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* fork: protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombsGlauber Costa2012-12-181-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because those architectures will draw their stacks directly from the page allocator, rather than the slab cache, we can directly pass __GFP_KMEMCG flag, and issue the corresponding free_pages. This code path is taken when the architecture doesn't define CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has THREAD_SIZE >= PAGE_SIZE. Luckily, most - if not all - of the remaining architectures fall in this category. This will guarantee that every stack page is accounted to the memcg the process currently lives on, and will have the allocations to fail if they go over limit. For the time being, I am defining a new variant of THREADINFO_GFP, not to mess with the other path. Once the slab is also tracked by memcg, we can get rid of that flag. Tested to successfully protect against :(){ :|:& };: Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Frederic Weisbecker <fweisbec@redhat.com> Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* res_counter: return amount of charges after res_counter_uncharge()Glauber Costa2012-12-181-7/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is useful to know how many charges are still left after a call to res_counter_uncharge. While it is possible to issue a res_counter_read after uncharge, this can be racy. If we need, for instance, to take some action when the counters drop down to 0, only one of the callers should see it. This is the same semantics as the atomic variables in the kernel. Since the current return value is void, we don't need to worry about anything breaking due to this change: nobody relied on that, and only users appearing from now on will be checking this value. Signed-off-by: Glauber Costa <glommer@parallels.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: JoonSoo Kim <js1304@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* irq: tsk->comm is an arrayAlan Cox2012-12-181-1/+1
| | | | | | | | | | The array check is useless so remove it. [akpm@linux-foundation.org: remove comment, per David] Signed-off-by: Alan Cox <alan@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-12-184-4/+31
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull (again) user namespace infrastructure changes from Eric Biederman: "Those bugs, those darn embarrasing bugs just want don't want to get fixed. Linus I just updated my mirror of your kernel.org tree and it appears you successfully pulled everything except the last 4 commits that fix those embarrasing bugs. When you get a chance can you please repull my branch" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Fix typo in description of the limitation of userns_install userns: Add a more complete capability subset test to commit_creds userns: Require CAP_SYS_ADMIN for most uses of setns. Fix cap_capable to only allow owners in the parent user namespace to have caps.
| * userns: Fix typo in description of the limitation of userns_installEric W. Biederman2012-12-141-1/+1
| | | | | | | | | | Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Add a more complete capability subset test to commit_credsEric W. Biederman2012-12-141-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When unsharing a user namespace we reduce our credentials to just what can be done in that user namespace. This is a subset of the credentials we previously had. Teach commit_creds to recognize this is a subset of the credentials we have had before and don't clear the dumpability flag. This allows an unprivileged program to do: unshare(CLONE_NEWUSER); fd = open("/proc/self/uid_map", O_RDWR); Where previously opening the uid_map writable would fail because the the task had been made non-dumpable. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Require CAP_SYS_ADMIN for most uses of setns.Eric W. Biederman2012-12-142-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds2012-12-179-49/+55
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc patches from Andrew Morton: "Incoming: - lots of misc stuff - backlight tree updates - lib/ updates - Oleg's percpu-rwsem changes - checkpatch - rtc - aoe - more checkpoint/restart support I still have a pile of MM stuff pending - Pekka should be merging later today after which that is good to go. A number of other things are twiddling thumbs awaiting maintainer merges." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits) scatterlist: don't BUG when we can trivially return a proper error. docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output fs, fanotify: add @mflags field to fanotify output docs: add documentation about /proc/<pid>/fdinfo/<fd> output fs, notify: add procfs fdinfo helper fs, exportfs: add exportfs_encode_inode_fh() helper fs, exportfs: escape nil dereference if no s_export_op present fs, epoll: add procfs fdinfo helper fs, eventfd: add procfs fdinfo helper procfs: add ability to plug in auxiliary fdinfo providers tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test breakpoint selftests: print failure status instead of cause make error kcmp selftests: print fail status instead of cause make error kcmp selftests: make run_tests fix mem-hotplug selftests: print failure status instead of cause make error cpu-hotplug selftests: print failure status instead of cause make error mqueue selftests: print failure status instead of cause make error vm selftests: print failure status instead of cause make error ubifs: use prandom_bytes mtd: nandsim: use prandom_bytes ...
