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gnupg/sm/base64.c
Werner Koch b008274afd Nuked almost all trailing white space. 
We better do this once and for all instead of cluttering all future
commits with diffs of trailing white spaces.  In the majority of cases
blank or single lines are affected and thus this change won't disturb
a git blame too much.  For future commits the pre-commit scripts
checks that this won't happen again.
2011-02-04 12:57:53 +01:00

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18 KiB
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/* base64.c
* Copyright (C) 2001, 2003, 2010 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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 General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <assert.h>
#include "gpgsm.h"
#include <ksba.h>
#include "i18n.h"
#ifdef HAVE_DOSISH_SYSTEM
#define LF "\r\n"
#else
#define LF "\n"
#endif
/* Data used by the reader callbacks. */
struct reader_cb_parm_s
{
estream_t fp;
unsigned char line[1024];
int linelen;
int readpos;
int have_lf;
unsigned long line_counter;
int allow_multi_pem; /* Allow processing of multiple PEM objects. */
int autodetect; /* Try to detect the input encoding. */
int assume_pem; /* Assume input encoding is PEM. */
int assume_base64; /* Assume input is base64 encoded. */
int identified;
int is_pem;
int is_base64;
int stop_seen;
int might_be_smime;
int eof_seen;
struct {
int idx;
unsigned char val;
int stop_seen;
} base64;
};
/* Data used by the writer callbacks. */
struct writer_cb_parm_s
{
estream_t stream; /* Output stream. */
const char *pem_name;
int wrote_begin;
int did_finish;
struct {
int idx;
int quad_count;
unsigned char radbuf[4];
} base64;
};
/* context for this module's functions */
struct base64_context_s {
union {
struct reader_cb_parm_s rparm;
struct writer_cb_parm_s wparm;
} u;
union {
ksba_reader_t reader;
ksba_writer_t writer;
} u2;
};
/* The base-64 character list */
static char bintoasc[64] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
/* The reverse base-64 list */
static unsigned char asctobin[256] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12,
0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24,
0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff
};
static int
has_only_base64 (const unsigned char *line, int linelen)
{
if (linelen < 20)
return 0;
for (; linelen; line++, linelen--)
{
if (*line == '\n' || (linelen > 1 && *line == '\r' && line[1] == '\n'))
break;
if ( !strchr (bintoasc, *line) )
return 0;
}
return 1; /* yes */
}
static int
is_empty_line (const unsigned char *line, int linelen)
{
if (linelen >= 2 && *line == '\r' && line[1] == '\n')
return 1;
if (linelen >= 1 && *line == '\n')
return 1;
return 0;
}
static int
base64_reader_cb (void *cb_value, char *buffer, size_t count, size_t *nread)
{
struct reader_cb_parm_s *parm = cb_value;
size_t n;
int c, c2;
*nread = 0;
if (!buffer)
return -1; /* not supported */
next:
if (!parm->linelen)
{
/* read an entire line or up to the size of the buffer */
parm->line_counter++;
parm->have_lf = 0;
for (n=0; n < DIM(parm->line);)
{
c = es_getc (parm->fp);
if (c == EOF)
{
parm->eof_seen = 1;
if (es_ferror (parm->fp))
return -1;
break;
}
parm->line[n++] = c;
if (c == '\n')
{
parm->have_lf = 1;
/* Fixme: we need to skip overlong lines while detecting
