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[Bug-tar] [PATCH] Option to detect tarbombs while extracting
From: |
Connor Behan |
Subject: |
[Bug-tar] [PATCH] Option to detect tarbombs while extracting |
Date: |
Sat, 7 Dec 2013 13:04:56 -0800 |
* src/common.h (one_top_level_option): New global.
(one_top_level): New global.
* src/extract.c (extr_init): If one_top_level_option is set, determine
the name one_top_level that might have to be prepended.
(extract_archive): If one_top_level_option is set, prepend one_top_level
to all names that don't already start with it.
* src/tar.c (ONE_TOP_LEVEL_OPTION): New contant.
(options): New option --one-top-level.
(parse_opt): Handle this option.
(decode_options): Make it conflict with --absolute-names.
* NEWS: Update.
* doc/tar.texi: Document new option.
---
NEWS | 10 ++++++++++
doc/tar.texi | 11 +++++++++++
src/common.h | 4 ++++
src/extract.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/tar.c | 11 +++++++++++
5 files changed, 92 insertions(+)
diff --git a/NEWS b/NEWS
index 1a264b0..17d0004 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,16 @@
GNU tar NEWS - User visible changes. 2013-11-17
Please send GNU tar bug reports to <address@hidden>
+version 1.27.90 (Git)
+
+* The --one-top-level option.
+
+This new command line option tells tar that the working directory
+(or the one passed to -C) should not be populated with more than one
+name directly under it. Instead, a newly created subdirectory is
+used whose name is equal to the archive name without the extension.
+For example, foo.tar.gz would be extracted to foo.
+
version 1.27.1 - Sergey Poznyakoff, 2013-11-17
diff --git a/doc/tar.texi b/doc/tar.texi
index 9fde5a0..f7376ac 100644
--- a/doc/tar.texi
+++ b/doc/tar.texi
@@ -3086,6 +3086,17 @@ Used when creating an archive. Prevents @command{tar}
from recursing into
directories that are on different file systems from the current
directory.
address@hidden
address@hidden --one-top-level
+Tells @command{tar} to create a new directory beneath the extraction directory
+(or the one passed to @option{-C}) and use it to guard against tarbombs. The
+name of the new directory will be equal to the name of the archive with the
+extension stripped off. If any archive names (after transformations from
address@hidden and @option{--strip-components}) do not already begin with
+it, the new directory will be prepended to the names immediately before
+extraction. Recognized extensions are @samp{.tar}, @samp{.taz}, @samp{.tbz},
address@hidden, @samp{.tb2}, @samp{.tgz}, @samp{.tlz} and @samp{.txz}.
+
@opsummary{overwrite}
@item --overwrite
diff --git a/src/common.h b/src/common.h
index 42fd539..1f3e48c 100644
--- a/src/common.h
+++ b/src/common.h
@@ -235,6 +235,10 @@ GLOBAL bool numeric_owner_option;
GLOBAL bool one_file_system_option;
+/* Create a top-level directory for extracting based on the archive name. */
+GLOBAL bool one_top_level_option;
+GLOBAL char *one_top_level;
+
/* Specified value to be put into tar file in place of stat () results, or
just null and -1 if such an override should not take place. */
GLOBAL char const *owner_name_option;
diff --git a/src/extract.c b/src/extract.c
index 9b6b7f9..80666a6 100644
--- a/src/extract.c
+++ b/src/extract.c
