mirror of git://git.gnupg.org/gnupg.git
450 lines
11 KiB
C
450 lines
11 KiB
C
/* gpgtar-extract.c - Extract from a TAR archive
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* Copyright (C) 2016-2017, 2019-2022 g10 Code GmbH
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* Copyright (C) 2010, 2012, 2013 Werner Koch
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* Copyright (C) 2010 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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* SPDX-License-Identifier: GPL-3.0-or-later
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*/
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#include <config.h>
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#include <errno.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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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <assert.h>
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#include "../common/i18n.h"
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#include "../common/exectool.h"
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#include "../common/sysutils.h"
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#include "../common/ccparray.h"
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#include "gpgtar.h"
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static gpg_error_t
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check_suspicious_name (const char *name)
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{
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size_t n;
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n = strlen (name);
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#ifdef HAVE_DOSISH_SYSTEM
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if (strchr (name, '\\'))
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{
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log_error ("filename '%s' contains a backslash - "
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"can't extract on this system\n", name);
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return gpg_error (GPG_ERR_INV_NAME);
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}
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#endif /*HAVE_DOSISH_SYSTEM*/
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if (!n
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|| strstr (name, "//")
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|| strstr (name, "/../")
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|| !strncmp (name, "../", 3)
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|| (n >= 3 && !strcmp (name+n-3, "/.." )))
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{
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log_error ("filename '%s' has suspicious parts - not extracting\n",
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name);
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return gpg_error (GPG_ERR_INV_NAME);
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}
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return 0;
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}
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static gpg_error_t
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extract_regular (estream_t stream, const char *dirname,
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tarinfo_t info, tar_header_t hdr, strlist_t exthdr)
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{
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gpg_error_t err;
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char record[RECORDSIZE];
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size_t n, nbytes, nwritten;
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char *fname_buffer = NULL;
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const char *fname;
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estream_t outfp = NULL;
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strlist_t sl;
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fname = hdr->name;
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for (sl = exthdr; sl; sl = sl->next)
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if (sl->flags == 1)
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fname = sl->d;
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err = check_suspicious_name (fname);
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if (err)
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goto leave;
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fname_buffer = strconcat (dirname, "/", fname, NULL);
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if (!fname_buffer)
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{
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err = gpg_error_from_syserror ();
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log_error ("error creating filename: %s\n", gpg_strerror (err));
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goto leave;
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}
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fname = fname_buffer;
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if (opt.dry_run)
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outfp = es_fopenmem (0, "wb");
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else
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outfp = es_fopen (fname, "wb");
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if (!outfp)
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{
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err = gpg_error_from_syserror ();
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log_error ("error creating '%s': %s\n", fname, gpg_strerror (err));
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goto leave;
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}
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for (n=0; n < hdr->nrecords;)
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{
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err = read_record (stream, record);
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if (err)
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goto leave;
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info->nblocks++;
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n++;
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if (n < hdr->nrecords || (hdr->size && !(hdr->size % RECORDSIZE)))
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nbytes = RECORDSIZE;
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else
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nbytes = (hdr->size % RECORDSIZE);
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nwritten = es_fwrite (record, 1, nbytes, outfp);
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if (nwritten != nbytes)
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{
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err = gpg_error_from_syserror ();
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log_error ("error writing '%s': %s\n", fname, gpg_strerror (err));
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goto leave;
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}
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}
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/* Fixme: Set permissions etc. */
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leave:
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if (!err && opt.verbose)
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log_info ("extracted '%s'\n", fname);
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es_fclose (outfp);
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if (err && fname && outfp)
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{
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if (gnupg_remove (fname))
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log_error ("error removing incomplete file '%s': %s\n",
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fname, gpg_strerror (gpg_error_from_syserror ()));
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}
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xfree (fname_buffer);
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return err;
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}
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static gpg_error_t
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extract_directory (const char *dirname, tar_header_t hdr, strlist_t exthdr)
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{
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gpg_error_t err;
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const char *name;
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char *fname = NULL;
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strlist_t sl;
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name = hdr->name;
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for (sl = exthdr; sl; sl = sl->next)
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if (sl->flags == 1)
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name = sl->d;
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err = check_suspicious_name (name);
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if (err)
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goto leave;
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fname = strconcat (dirname, "/", name, NULL);
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if (!fname)
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{
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err = gpg_error_from_syserror ();
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log_error ("error creating filename: %s\n", gpg_strerror (err));
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goto leave;
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}
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/* Remove a possible trailing slash. */
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if (fname[strlen (fname)-1] == '/')
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fname[strlen (fname)-1] = 0;
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if (! opt.dry_run && gnupg_mkdir (fname, "-rwx------"))
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{
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err = gpg_error_from_syserror ();
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if (gpg_err_code (err) == GPG_ERR_EEXIST)
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{
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/* Ignore existing directories while extracting. */
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err = 0;
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}
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if (gpg_err_code (err) == GPG_ERR_ENOENT)
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{
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/* Try to create the directory with parents but keep the
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original error code in case of a failure. */
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int rc = 0;
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char *p;
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size_t prefixlen;
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/* (PREFIXLEN is the length of the new directory we use to
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* extract the tarball.) */
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prefixlen = strlen (dirname) + 1;
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for (p = fname+prefixlen; (p = strchr (p, '/')); p++)
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{
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*p = 0;
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rc = gnupg_mkdir (fname, "-rwx------");
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*p = '/';
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if (rc)
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break;
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}
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if (!rc && !gnupg_mkdir (fname, "-rwx------"))
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err = 0;
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}
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if (err)
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log_error ("error creating directory '%s': %s\n",
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fname, gpg_strerror (err));
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}
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leave:
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if (!err && opt.verbose)
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log_info ("created '%s/'\n", fname);
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xfree (fname);
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return err;
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}
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static gpg_error_t
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extract (estream_t stream, const char *dirname, tarinfo_t info,
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tar_header_t hdr, strlist_t exthdr)
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{
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gpg_error_t err;
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size_t n;
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if (hdr->typeflag == TF_REGULAR || hdr->typeflag == TF_UNKNOWN)
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err = extract_regular (stream, dirname, info, hdr, exthdr);
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else if (hdr->typeflag == TF_DIRECTORY)
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err = extract_directory (dirname, hdr, exthdr);
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else
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{
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char record[RECORDSIZE];
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log_info ("unsupported file type %d for '%s' - skipped\n",
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(int)hdr->typeflag, hdr->name);
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for (err = 0, n=0; !err && n < hdr->nrecords; n++)
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{
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err = read_record (stream, record);
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if (!err)
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info->nblocks++;
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}
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}
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return err;
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}
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/* Create a new directory to be used for extracting the tarball.