| * | pidns: remove unused is_container_init()Gao feng2012-12-171-15/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 1cdcbec1a337 ("CRED: Neuter sys_capset()") is_container_init() has no callers. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Cc: David Howells <dhowells@redhat.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Cc: James Morris <jmorris@namei.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | ptrace: introduce PTRACE_O_EXITKILLOleg Nesterov2012-12-171-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ptrace jailers want to be sure that the tracee can never escape from the control. However if the tracer dies unexpectedly the tracee continues to run in potentially unsafe mode. Add the new ptrace option PTRACE_O_EXITKILL. If the tracer exits it sends SIGKILL to every tracee which has this bit set. Note that the new option is not equal to the last-option << 1. Because currently all options have an event, and the new one starts the eventless group. It uses the random 20 bit, so we have the room for 12 more events, but we can also add the new eventless options below this one. Suggested by Amnon Shiloh. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Tested-by: Amnon Shiloh <u3557@miso.sublimeip.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: Chris Evans <scarybeasts@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | compat: generic compat_sys_sched_rr_get_interval() implementationCatalin Marinas2012-12-171-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function is used by sparc, powerpc tile and arm64 for compat support. The patch adds a generic implementation with a wrapper for PowerPC to do the u32->int sign extension. The reason for a single patch covering powerpc, tile, sparc and arm64 is to keep it bisectable, otherwise kernel building may fail with mismatched function declarations. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> [for tile] Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | trace: use kbasename()Andy Shevchenko2012-12-171-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | printk: boot_delay should only affect outputAndrew Cooks2012-12-171-19/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The boot_delay parameter affects all printk(), even if the log level prevents visible output from the call. It results in delays greater than the user intended without purpose. This patch changes the behaviour of boot_delay to only delay output. Signed-off-by: Andrew Cooks <acooks@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | watchdog: store the watchdog sample period as a variableChuansheng Liu2012-12-171-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently getting the sample period is always thru a complex calculation: get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5). We can store the sample period as a variable, and set it as __read_mostly type. Signed-off-by: liu chuansheng <chuansheng.liu@intel.com> Cc: Don Zickus <dzickus@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | lseek: the "whence" argument is called "whence"Andrew Morton2012-12-171-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | But the kernel decided to call it "origin" instead. Fix most of the sites. Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | kernel: remove reference to feature-removal-schedule.txtTao Ma2012-12-172-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 9c0ece069b32 ("Get rid of Documentation/feature-removal.txt"), Linus removed feature-removal-schedule.txt from Documentation, but there is still some reference to this file. So remove them. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2012-12-1714-115/+371
|\ \ \ | |/ / |/| / | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull user namespace changes from Eric Biederman: "While small this set of changes is very significant with respect to containers in general and user namespaces in particular. The user space interface is now complete. This set of changes adds support for unprivileged users to create user namespaces and as a user namespace root to create other namespaces. The tyranny of supporting suid root preventing unprivileged users from using cool new kernel features is broken. This set of changes completes the work on setns, adding support for the pid, user, mount namespaces. This set of changes includes a bunch of basic pid namespace cleanups/simplifications. Of particular significance is the rework of the pid namespace cleanup so it no longer requires sending out tendrils into all kinds of unexpected cleanup paths for operation. At least one case of broken error handling is fixed by this cleanup. The files under /proc/<pid>/ns/ have been converted from regular files to magic symlinks which prevents incorrect caching by the VFS, ensuring the files always refer to the namespace the process is currently using and ensuring that the ptrace_mayaccess permission checks are always applied. The files under /proc/<pid>/ns/ have been given stable inode numbers so it is now possible to see if different processes share the same namespaces. Through the David Miller's net tree are changes to relax many of the permission checks in the networking stack to allowing the user namespace root to usefully use the networking stack. Similar changes for the mount namespace and the pid namespace are coming through my tree. Two small changes to add user namespace support were commited here adn in David Miller's -net tree so that I could complete the work on the /proc/<pid>/ns/ files in this tree. Work remains to make it safe to build user namespaces and 9p, afs, ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the Kconfig guard remains in place preventing that user namespaces from being built when any of those filesystems are enabled. Future design work remains to allow root users outside of the initial user namespace to mount more than just /proc and /sys." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits) proc: Usable inode numbers for the namespace file descriptors. proc: Fix the namespace inode permission checks. proc: Generalize proc inode allocation userns: Allow unprivilged mounts of proc and sysfs userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file procfs: Print task uids and gids in the userns that opened the proc file userns: Implement unshare of the user namespace userns: Implent proc namespace operations userns: Kill task_user_ns userns: Make create_new_namespaces take a user_ns parameter userns: Allow unprivileged use of setns. userns: Allow unprivileged users to create new namespaces userns: Allow setting a userns mapping to your current uid. userns: Allow chown and setgid preservation userns: Allow unprivileged users to create user namespaces. userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped userns: fix return value on mntns_install() failure vfs: Allow unprivileged manipulation of the mount namespace. vfs: Only support slave subtrees across different user namespaces vfs: Add a user namespace reference from struct mnt_namespace ...