the dashed lines */
break;
}
}
parm->linelen = n;
if (!n)
return -1; /* eof */
parm->readpos = 0;
}
if (!parm->identified)
{
if (!parm->autodetect)
{
if (parm->assume_pem)
{
/* wait for the header line */
parm->linelen = parm->readpos = 0;
if (!parm->have_lf
|| strncmp ((char*)parm->line, "-----BEGIN ", 11)
|| !strncmp ((char*)parm->line+11, "PGP ", 4))
goto next;
parm->is_pem = 1;
}
else if (parm->assume_base64)
parm->is_base64 = 1;
}
else if (parm->line_counter == 1 && !parm->have_lf)
{
/* first line too long - assume DER encoding */
parm->is_pem = 0;
}
else if (parm->line_counter == 1 && parm->linelen && *parm->line == 0x30)
{
/* the very first byte does pretty much look like a SEQUENCE tag*/
parm->is_pem = 0;
}
else if ( parm->have_lf
&& !strncmp ((char*)parm->line, "-----BEGIN ", 11)
&& strncmp ((char *)parm->line+11, "PGP ", 4) )
{
/* Fixme: we must only compare if the line really starts at
the beginning */
parm->is_pem = 1;
parm->linelen = parm->readpos = 0;
}
else if ( parm->have_lf && parm->line_counter == 1
&& parm->linelen >= 13
&& !ascii_memcasecmp (parm->line, "Content-Type:", 13))
{ /* might be a S/MIME body */
parm->might_be_smime = 1;
parm->linelen = parm->readpos = 0;
goto next;
}
else if (parm->might_be_smime == 1
&& is_empty_line (parm->line, parm->linelen))
{
parm->might_be_smime = 2;
parm->linelen = parm->readpos = 0;
goto next;
}
else if (parm->might_be_smime == 2)
{
parm->might_be_smime = 0;
if ( !has_only_base64 (parm->line, parm->linelen))
{
parm->linelen = parm->readpos = 0;
goto next;
}
parm->is_pem = 1;
}
else
{
parm->linelen = parm->readpos = 0;
goto next;
}
parm->identified = 1;
parm->base64.stop_seen = 0;
parm->base64.idx = 0;
}
n = 0;
if (parm->is_pem || parm->is_base64)
{
if (parm->is_pem && parm->have_lf
&& !strncmp ((char*)parm->line, "-----END ", 9))
{
parm->identified = 0;
parm->linelen = parm->readpos = 0;
/* If the caller want to read multiple PEM objects from one
file, we have to reset our internal state and return a
EOF immediately. The caller is the expected to use
ksba_reader_clear to clear the EOF condition and continue
to read. If we don't want to do that we just return 0
bytes which will force the ksba_reader to skip until
EOF. */
if (parm->allow_multi_pem)
{
parm->identified = 0;
parm->autodetect = 0;
parm->assume_pem = 1;
parm->stop_seen = 0;
return -1; /* Send EOF now. */
}
}
else if (parm->stop_seen)
{ /* skip the rest of the line */
parm->linelen = parm->readpos = 0;
}
else
{
int idx = parm->base64.idx;
unsigned char val = parm->base64.val;
while (n < count && parm->readpos < parm->linelen )
{
c = parm->line[parm->readpos++];
if (c == '\n' || c == ' ' || c == '\r' || c == '\t')
continue;
if (c == '=')
{ /* pad character: stop */
if (idx == 1)
buffer[n++] = val;
parm->stop_seen = 1;
break;
}
if( (c = asctobin[(c2=c)]) == 255 )
{
log_error (_("invalid radix64 character %02x skipped\n"),
c2);
continue;
}
switch (idx)
{
case 0:
val = c << 2;
break;
case 1:
val |= (c>>4)&3;
buffer[n++] = val;
val = (c<<4)&0xf0;
break;
case 2:
val |= (c>>2)&15;
buffer[n++] = val;
val = (c<<6)&0xc0;
break;
case 3:
val |= c&0x3f;
buffer[n++] = val;
break;
}
idx = (idx+1) % 4;
}
if (parm->readpos == parm->linelen)
parm->linelen = parm->readpos = 0;
parm->base64.idx = idx;
parm->base64.val = val;
}
}
else
{ /* DER encoded */
while (n < count && parm->readpos < parm->linelen)
