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path: root/pkg/sentry/kernel/task.go
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2021-04-02Implement cgroupfs.Rahat Mahmood
A skeleton implementation of cgroupfs. It supports trivial cpu and memory controllers with no support for hierarchies. PiperOrigin-RevId: 366561126
2021-03-29[syserror] Split usermem packageZach Koopmans
Split usermem package to help remove syserror dependency in go_marshal. New hostarch package contains code not dependent on syserror. PiperOrigin-RevId: 365651233
2021-02-24Add YAMA security module restrictions on ptrace(2).Dean Deng
Restrict ptrace(2) according to the default configurations of the YAMA security module (mode 1), which is a common default among various Linux distributions. The new access checks only permit the tracer to proceed if one of the following conditions is met: a) The tracer is already attached to the tracee. b) The target is a descendant of the tracer. c) The target has explicitly given permission to the tracer through the PR_SET_PTRACER prctl. d) The tracer has CAP_SYS_PTRACE. See security/yama/yama_lsm.c for more details. Note that these checks are added to CanTrace, which is checked for PTRACE_ATTACH as well as some other operations, e.g., checking a process' memory layout through /proc/[pid]/mem. Since this patch adds restrictions to ptrace, it may break compatibility for applications run by non-root users that, for instance, rely on being able to trace processes that are not descended from the tracer (e.g., `gdb -p`). YAMA restrictions can be turned off by setting /proc/sys/kernel/yama/ptrace_scope to 0, or exceptions can be made on a per-process basis with the PR_SET_PTRACER prctl. Reported-by: syzbot+622822d8bca08c99e8c8@syzkaller.appspotmail.com PiperOrigin-RevId: 359237723
2020-11-13Check for misuse of kernel.Task as context.Context.Jamie Liu
Checks in Task.block() and Task.Value() are conditional on race detection being enabled, since these functions are relatively hot. Checks in Task.SleepStart() and Task.UninterruptibleSleepStart() are enabled unconditionally, since these functions are not thought to lie on any critical paths, and misuse of these functions is required for b/168241471 to manifest. PiperOrigin-RevId: 342342175
2020-11-12Rename kernel.TaskContext to kernel.TaskImage.Jamie Liu
This reduces confusion with context.Context (which is also relevant to kernel.Tasks) and is consistent with existing function kernel.LoadTaskImage(). PiperOrigin-RevId: 342167298
2020-10-14Fix shm reference leak.Dean Deng
All shm segments in an IPC namespace should be released once that namespace is destroyed. Add reference counting to IPCNamespace so that once the last task with a reference on it exits, we can trigger a destructor that will clean up all shm segments that have not been explicitly freed by the application. PiperOrigin-RevId: 337032977
2020-10-13[vfs2] Don't take reference in Task.MountNamespaceVFS2 and MountNamespace.Root.Dean Deng
This fixes reference leaks related to accidentally forgetting to DecRef() after calling one or the other. PiperOrigin-RevId: 336918922
2020-10-03Fix kcov enabling and disabling procedures.Dean Deng
- When the KCOV_ENABLE_TRACE ioctl is called with the trace kind KCOV_TRACE_PC, the kcov mode should be set to KCOV_*MODE*_TRACE_PC. - When the owning task of kcov exits, the memory mapping should not be cleared so it can be used by other tasks. - Add more tests (also tested on native Linux kcov). PiperOrigin-RevId: 335202585
2020-08-25Expose basic coverage information to userspace through kcov interface.Dean Deng