@@ -191,6 +191,35 @@ extr_init (void)
umask (newdir_umask); /* restore the kernel umask */
current_umask = newdir_umask;
}
+
+ /* If the user wants to guarantee that everything is under one directory,
+ determine its name now and let it be created later. */
+ if (one_top_level_option)
+ {
+ int i;
+ char *base = base_name (archive_name_array[0]);
+
+ for (i = strlen (base) - 1; i > 2; i--)
+ if (!strncmp (base + i - 3, ".tar", 4) ||
+ !strncmp (base + i - 3, ".taz", 4) ||
+ !strncmp (base + i - 3, ".tbz", 4) ||
+ !strncmp (base + i - 3, ".tb2", 4) ||
+ !strncmp (base + i - 3, ".tgz", 4) ||
+ !strncmp (base + i - 3, ".tlz", 4) ||
+ !strncmp (base + i - 3, ".txz", 4)) break;
+
+ if (i <= 3)
+ {
+ one_top_level_option = false;
+ free (base);
+ return;
+ }
+
+ one_top_level = xmalloc (i - 2);
+ strncpy (one_top_level, base, i - 3);
+ one_top_level[i - 3] = '\0';
+ free (base);
+ }
}
/* Use fchmod if possible, fchmodat otherwise. */
@@ -1578,6 +1607,30 @@ prepare_to_extract (char const *file_name, int typeflag,
tar_extractor_t *fun)
return 1;
}
+void
+maybe_prepend_name (char **file_name)
+{
+ int i;
+
+ for (i = 0; i < strlen (*file_name); i++)
+ if (!ISSLASH ((*file_name)[i]) && ((*file_name)[i]) != '.') break;
+
+ if (i == strlen (*file_name))
+ return;
+
+ if (!strncmp (*file_name + i, one_top_level, strlen (one_top_level)))
+ return;
+
+ char *new_name = xmalloc (strlen (one_top_level) + strlen (*file_name) + 2);
+
+ strcpy (new_name, one_top_level);
+ strcat (new_name, "/");
+ strcat (new_name, *file_name);
+
+ free (*file_name);
+ *file_name = new_name;
+}
+
/* Extract a file from the archive. */
void
extract_archive (void)
@@ -1628,6 +1681,9 @@ extract_archive (void)
typeflag = sparse_member_p (¤t_stat_info) ?
GNUTYPE_SPARSE : current_header->header.typeflag;
+ if (one_top_level_option)
+ maybe_prepend_name (¤t_stat_info.file_name);
+
if (prepare_to_extract (current_stat_info.file_name, typeflag, &fun))
{
if (fun && (*fun) (current_stat_info.file_name, typeflag)
diff --git a/src/tar.c b/src/tar.c
index 4f5017d..19da7f7 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -319,6 +319,7 @@ enum
OCCURRENCE_OPTION,
OLD_ARCHIVE_OPTION,
ONE_FILE_SYSTEM_OPTION,
+ ONE_TOP_LEVEL_OPTION,
OVERWRITE_DIR_OPTION,
OVERWRITE_OPTION,
OWNER_OPTION,
@@ -489,6 +490,9 @@ static struct argp_option options[] = {
{"keep-directory-symlink", KEEP_DIRECTORY_SYMLINK_OPTION, 0, 0,
N_("preserve existing symlinks to directories when extracting"),
GRID+1 },
+ {"one-top-level", ONE_TOP_LEVEL_OPTION, 0, 0,
+ N_("create a subdirectory to avoid having loose files extracted"),
+ GRID+1 },
#undef GRID
#define GRID 40
@@ -1438,6 +1442,10 @@ parse_opt (int key, char *arg, struct argp_state *state)
one_file_system_option = true;
break;
+ case ONE_TOP_LEVEL_OPTION:
+ one_top_level_option = true;
+ break;
+
case 'l':
check_links_option = 1;
break;
@@ -2390,6 +2398,9 @@ decode_options (int argc, char **argv)
subcommand_string (subcommand_option)));
}
+ if (one_top_level_option && absolute_names_option)
+ USAGE_ERROR ((0, 0, _("--one-top-level cannot be used with
--absolute-names")));
+
if (archive_names == 0)
{
/* If no archive file name given, try TAPE from the environment, or
--
1.8.4
- [Bug-tar] [PATCH] Option to detect tarbombs while extracting,
Connor Behan <=