From: Eric Sandeen <esandeen@redhat.com>
Date: Fri, 4 Aug 2006 15:35:34 +0000 (-0500)
Subject: Have ext3 reject file handles with bad inode numbers early
X-Git-Tag: v2.6.17.11~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bd2a1e115cf239c708747bae1cf1c0757686af50;p=thirdparty%2Fkernel%2Fstable.git

Have ext3 reject file handles with bad inode numbers early

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>
---

diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index f8a5266ea1ffe..86534ad79341a 100644
--- a/fs/ext3/super.c
+++ b/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 {