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* autofs4 - fix device ioctl mount lookupIan Kent2013-09-08
| | | | | | | | | | | | | | | | | When reconnecting to automounts at startup an autofs ioctl is used to find the device and inode of existing mounts so they can be used to open a file descriptor of possibly covered mounts. At this time the the caller might not yet "own" the mount so it can trigger calling ->d_automount(). This causes automount to hang when trying to reconnect to direct or offset mount types. Consequently kern_path() can't be used but kern_path_mountpoint() can be. Signed-off-by: Ian Kent <raven@themaw.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* introduce kern_path_mountpoint()Al Viro2013-09-08
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* rename user_path_umountat() to user_path_mountpoint_at()Al Viro2013-09-08
| | | | | | | ... 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>
* take unlazy_walk() into umount_lookup_last()Al Viro2013-09-08
| | | | | | ... and massage it a bit to reduce nesting Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.cAl Viro2013-09-07
| | | | | | | | | kernel/cgroup.c is the only place in the tree that relies on eventfd.h pulling file.h; move that include there. Switch from eventfd_fget()/fput() to fdget()/fdput(), while we are at it - eventfd_ctx_fileget() will fail on non-eventfd descriptors just fine, no need to do that check twice... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* prune_super(): sb->s_op is never NULLAl Viro2013-09-07
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* exportfs: don't assume that ->iterate() won't feed us too long entriesAl Viro2013-09-07
| | | | | | | | On some filesystems it's impossible even with fs corruption, but we'd better not rely on that, what with memcpy() into on-stack array we are doing there. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* afs: get rid of redundant ->d_name.len checksAl Viro2013-09-07
| | | | | | | | | No dentry can get to directory modification methods without having passed either ->lookup() or ->atomic_open(); if name is rejected by those two (or by ->d_hash()) with an error, it won't be seen by anything else. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* lockref: add ability to mark lockrefs "dead"Linus Torvalds2013-09-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only actual current lockref user (dcache) uses zero reference counts even for perfectly live dentries, because it's a cache: there may not be any users, but that doesn't mean that we want to throw away the dentry. At the same time, the dentry cache does have a notion of a truly "dead" dentry that we must not even increment the reference count of, because we have pruned it and it is not valid. Currently that distinction is not visible in the lockref itself, and the dentry cache validation uses "lockref_get_or_lock()" to either get a new reference to a dentry that already had existing references (and thus cannot be dead), or get the dentry lock so that we can then verify the dentry and increment the reference count under the lock if that verification was successful. That's all somewhat complicated. This adds the concept of being "dead" to the lockref itself, by simply using a count that is negative. This allows a usage scenario where we can increment the refcount of a dentry without having to validate it, and pushing the special "we killed it" case into the lockref code. The dentry code itself doesn't actually use this yet, and it's probably too late in the merge window to do that code (the dentry_kill() code with its "should I decrement the count" logic really is pretty complex code), but let's introduce the concept at the lockref level now. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockref: fix docbook argument namesLinus Torvalds2013-09-07
| | | | | | | | The code got rewritten, but the comments got copied as-is from older versions, and as a result the argument name in the comment didn't actually match the code any more. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-09-07
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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()
| * constify dcache.c inlined helpers where possibleAl Viro2013-09-05
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fuse: drop dentry on failed revalidateAnand Avati2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | Drop a subtree when we find that it has moved or been delated. This can be done as long as there are no submounts under this location. If the directory was moved and we come across the same directory in a future lookup it will be reconnected by d_materialise_unique(). Signed-off-by: Anand Avati <avati@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fuse: clean up return in fuse_dentry_revalidate()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | On errors unrelated to the filesystem's state (ENOMEM, ENOTCONN) return the error itself from ->d_revalidate() insted of returning zero (invalid). Also make a common label for invalidating the dentry. This will be used by the next patch. