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gpgtar-extract.c
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/* gpgtar-extract.c - Extract from a TAR archive
* Copyright (C) 2016-2017, 2019-2022 g10 Code GmbH
* Copyright (C) 2010, 2012, 2013 Werner Koch
* Copyright (C) 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 <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#include <config.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "../common/i18n.h"
#include <gpg-error.h>
#include "../common/exechelp.h"
#include "../common/sysutils.h"
#include "../common/ccparray.h"
#include "gpgtar.h"
static gpg_error_t
check_suspicious_name (const char *name, tarinfo_t info)
{
size_t n;
n = strlen (name);
#ifdef HAVE_DOSISH_SYSTEM
if (strchr (name, '\\'))
{
log_error ("filename '%s' contains a backslash - "
"can't extract on this system\n", name);
info->skipped_badname++;
return gpg_error (GPG_ERR_INV_NAME);
}
#endif /*HAVE_DOSISH_SYSTEM*/
if (!n
|| strstr (name, "//")
|| strstr (name, "/../")
|| !strncmp (name, "../", 3)
|| (n >= 3 && !strcmp (name+n-3, "/.." )))
{
log_error ("filename '%s' has suspicious parts - not extracting\n",
name);
info->skipped_suspicious++;
return gpg_error (GPG_ERR_INV_NAME);
}
return 0;
}
static gpg_error_t
extract_regular (estream_t stream, const char *dirname,
tarinfo_t info, tar_header_t hdr, strlist_t exthdr)
{
gpg_error_t err;
char record[RECORDSIZE];
size_t n, nbytes, nwritten;
char *fname_buffer = NULL;
const char *fname;
estream_t outfp = NULL;
strlist_t sl;
fname = hdr->name;
for (sl = exthdr; sl; sl = sl->next)
if (sl->flags == 1)
fname = sl->d;
err = check_suspicious_name (fname, info);
if (err)
goto leave;
fname_buffer = strconcat (dirname, "/", fname, NULL);
if (!fname_buffer)
{
err = gpg_error_from_syserror ();
log_error ("error creating filename: %s\n", gpg_strerror (err));
goto leave;
}
fname = fname_buffer;
if (opt.dry_run)
outfp = es_fopen ("/dev/null", "wb");
else
outfp = es_fopen (fname, "wb,sysopen");
if (!outfp)
{
err = gpg_error_from_syserror ();
log_error ("error creating '%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
for (n=0; n < hdr->nrecords;)
{
err = read_record (stream, record);
if (err)
goto leave;
info->nblocks++;
n++;
if (n < hdr->nrecords || (hdr->size && !(hdr->size % RECORDSIZE)))
nbytes = RECORDSIZE;
else
nbytes = (hdr->size % RECORDSIZE);
nwritten = es_fwrite (record, 1, nbytes, outfp);
if (nwritten != nbytes)
{
err = gpg_error_from_syserror ();
log_error ("error writing '%s': %s\n", fname, gpg_strerror (err));
goto leave;
}
}
/* Fixme: Set permissions etc. */
leave:
if (!err)
{
if (opt.verbose)
log_info ("extracted '%s'\n", fname);
info->nextracted++;
}
es_fclose (outfp);
if (err && fname && outfp)
{
if (gnupg_remove (fname))
log_error ("error removing incomplete file '%s': %s\n",
fname, gpg_strerror (gpg_error_from_syserror ()));
}
xfree (fname_buffer);
return err;
}
static gpg_error_t
extract_directory (const char *dirname, tarinfo_t info,
tar_header_t hdr, strlist_t exthdr)
{
gpg_error_t err;
const char *name;
char *fname = NULL;
strlist_t sl;
name = hdr->name;
for (sl = exthdr; sl; sl = sl->next)
if (sl->flags == 1)
name = sl->d;
err = check_suspicious_name (name, info);
if (err)
goto leave;
fname = strconcat (dirname, "/", name, NULL);
if (!fname)
{
err = gpg_error_from_syserror ();
log_error ("error creating filename: %s\n", gpg_strerror (err));
goto leave;
}
/* Remove a possible trailing slash. */
if (fname[strlen (fname)-1] == '/')
fname[strlen (fname)-1] = 0;
if (! opt.dry_run && gnupg_mkdir (fname, "-rwx------"))
{
err = gpg_error_from_syserror ();
if (gpg_err_code (err) == GPG_ERR_EEXIST)
{
/* Ignore existing directories while extracting. */
err = 0;
}
if (gpg_err_code (err) == GPG_ERR_ENOENT)
