Fix tar2sqfs: check for empty names or './' entrty

This commit makes sure entries with empty file names are
skipped by tar2sqfs.

The case of a directory with the name './' is treated specially,
because tar can generate in some common use cases.

For instance:

$ mkdir foo
$ touch foo/bar
$ tar -C ./foo -c . > out.tar
$ tar tf out.tar

will generate a tar file with an entry named './'.

For the future it might be interesting to turn that into the root
inode somehow.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 14 insertions, 0 deletions

diff --git a/tar/tar2sqfs.c b/tar/tar2sqfs.c
index 627cae9..30f1abb 100644
--- a/tar/tar2sqfs.c
+++ b/tar/tar2sqfs.c
@@ -345,12 +345,26 @@ static int process_tar_ball(void)
 
 		skip = false;
 
+		if (hdr.name != NULL && strcmp(hdr.name, "./") == 0 &&
+		    S_ISDIR(hdr.sb.st_mode)) {
+			/* XXX: tar entries might be prefixed with ./ which is
+			   stripped by cannonicalize_name, but the tar file may
+			   contain a directory entry named './' */
+			clear_header(&hdr);
+			continue;
+		}
+
 		if (hdr.name == NULL || canonicalize_name(hdr.name) != 0) {
 			fprintf(stderr, "skipping '%s' (invalid name)\n",
 				hdr.name);
 			skip = true;
 		}
 
+		if (hdr.name[0] == '\0') {
+			fputs("skipping entry with empty name\n", stderr);
+			skip = true;
+		}
+
 		if (!skip && hdr.unknown_record) {
 			fprintf(stderr, "%s: unknown entry type\n", hdr.name);
 			skip = true;