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* 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/+17Star
| | | | | | | | | 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. Biederman2012-11-191-1/+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>
* Merge branch 'akpm' (Andrew's fixes)Linus Torvalds2012-10-261-1/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge misc fixes from Andrew Morton: "18 total. 15 fixes and some updates to a device_cgroup patchset which bring it up to date with the version which I should have merged in the first place." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (18 patches) fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check gen_init_cpio: avoid stack overflow when expanding drivers/rtc/rtc-imxdi.c: add missing spin lock initialization mm, numa: avoid setting zone_reclaim_mode unless a node is sufficiently distant pidns: limit the nesting depth of pid namespaces drivers/dma/dw_dmac: make driver's endianness configurable mm/mmu_notifier: allocate mmu_notifier in advance tools/testing/selftests/epoll/test_epoll.c: fix build UAPI: fix tools/vm/page-types.c mm/page_alloc.c:alloc_contig_range(): return early for err path rbtree: include linux/compiler.h for definition of __always_inline genalloc: stop crashing the system when destroying a pool backlight: ili9320: add missing SPI dependency device_cgroup: add proper checking when changing default behavior device_cgroup: stop using simple_strtoul() device_cgroup: rename deny_all to behavior cgroup: fix invalid rcu dereference mm: fix XFS oops due to dirty pages without buffers on s390
| * pidns: limit the nesting depth of pid namespacesAndrew Vagin2012-10-251-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'struct pid' is a "variable sized struct" - a header with an array of upids at the end. The size of the array depends on a level (depth) of pid namespaces. Now a level of pidns is not limited, so 'struct pid' can be more than one page. Looks reasonable, that it should be less than a page. MAX_PIS_NS_LEVEL is not calculated from PAGE_SIZE, because in this case it depends on architectures, config options and it will be reduced, if someone adds a new fields in struct pid or struct upid. I suggest to set MAX_PIS_NS_LEVEL = 32, because it saves ability to expand "struct pid" and it's more than enough for all known for me use-cases. When someone finds a reasonable use case, we can add a config option or a sysctl parameter. In addition it will reduce the effect of another problem, when we have many nested namespaces and the oldest one starts dying. zap_pid_ns_processe will be called for each namespace and find_vpid will be called for each process in a namespace. find_vpid will be called minimum max_level^2 / 2 times. The reason of that is that when we found a bit in pidmap, we can't determine this pidns is top for this process or it isn't. vpid is a heavy operation, so a fork bomb, which create many nested namespace, can make a system inaccessible for a long time. For example my system becomes inaccessible for a few minutes with 4000 processes. [akpm@linux-foundation.org: return -EINVAL in response to excessive nesting, not -ENOMEM] Signed-off-by: Andrew Vagin <avagin@openvz.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Makefile: Documentation for external tool should be correctH. Peter Anvin2012-10-261-4/+2Star
|/ | | | | | | | | | | | | | | | | | | | | If one includes documentation for an external tool, it should be correct. This is not: 1. Overriding the input to rngd should typically be neither necessary nor desired. This is especially so since newer versions of rngd support a number of different *types* of sources. 2. The default kernel-exported device is called /dev/hwrng not /dev/hwrandom nor /dev/hw_random (both of which were used in the past; however, kernel and udev seem to have converged on /dev/hwrng.) Overall it is better if the documentation for rngd is kept with rngd rather than in a kernel Makefile. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: David Howells <dhowells@redhat.com> Cc: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-3.7-fixes' of ↵Linus Torvalds2012-10-251-31/+10Star
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "This pull request contains three fixes. Two are reverts of task_lock() removal in cgroup fork path. The optimizations incorrectly assumed that threadgroup_lock can protect process forks (as opposed to thread creations) too. Further cleanup of cgroup fork path is scheduled. The third fixes cgroup emptiness notification loss." * 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: Revert "cgroup: Remove task_lock() from cgroup_post_fork()" Revert "cgroup: Drop task_lock(parent) on cgroup_fork()" cgroup: notify_on_release may not be triggered in some cases
