > 2 ? b32enc[bits >> 15 & 0x1f] : '=';
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out[5] = ilen > 3 ? b32enc[bits >> 10 & 0x1f] : '=';
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out[6] = ilen > 3 ? b32enc[bits >> 5 & 0x1f] : '=';
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out[7] = '=';
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*olen += 8;
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out += 8;
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}
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out[0] = '\0';
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++*olen;
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return (0);
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}
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/*
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* Decode data in RFC 4648 base 32 representation, stopping at the
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* terminating NUL, the first invalid (non-base32, non-whitespace)
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* character or after len characters, whichever comes first.
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*
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* Padding is handled sloppily: any padding character following the data
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* is silently consumed. This not only simplifies the code but ensures
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* compatibility with implementations which do not emit or understand
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* padding.
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*
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* The olen argument is used by the caller to pass the size of the buffer
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* and by base32_dec() to return the amount of data successfully decoded.
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* If the buffer is too small, base32_dec() discards the excess data, but
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* returns the total amount.
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*/
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int
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base32_dec(const char *cin, size_t ilen, char *out, size_t *olen)
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{
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const uint8_t *in = (const uint8_t *)cin;
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size_t len;
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int bits, shift, padding;
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for (bits = shift = padding = len = 0; ilen && *in; --ilen, ++in) {
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if (*in == ' ' || *in == '\t' || *in == '\r' || *in == '\n' ||
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(padding && *in == '=')) {
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/* consume */
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continue;
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} else if (!padding && b32dec[*in] >= 0) {
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/* shift into accumulator */
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shift += 5;
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bits = bits << 5 | b32dec[*in];
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} else if (!padding && shift > 0 && shift < 5 && *in == '=') {
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/* final byte */
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shift = 0;
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padding = 1;
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} else {
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/* error */
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*olen = 0;
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errno = EINVAL;
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return (-1);
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}
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if (shift >= 8) {
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/* output accumulated byte */
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shift -= 8;
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if (len++ < *olen)
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*out++ = (bits >> shift) & 0xff;
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}
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}
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/* report decoded length */
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if (len > *olen) {
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/* overflow */
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*olen = len;
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errno = ENOSPC;
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return (-1);
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}
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*olen = len;
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return (0);
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}
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