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From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        linux-fsdevel@vger.kernel.org
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        Christian Brauner <christian.brauner@ubuntu.com>,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH v2 26/39] ioctl: handle idmapped mounts
Date:   Sun, 15 Nov 2020 11:37:05 +0100
Message-Id: <20201115103718.298186-27-christian.brauner@ubuntu.com>
In-Reply-To: <20201115103718.298186-1-christian.brauner@ubuntu.com>
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Enable generic ioctls to handle idmapped mounts by passing down the mount's
user namespace.

Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
patch introduced
---
 fs/remap_range.c   | 7 +++++--
 fs/verity/enable.c | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/remap_range.c b/fs/remap_range.c
index 9e5b27641756..fe7f07228462 100644
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -432,13 +432,16 @@ EXPORT_SYMBOL(vfs_clone_file_range);
 /* Check whether we are allowed to dedupe the destination file */
 static bool allow_file_dedupe(struct file *file)
 {
+	struct user_namespace *user_ns = mnt_user_ns(file->f_path.mnt);
+	struct inode *inode = file_inode(file);
+
 	if (capable(CAP_SYS_ADMIN))
 		return true;
 	if (file->f_mode & FMODE_WRITE)
 		return true;
-	if (uid_eq(current_fsuid(), file_inode(file)->i_uid))
+	if (uid_eq(current_fsuid(), i_uid_into_mnt(user_ns, inode)))
 		return true;
-	if (!inode_permission(&init_user_ns, file_inode(file), MAY_WRITE))
+	if (!inode_permission(user_ns, inode, MAY_WRITE))
 		return true;
 	return false;
 }
diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index 7449ef0050f4..8b9ea0f0850f 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -369,7 +369,7 @@ int fsverity_ioctl_enable(struct file *filp, const void __user *uarg)
 	 * has verity enabled, and to stabilize the data being hashed.
 	 */
 
-	err = inode_permission(&init_user_ns, inode, MAY_WRITE);
+	err = inode_permission(mnt_user_ns(filp->f_path.mnt), inode, MAY_WRITE);
 	if (err)
 		return err;
 
-- 
2.29.2