From mboxrd@z Thu Jan 1 00:00:00 1970 From: Seth Forshee Subject: [PATCH RESEND v2 11/18] fs: Ensure the mounter of a filesystem is privileged towards its inodes Date: Mon, 4 Jan 2016 12:03:50 -0600 Message-ID: <1451930639-94331-12-git-send-email-seth.forshee@canonical.com> References: <1451930639-94331-1-git-send-email-seth.forshee@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1451930639-94331-1-git-send-email-seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: fuse-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: "Eric W. Biederman" , Alexander Viro , Serge Hallyn Cc: linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Seth Forshee , dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Miklos Szeredi , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Austin S Hemmelgarn , linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, selinux-+05T5uksL2qpZYMLLGbcSA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-raid.ids The mounter of a filesystem should be privileged towards the inodes of that filesystem. Extend the checks in inode_owner_or_capable() and capable_wrt_inode_uidgid() to permit access by users priviliged in the user namespace of the inode's superblock. Signed-off-by: Seth Forshee Acked-by: Serge Hallyn --- fs/inode.c | 3 +++ kernel/capability.c | 13 +++++++++---- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 1be5f9003eb3..01c036fe1950 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1962,6 +1962,9 @@ bool inode_owner_or_capable(const struct inode *inode) ns = current_user_ns(); if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) return true; + + if (ns_capable(inode->i_sb->s_user_ns, CAP_FOWNER)) + return true; return false; } EXPORT_SYMBOL(inode_owner_or_capable); diff --git a/kernel/capability.c b/kernel/capability.c index 45432b54d5c6..5137a38a5670 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -437,13 +437,18 @@ EXPORT_SYMBOL(file_ns_capable); * * Return true if the current task has the given capability targeted at * its own user namespace and that the given inode's uid and gid are - * mapped into the current user namespace. + * mapped into the current user namespace, or if the current task has + * the capability towards the user namespace of the inode's superblock. */ bool capable_wrt_inode_uidgid(const struct inode *inode, int cap) { - struct user_namespace *ns = current_user_ns(); + struct user_namespace *ns; - return ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && - kgid_has_mapping(ns, inode->i_gid); + ns = current_user_ns(); + if (ns_capable(ns, cap) && kuid_has_mapping(ns, inode->i_uid) && + kgid_has_mapping(ns, inode->i_gid)) + return true; + + return ns_capable(inode->i_sb->s_user_ns, cap); } EXPORT_SYMBOL(capable_wrt_inode_uidgid); -- 1.9.1 ------------------------------------------------------------------------------