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 822ED17C9E for ; Tue, 1 Oct 2024 13:58:44 +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=1727791124; cv=none; b=VVV1DnAjcETwQGaFP0IGZ6nZH8Hf2machPEoVesTy709POSSqr9fvQX/gobukwzjTWwidkJ7xmbpZb9n4e6vB6sYqB0Mj2TUQ5d0FGN9HrJ4zgaqLN7BxXrasITJvnjQ7F+hgzGxZCpY5D/6QxlIRkwRIR2BxVG6U7KF+li1qdo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727791124; c=relaxed/simple; bh=iJsk4+gJuZuXCnn9GiFBhBd2FnS7oWT7N7gQ6JcTbqM=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=drAuNv6Cj9MaQoykpuduq8rnFBWSpVk+uJIKsC/EzXMb+ULj71V2lgAI73puHxczj3IUiY+DqeUeaZ+7bYyIW2g99r5PwNOa3ZHHC0BEcBeoeHEgLdujYAbupJtqGEmDVC4s+AD8l0CZvu4qHxHwajG/cDzG26sLjeZmqF7Ue90= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ar0Q1fKm; 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="Ar0Q1fKm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA781C4CEC6; Tue, 1 Oct 2024 13:58:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727791124; bh=iJsk4+gJuZuXCnn9GiFBhBd2FnS7oWT7N7gQ6JcTbqM=; h=Subject:To:Cc:From:Date:From; b=Ar0Q1fKm3zeIceo8fWxVvlQkvdNRQlWQWlKAFTnXOqe0qFoRYjJ7wcxR6GFcjYTSL bPZaz3gzaB5OCByfmLp6xcWAXyAHLmf3MB+0IiAGF2Qyw+3opGK20SBp/UpIH0XjdU q+feRZHOVXDhj3X/oKWTI5g95jB1fpSxaPXUTyfU= Subject: FAILED: patch "[PATCH] f2fs: Require FMODE_WRITE for atomic write ioctls" failed to apply to 5.4-stable tree To: jannh@google.com,chao@kernel.org,ebiggers@google.com,jaegeuk@kernel.org Cc: From: Date: Tue, 01 Oct 2024 15:58:35 +0200 Message-ID: <2024100135-magenta-resigned-365f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 4f5a100f87f32cb65d4bb1ad282a08c92f6f591e # git commit -s git send-email --to '' --in-reply-to '2024100135-magenta-resigned-365f@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: 4f5a100f87f3 ("f2fs: Require FMODE_WRITE for atomic write ioctls") 01beba7957a2 ("fs: port inode_owner_or_capable() to mnt_idmap") f2d40141d5d9 ("fs: port inode_init_owner() to mnt_idmap") 4609e1f18e19 ("fs: port ->permission() to pass mnt_idmap") 8782a9aea3ab ("fs: port ->fileattr_set() to pass mnt_idmap") 13e83a4923be ("fs: port ->set_acl() to pass mnt_idmap") 77435322777d ("fs: port ->get_acl() to pass mnt_idmap") 011e2b717b1b ("fs: port ->tmpfile() to pass mnt_idmap") 5ebb29bee8d5 ("fs: port ->mknod() to pass mnt_idmap") c54bd91e9eab ("fs: port ->mkdir() to pass mnt_idmap") 7a77db95511c ("fs: port ->symlink() to pass mnt_idmap") 6c960e68aaed ("fs: port ->create() to pass mnt_idmap") b74d24f7a74f ("fs: port ->getattr() to pass mnt_idmap") c1632a0f1120 ("fs: port ->setattr() to pass mnt_idmap") abf08576afe3 ("fs: port vfs_*() helpers to struct mnt_idmap") 6022ec6ee2c3 ("Merge tag 'ntfs3_for_6.2' of https://github.com/Paragon-Software-Group/linux-ntfs3") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 4f5a100f87f32cb65d4bb1ad282a08c92f6f591e Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 6 Aug 2024 16:07:16 +0200 Subject: [PATCH] f2fs: Require FMODE_WRITE for atomic write ioctls The F2FS ioctls for starting and committing atomic writes check for inode_owner_or_capable(), but this does not give LSMs like SELinux or Landlock an opportunity to deny the write access - if the caller's FSUID matches the inode's UID, inode_owner_or_capable() immediately returns true. There are scenarios where LSMs want to deny a process the ability to write particular files, even files that the FSUID of the process owns; but this can currently partially be bypassed using atomic write ioctls in two ways: - F2FS_IOC_START_ATOMIC_REPLACE + F2FS_IOC_COMMIT_ATOMIC_WRITE can truncate an inode to size 0 - F2FS_IOC_START_ATOMIC_WRITE + F2FS_IOC_ABORT_ATOMIC_WRITE can revert changes another process concurrently made to a file Fix it by requiring FMODE_WRITE for these operations, just like for F2FS_IOC_MOVE_RANGE. Since any legitimate caller should only be using these ioctls when intending to write into the file, that seems unlikely to break anything. Fixes: 88b88a667971 ("f2fs: support atomic writes") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Reviewed-by: Chao Yu Reviewed-by: Eric Biggers Signed-off-by: Jaegeuk Kim diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index bddcb2cd945a..2c591fbc75a9 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -2131,6 +2131,9 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) loff_t isize; int ret; + if (!(filp->f_mode & FMODE_WRITE)) + return -EBADF; + if (!inode_owner_or_capable(idmap, inode)) return -EACCES; @@ -2239,6 +2242,9 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp) struct mnt_idmap *idmap = file_mnt_idmap(filp); int ret; + if (!(filp->f_mode & FMODE_WRITE)) + return -EBADF; + if (!inode_owner_or_capable(idmap, inode)) return -EACCES; @@ -2271,6 +2277,9 @@ static int f2fs_ioc_abort_atomic_write(struct file *filp) struct mnt_idmap *idmap = file_mnt_idmap(filp); int ret; + if (!(filp->f_mode & FMODE_WRITE)) + return -EBADF; + if (!inode_owner_or_capable(idmap, inode)) return -EACCES;