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/* b64enc.c - Simple Base64 encoder.
* Copyright (C) 2001, 2003, 2004, 2008, 2010,
* 2011 Free Software Foundation, Inc.
* Copyright (C) 2001, 2003, 2004, 2008, 2010,
* 2011, 2018 g10 Code GmbH
*
* This file is part of Libgpg-error.
*
* 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 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/>.
* SPDX-License-Identifier: LGPL-2.1-or-later
*
* This file was originally a part of GnuPG.
*/
#include <config.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "gpgrt-int.h"
#define B64ENC_DID_HEADER 1
#define B64ENC_DID_TRAILER 2
#define B64ENC_NO_LINEFEEDS 16
#define B64ENC_USE_PGPCRC 32
/* The base-64 character list */
static unsigned char const bintoasc[64] = ("ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/");
/* Stuff required to create the OpenPGP CRC. This crc_table has been
created using this code:
#include <stdio.h>
#include <stdint.h>
#define CRCPOLY 0x864CFB
int
main (void)
{
int i, j;
uint32_t t;
uint32_t crc_table[256];
crc_table[0] = 0;
for (i=j=0; j < 128; j++ )
{
t = crc_table[j];
if ( (t & 0x00800000) )
{
t <<= 1;
crc_table[i++] = t ^ CRCPOLY;
crc_table[i++] = t;
}
else
{
t <<= 1;
crc_table[i++] = t;
crc_table[i++] = t ^ CRCPOLY;
}
}
puts ("static const u32 crc_table[256] = {");
for (i=j=0; i < 256; i++)
{
printf ("%s 0x%08lx", j? "":" ", (unsigned long)crc_table[i]);
if (i != 255)
{
putchar (',');
if ( ++j > 5)
{
j = 0;
putchar ('\n');
}
}
}
puts ("\n};");
return 0;
}
*/
#define CRCINIT 0xB704CE
static const uint32_t crc_table[256] = {
0x00000000, 0x00864cfb, 0x018ad50d, 0x010c99f6, 0x0393e6e1, 0x0315aa1a,
0x021933ec, 0x029f7f17, 0x07a18139, 0x0727cdc2, 0x062b5434, 0x06ad18cf,
0x043267d8, 0x04b42b23, 0x05b8b2d5, 0x053efe2e, 0x0fc54e89, 0x0f430272,
0x0e4f9b84, 0x0ec9d77f, 0x0c56a868, 0x0cd0e493, 0x0ddc7d65, 0x0d5a319e,
0x0864cfb0, 0x08e2834b, 0x09ee1abd, 0x09685646, 0x0bf72951, 0x0b7165aa,
0x0a7dfc5c, 0x0afbb0a7, 0x1f0cd1e9, 0x1f8a9d12, 0x1e8604e4, 0x1e00481f,
0x1c9f3708, 0x1c197bf3, 0x1d15e205, 0x1d93aefe, 0x18ad50d0, 0x182b1c2b,
0x192785dd, 0x19a1c926, 0x1b3eb631, 0x1bb8faca, 0x1ab4633c, 0x1a322fc7,
0x10c99f60, 0x104fd39b, 0x11434a6d, 0x11c50696, 0x135a7981, 0x13dc357a,
0x12d0ac8c, 0x1256e077, 0x17681e59, 0x17ee52a2, 0x16e2cb54, 0x166487af,
0x14fbf8b8, 0x147db443, 0x15712db5, 0x15f7614e, 0x3e19a3d2, 0x3e9fef29,
0x3f9376df, 0x3f153a24, 0x3d8a4533, 0x3d0c09c8, 0x3c00903e, 0x3c86dcc5,
0x39b822eb, 0x393e6e10, 0x3832f7e6, 0x38b4bb1d, 0x3a2bc40a, 0x3aad88f1,
0x3ba11107, 0x3b275dfc, 0x31dced5b, 0x315aa1a0, 0x30563856, 0x30d074ad,
0x324f0bba, 0x32c94741, 0x33c5deb7, 0x3343924c, 0x367d6c62, 0x36fb2099,
0x37f7b96f, 0x3771f594, 0x35ee8a83, 0x3568c678, 0x34645f8e, 0x34e21375,
0x2115723b, 0x21933ec0, 0x209fa736, 0x2019ebcd, 0x228694da, 0x2200d821,
0x230c41d7, 0x238a0d2c, 0x26b4f302, 0x2632bff9, 0x273e260f, 0x27b86af4,
0x252715e3, 0x25a15918, 0x24adc0ee, 0x242b8c15, 0x2ed03cb2, 0x2e567049,