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fuse: use d_materialise_unique()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use d_materialise_unique() instead of d_splice_alias(). This allows dentry subtrees to be moved to a new place if there moved, even if something is referencing a dentry in the subtree (open fd, cwd, etc..). This will also allow us to drop a subtree if it is found to be replaced by something else. In this case the disconnected subtree can later be reconnected to its new location. d_materialise_unique() ensures that a directory entry only ever has one alias. We keep fc->inst_mutex around the calls for d_materialise_unique() on directories to prevent a race with mkdir "stealing" the inode. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * sysfs: use check_submounts_and_drop()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Do have_submounts(), shrink_dcache_parent() and d_drop() atomically. check_submounts_and_drop() can deal with negative dentries and non-directories as well. Non-directories can also be mounted on. And just like directories we don't want these to disappear with invalidation. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * nfs: use check_submounts_and_drop()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Do have_submounts(), shrink_dcache_parent() and d_drop() atomically. check_submounts_and_drop() can deal with negative dentries and non-directories as well. Non-directories can also be mounted on. And just like directories we don't want these to disappear with invalidation. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * gfs2: use check_submounts_and_drop()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Do have_submounts(), shrink_dcache_parent() and d_drop() atomically. check_submounts_and_drop() can deal with negative dentries and non-directories as well. Non-directories can also be mounted on. And just like directories we don't want these to disappear with invalidation. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * afs: use check_submounts_and_drop()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | Do have_submounts(), shrink_dcache_parent() and d_drop() atomically. check_submounts_and_drop() can deal with negative dentries as well. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: check unlinked ancestors before mountMiklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * vfs: check submounts and drop atomicallyMiklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. Process A: have_submounts() -> returns false Process B: mount() -> success Process A: d_drop() This patch prepares the ground for the fix by doing the following operations all under the same rename lock: have_submounts() shrink_dcache_parent() d_drop() This is actually an optimization since have_submounts() and shrink_dcache_parent() both traverse the same dentry tree separately. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: David Howells <dhowells@redhat.com> CC: Steven Whitehouse <swhiteho@redhat.com> CC: Trond Myklebust <Trond.Myklebust@netapp.com> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: add d_walk()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | This one replaces three instances open coded tree walking (have_submounts, select_parent, d_genocide) with a common helper. In addition to slightly reducing the kernel size, this simplifies the callers and makes them less bug prone. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: restructure d_genocide()Miklos Szeredi2013-09-05
| | | | | | | | | | | | | | | | | | | | | | It shouldn't matter when we decrement the refcount during the walk as long as we do it exactly once. Restructure d_genocide() to do the killing on entering the dentry instead of when leaving it. This helps creating a common helper for tree walking. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-linus' of ↵Linus Torvalds2013-09-07
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. Biederman2013-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | capabilities: allow nice if we are privilegedSerge Hallyn2013-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We allow task A to change B's nice level if it has a supserset of B's privileges, or of it has CAP_SYS_NICE. Also allow it if A has CAP_SYS_NICE with respect to B - meaning it is root in the same namespace, or it created B's namespace. Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | pidns: Don't have unshare(CLONE_NEWPID) imply CLONE_THREADEric W. Biederman2013-08-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I goofed when I made unshare(CLONE_NEWPID) only work in a single-threaded process. There is no need for that requirement and in fact I analyzied things right for setns. The hard requirement is for tasks that share a VM to all be in the pid namespace and we properly prevent that in do_fork. Just to be certain I took a look through do_wait and forget_original_parent and there are no cases that make it any harder for children to be in the multiple pid namespaces than it is for children to be in the same pid namespace. I also performed a check to see if there were in uses of task->nsproxy_pid_ns I was not familiar with, but it is only used when allocating a new pid for a new task, and in checks to prevent craziness from happening. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | userns: Allow PR_CAPBSET_DROP in a user namespace.Eric W. Biederman2013-08-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As the capabilites and capability bounding set are per user namespace properties it is safe to allow changing them with just CAP_SETPCAP permission in the user namespace. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Tested-by: Richard Weinberger <richard@nod.at> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | namespaces: Simplify copy_namespaces so it is clear what is going on.Eric W. Biederman2013-08-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the test for the impossible case where tsk->nsproxy == NULL. Fork will never be called with tsk->nsproxy == NULL. Only call get_nsproxy when we don't need to generate a new_nsproxy, and mark the case where we don't generate a new nsproxy as likely. Remove the code to drop an unnecessarily acquired nsproxy value. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | pidns: Fix hang in zap_pid_ns_processes by sending a potentially extra wakeupEric W. Biederman2013-08-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Serge Hallyn <serge.hallyn@ubuntu.com> writes: > Since commit af4b8a83add95ef40716401395b44a1b579965f4 it's been > possible to get into a situation where a pidns reaper is > <defunct>, reparented to host pid 1, but never reaped. How to > reproduce this is documented at > > https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1168526 > (and see > https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1168526/comments/13) > In short, run repeated starts of a container whose init is > > Process.exit(0); > > sysrq-t when such a task is playing zombie shows: > > [ 131.132978] init x ffff88011fc14580 0 2084 2039 0x00000000 > [ 131.132978] ffff880116e89ea8 0000000000000002 ffff880116e89fd8 0000000000014580 > [ 131.132978] ffff880116e89fd8 0000000000014580 ffff8801172a0000 ffff8801172a0000 > [ 131.132978] ffff8801172a0630 ffff88011729fff0 ffff880116e14650 ffff88011729fff0 > [ 131.132978] Call Trace: > [ 131.132978] [<ffffffff816f6159>] schedule+0x29/0x70 > [ 131.132978] [<ffffffff81064591>] do_exit+0x6e1/0xa40 > [ 131.132978] [<ffffffff81071eae>] ? signal_wake_up_state+0x1e/0x30 > [ 131.132978] [<ffffffff8106496f>] do_group_exit+0x3f/0xa0 > [ 131.132978] [<ffffffff810649e4>] SyS_exit_group+0x14/0x20 > [ 131.132978] [<ffffffff8170102f>] tracesys+0xe1/0xe6 > > Further debugging showed that every time this happened, zap_pid_ns_processes() > started with nr_hashed being 3, while we were expecting it to drop to 2. > Any time it didn't happen, nr_hashed was 1 or 2. So the reaper was > waiting for nr_hashed to become 2, but free_pid() only wakes the reaper > if nr_hashed hits 1. The issue is that when the task group leader of an init process exits before other tasks of the init process when the init process finally exits it will be a secondary task sleeping in zap_pid_ns_processes and waiting to wake up when the number of hashed pids drops to two. This case waits forever as free_pid only sends a wake up when the number of hashed pids drops to 1. To correct this the simple strategy of sending a possibly unncessary wake up when the number of hashed pids drops to 2 is adopted. Sending one extraneous wake up is relatively harmless, at worst we waste a little cpu time in the rare case when a pid namespace appropaches exiting. We can detect the case when the pid namespace drops to just two pids hashed race free in free_pid. Dereferencing pid_ns->child_reaper with the pidmap_lock held is safe without out the tasklist_lock because it is guaranteed that the detach_pid will be called on the child_reaper before it is freed and detach_pid calls __change_pid which calls free_pid which takes the pidmap_lock. __change_pid only calls free_pid if this is the last use of the pid. For a thread that is not the thread group leader the threads pid will only ever have one user because a threads pid is not allowed to be the pid of a process, of a process group or a session. For a thread that is a thread group leader all of the other threads of that process will be reaped before it is allowed for the thread group leader to be reaped ensuring there will only be one user of the threads pid as a process pid. Furthermore because the thread is the init process of a pid namespace all of the other processes in the pid namespace will have also been already freed leading to the fact that the pid will not be used as a session pid or a process group pid for any other running process. CC: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Tested-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Serge Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | sysfs: Restrict mounting sysfsEric W. Biederman2013-08-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't allow mounting sysfs unless the caller has CAP_SYS_ADMIN rights over the net namespace. The principle here is if you create or have capabilities over it you can mount it, otherwise you get to live with what other people have mounted. Instead of testing this with a straight forward ns_capable call, perform this check the long and torturous way with kobject helpers, this keeps direct knowledge of namespaces out of sysfs, and preserves the existing sysfs abstractions. