[patch 01/20] Have ext3 reject file handles with bad inode numbers early

Greg KH
2006-08-21T18:47:56Z

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-stable review patch. If anyone has any objections, please let us know.

------------------
blatantly ripped off from Neil Brown's ext2 patch.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/ext3/super.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)

--- linux-2.6.17.8.orig/fs/ext3/super.c
+++ linux-2.6.17.8/fs/ext3/super.c
@@ -620,8 +620,48 @@ static struct super_operations ext3_sops
#endif
};

+static struct dentry *ext3_get_dentry(struct super_block *sb, void *vobjp)
+{
+ __u32 *objp = vobjp;
+ unsigned long ino = objp[0];
+ __u32 generation = objp[1];
+ struct inode *inode;
+ struct dentry *result;
+
+ if (ino != EXT3_ROOT_INO && ino < EXT3_FIRST_INO(sb))
+ return ERR_PTR(-ESTALE);
+ if (ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count))
+ return ERR_PTR(-ESTALE);
+
+ /* iget isn't really right if the inode is currently unallocated!!
+ * ext3_read_inode currently does appropriate checks, but
+ * it might be "neater" to call ext3_get_inode first and check
+ * if the inode is valid.....
+ */
+ inode = iget(sb, ino);
+ if (inode == NULL)
+ return ERR_PTR(-ENOMEM);
+ if (is_bad_inode(inode)
+ || (generation && inode->i_generation != generation)
+ ) {
+ /* we didn't find the right inode.. */
+ iput(inode);
+ return ERR_PTR(-ESTALE);
+ }
+ /* now to find a dentry.
+ * If possible, get a well-connected one
+ */
+ result = d_alloc_anon(inode);
+ if (!result) {
+ iput(inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ return result;
+}
+
static struct export_operations ext3_export_ops = {
.get_parent = ext3_get_parent,
+ .get_dentry = ext3_get_dentry,
};

enum {

--