| * proc: Usable inode numbers for the namespace file descriptors.Eric W. Biederman2012-11-205-1/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: For /proc/self/{uid,gid}_map derive the lower userns from the struct ↵Eric W. Biederman2012-11-201-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | file To keep things sane in the context of file descriptor passing derive the user namespace that uids are mapped into from the opener of the file instead of from current. When writing to the maps file the lower user namespace must always be the parent user namespace, or setting the mapping simply does not make sense. Enforce that the opener of the file was in the parent user namespace or the user namespace whose mapping is being set. Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Implement unshare of the user namespaceEric W. Biederman2012-11-203-7/+41
| | | | | | | | | | | | | | | | | | | | | | | | - Add CLONE_THREAD to the unshare flags if CLONE_NEWUSER is selected As changing user namespaces is only valid if all there is only a single thread. - Restore the code to add CLONE_VM if CLONE_THREAD is selected and the code to addCLONE_SIGHAND if CLONE_VM is selected. Making the constraints in the code clear. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Implent proc namespace operationsEric W. Biederman2012-11-201-17/+73
| | | | | | | | | | | | | | | | | | | | | | | | This allows entering a user namespace, and the ability to store a reference to a user namespace with a bind mount. Addition of missing userns_ns_put in userns_install from Gao feng <gaofeng@cn.fujitsu.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Kill task_user_nsEric W. Biederman2012-11-202-4/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The task_user_ns function hides the fact that it is getting the user namespace from struct cred on the task. struct cred may go away as soon as the rcu lock is released. This leads to a race where we can dereference a stale user namespace pointer. To make it obvious a struct cred is involved kill task_user_ns. To kill the race modify the users of task_user_ns to only reference the user namespace while the rcu lock is held. Cc: Kees Cook <keescook@chromium.org> Cc: James Morris <james.l.morris@oracle.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Make create_new_namespaces take a user_ns parameterEric W. Biederman2012-11-202-14/+17
| | | | | | | | | | | | | | | | | | | | | | | | Modify create_new_namespaces to explicitly take a user namespace parameter, instead of implicitly through the task_struct. This allows an implementation of unshare(CLONE_NEWUSER) where the new user namespace is not stored onto the current task_struct until after all of the namespaces are created. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Allow unprivileged use of setns.Eric W. Biederman2012-11-202-4/+6
| | | | | | | | | | | | | | | | | | | | - Push the permission check from the core setns syscall into the setns install methods where the user namespace of the target namespace can be determined, and used in a ns_capable call. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Allow unprivileged users to create new namespacesEric W. Biederman2012-11-201-2/+3
| | | | | | | | | | | | | | | | If an unprivileged user has the appropriate capabilities in their current user namespace allow the creation of new namespaces. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Allow setting a userns mapping to your current uid.Eric W. Biederman2012-11-201-0/+15
| | | | | | | | | | Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: Allow unprivileged users to create user namespaces.Eric W. Biederman2012-11-191-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we have been through every permission check in the kernel having uid == 0 and gid == 0 in your local user namespace no longer adds any special privileges. Even having a full set of caps in your local user namespace is safe because capabilies are relative to your local user namespace, and do not confer unexpected privileges. Over the long term this should allow much more of the kernels functionality to be safely used by non-root users. Functionality like unsharing the mount namespace that is only unsafe because it can fool applications whose privileges are raised when they are executed. Since those applications have no privileges in a user namespaces it becomes safe to spoof and confuse those applications all you want. Those capabilities will still need to be enabled carefully because we may still need things like rlimits on the number of unprivileged mounts but that is to avoid DOS attacks not to avoid fooling root owned processes. 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. Biederman2012-11-191-1/+1
| | | | | | | | | | | | | | 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>