buffer[n++] = parm->line[parm->readpos++];
if (parm->readpos == parm->linelen)
parm->linelen = parm->readpos = 0;
}
*nread = n;
return 0;
}
static int
simple_reader_cb (void *cb_value, char *buffer, size_t count, size_t *nread)
{
struct reader_cb_parm_s *parm = cb_value;
size_t n;
int c = 0;
*nread = 0;
if (!buffer)
return -1; /* not supported */
for (n=0; n < count; n++)
{
c = es_getc (parm->fp);
if (c == EOF)
{
parm->eof_seen = 1;
if (es_ferror (parm->fp))
return -1;
if (n)
break; /* Return what we have before an EOF. */
return -1;
}
*(byte *)buffer++ = c;
}
*nread = n;
return 0;
}
static int
base64_writer_cb (void *cb_value, const void *buffer, size_t count)
{
struct writer_cb_parm_s *parm = cb_value;
unsigned char radbuf[4];
int i, c, idx, quad_count;
const unsigned char *p;
estream_t stream = parm->stream;
if (!count)
return 0;
if (!parm->wrote_begin)
{
if (parm->pem_name)
{
es_fputs ("-----BEGIN ", stream);
es_fputs (parm->pem_name, stream);
es_fputs ("-----\n", stream);
}
parm->wrote_begin = 1;
parm->base64.idx = 0;
parm->base64.quad_count = 0;
}
idx = parm->base64.idx;
quad_count = parm->base64.quad_count;
for (i=0; i < idx; i++)
radbuf[i] = parm->base64.radbuf[i];
for (p=buffer; count; p++, count--)
{
radbuf[idx++] = *p;
if (idx > 2)
{
idx = 0;
c = bintoasc[(*radbuf >> 2) & 077];
es_putc (c, stream);
c = bintoasc[(((*radbuf<<4)&060)|((radbuf[1] >> 4)&017))&077];
es_putc (c, stream);
c = bintoasc[(((radbuf[1]<<2)&074)|((radbuf[2]>>6)&03))&077];
es_putc (c, stream);
c = bintoasc[radbuf[2]&077];
es_putc (c, stream);
if (++quad_count >= (64/4))
{
es_fputs (LF, stream);
quad_count = 0;
}
}
}
for (i=0; i < idx; i++)
parm->base64.radbuf[i] = radbuf[i];
parm->base64.idx = idx;
parm->base64.quad_count = quad_count;
return es_ferror (stream)? gpg_error_from_syserror () : 0;
}
/* This callback is only used in stream mode. Hiowever, we don't
restrict it to this. */
static int
plain_writer_cb (void *cb_value, const void *buffer, size_t count)
{
struct writer_cb_parm_s *parm = cb_value;
estream_t stream = parm->stream;
if (!count)
return 0;
es_write (stream, buffer, count, NULL);
return es_ferror (stream)? gpg_error_from_syserror () : 0;
}
static int
base64_finish_write (struct writer_cb_parm_s *parm)
{
unsigned char radbuf[4];
int i, c, idx, quad_count;
estream_t stream = parm->stream;
if (!parm->wrote_begin)
return 0; /* Nothing written or we are not called in base-64 mode. */
/* flush the base64 encoding */
idx = parm->base64.idx;
quad_count = parm->base64.quad_count;
for (i=0; i < idx; i++)
radbuf[i] = parm->base64.radbuf[i];
if (idx)
{
c = bintoasc[(*radbuf>>2)&077];
es_putc (c, stream);
if (idx == 1)
{
c = bintoasc[((*radbuf << 4) & 060) & 077];
es_putc (c, stream);
es_putc ('=', stream);
es_putc ('=', stream);
}
else
{
c = bintoasc[(((*radbuf<<4)&060)|((radbuf[1]>>4)&017))&077];
es_putc (c, stream);
c = bintoasc[((radbuf[1] << 2) & 074) & 077];
es_putc (c, stream);
es_putc ('=', stream);
}
if (++quad_count >= (64/4))
{
es_fputs (LF, stream);
quad_count = 0;
}
}
if (quad_count)
es_fputs (LF, stream);
if (parm->pem_name)
{
es_fputs ("-----END ", stream);
es_fputs (parm->pem_name, stream);
es_fputs ("-----\n", stream);
}
return es_ferror (stream)? gpg_error_from_syserror () : 0;
}
/* Create a reader for the given file descriptor. Depending on the
control information an input decoding is automagically choosen.