| * Revert "cgroup: Remove task_lock() from cgroup_post_fork()"Tejun Heo2012-10-191-12/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable@vger.kernel.org
| * Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"Tejun Heo2012-10-191-17/+6Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 7e381b0eb1e1a9805c37335562e8dc02e7d7848c. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan <lizefan@huawei.com> Bitterly-Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable@vger.kernel.org
| * cgroup: notify_on_release may not be triggered in some casesDaisuke Nishimura2012-10-171-2/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | notify_on_release must be triggered when the last process in a cgroup is move to another. But if the first(and only) process in a cgroup is moved to another, notify_on_release is not triggered. # mkdir /cgroup/cpu/SRC # mkdir /cgroup/cpu/DST # # echo 1 >/cgroup/cpu/SRC/notify_on_release # echo 1 >/cgroup/cpu/DST/notify_on_release # # sleep 300 & [1] 8629 # # echo 8629 >/cgroup/cpu/SRC/tasks # echo 8629 >/cgroup/cpu/DST/tasks -> notify_on_release for /SRC must be triggered at this point, but it isn't. This is because put_css_set() is called before setting CGRP_RELEASABLE in cgroup_task_migrate(), and is a regression introduce by the commit:74a1166d(cgroups: make procs file writable), which was merged into v3.0. Cc: Ben Blum <bblum@andrew.cmu.edu> Cc: <stable@vger.kernel.org> # v3.0.x and later Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Tejun Heo <tj@kernel.org>
* | Merge branch 'for-3.7-fixes' of ↵Linus Torvalds2012-10-251-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq Pull workqueue fix from Tejun Heo: "This pull request contains one patch from Dan Magenheimer to fix cancel_delayed_work() regression introduced by its reimplementation using try_to_grab_pending(). The reimplementation made it incorrectly return %true when the work item is idle. There aren't too many consumers of the return value but it broke at least ramster." * 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: cancel_delayed_work() should return %false if work item is idle
| * | workqueue: cancel_delayed_work() should return %false if work item is idleDan Magenheimer2012-10-241-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 57b30ae77b ("workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()") made cancel_delayed_work() always return %true unless someone else is also trying to cancel the work item, which is broken - if the target work item is idle, the return value should be %false. try_to_grab_pending() indicates that the target work item was idle by zero return value. Use it for return. Note that this brings cancel_delayed_work() in line with __cancel_work_timer() in return value handling. Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>
* | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2012-10-242-183/+166Star
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "Most of these are uprobes race fixes from Oleg, and their preparatory cleanups. (It's larger than what I'd normally send for an -rc kernel, but they looked significant enough to not delay them.) There's also an oprofile fix and an uncore PMU fix." * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits) perf/x86: Disable uncore on virtualized CPUs oprofile, x86: Fix wrapping bug in op_x86_get_ctrl() ring-buffer: Check for uninitialized cpu buffer before resizing uprobes: Fix the racy uprobe->flags manipulation uprobes: Fix prepare_uprobe() race with itself uprobes: Introduce prepare_uprobe() uprobes: Fix handle_swbp() vs unregister() + register() race uprobes: Do not delete uprobe if uprobe_unregister() fails uprobes: Don't return success if alloc_uprobe() fails uprobes/x86: Only rep+nop can be emulated correctly uprobes: Simplify is_swbp_at_addr(), remove stale comments uprobes: Kill set_orig_insn()->is_swbp_at_addr() uprobes: Introduce copy_opcode(), kill read_opcode() uprobes: Kill set_swbp()->is_swbp_at_addr() uprobes: Restrict valid_vma(false) to skip VM_SHARED vmas uprobes: Change valid_vma() to demand VM_MAYEXEC rather than VM_EXEC uprobes: Change write_opcode() to use FOLL_FORCE uprobes: Move clear_thread_flag(TIF_UPROBE) to uprobe_notify_resume() uprobes: Kill UTASK_BP_HIT state uprobes: Fix UPROBE_SKIP_SSTEP checks in handle_swbp() ...