| * pidns: Support unsharing the pid namespace.Eric W. Biederman2012-11-193-10/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unsharing of the pid namespace unlike unsharing of other namespaces does not take affect immediately. Instead it affects the children created with fork and clone. The first of these children becomes the init process of the new pid namespace, the rest become oddball children of pid 0. From the point of view of the new pid namespace the process that created it is pid 0, as it's pid does not map. A couple of different semantics were considered but this one was settled on because it is easy to implement and it is usable from pam modules. The core reasons for the existence of unshare. I took a survey of the callers of pam modules and the following appears to be a representative sample of their logic. { setup stuff include pam child = fork(); if (!child) { setuid() exec /bin/bash } waitpid(child); pam and other cleanup } As you can see there is a fork to create the unprivileged user space process. Which means that the unprivileged user space process will appear as pid 1 in the new pid namespace. Further most login processes do not cope with extraneous children which means shifting the duty of reaping extraneous child process to the creator of those extraneous children makes the system more comprehensible. The practical reason for this set of pid namespace semantics is that it is simple to implement and verify they work correctly. Whereas an implementation that requres changing the struct pid on a process comes with a lot more races and pain. Not the least of which is that glibc caches getpid(). These semantics are implemented by having two notions of the pid namespace of a proces. There is task_active_pid_ns which is the pid namspace the process was created with and the pid namespace that all pids are presented to that process in. The task_active_pid_ns is stored in the struct pid of the task. Then there is the pid namespace that will be used for children that pid namespace is stored in task->nsproxy->pid_ns. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * pidns: Consolidate initialzation of special init task stateEric W. Biederman2012-11-191-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of setting child_reaper and SIGNAL_UNKILLABLE one way for the system init process, and another way for pid namespace init processes test pid->nr == 1 and use the same code for both. For the global init this results in SIGNAL_UNKILLABLE being set much earlier in the initialization process. This is a small cleanup and it paves the way for allowing unshare and enter of the pid namespace as that path like our global init also will not set CLONE_NEWPID. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * pidns: Add setns supportEric W. Biederman2012-11-191-0/+54
| | | | | | | | | | | | | | | | | | | | | | - Pid namespaces are designed to be inescapable so verify that the passed in pid namespace is a child of the currently active pid namespace or the currently active pid namespace itself. Allowing the currently active pid namespace is important so the effects of an earlier setns can be cancelled. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * pidns: Deny strange cases when creating pid namespaces.Eric W. Biederman2012-11-191-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | task_active_pid_ns(current) != current->ns_proxy->pid_ns will soon be allowed to support unshare and setns. The definition of creating a child pid namespace when task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that we create a child pid namespace of current->ns_proxy->pid_ns. However that leads to strange cases like trying to have a single process be init in multiple pid namespaces, which is racy and hard to think about. The definition of creating a child pid namespace when task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that we create a child pid namespace of task_active_pid_ns(current). While that seems less racy it does not provide any utility. Therefore define the semantics of creating a child pid namespace when task_active_pid_ns(current) != current->ns_proxy->pid_ns to be that the pid namespace creation fails. That is easy to implement and easy to think about. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * pidns: Wait in zap_pid_ns_processes until pid_ns->nr_hashed == 1Eric W. Biederman2012-11-193-26/+17
