Commit ee527162 authored Oct 14, 2010 by Jeff Mahoney Committed by Christoph Hellwig Oct 14, 2010

hfsplus: fix oops on mount with corrupted btree extent records



A particular fsfuzzer run caused an hfs file system to crash on mount. This
is due to a corrupted MDB extent record causing a miscalculation of
HFSPLUS_I(inode)->first_blocks for the extent tree. If the extent records
are zereod out, then it won't trigger the first_blocks special case and
instead falls through to the extent code, which we're in the middle
of initializing.

This patch catches the 0 size extent records, reports the corruption,
and fails the mount.

[hch: ported of commit 47f365eb from hfs]

Reported-by: Ramon de Carvalho Valle <rcvalle@linux.vnet.ibm.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Christoph Hellwig <hch@tuxera.com>

parent 40de9a7c

fs/hfsplus/btree.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -39,10 +39,16 @@ struct hfs_btree hfs_btree_open(struct super_block sb, u32 id)
		goto free_tree;
		tree->inode = inode;

		if (!HFSPLUS_I(tree->inode)->first_blocks) {
		printk(KERN_ERR
		"hfs: invalid btree extent records (0 size).\n");
		goto free_inode;
		}

		mapping = tree->inode->i_mapping;
		page = read_mapping_page(mapping, 0, NULL);
		if (IS_ERR(page))
		goto free_tree;
		goto free_inode;

		/* Load the header */
		head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
		@@ -89,8 +95,9 @@ struct hfs_btree hfs_btree_open(struct super_block sb, u32 id)
		fail_page:
		tree->inode->i_mapping->a_ops = &hfsplus_aops;
		page_cache_release(page);
		free_tree:
		free_inode:
		iput(tree->inode);
		free_tree:
		kfree(tree);
		return NULL;
		}

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