| * \ Merge branch 'tip/perf/urgent' of ↵Ingo Molnar2012-10-211-0/+4
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent Pull ftrace ring-buffer resizing fix from Steve Rostedt. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | ring-buffer: Check for uninitialized cpu buffer before resizingVaibhav Nagarnaik2012-10-111-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With a system where, num_present_cpus < num_possible_cpus, even if all CPUs are online, non-present CPUs don't have per_cpu buffers allocated. If per_cpu/<cpu>/buffer_size_kb is modified for such a CPU, it can cause a panic due to NULL dereference in ring_buffer_resize(). To fix this, resize operation is allowed only if the per-cpu buffer has been initialized. Link: http://lkml.kernel.org/r/1349912427-6486-1-git-send-email-vnagarnaik@google.com Cc: stable@vger.kernel.org # 3.5+ Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | Merge branch 'uprobes/core' of ↵Ingo Molnar2012-10-211-183/+162Star
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/urgent Pull various uprobes bugfixes from Oleg Nesterov - mostly race and failure path fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | uprobes: Fix the racy uprobe->flags manipulationOleg Nesterov2012-10-071-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multiple threads can manipulate uprobe->flags, this is obviously unsafe. For example mmap can set UPROBE_COPY_INSN while register tries to set UPROBE_RUN_HANDLER, the latter can also race with can_skip_sstep() which clears UPROBE_SKIP_SSTEP. Change this code to use bitops. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Fix prepare_uprobe() race with itselfOleg Nesterov2012-10-071-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | install_breakpoint() is called under mm->mmap_sem, this protects set_swbp() but not prepare_uprobe(). Two or more different tasks can call install_breakpoint()->prepare_uprobe() at the same time, this leads to numerous problems if UPROBE_COPY_INSN is not set. Just for example, the second copy_insn() can corrupt the already analyzed/fixuped uprobe->arch.insn and race with handle_swbp(). This patch simply adds uprobe->copy_mutex to serialize this code. We could probably reuse ->consumer_rwsem, but this would mean that consumer->handler() can not use mm->mmap_sem, not good. Note: this is another temporary ugly hack until we move this logic into uprobe_register(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Introduce prepare_uprobe()Oleg Nesterov2012-10-071-19/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Preparation. Extract the copy_insn/arch_uprobe_analyze_insn code from install_breakpoint() into the new helper, prepare_uprobe(). And move uprobe->flags defines from uprobes.h to uprobes.c, nobody else can use them anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Fix handle_swbp() vs unregister() + register() raceOleg Nesterov2012-10-071-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Strictly speaking this race was added by me in 56bb4cf6. However I think that this bug is just another indication that we should move copy_insn/uprobe_analyze_insn code from install_breakpoint() to uprobe_register(), there are a lot of other reasons for that. Until then, add a hack to close the race. A task can hit uprobe U1, but before it calls find_uprobe() this uprobe can be unregistered *AND* another uprobe U2 can be added to uprobes_tree at the same inode/offset. In this case handle_swbp() will use the not-fully-initialized U2, in particular its arch.insn for xol. Add the additional !UPROBE_COPY_INSN check into handle_swbp(), if this flag is not set we simply restart as if the new uprobe was not inserted yet. This is not very nice, we need barriers, but we will remove this hack when we change uprobe_register(). Note: with or without this patch install_breakpoint() can race with itself, yet another reson to kill UPROBE_COPY_INSN altogether. And even the usage of uprobe->flags is not safe. See the next patches. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Do not delete uprobe if uprobe_unregister() failsOleg Nesterov2012-10-071-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | delete_uprobe() must not be called if register_for_each_vma(false) fails to remove all breakpoints, __uprobe_unregister() is correct. The problem is that register_for_each_vma(false) always returns 0 and thus this logic does not work. 1. Change verify_opcode() to return 0 rather than -EINVAL when unregister detects the !is_swbp insn, we can treat this case as success and currently unregister paths ignore the error code anyway. 2. Change remove_breakpoint() to propagate the error code from write_opcode(). 3. Change register_for_each_vma(is_register => false) to remove as much breakpoints as possible but return non-zero if remove_breakpoint() fails at least once. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Don't return success if alloc_uprobe() failsOleg Nesterov2012-10-071-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If alloc_uprobe() fails uprobe_register() should return ENOMEM, not 0. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Simplify is_swbp_at_addr(), remove stale commentsOleg Nesterov2012-09-291-49/+24Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the previous change is_swbp_at_addr() is always called with current->mm. Remove this check and move it close to its single caller. Also, remove the obsolete comment about is_swbp_at_addr() and uprobe_state.count. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Kill set_orig_insn()->is_swbp_at_addr()Oleg Nesterov2012-09-291-9/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unlike set_swbp(), set_orig_insn()->is_swbp_at_addr() makes sense, although it can't prevent all confusions. But the usage of is_swbp_at_addr() is equally confusing, and it adds the extra get_user_pages() we can avoid. This patch removes set_orig_insn()->is_swbp_at_addr() but changes write_opcode() to do the necessary checks before replace_page(). Perhaps it also makes sense to ensure PAGE_MAPPING_ANON in unregister case. find_active_uprobe() becomes the only user of is_swbp_at_addr(), we can change its semantics. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Introduce copy_opcode(), kill read_opcode()Oleg Nesterov2012-09-291-44/+19Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No functional changes, preparations. 1. Extract the kmap-and-memcpy code from read_opcode() into the new trivial helper, copy_opcode(). The next patch will add another user. 2. read_opcode() becomes really trivial, fold it into its single caller, is_swbp_at_addr(). 3. Remove "auprobe" argument from write_opcode(), it is not used since f403072c6. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Kill set_swbp()->is_swbp_at_addr()Oleg Nesterov2012-09-291-11/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A separate patch for better documentation. set_swbp()->is_swbp_at_addr() is not needed for correctness, it is harmless to do the unnecessary __replace_page(old_page, new_page) when these 2 pages are identical. And it can not be counted as optimization. mmap/register races are very unlikely, while in the likely case is_swbp_at_addr() adds the extra get_user_pages() even if the caller is uprobe_mmap(current->mm) and returns false. Note also that the semantics/usage of is_swbp_at_addr() in uprobe.c is confusing. set_swbp() uses it to detect the case when this insn was already modified by uprobes, that is why it should always compare the opcode with UPROBE_SWBP_INSN even if the hardware (like powerpc) has other trap insns. It doesn't matter if this breakpoint was in fact installed by gdb or application itself, we are going to "steal" this breakpoint anyway and execute the original insn from vm_file even if it no longer matches the memory. OTOH, handle_swbp()->find_active_uprobe() uses is_swbp_at_addr() to figure out whether we need to send SIGTRAP or not if we can not find uprobe, so in this case it should return true for all trap variants, not only for UPROBE_SWBP_INSN. This patch removes set_swbp()->is_swbp_at_addr(), the next patches will remove it from set_orig_insn() which is similar to set_swbp() in this respect. So the only caller will be handle_swbp() and we can make its semantics clear. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Restrict valid_vma(false) to skip VM_SHARED vmasOleg Nesterov2012-09-291-9/+4Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | valid_vma(false) ignores ->vm_flags, this is not actually right. We should never try to write into MAP_SHARED mapping, this can confuse an apllication which actually writes to ->vm_file. With this patch valid_vma(false) ignores VM_WRITE only but checks other (immutable) bits checked by valid_vma(true). This can also speedup uprobe_munmap() and uprobe_unregister(). Note: even after this patch _unregister can confuse the probed application if it does mprotect(PROT_WRITE) after _register and installs "int3", but this is hardly possible to avoid and this doesn't differ from gdb case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Change valid_vma() to demand VM_MAYEXEC rather than VM_EXECOleg Nesterov2012-09-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | uprobe_register() or uprobe_mmap() requires VM_READ | VM_EXEC, this is not right. An apllication can do mprotect(PROT_EXEC) later and execute this code. Change valid_vma(is_register => true) to check VM_MAYEXEC instead. No need to check VM_MAYREAD, it is always set. