ecryptfs: Fix refcnt leak on ecryptfs_follow_link() error path

If ->follow_link handler return the error, it should decrement
nd->path refcnt. But, ecryptfs_follow_link() doesn't decrement.

This patch fix it by using usual nd_set_link() style error handling,
instead of playing with nd->path.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 429ca0b..7f85450 100644 (file)
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -715,31 +715,31 @@ static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
        /* Released in ecryptfs_put_link(); only release here on error */
        buf = kmalloc(len, GFP_KERNEL);
        if (!buf) {
-               rc = -ENOMEM;
+               buf = ERR_PTR(-ENOMEM);
                goto out;
        }
        old_fs = get_fs();
        set_fs(get_ds());
        rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
        set_fs(old_fs);
-       if (rc < 0)
-               goto out_free;
-       else
+       if (rc < 0) {
+               kfree(buf);
+               buf = ERR_PTR(rc);
+       } else
                buf[rc] = '\0';
-       rc = 0;
-       nd_set_link(nd, buf);
-       goto out;
-out_free:
-       kfree(buf);
 out:
-       return ERR_PTR(rc);
+       nd_set_link(nd, buf);
+       return NULL;
 }
 
 static void
 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 {
-       /* Free the char* */
-       kfree(nd_get_link(nd));
+       char *buf = nd_get_link(nd);
+       if (!IS_ERR(buf)) {
+               /* Free the char* */
+               kfree(buf);
+       }
 }
 
 /**