From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354AbdKVWZK (ORCPT ); Wed, 22 Nov 2017 17:25:10 -0500 Received: from omzsmtpe03.verizonbusiness.com ([199.249.25.208]:10338 "EHLO omzsmtpe03.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752306AbdKVWZF (ORCPT ); Wed, 22 Nov 2017 17:25:05 -0500 From: alexander.levin@verizon.com Cc: "Eric W. Biederman" , alexander.levin@verizon.com X-Host: surveyor.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 16/54] libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount Thread-Topic: [PATCH AUTOSEL for 4.9 16/54] libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount Thread-Index: AQHTY+CVzepNmLWXa0+e+r7o4BnxYw== Date: Wed, 22 Nov 2017 22:23:55 +0000 Message-ID: <20171122222344.19782-16-alexander.levin@verizon.com> References: <20171122222344.19782-1-alexander.levin@verizon.com> In-Reply-To: <20171122222344.19782-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMNGTca002004 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 --- fs/libfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/libfs.c b/fs/libfs.c index 48826d4da189..9588780ad43e 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -245,7 +245,8 @@ struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name, 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); -- 2.11.0