ext4: check block device size on mount

Signed-off-by: Thiemo Nagel <thiemo.nagel@ph.tum.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 9 insertions, 0 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9987bba99db..2958f4e6f22 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2508,6 +2508,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
         if (EXT4_BLOCKS_PER_GROUP(sb) == 0)
                 goto cantfind_ext4;
 
+        /* check blocks count against device size */
+        blocks_count = sb->s_bdev->bd_inode->i_size >> sb->s_blocksize_bits;
+        if (blocks_count && ext4_blocks_count(es) > blocks_count) {
+                printk(KERN_WARNING "EXT4-fs: bad geometry: block count %llu "
+                       "exceeds size of device (%llu blocks)\n",
+                       ext4_blocks_count(es), blocks_count);
+                goto failed_mount;
+        }
+
         /*
          * It makes no sense for the first data block to be beyond the end
          * of the filesystem.