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* initmpfs: move rootfs code from fs/ramfs/ to init/Rob Landley2013-09-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | When the rootfs code was a wrapper around ramfs, having them in the same file made sense. Now that it can wrap another filesystem type, move it in with the init code instead. This also allows a subsequent patch to access rootfstype= command line arg. Signed-off-by: Rob Landley <rob@landley.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen Warren <swarren@nvidia.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jim Cromie <jim.cromie@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rename user_path_umountat() to user_path_mountpoint_at()Al Viro2013-09-081-1/+1
| | | | | | | ... and move the extern from linux/namei.h to fs/internal.h, along with that of vfs_path_lookup(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-09-071-6/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs pile 2 (of many) from Al Viro: "Mostly Miklos' series this time" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: constify dcache.c inlined helpers where possible fuse: drop dentry on failed revalidate fuse: clean up return in fuse_dentry_revalidate() fuse: use d_materialise_unique() sysfs: use check_submounts_and_drop() nfs: use check_submounts_and_drop() gfs2: use check_submounts_and_drop() afs: use check_submounts_and_drop() vfs: check unlinked ancestors before mount vfs: check submounts and drop atomically vfs: add d_walk() vfs: restructure d_genocide()
| * vfs: check unlinked ancestors before mountMiklos Szeredi2013-09-051-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We check submounts before doing d_drop() on a non-empty directory dentry in NFS (have_submounts()), but we do not exclude a racing mount. Nor do we prevent mounts to be added to the disconnected subtree using relative paths after the d_drop(). This patch fixes these issues by checking for unlinked (unhashed, non-root) ancestors before proceeding with the mount. This is done with rename seqlock taken for write and with ->d_lock grabbed on each ancestor in turn, including our dentry itself. This ensures that the only one of check_submounts_and_drop() or has_unlinked_ancestor() can succeed. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-linus' of ↵Linus Torvalds2013-09-071-26/+95
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace changes from Eric Biederman: "This is an assorted mishmash of small cleanups, enhancements and bug fixes. The major theme is user namespace mount restrictions. nsown_capable is killed as it encourages not thinking about details that need to be considered. A very hard to hit pid namespace exiting bug was finally tracked and fixed. A couple of cleanups to the basic namespace infrastructure. Finally there is an enhancement that makes per user namespace capabilities usable as capabilities, and an enhancement that allows the per userns root to nice other processes in the user namespace" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Kill nsown_capable it makes the wrong thing easy capabilities: allow nice if we are privileged pidns: Don't have unshare(CLONE_NEWPID) imply CLONE_THREAD userns: Allow PR_CAPBSET_DROP in a user namespace. namespaces: Simplify copy_namespaces so it is clear what is going on. pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeup sysfs: Restrict mounting sysfs userns: Better restrictions on when proc and sysfs can be mounted vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces kernel/nsproxy.c: Improving a snippet of code. proc: Restrict mounting the proc filesystem vfs: Lock in place mounts from more privileged users
| * userns: Kill nsown_capable it makes the wrong thing easyEric W. Biederman2013-08-301-2/+2
| | | | | | | | | | | | | | | | | | | | nsown_capable is a special case of ns_capable essentially for just CAP_SETUID and CAP_SETGID. For the existing users it doesn't noticably simplify things and from the suggested patches I have seen it encourages people to do the wrong thing. So remove nsown_capable. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Better restrictions on when proc and sysfs can be mountedEric W. Biederman2013-08-261-12/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rely on the fact that another flavor of the filesystem is already mounted and do not rely on state in the user namespace. Verify that the mounted filesystem is not covered in any significant way. I would love to verify that the previously mounted filesystem has no mounts on top but there are at least the directories /proc/sys/fs/binfmt_misc and /sys/fs/cgroup/ that exist explicitly for other filesystems to mount on top of. Refactor the test into a function named fs_fully_visible and call that function from the mount routines of proc and sysfs. This makes this test local to the filesystems involved and the results current of when the mounts take place, removing a weird threading of the user namespace, the mount namespace and the filesystems themselves. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespacesEric W. Biederman2013-08-261-12/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't copy bind mounts of /proc/<pid>/ns/mnt between namespaces. These files hold references to a mount namespace and copying them between namespaces could result in a reference counting loop. The current mnt_ns_loop test prevents loops on the assumption that mounts don't cross between namespaces. Unfortunately unsharing a mount namespace and shared substrees can both cause mounts to propogate between mount namespaces. Add two flags CL_COPY_UNBINDABLE and CL_COPY_MNT_NS_FILE are added to control this behavior, and CL_COPY_ALL is redefined as both of them. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * vfs: Lock in place mounts from more privileged usersEric W. Biederman2013-07-241-0/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creating a less privileged mount namespace or propogating mounts from a more privileged to a less privileged mount namespace lock the submounts so they may not be unmounted individually in the child mount namespace revealing what is under them. This enforces the reasonable expectation that it is not possible to see under a mount point. Most of the time mounts are on empty directories and revealing that does not matter, however I have seen an occassionaly sloppy configuration where there were interesting things concealed under a mount point that probably should not be revealed. Expirable submounts are not locked because they will eventually unmount automatically so whatever is under them already needs to be safe for unprivileged users to access. From a practical standpoint these restrictions do not appear to be significant for unprivileged users of the mount namespace. Recursive bind mounts and pivot_root continues to work, and mounts that are created in a mount namespace may be unmounted there. All of which means that the common idiom of keeping a directory of interesting files and using pivot_root to throw everything else away continues to work just fine. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | vfs: allow umount to handle mountpoints without revalidating themJeff Layton2013-09-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Christopher reported a regression where he was unable to unmount a NFS filesystem where the root had gone stale. The problem is that d_revalidate handles the root of the filesystem differently from other dentries, but d_weak_revalidate does not. We could simply fix this by making d_weak_revalidate return success on IS_ROOT dentries, but there are cases where we do want to revalidate the root of the fs. A umount is really a special case. We generally aren't interested in anything but the dentry and vfsmount that's attached at that point. If the inode turns out to be stale we just don't care since the intent is to stop using it anyway. Try to handle this situation better by treating umount as a special case in the lookup code. Have it resolve the parent using normal means, and then do a lookup of the final dentry without revalidating it. In most cases, the final lookup will come out of the dcache, but the case where there's a trailing symlink or !LAST_NORM entry on the end complicates things a bit. Cc: Neil Brown <neilb@suse.de> Reported-by: Christopher T Vogan <cvogan@us.ibm.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | VFS: collect_mounts() should return an ERR_PTRDan Carpenter2013-08-241-1/+1
|/ | | | | | | | | | | | | This should actually be returning an ERR_PTR on error instead of NULL. That was how it was designed and all the callers expect it. [AV: actually, that's what "VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errors" missed - originally collect_mounts() was expected to return NULL on failure] Cc: <stable@vger.kernel.org> # 3.10+ Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* create_mnt_ns: unidiomatic use of list_add()Al Viro2013-05-041-1/+1
| | | | | | | | | | while list_add(A, B) and list_add(B, A) are equivalent when both A and B are guaranteed to be empty, the usual idiom is list_add(what, where), not the other way round... Not a bug per se, but only by accident and it makes RTFS harder for no good reason. Spotted-by: Rajat Sharma <fs.rajat@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* do_mount(): fix a leak introduced in 3.9 ("mount: consolidate permission ↵Al Viro2013-05-041-3/+2
| | | | | | | | checks") Cc: stable@vger.kernel.org Bisected-by: Michael Leun <lkml20130126@newton.leun.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-05-011-146/+195
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...