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Returns the name of the directory which must be freed by the
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caller. In case of an error a diagnostic is printed and NULL
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returned. */
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static char *
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create_directory (const char *dirprefix)
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{
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gpg_error_t err = 0;
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char *prefix_buffer = NULL;
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char *dirname = NULL;
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size_t n;
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int idx;
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/* Remove common suffixes. */
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n = strlen (dirprefix);
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if (n > 4 && (!compare_filenames (dirprefix + n - 4, EXTSEP_S GPGEXT_GPG)
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|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pgp")
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|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "asc")
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|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pem")
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|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7m")
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|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7e")))
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{
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prefix_buffer = xtrystrdup (dirprefix);
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if (!prefix_buffer)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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prefix_buffer[n-4] = 0;
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dirprefix = prefix_buffer;
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}
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for (idx=1; idx < 5000; idx++)
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{
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xfree (dirname);
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dirname = xtryasprintf ("%s_%d_", dirprefix, idx);
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if (!dirname)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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if (!gnupg_mkdir (dirname, "-rwx------"))
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goto leave; /* Ready. */
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if (errno != EEXIST && errno != ENOTDIR)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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}
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err = gpg_error (GPG_ERR_LIMIT_REACHED);
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leave:
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if (err)
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{
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log_error ("error creating an extract directory: %s\n",
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gpg_strerror (err));
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xfree (dirname);
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dirname = NULL;
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}
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xfree (prefix_buffer);
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return dirname;
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}
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gpg_error_t
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gpgtar_extract (const char *filename, int decrypt)
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{
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gpg_error_t err;
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estream_t stream;
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estream_t cipher_stream = NULL;
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tar_header_t header = NULL;
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strlist_t extheader = NULL;
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const char *dirprefix = NULL;
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char *dirname = NULL;
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struct tarinfo_s tarinfo_buffer;
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tarinfo_t tarinfo = &tarinfo_buffer;
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memset (&tarinfo_buffer, 0, sizeof tarinfo_buffer);
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if (filename)
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{
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if (!strcmp (filename, "-"))
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stream = es_stdin;
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else
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stream = es_fopen (filename, "rb");
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if (!stream)
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{
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err = gpg_error_from_syserror ();
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log_error ("error opening '%s': %s\n", filename, gpg_strerror (err));
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return err;
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}
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}
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else
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stream = es_stdin;
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if (stream == es_stdin)
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es_set_binary (es_stdin);
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if (decrypt)
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{
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strlist_t arg;
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ccparray_t ccp;
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const char **argv;
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cipher_stream = stream;
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stream = es_fopenmem (0, "rwb");
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if (! stream)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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ccparray_init (&ccp, 0);
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ccparray_put (&ccp, "--decrypt");
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for (arg = opt.gpg_arguments; arg; arg = arg->next)
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ccparray_put (&ccp, arg->d);
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ccparray_put (&ccp, NULL);
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argv = ccparray_get (&ccp, NULL);
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if (!argv)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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err = gnupg_exec_tool_stream (opt.gpg_program, argv,
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cipher_stream, NULL, stream, NULL, NULL);
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xfree (argv);
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if (err)
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goto leave;
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err = es_fseek (stream, 0, SEEK_SET);
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if (err)
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goto leave;
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}
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if (opt.directory)
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dirname = xtrystrdup (opt.directory);
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else
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{
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if (opt.filename)
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{
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dirprefix = strrchr (opt.filename, '/');
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if (dirprefix)
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dirprefix++;
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else
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dirprefix = opt.filename;
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}
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else if (filename)
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{
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dirprefix = strrchr (filename, '/');
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if (dirprefix)
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dirprefix++;
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else
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dirprefix = filename;
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}
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if (!dirprefix || !*dirprefix)
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dirprefix = "GPGARCH";
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dirname = create_directory (dirprefix);
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if (!dirname)
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{
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err = gpg_error (GPG_ERR_GENERAL);
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goto leave;
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}
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}
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if (opt.verbose)
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log_info ("extracting to '%s/'\n", dirname);
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for (;;)
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{
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err = gpgtar_read_header (stream, tarinfo, &header, &extheader);
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if (err || header == NULL)
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goto leave;
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err = extract (stream, dirname, tarinfo, header, extheader);
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if (err)
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goto leave;
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free_strlist (extheader);
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extheader = NULL;
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xfree (header);
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header = NULL;
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}
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leave:
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free_strlist (extheader);
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xfree (header);
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xfree (dirname);
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if (stream != es_stdin)
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es_fclose (stream);
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if (stream != cipher_stream)
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es_fclose (cipher_stream);
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return err;
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}
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