mtd-utils: Fix various TOCTOU issues

This patch restructures various code parts that follow the pattern
of "stat(x, &sb) ... makes_sense(&sb) ... open(x)".

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

1 files changed, 8 insertions, 6 deletions

diff --git a/misc-utils/ftl_format.c b/misc-utils/ftl_format.c
index bf3c8f2..34d436c 100644
--- a/misc-utils/ftl_format.c
+++ b/misc-utils/ftl_format.c
@@ -312,18 +312,20 @@ int main(int argc, char *argv[])
 		exit(errflg > 0 ? EXIT_SUCCESS : EXIT_FAILURE);
 	}
 
-	if (stat(argv[optind], &buf) != 0) {
+	fd = open(argv[optind], O_RDWR);
+	if (fd == -1) {
+		perror("open failed");
+		exit(EXIT_FAILURE);
+	}
+	if (fstat(fd, &buf) != 0) {
 		perror("status check failed");
+		close(fd);
 		exit(EXIT_FAILURE);
 	}
 	if (!(buf.st_mode & S_IFCHR)) {
 		fprintf(stderr, "%s is not a character special device\n",
 				argv[optind]);
-		exit(EXIT_FAILURE);
-	}
-	fd = open(argv[optind], O_RDWR);
-	if (fd == -1) {
-		perror("open failed");
+		close(fd);
 		exit(EXIT_FAILURE);
 	}