| * proc: Split the namespace stuff out into linux/proc_ns.hDavid Howells2013-05-011-3/+3
| | | | | | | | | | | | | | | | | | | | Split the proc namespace stuff out into linux/proc_ns.h. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fold release_mounts() into namespace_unlock()Al Viro2013-04-091-23/+30
| | | | | | | | | | | | | | | | | | ... and provide namespace_lock() as a trivial wrapper; switch to those two consistently. Result is patterned after rtnl_lock/rtnl_unlock pair. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * switch unlock_mount() to namespace_unlock(), convert all umount_tree() callersAl Viro2013-04-091-19/+14
| | | | | | | | | | | | | | which allows to kill the last argument of umount_tree() and make release_mounts() static. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * more conversions to namespace_unlock()Al Viro2013-04-091-14/+6
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * get rid of the second argument of shrink_submounts()Al Viro2013-04-091-4/+4
| | | | | | | | | | | | ... it's always &unmounted. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * saner umount_tree()/release_mounts(), part 1Al Viro2013-04-091-4/+13
| | | | | | | | | | | | | | | | | | global list of release_mounts() fodder, protected by namespace_sem; eventually, all umount_tree() callers will use it as kill list. Helper picking the contents of that list, releasing namespace_sem and doing release_mounts() on what it got. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * get rid of full-hash scan on detaching vfsmountsAl Viro2013-04-091-92/+137
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-linus' of ↵Linus Torvalds2013-04-091-1/+1
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro: "A nasty bug in fs/namespace.c caught by Andrey + a couple of less serious unpleasantness - ecryptfs misc device playing hopeless games with try_module_get() and palinfo procfs support being... not quite correctly done, to be polite." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mnt: release locks on error path in do_loopback palinfo fixes procfs: add proc_remove_subtree() ecryptfs: close rmmod race
| * mnt: release locks on error path in do_loopbackAndrey Vagin2013-04-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | do_loopback calls lock_mount(path) and forget to unlock_mount if clone_mnt or copy_mnt fails. [ 77.661566] ================================================ [ 77.662939] [ BUG: lock held when returning to user space! ] [ 77.664104] 3.9.0-rc5+ #17 Not tainted [ 77.664982] ------------------------------------------------ [ 77.666488] mount/514 is leaving the kernel with locks still held! [ 77.668027] 2 locks held by mount/514: [ 77.668817] #0: (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff811cca22>] lock_mount+0x32/0xe0 [ 77.671755] #1: (&namespace_sem){+++++.}, at: [<ffffffff811cca3a>] lock_mount+0x4a/0xe0 Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | userns: Restrict when proc and sysfs can be mountedEric W. Biederman2013-03-271-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Only allow unprivileged mounts of proc and sysfs if they are already mounted when the user namespace is created. proc and sysfs are interesting because they have content that is per namespace, and so fresh mounts are needed when new namespaces are created while at the same time proc and sysfs have content that is shared between every instance. Respect the policy of who may see the shared content of proc and sysfs by only allowing new mounts if there was an existing mount at the time the user namespace was created. In practice there are only two interesting cases: proc and sysfs are mounted at their usual places, proc and sysfs are not mounted at all (some form of mount namespace jail). Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | vfs: Carefully propogate mounts across user namespacesEric W. Biederman2013-03-271-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As a matter of policy MNT_READONLY should not be changable if the original mounter had more privileges than creator of the mount namespace. Add the flag CL_UNPRIVILEGED to note when we are copying a mount from a mount namespace that requires more privileges to a mount namespace that requires fewer privileges. When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT if any of the mnt flags that should never be changed are set. This protects both mount propagation and the initial creation of a less privileged mount namespace. Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | vfs: Add a mount flag to lock read only bind mountsEric W. Biederman2013-03-271-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | userns: Don't allow creation if the user is chrootedEric W. Biederman2013-03-271-0/+24
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Guarantee that the policy of which files may be access that is established by setting the root directory will not be violated by user namespaces by verifying that the root directory points to the root of the mount namespace at the time of user namespace creation. Changing the root is a privileged operation, and as a matter of policy it serves to limit unprivileged processes to files below the current root directory. For reasons of simplicity and comprehensibility the privilege to change the root directory is gated solely on the CAP_SYS_CHROOT capability in the user namespace. Therefore when creating a user namespace we must ensure that the policy of which files may be access can not be violated by changing the root directory. Anyone who runs a processes in a chroot and would like to use user namespace can setup the same view of filesystems with a mount namespace instead. With this result that this is not a practical limitation for using user namespaces. Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* new helper: file_inode(file)Al Viro2013-02-221-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mount: consolidate permission checksAl Viro2013-02-221-33/+7