{
/* Try to create the directory with parents but keep the
original error code in case of a failure. */
int rc = 0;
char *p;
size_t prefixlen;
/* (PREFIXLEN is the length of the new directory we use to
* extract the tarball.) */
prefixlen = strlen (dirname) + 1;
for (p = fname+prefixlen; (p = strchr (p, '/')); p++)
{
*p = 0;
rc = gnupg_mkdir (fname, "-rwx------");
if (gpg_err_code (rc) == GPG_ERR_EEXIST)
rc = 0;
*p = '/';
if (rc)
break;
}
if (!rc && !gnupg_mkdir (fname, "-rwx------"))
err = 0;
}
if (err)
log_error ("error creating directory '%s': %s\n",
fname, gpg_strerror (err));
}
leave:
if (!err && opt.verbose)
log_info ("created '%s/'\n", fname);
xfree (fname);
return err;
}
static gpg_error_t
extract (estream_t stream, const char *dirname, tarinfo_t info,
tar_header_t hdr, strlist_t exthdr)
{
gpg_error_t err;
size_t n;
if (hdr->typeflag == TF_REGULAR || hdr->typeflag == TF_UNKNOWN)
err = extract_regular (stream, dirname, info, hdr, exthdr);
else if (hdr->typeflag == TF_DIRECTORY)
err = extract_directory (dirname, info, hdr, exthdr);
else
{
char record[RECORDSIZE];
log_info ("unsupported file type %d for '%s' - skipped\n",
(int)hdr->typeflag, hdr->name);
if (hdr->typeflag == TF_SYMLINK)
info->skipped_symlinks++;
else if (hdr->typeflag == TF_HARDLINK)
info->skipped_hardlinks++;
else
info->skipped_other++;
for (err = 0, n=0; !err && n < hdr->nrecords; n++)
{
err = read_record (stream, record);
if (!err)
info->nblocks++;
}
}
return err;
}
/* Create a new directory to be used for extracting the tarball.
Returns the name of the directory which must be freed by the
caller. In case of an error a diagnostic is printed and NULL
returned. */
static char *
create_directory (const char *dirprefix)
{
gpg_error_t err = 0;
char *prefix_buffer = NULL;
char *dirname = NULL;
size_t n;
int idx;
/* Remove common suffixes. */
n = strlen (dirprefix);
if (n > 4 && (!compare_filenames (dirprefix + n - 4, EXTSEP_S GPGEXT_GPG)
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pgp")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "asc")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "pem")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7m")
|| !compare_filenames (dirprefix + n - 4, EXTSEP_S "p7e")))
{
prefix_buffer = xtrystrdup (dirprefix);
if (!prefix_buffer)
{
err = gpg_error_from_syserror ();
goto leave;
}
prefix_buffer[n-4] = 0;
dirprefix = prefix_buffer;
}
for (idx=1; idx < 5000; idx++)
{
xfree (dirname);
dirname = xtryasprintf ("%s_%d_", dirprefix, idx);
if (!dirname)
{
err = gpg_error_from_syserror ();
goto leave;
}
if (!gnupg_mkdir (dirname, "-rwx------"))
goto leave; /* Ready. */
if (errno != EEXIST && errno != ENOTDIR)
{
err = gpg_error_from_syserror ();
goto leave;
}
}
err = gpg_error (GPG_ERR_LIMIT_REACHED);
leave:
if (err)
{
log_error ("error creating an extract directory: %s\n",
gpg_strerror (err));
xfree (dirname);
dirname = NULL;
}
xfree (prefix_buffer);
return dirname;
}
gpg_error_t
gpgtar_extract (const char *filename, int decrypt)
{
gpg_error_t err;
estream_t stream = NULL;
tar_header_t header = NULL;
strlist_t extheader = NULL;
const char *dirprefix = NULL;
char *dirname = NULL;
struct tarinfo_s tarinfo_buffer;
tarinfo_t tarinfo = &tarinfo_buffer;
pid_t pid = (pid_t)(-1);
char *logfilename = NULL;
unsigned long long notextracted;
memset (&tarinfo_buffer, 0, sizeof tarinfo_buffer);
if (opt.directory)
dirname = xtrystrdup (opt.directory);
else
{
if (opt.filename)
{
dirprefix = strrchr (opt.filename, '/');
if (dirprefix)
dirprefix++;
else
dirprefix = opt.filename;
}
else if (filename)
{
dirprefix = strrchr (filename, '/');
if (dirprefix)
dirprefix++;
else
dirprefix = filename;
}
if (!dirprefix || !*dirprefix)
dirprefix = "GPGARCH";
dirname = create_directory (dirprefix);