The function returns a Base64Context object which must be passed to
the gpgme_destroy_reader function. The created KsbaReader object
is also returned, but the caller must not call the
ksba_reader_release function on. If ALLOW_MULTI_PEM is true, the
reader expects that the caller uses ksba_reader_clear after EOF
until no more objects were found. */
int
gpgsm_create_reader (Base64Context *ctx,
ctrl_t ctrl, estream_t fp, int allow_multi_pem,
ksba_reader_t *r_reader)
{
int rc;
ksba_reader_t r;
*r_reader = NULL;
*ctx = xtrycalloc (1, sizeof **ctx);
if (!*ctx)
return out_of_core ();
(*ctx)->u.rparm.allow_multi_pem = allow_multi_pem;
rc = ksba_reader_new (&r);
if (rc)
{
xfree (*ctx); *ctx = NULL;
return rc;
}
(*ctx)->u.rparm.fp = fp;
if (ctrl->is_pem)
{
(*ctx)->u.rparm.assume_pem = 1;
(*ctx)->u.rparm.assume_base64 = 1;
rc = ksba_reader_set_cb (r, base64_reader_cb, &(*ctx)->u.rparm);
}
else if (ctrl->is_base64)
{
(*ctx)->u.rparm.assume_base64 = 1;
rc = ksba_reader_set_cb (r, base64_reader_cb, &(*ctx)->u.rparm);
}
else if (ctrl->autodetect_encoding)
{
(*ctx)->u.rparm.autodetect = 1;
rc = ksba_reader_set_cb (r, base64_reader_cb, &(*ctx)->u.rparm);
}
else
rc = ksba_reader_set_cb (r, simple_reader_cb, &(*ctx)->u.rparm);
if (rc)
{
ksba_reader_release (r);
xfree (*ctx); *ctx = NULL;
return rc;
}
(*ctx)->u2.reader = r;
*r_reader = r;
return 0;
}
int
gpgsm_reader_eof_seen (Base64Context ctx)
{
return ctx && ctx->u.rparm.eof_seen;
}
void
gpgsm_destroy_reader (Base64Context ctx)
{
if (!ctx)
return;
ksba_reader_release (ctx->u2.reader);
xfree (ctx);
}
/* Create a writer for the given STREAM. Depending on
the control information an output encoding is automagically
choosen. The function returns a Base64Context object which must be
passed to the gpgme_destroy_writer function. The created
KsbaWriter object is also returned, but the caller must not call
the ksba_reader_release function on it. */
int
gpgsm_create_writer (Base64Context *ctx, ctrl_t ctrl, estream_t stream,
ksba_writer_t *r_writer)
{
int rc;
ksba_writer_t w;
*r_writer = NULL;
*ctx = xtrycalloc (1, sizeof **ctx);
if (!*ctx)
return out_of_core ();
rc = ksba_writer_new (&w);
if (rc)
{
xfree (*ctx); *ctx = NULL;
return rc;
}
if (ctrl->create_pem || ctrl->create_base64)
{
(*ctx)->u.wparm.stream = stream;
if (ctrl->create_pem)
(*ctx)->u.wparm.pem_name = ctrl->pem_name? ctrl->pem_name
: "CMS OBJECT";
rc = ksba_writer_set_cb (w, base64_writer_cb, &(*ctx)->u.wparm);
}
else if (stream)
{
(*ctx)->u.wparm.stream = stream;
rc = ksba_writer_set_cb (w, plain_writer_cb, &(*ctx)->u.wparm);
}
else
rc = gpg_error (GPG_ERR_INV_ARG);
if (rc)
{
ksba_writer_release (w);
xfree (*ctx); *ctx = NULL;
return rc;
}
(*ctx)->u2.writer = w;
*r_writer = w;
return 0;
}
int
gpgsm_finish_writer (Base64Context ctx)
{
struct writer_cb_parm_s *parm;
if (!ctx)
return gpg_error (GPG_ERR_INV_VALUE);
parm = &ctx->u.wparm;
if (parm->did_finish)
return 0; /* Already done. */
parm->did_finish = 1;
if (!parm->stream)
return 0; /* Callback was not used. */
return base64_finish_write (parm);
}
void
gpgsm_destroy_writer (Base64Context ctx)
{
if (!ctx)
return;
ksba_writer_release (ctx->u2.writer);
xfree (ctx);
}
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