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Change write_opcode() to use FOLL_FORCEOleg Nesterov2012-09-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | write_opcode()->get_user_pages() needs FOLL_FORCE to ensure we can read the page even if the probed task did mprotect(PROT_NONE) after uprobe_register(). Without FOLL_WRITE, FOLL_FORCE doesn't have any side effect but allows to read the !VM_READ memory. Otherwiese the subsequent uprobe_unregister()->set_orig_insn() fails and we leak "int3". If that task does mprotect(PROT_READ | EXEC) and execute the probed insn later it will be killed. Note: in fact this is also needed for _register, see the next patch. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Move clear_thread_flag(TIF_UPROBE) to uprobe_notify_resume()Oleg Nesterov2012-09-291-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move clear_thread_flag(TIF_UPROBE) from do_notify_resume() to uprobe_notify_resume() for !CONFIG_UPROBES case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Kill UTASK_BP_HIT stateOleg Nesterov2012-09-291-20/+9Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kill UTASK_BP_HIT state, it buys nothing but complicates the code. It is only used in uprobe_notify_resume() to decide who should be called, we can check utask->active_uprobe != NULL instead. And this allows us to simplify handle_swbp(), no need to clear utask->state. Likewise we could kill UTASK_SSTEP, but UTASK_BP_HIT is worse and imho should die. The problem is, it creates the special case when task->utask is NULL, we can't distinguish RUNNING and BP_HIT. With this patch utask == NULL always means RUNNING. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Fix UPROBE_SKIP_SSTEP checks in handle_swbp()Oleg Nesterov2012-09-291-16/+15Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If handle_swbp()->add_utask() fails but UPROBE_SKIP_SSTEP is set, cleanup_ret: path do not restart the insn, this is wrong. Remove this check and add the additional label for can_skip_sstep() = T case. Note also that UPROBE_SKIP_SSTEP can be false positive, we simply can not trust it unless arch_uprobe_skip_sstep() was already called. Also, move another UPROBE_SKIP_SSTEP check before can_skip_sstep() into this helper, this looks more clean and understandable. Note: probably we should rename "skip" to "emulate" and I think that "clear UPROBE_SKIP_SSTEP" should be moved to arch_can_skip. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Do not setup ->active_uprobe/state prematurelyOleg Nesterov2012-09-291-6/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | handle_swbp() sets utask->active_uprobe before handler_chain(), and UTASK_SSTEP before pre_ssout(). This complicates the code for no reason, arch_ hooks or consumer->handler() should not (and can't) use this info. Change handle_swbp() to initialize them after pre_ssout(), and remove the no longer needed cleanup-utask code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> cked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
| | * | | uprobes: Do not leak UTASK_BP_HIT if find_active_uprobe() failsOleg Nesterov2012-09-291-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If handle_swbp()->find_active_uprobe() fails we return with utask->state = UTASK_BP_HIT. Change handle_swbp() to reset utask->state at the start. Note that we do this unconditionally, see the next patch(es). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
* | | | | module_signing: fix printk format warningRandy Dunlap2012-10-221-1/+1
|/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the warning: kernel/module_signing.c:195:2: warning: format '%lu' expects type 'long unsigned int', but argument 3 has type 'size_t' by using the proper 'z' modifier for printing a size_t. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | use clamp_t in UNAME26 fixKees Cook2012-10-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The min/max call needed to have explicit types on some architectures (e.g. mn10300). Use clamp_t instead to avoid the warning: kernel/sys.c: In function 'override_release': kernel/sys.c:1287:10: warning: comparison of distinct pointer types lacks a cast [enabled by default] Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | MODSIGN: Move the magic string to the end of a module and eliminate the searchDavid Howells2012-10-203-28/+25Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Emit the magic string that indicates a module has a signature after the signature data instead of before it. This allows module_sig_check() to be made simpler and faster by the elimination of the search for the magic string. Instead we just need to do a single memcmp(). This works because at the end of the signature data there is the fixed-length signature information block. This block then falls immediately prior to the magic number. From the contents of the information block, it is trivial to calculate the size of the signature data and thus the size of the actual module data. