Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936525Ab3DKVIa (ORCPT ); Thu, 11 Apr 2013 17:08:30 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:9226 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935679Ab3DKUtL (ORCPT ); Thu, 11 Apr 2013 16:49:11 -0400 X-Authority-Analysis: v=2.0 cv=F+XVh9dN c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=3BRh_vqWWtsA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=faD4RiZyQDsA:10 a=PtDNVHqPAAAA:8 a=VwQbUJbxAAAA:8 a=DfNHnWVPAAAA:8 a=YWODpuaXHh98yajew5wA:9 a=wYE_KDyynt4A:10 a=lBRciGGoxdUA:10 a=jeBq3FmKZ4MA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-Id: <20130411202604.352966800@goodmis.org> User-Agent: quilt/0.60-1 Date: Thu, 11 Apr 2013 16:26:53 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Serge Hallyn , "Eric W. Biederman" Subject: [ 110/171 ] vfs: Add a mount flag to lock read only bind mounts References: <20130411202503.783159048@goodmis.org> Content-Disposition: inline; filename=0110-vfs-Add-a-mount-flag-to-lock-read-only-bind-mounts.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1880 Lines: 62 3.6.11.2 stable review patch. If anyone has any objections, please let me know. ------------------ From: "Eric W. Biederman" [ Upstream commit 90563b198e4c6674c63672fae1923da467215f45 ] When a read-only bind mount is copied from mount namespace in a higher privileged user namespace to a mount namespace in a lesser privileged user namespace, it should not be possible to remove the the read-only restriction. Add a MNT_LOCK_READONLY mount flag to indicate that a mount must remain read-only. CC: stable@vger.kernel.org Acked-by: Serge Hallyn Signed-off-by: "Eric W. Biederman" Signed-off-by: Steven Rostedt --- fs/namespace.c | 3 +++ include/linux/mount.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/fs/namespace.c b/fs/namespace.c index c48b0d3..48c7edb 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1702,6 +1702,9 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags) if (readonly_request == __mnt_is_readonly(mnt)) return 0; + if (mnt->mnt_flags & MNT_LOCK_READONLY) + return -EPERM; + if (readonly_request) error = mnt_make_readonly(real_mount(mnt)); else diff --git a/include/linux/mount.h b/include/linux/mount.h index d7029f4..73005f9 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -47,6 +47,8 @@ struct mnt_namespace; #define MNT_INTERNAL 0x4000 +#define MNT_LOCK_READONLY 0x400000 + struct vfsmount { struct dentry *mnt_root; /* root of the mounted tree */ struct super_block *mnt_sb; /* pointer to superblock */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/