Commit 5e24e9af authored Jun 23, 2016 by Liu Bo Committed by David Sterba Jul 26, 2016

Btrfs: error out if generic_bin_search get invalid arguments



With btrfs-corrupt-block, one can set btree node/leaf's field, if
we assign a negative value to node/leaf, we can get various hangs,
eg. if extent_root's nritems is -2ULL, then we get stuck in
 btrfs_read_block_groups() because it has a while loop and
btrfs_search_slot() on extent_root will always return the first
 child.

This lets us know what's happening and returns a EINVAL to callers
instead of returning the first item.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 6fb37b75

fs/btrfs/ctree.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1771,6 +1771,14 @@ static noinline int generic_bin_search(struct extent_buffer *eb,
		unsigned long map_len = 0;
		int err;

		if (low > high) {
		btrfs_err(eb->fs_info,
		"%s: low (%d) > high (%d) eb %llu owner %llu level %d",
		__func__, low, high, eb->start,
		btrfs_header_owner(eb), btrfs_header_level(eb));
		return -EINVAL;
		}

		while (low < high) {
		mid = (low + high) / 2;
		offset = p + mid * item_size;