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Commit ee527162 authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Christoph Hellwig
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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: default avatarRamon de Carvalho Valle <rcvalle@linux.vnet.ibm.com>
Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarChristoph Hellwig <hch@tuxera.com>
parent 40de9a7c

fs/hfsplus/btree.c

+9 −2
Original line number Original line Diff line number Diff line
@@ -39,10 +39,16 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id) 
		goto free_tree;

		goto free_tree;

	tree->inode = inode;

	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;

	mapping = tree->inode->i_mapping;

	page = read_mapping_page(mapping, 0, NULL);

	page = read_mapping_page(mapping, 0, NULL);

	if (IS_ERR(page))

	if (IS_ERR(page))

		goto free_tree;

		goto free_inode;





	/* Load the header */

	/* Load the header */

	head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));

	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:

 fail_page:

	tree->inode->i_mapping->a_ops = &hfsplus_aops;

	tree->inode->i_mapping->a_ops = &hfsplus_aops;

	page_cache_release(page);

	page_cache_release(page);

 free_tree:

 free_inode:

	iput(tree->inode);

	iput(tree->inode);

 free_tree:

	kfree(tree);

	kfree(tree);

	return NULL;

	return NULL;

}

}