[PATCH] knfsd: Have ext2 reject file handles with bad inode numbers early
This prevents bad inode numbers from triggering errors in ext2_get_inode.
[akpm@osdl.org: speedup, cleanup]
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 681dea8..ca5bfb6 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -251,6 +251,44 @@
#endif
};
+static struct dentry *ext2_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 < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
+ return ERR_PTR(-ESTALE);
+ if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
+ return ERR_PTR(-ESTALE);
+
+ /* iget isn't really right if the inode is currently unallocated!!
+ * ext2_read_inode currently does appropriate checks, but
+ * it might be "neater" to call ext2_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;
+}
+
/* Yes, most of these are left as NULL!!
* A NULL value implies the default, which works with ext2-like file
* systems, but can be improved upon.
@@ -258,6 +296,7 @@
*/
static struct export_operations ext2_export_ops = {
.get_parent = ext2_get_parent,
+ .get_dentry = ext2_get_dentry,
};
static unsigned long get_sb_block(void **data)