| | | | | | ... and ask for global CAP_SYS_ADMIN only for superblock-level remounts Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* get rid of unprotected dereferencing of mnt->mnt_nsAl Viro2013-02-221-12/+17
| | | | | | | | | | It's safe only under namespace_sem or vfsmount_lock; all places in fs/namespace.c that want mnt->mnt_ns->user_ns actually want to use current->nsproxy->mnt_ns->user_ns (note the calls of check_mnt() in there). Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs, freeze: use ACCESS_ONCE() to guard access to ->mnt_flagsMiao Xie2012-12-201-1/+1
| | | | | | | | The compiler may optimize the while loop and make the check just be done once, so we should use ACCESS_ONCE() to guard access to ->mnt_flags Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* userns: Require CAP_SYS_ADMIN for most uses of setns.Eric W. Biederman2012-12-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andy Lutomirski <luto@amacapital.net> found a nasty little bug in the permissions of setns. With unprivileged user namespaces it became possible to create new namespaces without privilege. However the setns calls were relaxed to only require CAP_SYS_ADMIN in the user nameapce of the targed namespace. Which made the following nasty sequence possible. pid = clone(CLONE_NEWUSER | CLONE_NEWNS); if (pid == 0) { /* child */ system("mount --bind /home/me/passwd /etc/passwd"); } else if (pid != 0) { /* parent */ char path[PATH_MAX]; snprintf(path, sizeof(path), "/proc/%u/ns/mnt"); fd = open(path, O_RDONLY); setns(fd, 0); system("su -"); } Prevent this possibility by requiring CAP_SYS_ADMIN in the current user namespace when joing all but the user namespace. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* proc: Usable inode numbers for the namespace file descriptors.Eric W. Biederman2012-11-201-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* userns: fix return value on mntns_install() failureZhao Hongjiang2012-11-191-1/+1
| | | | | | | Change return value from -EINVAL to -EPERM when the permission check fails. Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* vfs: Allow unprivileged manipulation of the mount namespace.Eric W. Biederman2012-11-191-26/+43
| | | | | | | | | | | | | | | | - Add a filesystem flag to mark filesystems that are safe to mount as an unprivileged user. - Add a filesystem flag to mark filesystems that don't need MNT_NODEV when mounted by an unprivileged user. - Relax the permission checks to allow unprivileged users that have CAP_SYS_ADMIN permissions in the user namespace referred to by the current mount namespace to be allowed to mount, unmount, and move filesystems. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* vfs: Only support slave subtrees across different user namespacesEric W. Biederman2012-11-191-3/+8
| | | | | | | | | | | | Sharing mount subtress with mount namespaces created by unprivileged users allows unprivileged mounts created by unprivileged users to propagate to mount namespaces controlled by privileged users. Prevent nasty consequences by changing shared subtrees to slave subtress when an unprivileged users creates a new mount namespace. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* vfs: Add a user namespace reference from struct mnt_namespaceEric W. Biederman2012-11-191-8/+16
| | | | | | | This will allow for support for unprivileged mounts in a new user namespace. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* vfs: Add setns support for the mount namespaceEric W. Biederman2012-11-191-0/+95
| | | | | | | | | | | | | | | | | | | | | | | | | setns support for the mount namespace is a little tricky as an arbitrary decision must be made about what to set fs->root and fs->pwd to, as there is no expectation of a relationship between the two mount namespaces. Therefore I arbitrarily find the root mount point, and follow every mount on top of it to find the top of the mount stack. Then I set fs->root and fs->pwd to that location. The topmost root of the mount stack seems like a reasonable place to be. Bind mount support for the mount namespace inodes has the possibility of creating circular dependencies between mount namespaces. Circular dependencies can result in loops that prevent mount namespaces from every being freed. I avoid creating those circular dependencies by adding a sequence number to the mount namespace and require all bind mounts be of a younger mount namespace into an older mount namespace. Add a helper function proc_ns_inode so it is possible to detect when we are attempting to bind mound a namespace inode. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* vfs: define struct filename and have getname() return itJeff Layton2012-10-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | getname() is intended to copy pathname strings from userspace into a kernel buffer. The result is just a string in kernel space. It would however be quite helpful to be able to attach some ancillary info to the string. For instance, we could attach some audit-related info to reduce the amount of audit-related processing needed. When auditing is enabled, we could also call getname() on the string more than once and not need to recopy it from userspace. This patchset converts the getname()/putname() interfaces to return a struct instead of a string. For now, the struct just tracks the string in kernel space and the original userland pointer for it. Later, we'll add other information to the struct as it becomes convenient. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* consitify do_mount() argumentsAl Viro2012-10-111-6/+6
