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/* keybox-file.c - File operations
* Copyright (C) 2001, 2003 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 <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#include "keybox-defs.h"
#define IMAGELEN_LIMIT (5*1024*1024)
#if !defined(HAVE_FTELLO) && !defined(ftello)
static off_t
ftello (FILE *stream)
{
long int off;
off = ftell (stream);
if (off == -1)
return (off_t)-1;
return off;
}
#endif /* !defined(HAVE_FTELLO) && !defined(ftello) */
/* Read a block at the current position and return it in R_BLOB.
R_BLOB may be NULL to simply skip the current block. */
int
_keybox_read_blob (KEYBOXBLOB *r_blob, estream_t fp, int *skipped_deleted)
{
unsigned char *image;
size_t imagelen = 0;
int c1, c2, c3, c4, type;
int rc;
off_t off;
if (skipped_deleted)
*skipped_deleted = 0;
again:
if (r_blob)
*r_blob = NULL;
off = es_ftello (fp);
if (off == (off_t)-1)
return gpg_error_from_syserror ();
if ((c1 = es_getc (fp)) == EOF
|| (c2 = es_getc (fp)) == EOF
|| (c3 = es_getc (fp)) == EOF
|| (c4 = es_getc (fp)) == EOF
|| (type = es_getc (fp)) == EOF)
{
if ( c1 == EOF && !es_ferror (fp) )
return -1; /* eof */
if (!es_ferror (fp))
return gpg_error (GPG_ERR_TOO_SHORT);
return gpg_error_from_syserror ();
}
imagelen = ((unsigned int) c1 << 24) | (c2 << 16) | (c3 << 8 ) | c4;
if (imagelen < 5)
return gpg_error (GPG_ERR_TOO_SHORT);
if (!type)
{
/* Special treatment for empty blobs. */
if (es_fseek (fp, imagelen-5, SEEK_CUR))
return gpg_error_from_syserror ();
if (skipped_deleted)
*skipped_deleted = 1;
goto again;
}
if (imagelen > IMAGELEN_LIMIT) /* Sanity check. */
{
/* Seek forward so that the caller may choose to ignore this
record. */
if (es_fseek (fp, imagelen-5, SEEK_CUR))
return gpg_error_from_syserror ();
return gpg_error (GPG_ERR_TOO_LARGE);
}
if (!r_blob)
{
/* This blob shall be skipped. */
if (es_fseek (fp, imagelen-5, SEEK_CUR))
return gpg_error_from_syserror ();
return 0;
}
image = xtrymalloc (imagelen);
if (!image)
return gpg_error_from_syserror ();
image[0] = c1; image[1] = c2; image[2] = c3; image[3] = c4; image[4] = type;
if (es_fread (image+5, imagelen-5, 1, fp) != 1)
{
gpg_error_t tmperr = gpg_error_from_syserror ();
xfree (image);
return tmperr;
}
rc = _keybox_new_blob (r_blob, image, imagelen, off);
if (rc)
xfree (image);
return rc;
}
/* Write the block to the current file position */
int
_keybox_write_blob (KEYBOXBLOB blob, estream_t fp, FILE *outfp)
{
const unsigned char *image;
size_t length;
image = _keybox_get_blob_image (blob, &length);
if (length > IMAGELEN_LIMIT)
return gpg_error (GPG_ERR_TOO_LARGE);
if (fp)
{
if (es_fwrite (image, length, 1, fp) != 1)
return gpg_error_from_syserror ();
}
else
{
if (fwrite (image, length, 1, outfp) != 1)
return gpg_error_from_syserror ();
}
return 0;
}
/* Write a fresh header type blob. */
int
_keybox_write_header_blob (estream_t fp, int for_openpgp)
{
unsigned char image[32];
u32 val;
memset (image, 0, sizeof image);
/* Length of this blob. */
image[3] = 32;
image[4] = KEYBOX_BLOBTYPE_HEADER;
image[5] = 1; /* Version */
if (for_openpgp)
image[7] = 0x02; /* OpenPGP data may be available. */
memcpy (image+8, "KBXf", 4);
val = time (NULL);
/* created_at and last maintenance run. */
image[16] = (val >> 24);
image[16+1] = (val >> 16);
image[16+2] = (val >> 8);
image[16+3] = (val );
image[20] = (val >> 24);
image[20+1] = (val >> 16);
image[20+2] = (val >> 8);
image[20+3] = (val );
if (es_fwrite (image, 32, 1, fp) != 1)
return gpg_error_from_syserror ();
return 0;
}
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