Prevent division by zero on erroneous file systems.

ok pelikan@

2 files changed, 11 insertions, 2 deletions

diff --git a/sbin/fsck_ext2fs/setup.c b/sbin/fsck_ext2fs/setup.c
index c99e0ce7895..b46b55f246c 100644
--- a/sbin/fsck_ext2fs/setup.c
+++ b/sbin/fsck_ext2fs/setup.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: setup.c,v 1.20 2014/05/22 14:04:41 krw Exp $	*/
+/*	$OpenBSD: setup.c,v 1.21 2014/07/11 15:54:52 tobias Exp $	*/
 /*	$NetBSD: setup.c,v 1.1 1997/06/11 11:22:01 bouyer Exp $	*/
 
 /*
@@ -272,6 +272,9 @@ readsb(int listerr)
 	if (sblock.e2fs.e2fs_log_bsize > 2) {
 		badsb(listerr, "BAD LOG_BSIZE"); return (0);
 	}
+	if (sblock.e2fs.e2fs_bpg == 0) {
+		badsb(listerr, "BAD BLOCKS PER GROUP"); return (0);
+	}
 
 	/* compute the dynamic fields of the in-memory sb */
 	/* compute dynamic sb infos */
diff --git a/sys/ufs/ext2fs/ext2fs_vfsops.c b/sys/ufs/ext2fs/ext2fs_vfsops.c
index 7324c8c23b8..28c60197ffa 100644
--- a/sys/ufs/ext2fs/ext2fs_vfsops.c
+++ b/sys/ufs/ext2fs/ext2fs_vfsops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ext2fs_vfsops.c,v 1.72 2014/07/11 14:30:52 pelikan Exp $	*/
+/*	$OpenBSD: ext2fs_vfsops.c,v 1.73 2014/07/11 15:54:52 tobias Exp $	*/
 /*	$NetBSD: ext2fs_vfsops.c,v 1.1 1997/06/11 09:34:07 bouyer Exp $	*/
 
 /*
@@ -1080,6 +1080,12 @@ ext2fs_checksb(struct ext2fs *fs, int ronly)
 #endif
 		return (EIO);	   /* XXX needs translation */
 	}
+	if (fs->e2fs_bpg == 0) {
+#ifdef DIAGNOSTIC
+		printf("Ext2 fs: bad blocks per group: 0\n");
+#endif
+		return (EIO);
+	}
 	if (fs2h32(fs->e2fs_rev) > E2FS_REV0) {
 		if (fs2h32(fs->e2fs_first_ino) != EXT2_FIRSTINO) {
 			printf("Ext2 fs: unsupported first inode position");