| | | | | | | | | | | | | | | | | | Looking at pid_ns->nr_hashed is a bit simpler and it works for disjoint process trees that an unshare or a join of a pid_namespace may create. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * pidns: Don't allow new processes in a dead pid namespace.Eric W. Biederman2012-11-191-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Set nr_hashed to -1 just before we schedule the work to cleanup proc. Test nr_hashed just before we hash a new pid and if nr_hashed is < 0 fail. This guaranteees that processes never enter a pid namespaces after we have cleaned up the state to support processes in a pid namespace. Currently sending SIGKILL to all of the process in a pid namespace as init exists gives us this guarantee but we need something a little stronger to support unsharing and joining a pid namespace. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * pidns: Make the pidns proc mount/umount logic obvious.Eric W. Biederman2012-11-193-13/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Track the number of pids in the proc hash table. When the number of pids goes to 0 schedule work to unmount the kernel mount of proc. Move the mount of proc into alloc_pid when we allocate the pid for init. Remove the surprising calls of pid_ns_release proc in fork and proc_flush_task. Those code paths really shouldn't know about proc namespace implementation details and people have demonstrated several times that finding and understanding those code paths is difficult and non-obvious. Because of the call path detach pid is alwasy called with the rtnl_lock held free_pid is not allowed to sleep, so the work to unmounting proc is moved to a work queue. This has the side benefit of not blocking the entire world waiting for the unnecessary rcu_barrier in deactivate_locked_super. In the process of making the code clear and obvious this fixes a bug reported by Gao feng <gaofeng@cn.fujitsu.com> where we would leak a mount of proc during clone(CLONE_NEWPID|CLONE_NEWNET) if copy_pid_ns succeeded and copy_net_ns failed. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * pidns: Use task_active_pid_ns where appropriateEric W. Biederman2012-11-197-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The expressions tsk->nsproxy->pid_ns and task_active_pid_ns aka ns_of_pid(task_pid(tsk)) should have the same number of cache line misses with the practical difference that ns_of_pid(task_pid(tsk)) is released later in a processes life. Furthermore by using task_active_pid_ns it becomes trivial to write an unshare implementation for the the pid namespace. So I have used task_active_pid_ns everywhere I can. In fork since the pid has not yet been attached to the process I use ns_of_pid, to achieve the same effect. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| * pidns: Capture the user namespace and filter ns_last_pidEric W. Biederman2012-11-193-6/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | - Capture the the user namespace that creates the pid namespace - Use that user namespace to test if it is ok to write to /proc/sys/kernel/ns_last_pid. Zhao Hongjiang <zhaohongjiang@huawei.com> noticed I was missing a put_user_ns in when destroying a pid_ns. I have foloded his patch into this one so that bisects will work properly. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * userns: make each net (net_ns) belong to a user_nsEric W. Biederman2012-11-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The user namespace which creates a new network namespace owns that namespace and all resources created in it. This way we can target capability checks for privileged operations against network resources to the user_ns which created the network namespace in which the resource lives. Privilege to the user namespace which owns the network namespace, or any parent user namespace thereof, provides the same privilege to the network resource. This patch is reworked from a version originally by Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | sched: numa: Fix build error if CONFIG_NUMA_BALANCING && ↵Mel Gorman2012-12-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | !CONFIG_TRANSPARENT_HUGEPAGE Michal Hocko reported that the following build error occurs if CONFIG_NUMA_BALANCING is set without THP support kernel/sched/fair.c: In function ‘task_numa_work’: kernel/sched/fair.c:932:55: error: call to ‘__build_bug_failed’ declared with attribute error: BUILD_BUG failed The problem is that HPAGE_PMD_SHIFT triggers a BUILD_BUG() on !CONFIG_TRANSPARENT_HUGEPAGE. This patch addresses the problem. Reported-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2012-12-162-115/+25
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: "A quiet cycle for the security subsystem with just a few maintenance updates." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: Smack: create a sysfs mount point for smackfs Smack: use select not depends in Kconfig Yama: remove locking from delete path Yama: add RCU to drop read locking drivers/char/tpm: remove tasklet and cleanup KEYS: Use keyring_alloc() to create special keyrings KEYS: Reduce initial permissions on keys KEYS: Make the session and process keyrings per-thread seccomp: Make syscall skipping and nr changes more consistent key: Fix resource leak keys: Fix unreachable code KEYS: Add payload preparsing opportunity prior to key instantiate or update
| * \ Merge branch 'security-next-keys' of ↵James Morris2012-10-031-112/+15
| |\ \ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/security-keys into next-queue As requested by David.
