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-rw-r--r--archival/tar.c37
1 files changed, 19 insertions, 18 deletions
diff --git a/archival/tar.c b/archival/tar.c
index 0fc574dfd..280ded4e1 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -22,24 +22,6 @@
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-/* TODO: security with -C DESTDIR option can be enhanced.
- * Consider tar file created via:
- * $ tar cvf bug.tar anything.txt
- * $ ln -s /tmp symlink
- * $ tar --append -f bug.tar symlink
- * $ rm symlink
- * $ mkdir symlink
- * $ tar --append -f bug.tar symlink/evil.py
- *
- * This will result in an archive which contains:
- * $ tar --list -f bug.tar
- * anything.txt
- * symlink
- * symlink/evil.py
- *
- * Untarring it puts evil.py in '/tmp' even if the -C DESTDIR is given.
- * This doesn't feel right, and IIRC GNU tar doesn't do that.
- */
//config:config TAR
//config: bool "tar (40 kb)"
@@ -296,6 +278,23 @@ static void chksum_and_xwrite(int fd, struct tar_header_t* hp)
xwrite(fd, hp, sizeof(*hp));
}
+static void replace_symlink_placeholders(llist_t *list)
+{
+ while (list) {
+ char *target;
+
+ target = list->data + strlen(list->data) + 1;
+ if (symlink(target, list->data)) {
+ /* shared message */
+ bb_error_msg_and_die("can't create %slink '%s' to '%s'",
+ "sym",
+ list->data, target
+ );
+ }
+ list = list->link;
+ }
+}
+
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
static void writeLongname(int fd, int type, const char *name, int dir)
{
@@ -1252,6 +1251,8 @@ int tar_main(int argc UNUSED_PARAM, char **argv)
while (get_header_tar(tar_handle) == EXIT_SUCCESS)
bb_got_signal = EXIT_SUCCESS; /* saw at least one header, good */
+ replace_symlink_placeholders(tar_handle->symlink_placeholders);
+
/* Check that every file that should have been extracted was */
while (tar_handle->accept) {
if (!find_list_entry(tar_handle->reject, tar_handle->accept->data)