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | userns: Better restrictions on when proc and sysfs can be mountedEric W. Biederman2013-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. Biederman2013-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | kernel/nsproxy.c: Improving a snippet of code.Raphael S.Carvalho2013-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | It seems GCC generates a better code in that way, so I changed that statement. Btw, they have the same semantic, so I'm sending this patch due to performance issues. Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Raphael S.Carvalho <raphael.scarv@gmail.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * | proc: Restrict mounting the proc filesystemEric W. Biederman2013-08-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't allow mounting the proc filesystem unless the caller has CAP_SYS_ADMIN rights over the pid namespace. The principle here is if you create or have capabilities over it you can mount it, otherwise you get to live with what other people have mounted. Andy pointed out that this is needed to prevent users in a user namespace from remounting proc and specifying different hidepid and gid options on already existing proc mounts. Cc: stable@vger.kernel.org Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * | vfs: Lock in place mounts from more privileged usersEric W. Biederman2013-07-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | Merge branch 'next' of ↵Linus Torvalds2013-09-07
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "Nothing major for this kernel, just maintenance updates" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (21 commits) apparmor: add the ability to report a sha1 hash of loaded policy apparmor: export set of capabilities supported by the apparmor module apparmor: add the profile introspection file to interface apparmor: add an optional profile attachment string for profiles apparmor: add interface files for profiles and namespaces apparmor: allow setting any profile into the unconfined state apparmor: make free_profile available outside of policy.c apparmor: rework namespace free path apparmor: update how unconfined is handled apparmor: change how profile replacement update is done apparmor: convert profile lists to RCU based locking apparmor: provide base for multiple profiles to be replaced at once apparmor: add a features/policy dir to interface apparmor: enable users to query whether apparmor is enabled apparmor: remove minimum size check for vmalloc() Smack: parse multiple rules per write to load2, up to PAGE_SIZE-1 bytes Smack: network label match fix security: smack: add a hash table to quicken smk_find_entry() security: smack: fix memleak in smk_write_rules_list() xattr: Constify ->name member of "struct xattr". ...
| * \ \ Merge branch 'smack-for-3.12' of git://git.gitorious.org/smack-next/kernel ↵James Morris2013-08-22
| |\ \ \ | | | | | | | | | | | | | | | into ra-next
| | * | | Smack: parse multiple rules per write to load2, up to PAGE_SIZE-1 bytesRafal Krypa2013-08-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Smack interface for loading rules has always parsed only single rule from data written to it. This requires user program to call one write() per each rule it wants to load. This change makes it possible to write multiple rules, separated by new line character. Smack will load at most PAGE_SIZE-1 characters and properly return number of processed bytes. In case when user buffer is larger, it will be additionally truncated. All characters after last \n will not get parsed to avoid partial rule near input buffer boundary. Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
| | * | | Smack: network label match fixCasey Schaufler2013-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Smack code that matches incoming CIPSO tags with Smack labels reaches through the NetLabel interfaces and compares the network data with the CIPSO header associated with a Smack label. This was done in a ill advised attempt to optimize performance. It works so long as the categories fit in a single capset, but this isn't always the case. This patch changes the Smack code to use the appropriate NetLabel interfaces to compare the incoming CIPSO header with the CIPSO header associated with a label. It will always match the CIPSO headers correctly. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