| | * | KEYS: Make the session and process keyrings per-threadDavid Howells2012-10-021-112/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make the session keyring per-thread rather than per-process, but still inherited from the parent thread to solve a problem with PAM and gdm. The problem is that join_session_keyring() will reject attempts to change the session keyring of a multithreaded program but gdm is now multithreaded before it gets to the point of starting PAM and running pam_keyinit to create the session keyring. See: https://bugs.freedesktop.org/show_bug.cgi?id=49211 The reason that join_session_keyring() will only change the session keyring under a single-threaded environment is that it's hard to alter the other thread's credentials to effect the change in a multi-threaded program. The problems are such as: (1) How to prevent two threads both running join_session_keyring() from racing. (2) Another thread's credentials may not be modified directly by this process. (3) The number of threads is uncertain whilst we're not holding the appropriate spinlock, making preallocation slightly tricky. (4) We could use TIF_NOTIFY_RESUME and key_replace_session_keyring() to get another thread to replace its keyring, but that means preallocating for each thread. A reasonable way around this is to make the session keyring per-thread rather than per-process and just document that if you want a common session keyring, you must get it before you spawn any threads - which is the current situation anyway. Whilst we're at it, we can the process keyring behave in the same way. This means we can clean up some of the ickyness in the creds code. Basically, after this patch, the session, process and thread keyrings are about inheritance rules only and not about sharing changes of keyring. Reported-by: Mantas M. <grawity@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Ray Strode <rstrode@redhat.com>
| * | | seccomp: Make syscall skipping and nr changes more consistentAndy Lutomirski2012-10-021-3/+10
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes two issues that could cause incompatibility between kernel versions: - If a tracer uses SECCOMP_RET_TRACE to select a syscall number higher than the largest known syscall, emulate the unknown vsyscall by returning -ENOSYS. (This is unlikely to make a noticeable difference on x86-64 due to the way the system call entry works.) - On x86-64 with vsyscall=emulate, skipped vsyscalls were buggy. This updates the documentation accordingly. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Will Drewry <wad@chromium.org> Signed-off-by: James Morris <james.l.morris@oracle.com>
* | | Merge tag 'balancenuma-v11' of ↵Linus Torvalds2012-12-166-17/+352
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma Pull Automatic NUMA Balancing bare-bones from Mel Gorman: "There are three implementations for NUMA balancing, this tree (balancenuma), numacore which has been developed in tip/master and autonuma which is in aa.git. In almost all respects balancenuma is the dumbest of the three because its main impact is on the VM side with no attempt to be smart about scheduling. In the interest of getting the ball rolling, it would be desirable to see this much merged for 3.8 with the view to building scheduler smarts on top and adapting the VM where required for 3.9. The most recent set of comparisons available from different people are mel: https://lkml.org/lkml/2012/12/9/108 mingo: https://lkml.org/lkml/2012/12/7/331 tglx: https://lkml.org/lkml/2012/12/10/437 srikar: https://lkml.org/lkml/2012/12/10/397 The results are a mixed bag. In my own tests, balancenuma does reasonably well. It's dumb as rocks and does not regress against mainline. On the other hand, Ingo's tests shows that balancenuma is incapable of converging for this workloads driven by perf which is bad but is potentially explained by the lack of scheduler smarts. Thomas' results show balancenuma improves on mainline but falls far short of numacore or autonuma. Srikar's results indicate we all suffer on a large machine with imbalanced node sizes. My own testing showed that recent numacore results have improved dramatically, particularly in the last week but not universally. We've butted heads heavily on system CPU usage and high levels of migration even when it shows that overall performance is better. There are also cases where it regresses. Of interest is that for specjbb in some configurations it will regress for lower numbers of warehouses and show gains for higher numbers which is not reported by the tool by default and sometimes missed in treports. Recently I reported for numacore that the JVM was crashing with NullPointerExceptions but currently it's unclear what the source of this problem is. Initially I thought it was in how numacore batch handles PTEs but I'm no longer think this is the case. It's possible numacore is just able to trigger it due to higher rates of migration. These reports were quite late in the cycle so I/we would like to start with this tree as it contains much of the code we can agree on and has not changed significantly over the last 2-3 weeks." * tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits) mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable mm/rmap: Convert the struct anon_vma::mutex to an rwsem mm: migrate: Account a transhuge page properly when rate limiting mm: numa: Account for failed allocations and isolations as migration failures mm: numa: Add THP migration for the NUMA working set scanning fault case build fix mm: numa: Add THP migration for the NUMA working set scanning fault case. mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG mm: sched: numa: Control enabling and disabling of NUMA balancing mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships mm: numa: migrate: Set last_nid on newly allocated page mm: numa: split_huge_page: Transfer last_nid on tail page mm: numa: Introduce last_nid to the page frame sched: numa: Slowly increase the scanning period as NUMA faults are handled mm: numa: Rate limit setting of pte_numa if node is saturated mm: numa: Rate limit the amount of memory that is migrated between nodes mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting mm: numa: Migrate pages handled during a pmd_numa hinting fault mm: numa: Migrate on reference policy ...
