libext2fs: make sure the bitmap locations are valid when writing bitmaps

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c
index 7be4a55..1fe65f7 100644 (file)
--- a/lib/ext2fs/rw_bitmaps.c
+++ b/lib/ext2fs/rw_bitmaps.c
@@ -119,7 +119,7 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
                fs->flags |= EXT2_FLAG_DIRTY;
 
                blk = ext2fs_block_bitmap_loc(fs, i);
-               if (blk) {
+               if (blk && blk < ext2fs_blocks_count(fs->super)) {
                        retval = io_channel_write_blk64(fs->io, blk, 1,
                                                        block_buf);
                        if (retval) {
@@ -151,7 +151,7 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
                fs->flags |= EXT2_FLAG_DIRTY;
 
                blk = ext2fs_inode_bitmap_loc(fs, i);
-               if (blk) {
+               if (blk && blk < ext2fs_blocks_count(fs->super)) {
                        retval = io_channel_write_blk64(fs->io, blk, 1,
                                                      inode_buf);
                        if (retval) {
@@ -204,14 +204,14 @@ static errcode_t mark_uninit_bg_group_blocks(ext2_filsys fs)
                 * Mark block used for the block bitmap
                 */
                blk = ext2fs_block_bitmap_loc(fs, i);
-               if (blk)
+               if (blk && blk < ext2fs_blocks_count(fs->super))
                        ext2fs_mark_block_bitmap2(bmap, blk);
 
                /*
                 * Mark block used for the inode bitmap
                 */
                blk = ext2fs_inode_bitmap_loc(fs, i);
-               if (blk)
+               if (blk && blk < ext2fs_blocks_count(fs->super))
                        ext2fs_mark_block_bitmap2(bmap, blk);
        }
        return 0;