| | * | | security: smack: add a hash table to quicken smk_find_entry()Tomasz Stanislawski2013-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Accepted for the smack-next tree after changing the number of slots from 128 to 16. This patch adds a hash table to quicken searching of a smack label by its name. Basically, the patch improves performance of SMACK initialization. Parsing of rules involves translation from a string to a smack_known (aka label) entity which is done in smk_find_entry(). The current implementation of the function iterates over a global list of smack_known resulting in O(N) complexity for smk_find_entry(). The total complexity of SMACK initialization becomes O(rules * labels). Therefore it scales quadratically with a complexity of a system. Applying the patch reduced the complexity of smk_find_entry() to O(1) as long as number of label is in hundreds. If the number of labels is increased please update SMACK_HASH_SLOTS constant defined in security/smack/smack.h. Introducing the configuration of this constant with Kconfig or cmdline might be a good idea. The size of the hash table was adjusted experimentally. The rule set used by TIZEN contains circa 17K rules for 500 labels. The table above contains results of SMACK initialization using 'time smackctl apply' bash command. The 'Ref' is a kernel without this patch applied. The consecutive values refers to value of SMACK_HASH_SLOTS. Every measurement was repeated three times to reduce noise. | Ref | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | 512 -------------------------------------------------------------------------------------------- Run1 | 1.156 | 1.096 | 0.883 | 0.764 | 0.692 | 0.667 | 0.649 | 0.633 | 0.634 | 0.629 | 0.620 Run2 | 1.156 | 1.111 | 0.885 | 0.764 | 0.694 | 0.661 | 0.649 | 0.651 | 0.634 | 0.638 | 0.623 Run3 | 1.160 | 1.107 | 0.886 | 0.764 | 0.694 | 0.671 | 0.661 | 0.638 | 0.631 | 0.624 | 0.638 AVG | 1.157 | 1.105 | 0.885 | 0.764 | 0.693 | 0.666 | 0.653 | 0.641 | 0.633 | 0.630 | 0.627 Surprisingly, a single hlist is slightly faster than a double-linked list. The speed-up saturates near 64 slots. Therefore I chose value 128 to provide some margin if more labels were used. It looks that IO becomes a new bottleneck. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
| | * | | security: smack: fix memleak in smk_write_rules_list()Tomasz Stanislawski2013-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The smack_parsed_rule structure is allocated. If a rule is successfully installed then the last reference to the object is lost. This patch fixes this leak. Moreover smack_parsed_rule is allocated on stack because it no longer needed ofter smk_write_rules_list() is finished. Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
| * | | | apparmor: add the ability to report a sha1 hash of loaded policyJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide userspace the ability to introspect a sha1 hash value for each profile currently loaded. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
| * | | | apparmor: export set of capabilities supported by the apparmor moduleJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
| * | | | apparmor: add the profile introspection file to interfaceJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the dynamic namespace relative profiles file to the interace, to allow introspection of loaded profiles and their modes. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Kees Cook <kees@ubuntu.com>
| * | | | apparmor: add an optional profile attachment string for profilesJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the ability to take in and report a human readable profile attachment string for profiles so that attachment specifications can be easily inspected. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
| * | | | apparmor: add interface files for profiles and namespacesJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add basic interface files to access namespace and profile information. The interface files are created when a profile is loaded and removed when the profile or namespace is removed. Signed-off-by: John Johansen <john.johansen@canonical.com>
| * | | | apparmor: allow setting any profile into the unconfined stateJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow emulating the default profile behavior from boot, by allowing loading of a profile in the unconfined state into a new NS. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>
| * | | | apparmor: make free_profile available outside of policy.cJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | Signed-off-by: John Johansen <john.johansen@canonical.com>
| * | | | apparmor: rework namespace free pathJohn Johansen2013-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | namespaces now completely use the unconfined profile to track the refcount and rcu freeing cycle. So rework the code to simplify (track everything through the profile path right up to the end), and move the rcu_head from policy base to profile as the namespace no longer needs it. Signed-off-by: John Johansen <john.johansen@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com>