| * | | mm: sched: numa: Delay PTE scanning until a task is scheduled on a new nodeMel Gorman2012-12-113-1/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to the fact that migrations are driven by the CPU a task is running on there is no point tracking NUMA faults until one task runs on a new node. This patch tracks the first node used by an address space. Until it changes, PTE scanning is disabled and no NUMA hinting faults are trapped. This should help workloads that are short-lived, do not care about NUMA placement or have bound themselves to a single node. This takes advantage of the logic in "mm: sched: numa: Implement slow start for working set sampling" to delay when the checks are made. This will take advantage of processes that set their CPU and node bindings early in their lifetime. It will also potentially allow any initial load balancing to take place. Signed-off-by: Mel Gorman <mgorman@suse.de>
| * | | mm: sched: numa: Control enabling and disabling of NUMA balancing if ↵Mel Gorman2012-12-112-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | !SCHED_DEBUG The "mm: sched: numa: Control enabling and disabling of NUMA balancing" depends on scheduling debug being enabled but it's perfectly legimate to disable automatic NUMA balancing even without this option. This should take care of it. Signed-off-by: Mel Gorman <mgorman@suse.de>
| * | | mm: sched: numa: Control enabling and disabling of NUMA balancingMel Gorman2012-12-113-17/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds Kconfig options and kernel parameters to allow the enabling and disabling of automatic NUMA balancing. The existance of such a switch was and is very important when debugging problems related to transparent hugepages and we should have the same for automatic NUMA placement. Signed-off-by: Mel Gorman <mgorman@suse.de>
| * | | mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrateMel Gorman2012-12-113-8/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The PTE scanning rate and fault rates are two of the biggest sources of system CPU overhead with automatic NUMA placement. Ideally a proper policy would detect if a workload was properly placed, schedule and adjust the PTE scanning rate accordingly. We do not track the necessary information to do that but we at least know if we migrated or not. This patch scans slower if a page was not migrated as the result of a NUMA hinting fault up to sysctl_numa_balancing_scan_period_max which is now higher than the previous default. Once every minute it will reset the scanner in case of phase changes. This is hilariously crude and the numbers are arbitrary. Workloads will converge quite slowly in comparison to what a proper policy should be able to do. On the plus side, we will chew up less CPU for workloads that have no need for automatic balancing. Signed-off-by: Mel Gorman <mgorman@suse.de>
| * | | sched: numa: Slowly increase the scanning period as NUMA faults are handledMel Gorman2012-12-111-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the rate of scanning for an address space is controlled by the individual tasks. The next scan is simply determined by 2*p->numa_scan_period. The 2*p->numa_scan_period is arbitrary and never changes. At this point there is still no proper policy that decides if a task or process is properly placed. It just scans and assumes the next NUMA fault will place it properly. As it is assumed that pages will get properly placed over time, increase the scan window each time a fault is incurred. This is a big assumption as noted in the comments. It should be noted that changing to p->numa_scan_period will increase system CPU usage because now the scanning rate has effectively doubled. If that is a problem then the min_rate should be made 200ms instead of restoring the 2* logic. Signed-off-by: Mel Gorman <mgorman@suse.de>
| * | | mm: numa: Rate limit setting of pte_numa if node is saturatedMel Gorman2012-12-111-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If there are a large number of NUMA hinting faults and all of them are resulting in migrations it may indicate that memory is just bouncing uselessly around. NUMA balancing cost is likely exceeding any benefit from locality. Rate limit the PTE updates if the node is migration rate-limited. As noted in the comments, this distorts the NUMA faulting statistics. Signed-off-by: Mel Gorman <mgorman@suse.de>
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