From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 360112FA622; Tue, 17 Jun 2025 16:51:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750179118; cv=none; b=L2nj3TftRFJDMWWG8JJsh/SKGMYGXuv3AznWyUc6svCa+736mzqFtNERoCO7dndTzd228tbHlz+oP4c2Jxwt5hoaR4GOH2IixzD2nF/L//1C7HGrSDBJuypgCNtp11+M0LLKwLL0Q7W84D6aSEXvtPsH3Bp/XwyGzw9kiPs3ZI4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750179118; c=relaxed/simple; bh=KHZlFHKIW1MoQoJN6y34/ZPz90Wa2rj29vX4kzkN44g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=l0yenW2t308PPdN8QhlVKzfJyVJRrd9yFfx5hFxxtFTjmwU+/Dduuar5dJiInBkyYQ0pIMmNQPRoXPTHnv+Fo2/2xyTlFD92saYUn4GZOCURuBrH6x2VcNkzh5+bmG5fVVMJ9APi38u/r8wyUDqPVokWCB16zNvB+/TknuY5yT8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OYOkPwkb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="OYOkPwkb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1789C4CEE3; Tue, 17 Jun 2025 16:51:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750179118; bh=KHZlFHKIW1MoQoJN6y34/ZPz90Wa2rj29vX4kzkN44g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OYOkPwkbsrjpnV6eClmIbVjuKkI9rEpI3Q3zTlXi0KhPrymM4Po0Oi9zta4ybbw2E lrD4zzM8yZ4jeVcZ8mbKV0j72paOlmS0prqxvGgbgi9zo28stzKWjKbGvCJ6Mqvi8C hjH2kmBB2UJ7QuchX8ZbG+MJJRBpbliXttIlH8Vc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christian Brauner , Al Viro , Kazuma Kondo , Sasha Levin Subject: [PATCH 6.15 654/780] fs: allow clone_private_mount() for a path on real rootfs Date: Tue, 17 Jun 2025 17:26:02 +0200 Message-ID: <20250617152518.106661152@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152451.485330293@linuxfoundation.org> References: <20250617152451.485330293@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: KONDO KAZUMA(近藤　和真) [ Upstream commit 4954346d80fb047cb78776d9f2ebd6a050f80c5f ] Mounting overlayfs with a directory on real rootfs (initramfs) as upperdir has failed with following message since commit db04662e2f4f ("fs: allow detached mounts in clone_private_mount()"). [ 4.080134] overlayfs: failed to clone upperpath Overlayfs mount uses clone_private_mount() to create internal mount for the underlying layers. The commit made clone_private_mount() reject real rootfs because it does not have a parent mount and is in the initial mount namespace, that is not an anonymous mount namespace. This issue can be fixed by modifying the permission check of clone_private_mount() following [1]. Reviewed-by: Christian Brauner Fixes: db04662e2f4f ("fs: allow detached mounts in clone_private_mount()") Link: https://lore.kernel.org/all/20250514190252.GQ2023217@ZenIV/ [1] Link: https://lore.kernel.org/all/20250506194849.GT2023217@ZenIV/ Suggested-by: Al Viro Signed-off-by: Kazuma Kondo Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/namespace.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index e2780f413a2e0..07bc500a248ec 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2492,18 +2492,19 @@ struct vfsmount *clone_private_mount(const struct path *path) if (IS_MNT_UNBINDABLE(old_mnt)) return ERR_PTR(-EINVAL); - if (mnt_has_parent(old_mnt)) { - if (!check_mnt(old_mnt)) - return ERR_PTR(-EINVAL); - } else { - if (!is_mounted(&old_mnt->mnt)) - return ERR_PTR(-EINVAL); - - /* Make sure this isn't something purely kernel internal. */ - if (!is_anon_ns(old_mnt->mnt_ns)) + /* + * Make sure the source mount is acceptable. + * Anything mounted in our mount namespace is allowed. + * Otherwise, it must be the root of an anonymous mount + * namespace, and we need to make sure no namespace + * loops get created. + */ + if (!check_mnt(old_mnt)) { + if (!is_mounted(&old_mnt->mnt) || + !is_anon_ns(old_mnt->mnt_ns) || + mnt_has_parent(old_mnt)) return ERR_PTR(-EINVAL); - /* Make sure we don't create mount namespace loops. */ if (!check_for_nsfs_mounts(old_mnt)) return ERR_PTR(-EINVAL); } -- 2.39.5