From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46694 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752176AbdLFRAM (ORCPT ); Wed, 6 Dec 2017 12:00:12 -0500 Subject: Patch "libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount" has been added to the 4.9-stable tree To: ebiederm@xmission.com, alexander.levin@verizon.com, aranea@aixah.de, gregkh@linuxfoundation.org, viro@ZenIV.linux.org.uk Cc: , From: Date: Wed, 06 Dec 2017 17:59:36 +0100 Message-ID: <1512579576501@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: libfs-modify-mount_pseudo_xattr-to-be-clear-it-is-not-a-userspace-mount.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed Dec 6 17:39:55 CET 2017 From: "Eric W. Biederman" Date: Wed, 4 Jan 2017 17:37:27 +1300 Subject: libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount From: "Eric W. Biederman" [ Upstream commit 75422726b0f717d67db3283c2eb5bc14fa2619c5 ] Add MS_KERNMOUNT to the flags that are passed. Use sget_userns and force &init_user_ns instead of calling sget so that even if called from a weird context the internal filesystem will be considered to be in the intial user namespace. Luis Ressel reported that the the failure to pass MS_KERNMOUNT into mount_pseudo broke his in development graphics driver that uses the generic drm infrastructure. I am not certain the deriver was bug free in it's usage of that infrastructure but since mount_pseudo_xattr can never be triggered by userspace it is clearer and less error prone, and less problematic for the code to be explicit. Reported-by: Luis Ressel Tested-by: Luis Ressel Acked-by: Al Viro Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/libfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/libfs.c +++ b/fs/libfs.c @@ -245,7 +245,8 @@ struct dentry *mount_pseudo_xattr(struct struct inode *root; struct qstr d_name = QSTR_INIT(name, strlen(name)); - s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); + s = sget_userns(fs_type, NULL, set_anon_super, MS_KERNMOUNT|MS_NOUSER, + &init_user_ns, NULL); if (IS_ERR(s)) return ERR_CAST(s); Patches currently in stable-queue which might be from ebiederm@xmission.com are queue-4.9/libfs-modify-mount_pseudo_xattr-to-be-clear-it-is-not-a-userspace-mount.patch