0x2f5ae9bf, 0x2fdca544, 0x2d43da53, 0x2dc596a8, 0x2cc90f5e, 0x2c4f43a5,
0x2971bd8b, 0x29f7f170, 0x28fb6886, 0x287d247d, 0x2ae25b6a, 0x2a641791,
0x2b688e67, 0x2beec29c, 0x7c3347a4, 0x7cb50b5f, 0x7db992a9, 0x7d3fde52,
0x7fa0a145, 0x7f26edbe, 0x7e2a7448, 0x7eac38b3, 0x7b92c69d, 0x7b148a66,
0x7a181390, 0x7a9e5f6b, 0x7801207c, 0x78876c87, 0x798bf571, 0x790db98a,
0x73f6092d, 0x737045d6, 0x727cdc20, 0x72fa90db, 0x7065efcc, 0x70e3a337,
0x71ef3ac1, 0x7169763a, 0x74578814, 0x74d1c4ef, 0x75dd5d19, 0x755b11e2,
0x77c46ef5, 0x7742220e, 0x764ebbf8, 0x76c8f703, 0x633f964d, 0x63b9dab6,
0x62b54340, 0x62330fbb, 0x60ac70ac, 0x602a3c57, 0x6126a5a1, 0x61a0e95a,
0x649e1774, 0x64185b8f, 0x6514c279, 0x65928e82, 0x670df195, 0x678bbd6e,
0x66872498, 0x66016863, 0x6cfad8c4, 0x6c7c943f, 0x6d700dc9, 0x6df64132,
0x6f693e25, 0x6fef72de, 0x6ee3eb28, 0x6e65a7d3, 0x6b5b59fd, 0x6bdd1506,
0x6ad18cf0, 0x6a57c00b, 0x68c8bf1c, 0x684ef3e7, 0x69426a11, 0x69c426ea,
0x422ae476, 0x42aca88d, 0x43a0317b, 0x43267d80, 0x41b90297, 0x413f4e6c,
0x4033d79a, 0x40b59b61, 0x458b654f, 0x450d29b4, 0x4401b042, 0x4487fcb9,
0x461883ae, 0x469ecf55, 0x479256a3, 0x47141a58, 0x4defaaff, 0x4d69e604,
0x4c657ff2, 0x4ce33309, 0x4e7c4c1e, 0x4efa00e5, 0x4ff69913, 0x4f70d5e8,
0x4a4e2bc6, 0x4ac8673d, 0x4bc4fecb, 0x4b42b230, 0x49ddcd27, 0x495b81dc,
0x4857182a, 0x48d154d1, 0x5d26359f, 0x5da07964, 0x5cace092, 0x5c2aac69,
0x5eb5d37e, 0x5e339f85, 0x5f3f0673, 0x5fb94a88, 0x5a87b4a6, 0x5a01f85d,
0x5b0d61ab, 0x5b8b2d50, 0x59145247, 0x59921ebc, 0x589e874a, 0x5818cbb1,
0x52e37b16, 0x526537ed, 0x5369ae1b, 0x53efe2e0, 0x51709df7, 0x51f6d10c,
0x50fa48fa, 0x507c0401, 0x5542fa2f, 0x55c4b6d4, 0x54c82f22, 0x544e63d9,
0x56d11cce, 0x56575035, 0x575bc9c3, 0x57dd8538
};
/* Prepare for Base-64 writing to STREAM. If TITLE is not NULL and
* not an empty string, that string will be used as the title for the
* armor lines, with TITLE being an empty string, we don't write the
* header lines and furthermore even don't write any linefeeds. If
* TITLE starts with "PGP " the OpenPGP CRC checksum will be written
* as well. With TITLE being NULL, we merely don't write header but
* make sure that lines are not too long. Note, that we don't write
* anything unless at least one byte is written using b64enc_write.
* On success an enoder object is returned which needs to be released
* using _gpgrt_b64dec_finish. On error NULL is returned an ERRNO is
* set.
*/
gpgrt_b64state_t
_gpgrt_b64enc_start (estream_t stream, const char *title)
{
gpgrt_b64state_t state;
state = xtrycalloc (1, sizeof *state);
if (!state)
return NULL;
state->stream = stream;
if (title && !*title)
state->flags |= B64ENC_NO_LINEFEEDS;
else if (title)
{
if (!strncmp (title, "PGP ", 4))
{
state->flags |= B64ENC_USE_PGPCRC;
state->crc = CRCINIT;
}
state->title = xtrystrdup (title);
if (!state->title)
{
xfree (state);
return NULL;
}
}
return state;
}
/* Write NBYTES from BUFFER to the Base 64 stream identified by STATE.
* With BUFFER and NBYTES being 0, merely do a fflush on the stream.