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* do_add_mount()/umount -l racesAl Viro2012-09-221-2/+8
| | | | | | | | | | | | | | normally we deal with lock_mount()/umount races by checking that mountpoint to be is still in our namespace after lock_mount() has been done. However, do_add_mount() skips that check when called with MNT_SHRINKABLE in flags (i.e. from finish_automount()). The reason is that ->mnt_ns may be a temporary namespace created exactly to contain automounts a-la NFS4 referral handling. It's not the namespace of the caller, though, so check_mnt() would fail here. We still need to check that ->mnt_ns is non-NULL in that case, though. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: Add freezing handling to mnt_want_write() / mnt_drop_write()Jan Kara2012-07-311-20/+77
| | | | | | | | | | | | | | | | Most of places where we want freeze protection coincides with the places where we also have remount-ro protection. So make mnt_want_write() and mnt_drop_write() (and their _file alternative) prevent freezing as well. For the few cases that are really interested only in remount-ro protection provide new function variants. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa <kamal@canonical.com> Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com> Tested-by: Dann Frazier <dann.frazier@canonical.com> Tested-by: Massimo Morana <massimo.morana@canonical.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: Comment mount following codeDavid Howells2012-07-141-2/+14
| | | | | | | | | Add comments describing what the directions "up" and "down" mean and ref count handling to the VFS mount following family of functions. Signed-off-by: Valerie Aurora <vaurora@redhat.com> (Original author) Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errorsDavid Howells2012-07-141-55/+65
| | | | | | | | | | | | | | | | | | copy_tree() can theoretically fail in a case other than ENOMEM, but always returns NULL which is interpreted by callers as -ENOMEM. Change it to return an explicit error. Also change clone_mnt() for consistency and because union mounts will add new error cases. Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix. [AV: folded braino fix by Dan Carpenter] Original-author: Valerie Aurora <vaurora@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Valerie Aurora <valerie.aurora@gmail.com> Cc: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* get rid of magic in proc_namespace.cAl Viro2012-07-141-3/+3
| | | | | | | | don't rely on proc_mounts->m being the first field; container_of() is there for purpose. No need to bother with ->private, while we are at it - the same container_of will do nicely. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* get rid of ->mnt_longtermAl Viro2012-07-141-46/+7
| | | | | | | | | it's enough to set ->mnt_ns of internal vfsmounts to something distinct from all struct mnt_namespace out there; then we can just use the check for ->mnt_ns != NULL in the fast path of mntput_no_expire() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: umount_tree() might be called on subtree that had never made itAl Viro2012-05-301-1/+2
| | | | | | | | | | __mnt_make_shortterm() in there undoes the effect of __mnt_make_longterm() we'd done back when we set ->mnt_ns non-NULL; it should not be done to vfsmounts that had never gone through commit_tree() and friends. Kudos to lczerner for catching that one... Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* brlocks/lglocks: API cleanupsAndi Kleen2012-05-291-69/+70
| | | | | | | | | | | | | | | | | | | | | lglocks and brlocks are currently generated with some complicated macros in lglock.h. But there's no reason to not just use common utility functions and put all the data into a common data structure. In preparation, this patch changes the API to look more like normal function calls with pointers, not magic macros. The patch is rather large because I move over all users in one go to keep it bisectable. This impacts the VFS somewhat in terms of lines changed. But no actual behaviour change. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-01-081-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits) Kconfig: acpi: Fix typo in comment. misc latin1 to utf8 conversions devres: Fix a typo in devm_kfree comment btrfs: free-space-cache.c: remove extra semicolon. fat: Spelling s/obsolate/obsolete/g SCSI, pmcraid: Fix spelling error in a pmcraid_err() call tools/power turbostat: update fields in manpage mac80211: drop spelling fix types.h: fix comment spelling for 'architectures' typo fixes: aera -> area, exntension -> extension devices.txt: Fix typo of 'VMware'. sis900: Fix enum typo 'sis900_rx_bufer_status' decompress_bunzip2: remove invalid vi modeline treewide: Fix comment and string typo 'bufer' hyper-v: Update MAINTAINERS treewide: Fix typos in various parts of the kernel, and fix some comments. clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR gpio: Kconfig: drop unknown symbol 'CS5535_GPIO' leds: Kconfig: Fix typo 'D2NET_V2' sound: Kconfig: drop unknown symbol ARCH_CLPS7500 ... Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new kconfig additions, close to removed commented-out old ones)
| * Merge branch 'master' into for-nextJiri Kosina2011-11-131-0/+1
| |\ | | | | | | | | | | | | Sync with Linus tree to have 157550ff ("mtd: add GPMI-NAND driver in the config and Makefile") as I have patch depending on that one.
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