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | pidns: remove recursion from free_pid_ns()Cyrill Gorcunov2012-10-191-7/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | free_pid_ns() operates in a recursive fashion: free_pid_ns(parent) put_pid_ns(parent) kref_put(&ns->kref, free_pid_ns); free_pid_ns thus if there was a huge nesting of namespaces the userspace may trigger avalanche calling of free_pid_ns leading to kernel stack exhausting and a panic eventually. This patch turns the recursion into an iterative loop. Based on a patch by Andrew Vagin. [akpm@linux-foundation.org: export put_pid_ns() to modules] Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | kernel/sys.c: fix stack memory content leak via UNAME26Kees Cook2012-10-191-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calling uname() with the UNAME26 personality set allows a leak of kernel stack contents. This fixes it by defensively calculating the length of copy_to_user() call, making the len argument unsigned, and initializing the stack buffer to zero (now technically unneeded, but hey, overkill). CVE-2012-0957 Reported-by: PaX Team <pageexec@freemail.hu> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: PaX Team <pageexec@freemail.hu> Cc: Brad Spengler <spender@grsecurity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | printk: Fix scheduling-while-atomic problem in console_cpu_notify()Paul E. McKenney2012-10-171-1/+0Star
| |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The console_cpu_notify() function runs with interrupts disabled in the CPU_DYING case. It therefore cannot block, for example, as will happen when it calls console_lock(). Therefore, remove the CPU_DYING leg of the switch statement to avoid this problem. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'modules-next' of ↵Linus Torvalds2012-10-145-27/+578
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module signing support from Rusty Russell: "module signing is the highlight, but it's an all-over David Howells frenzy..." Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG. * 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits) X.509: Fix indefinite length element skip error handling X.509: Convert some printk calls to pr_devel asymmetric keys: fix printk format warning MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking MODSIGN: Make mrproper should remove generated files. MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs MODSIGN: Use the same digest for the autogen key sig as for the module sig MODSIGN: Sign modules during the build process MODSIGN: Provide a script for generating a key ID from an X.509 cert MODSIGN: Implement module signature checking MODSIGN: Provide module signing public keys to the kernel MODSIGN: Automatically generate module signing keys if missing MODSIGN: Provide Kconfig options MODSIGN: Provide gitignore and make clean rules for extra files MODSIGN: Add FIPS policy module: signature checking hook X.509: Add a crypto key parser for binary (DER) X.509 certificates MPILIB: Provide a function to read raw data into an MPI X.509: Add an ASN.1 decoder X.509: Add simple ASN.1 grammar compiler ...
| * | | MODSIGN: Make mrproper should remove generated files.Rusty Russell2012-10-101-1/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | It doesn't, because the clean targets don't include kernel/Makefile, and because two files were missing from the list. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * | | MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certsDavid Howells2012-10-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Place an indication that the certificate should use utf8 strings into the x509.genkey template generated by kernel/Makefile. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * | | MODSIGN: Use the same digest for the autogen key sig as for the module sigDavid Howells2012-10-101-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the same digest type for the autogenerated key signature as for the module signature so that the hash algorithm is guaranteed to be present in the kernel. Without this, the X.509 certificate loader may reject the X.509 certificate so generated because it was self-signed and the signature will be checked against itself - but this won't work if the digest algorithm must be loaded as a module. The symptom is that the key fails to load with the following message emitted into the kernel log: MODSIGN: Problem loading in-kernel X.509 certificate (-65) the error in brackets being -ENOPKG. What you should see is something like: MODSIGN: Loaded cert 'Magarathea: Glacier signing key: 9588321144239a119d3406d4c4cf1fbae1836fa0' Note that this doesn't apply to certificates that are not self-signed as we don't check those currently as they require the parent CA certificate to be available. Reported-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>