*/
gpg_err_code_t
_gpgrt_b64enc_write (gpgrt_b64state_t state, const void *buffer, size_t nbytes)
{
unsigned char radbuf[4];
int idx, quad_count;
const unsigned char *p;
if (state->lasterr)
return state->lasterr;
if (!nbytes)
{
if (buffer)
if (_gpgrt_fflush (state->stream))
goto write_error;
return 0;
}
if (!(state->flags & B64ENC_DID_HEADER))
{
if (state->title)
{
if ( _gpgrt_fputs ("-----BEGIN ", state->stream) == EOF
|| _gpgrt_fputs (state->title, state->stream) == EOF
|| _gpgrt_fputs ("-----\n", state->stream) == EOF)
goto write_error;
if ( (state->flags & B64ENC_USE_PGPCRC)
&& _gpgrt_fputs ("\n", state->stream) == EOF)
goto write_error;
}
state->flags |= B64ENC_DID_HEADER;
}
idx = state->idx;
quad_count = state->quad_count;
gpgrt_assert (idx < 4);
memcpy (radbuf, state->radbuf, idx);
if ( (state->flags & B64ENC_USE_PGPCRC) )
{
size_t n;
uint32_t crc = state->crc;
for (p=buffer, n=nbytes; n; p++, n-- )
crc = ((uint32_t)crc << 8) ^ crc_table[((crc >> 16)&0xff) ^ *p];
state->crc = (crc & 0x00ffffff);
}
for (p=buffer; nbytes; p++, nbytes--)
{
radbuf[idx++] = *p;
if (idx > 2)
{
char tmp[4];
tmp[0] = bintoasc[(*radbuf >> 2) & 077];
tmp[1] = bintoasc[(((*radbuf<<4)&060)|((radbuf[1] >> 4)&017))&077];
tmp[2] = bintoasc[(((radbuf[1]<<2)&074)|((radbuf[2]>>6)&03))&077];
tmp[3] = bintoasc[radbuf[2]&077];
for (idx=0; idx < 4; idx++)
_gpgrt_fputc (tmp[idx], state->stream);
idx = 0;
if (_gpgrt_ferror (state->stream))
goto write_error;
if (++quad_count >= (64/4))
{
quad_count = 0;
if (!(state->flags & B64ENC_NO_LINEFEEDS)
&& _gpgrt_fputs ("\n", state->stream) == EOF)
goto write_error;
}
}
}
memcpy (state->radbuf, radbuf, idx);
state->idx = idx;
state->quad_count = quad_count;
return 0;
write_error:
state->lasterr = _gpg_err_code_from_syserror ();
if (state->title)
{
xfree (state->title);
state->title = NULL;
}
return state->lasterr;
}
gpg_err_code_t
_gpgrt_b64enc_finish (gpgrt_b64state_t state)
{
gpg_err_code_t err = 0;
unsigned char radbuf[4];
int idx, quad_count;
char tmp[4];
if (!state)
return 0; /* Already released. */
if (state->using_decoder)
{
err = GPG_ERR_CONFLICT; /* State was created for the decoder. */
goto cleanup;
}
if (state->lasterr)
{
err = state->lasterr;
goto cleanup;
}
if (!(state->flags & B64ENC_DID_HEADER))
goto cleanup;
/* Flush the base64 encoding */
idx = state->idx;
quad_count = state->quad_count;
gpgrt_assert (idx < 4);
memcpy (radbuf, state->radbuf, idx);
if (idx)
{
tmp[0] = bintoasc[(*radbuf>>2)&077];
if (idx == 1)
{
tmp[1] = bintoasc[((*radbuf << 4) & 060) & 077];
tmp[2] = '=';
tmp[3] = '=';
}
else
{
tmp[1] = bintoasc[(((*radbuf<<4)&060)|((radbuf[1]>>4)&017))&077];
tmp[2] = bintoasc[((radbuf[1] << 2) & 074) & 077];
tmp[3] = '=';
}
for (idx=0; idx < 4; idx++)
_gpgrt_fputc (tmp[idx], state->stream);
if (_gpgrt_ferror (state->stream))
goto write_error;
if (++quad_count >= (64/4))
{
quad_count = 0;
if (!(state->flags & B64ENC_NO_LINEFEEDS)
&& _gpgrt_fputs ("\n", state->stream) == EOF)
goto write_error;
}
}
/* Finish the last line and write the trailer. */
if (quad_count
&& !(state->flags & B64ENC_NO_LINEFEEDS)
&& _gpgrt_fputs ("\n", state->stream) == EOF)
goto write_error;
if ( (state->flags & B64ENC_USE_PGPCRC) )
{
/* Write the CRC. */
_gpgrt_fputs ("=", state->stream);
radbuf[0] = state->crc >>16;
radbuf[1] = state->crc >> 8;
radbuf[2] = state->crc;
tmp[0] = bintoasc[(*radbuf>>2)&077];
tmp[1] = bintoasc[(((*radbuf<<4)&060)|((radbuf[1]>>4)&017))&077];
tmp[2] = bintoasc[(((radbuf[1]<<2)&074)|((radbuf[2]>>6)&03))&077];
tmp[3] = bintoasc[radbuf[2]&077];
for (idx=0; idx < 4; idx++)
_gpgrt_fputc (tmp[idx], state->stream);
if (_gpgrt_ferror (state->stream))
goto write_error;
if (!(state->flags & B64ENC_NO_LINEFEEDS)
&& _gpgrt_fputs ("\n", state->stream) == EOF)
goto write_error;
}
if (state->title)
{
if ( _gpgrt_fputs ("-----END ", state->stream) == EOF
|| _gpgrt_fputs (state->title, state->stream) == EOF
|| _gpgrt_fputs ("-----\n", state->stream) == EOF)
goto write_error;
}
cleanup:
xfree (state->title);
xfree (state);
return err;
write_error:
err = gpg_error_from_syserror ();
goto cleanup;
}

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