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authorJeff Mahoney <jeffm@suse.com>2010-10-14 09:53:37 -0400
committerChristoph Hellwig <hch@lst.de>2010-10-14 09:53:37 -0400
commitee52716245877b821f5ddbb3ace85b73084fb450 (patch)
tree3d85d8fce3bde7b1601878074cdec622705d1af2 /fs/hfsplus
parent40de9a7cebc4e0b23cd6863c84c2279f0ccadebb (diff)
downloadlinux-ee52716245877b821f5ddbb3ace85b73084fb450.tar.gz
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 47f365eb575735c6b2edf5d08e0d16d26a9c23bd 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>
Diffstat (limited to 'fs/hfsplus')
-rw-r--r--fs/hfsplus/btree.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index 8306479f6b3a..d4bd864ce108 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -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;
 }