if (!dirname)
{
err = gpg_error (GPG_ERR_GENERAL);
goto leave;
}
}
if (opt.verbose)
log_info ("extracting to '%s/'\n", dirname);
if (decrypt)
{
strlist_t arg;
ccparray_t ccp;
int except[2] = { -1, -1 };
const char **argv;
ccparray_init (&ccp, 0);
if (opt.batch)
ccparray_put (&ccp, "--batch");
if (opt.require_compliance)
ccparray_put (&ccp, "--require-compliance");
if (opt.status_fd != -1)
{
static char tmpbuf[40];
snprintf (tmpbuf, sizeof tmpbuf, "--status-fd=%d", opt.status_fd);
ccparray_put (&ccp, tmpbuf);
except[0] = opt.status_fd;
}
if (opt.with_log)
{
ccparray_put (&ccp, "--log-file");
logfilename = xstrconcat (dirname, ".log", NULL);
ccparray_put (&ccp, logfilename);
}
ccparray_put (&ccp, "--output");
ccparray_put (&ccp, "-");
ccparray_put (&ccp, "--decrypt");
for (arg = opt.gpg_arguments; arg; arg = arg->next)
ccparray_put (&ccp, arg->d);
if (filename)
{
ccparray_put (&ccp, "--");
ccparray_put (&ccp, filename);
}
ccparray_put (&ccp, NULL);
argv = ccparray_get (&ccp, NULL);
if (!argv)
{
err = gpg_error_from_syserror ();
goto leave;
}
err = gnupg_spawn_process (opt.gpg_program, argv,
except[0] == -1? NULL : except,
((filename? 0 : GNUPG_SPAWN_KEEP_STDIN)
| GNUPG_SPAWN_KEEP_STDERR),
NULL, &stream, NULL, &pid);
xfree (argv);
if (err)
goto leave;
es_set_binary (stream);
}
else if (filename)
{
if (!strcmp (filename, "-"))
stream = es_stdin;
else
stream = es_fopen (filename, "rb,sysopen");
if (!stream)
{
err = gpg_error_from_syserror ();
log_error ("error opening '%s': %s\n", filename, gpg_strerror (err));
return err;
}
if (stream == es_stdin)
es_set_binary (es_stdin);
}
else
{
stream = es_stdin;
es_set_binary (es_stdin);
}
for (;;)
{
err = gpgtar_read_header (stream, tarinfo, &header, &extheader);
if (err || header == NULL)
goto leave;
err = extract (stream, dirname, tarinfo, header, extheader);
if (err)
goto leave;
free_strlist (extheader);
extheader = NULL;
xfree (header);
header = NULL;
}
if (pid != (pid_t)(-1))
{
int exitcode;
err = es_fclose (stream);
stream = NULL;
if (err)
log_error ("error closing pipe: %s\n", gpg_strerror (err));
else
{
err = gnupg_wait_process (opt.gpg_program, pid, 1, &exitcode);
if (err)
log_error ("running %s failed (exitcode=%d): %s",
opt.gpg_program, exitcode, gpg_strerror (err));
gnupg_release_process (pid);
pid = (pid_t)(-1);
}
}
leave:
notextracted = tarinfo->skipped_badname;
notextracted += tarinfo->skipped_suspicious;
notextracted += tarinfo->skipped_symlinks;
notextracted += tarinfo->skipped_hardlinks;
notextracted += tarinfo->skipped_other;
if (opt.status_stream)
es_fprintf (opt.status_stream, "[GNUPG:] GPGTAR_EXTRACT"
" %llu %llu %lu %lu %lu %lu %lu\n",
tarinfo->nextracted,
notextracted,
tarinfo->skipped_badname,
tarinfo->skipped_suspicious,
tarinfo->skipped_symlinks,
tarinfo->skipped_hardlinks,
tarinfo->skipped_other);
if (notextracted && !opt.quiet)
{
log_info ("Number of files not extracted: %llu\n", notextracted);
if (tarinfo->skipped_badname)
log_info (" invalid name: %lu\n", tarinfo->skipped_badname);
if (tarinfo->skipped_suspicious)
log_info (" suspicious name: %lu\n", tarinfo->skipped_suspicious);
if (tarinfo->skipped_symlinks)
log_info (" symlink: %lu\n", tarinfo->skipped_symlinks);
if (tarinfo->skipped_hardlinks)
log_info (" hardlink: %lu\n", tarinfo->skipped_hardlinks);
if (tarinfo->skipped_other)
log_info (" other reason: %lu\n", tarinfo->skipped_other);
}
free_strlist (extheader);
xfree (header);
xfree (dirname);
xfree (logfilename);
if (stream != es_stdin)
es_fclose (stream);
return err;
}

File Metadata

Mime Type
text/x-c
Expires
Sat, Jan 3, 11:46 PM (9 h, 38 m)
Storage Engine
local-disk
Storage Format
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Storage Handle
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