In Linux, a kernel configuration is set that compiles the kernel with a custom function that is called at the beginning of every basic block, which updates the memory-mapped coverage information. The Go coverage tool does not allow us to inject arbitrary instructions into basic blocks, but it does provide data that we can convert to a kcov-like format and transfer them to userspace through a memory mapping. Note that this is not a strict implementation of kcov, which is especially tricky to do because we do not have the same coverage tools available in Go that that are available for the actual Linux kernel. In Linux, a kernel configuration is set that compiles the kernel with a custom function that is called at the beginning of every basic block to write program counters to the kcov memory mapping. In Go, however, coverage tools only give us a count of basic blocks as they are executed. Every time we return to userspace, we collect the coverage information and write out PCs for each block that was executed, providing userspace with the illusion that the kcov data is always up to date. For convenience, we also generate a unique synthetic PC for each block instead of using actual PCs. Finally, we do not provide thread-specific coverage data (each kcov instance only contains PCs executed by the thread owning it); instead, we will supply data for any file specified by -- instrumentation_filter. Also, fix issue in nogo that was causing pkg/coverage:coverage_nogo compilation to fail. PiperOrigin-RevId: 328426526
2020-08-03Plumbing context.Context to DecRef() and Release().Nayana Bidari
context is passed to DecRef() and Release() which is needed for SO_LINGER implementation. PiperOrigin-RevId: 324672584
2020-07-23Implement get/set_robust_list.Nicolas Lacasse
PiperOrigin-RevId: 322904430
2020-07-23Add task work mechanism.Dean Deng
Like task_work in Linux, this allows us to register callbacks to be executed before returning to userspace. This is needed for kcov support, which requires coverage information to be up-to-date whenever we are in user mode. We will provide coverage data through the kcov interface to enable coverage-directed fuzzing in syzkaller. One difference from Linux is that task work cannot queue work before the transition to userspace that it precedes; queued work will be picked up before the next transition. PiperOrigin-RevId: 322889984
2020-04-23Enable automated marshalling for mempolicy syscalls.Rahat Mahmood
PiperOrigin-RevId: 308170679
2020-04-13Port socket-related syscalls to VFS2.Dean Deng
Note that most kinds of sockets are not yet supported in VFS2 (only Unix sockets are partially supported at the moment), so these syscalls will still generally fail. Enabling them allows us to begin running socket tests for VFS2 as more features are ported over. Updates #1476, #1478, #1484, #1485. PiperOrigin-RevId: 306292294
2020-03-26Support owner matching for iptables.Nayana Bidari
This feature will match UID and GID of the packet creator, for locally generated packets. This match is only valid in the OUTPUT and POSTROUTING chains. Forwarded packets do not have any socket associated with them. Packets from kernel threads do have a socket, but usually no owner.
2020-03-13Fix oom_score_adj.Jamie Liu
- Make oomScoreAdj a ThreadGroup field (Linux: signal_struct::oom_score_adj). - Avoid deadlock caused by Task.OOMScoreAdj()/SetOOMScoreAdj() locking Task.mu and TaskSet.mu in the wrong order (via Task.ExitState()). PiperOrigin-RevId: 300814698
2020-03-05Stub oom_score_adj and oom_score.Ian Lewis
Adds an oom_score_adj and oom_score proc file stub. oom_score_adj accepts writes of values -1000 to 1000 and persists the value with the task. New tasks inherit the parent's oom_score_adj. oom_score is a read-only stub that always returns the value '0'. Issue #202 PiperOrigin-RevId: 299245355
2020-02-25Port most syscalls to VFS2.Jamie Liu
pipe and pipe2 aren't ported, pending a slight rework of pipe FDs for VFS2. mount and umount2 aren't ported out of temporary laziness. access and faccessat need additional FSImpl methods to implement properly, but are stubbed to prevent googletest from CHECK-failing. Other syscalls require additional plumbing. Updates #1623 PiperOrigin-RevId: 297188448
2020-02-20Initial network namespace support.gVisor bot
TCP/IP will work with netstack networking. hostinet doesn't work, and sockets will have the same behavior as it is now. Before the userspace is able to create device, the default loopback device can be used to test. /proc/net and /sys/net will still be connected to the root network stack; this is the same behavior now. Issue #1833 PiperOrigin-RevId: 296309389
2020-02-14Plumb VFS2 inside the SentrygVisor bot
- Added fsbridge package with interface that can be used to open and read from VFS1 and VFS2 files. - Converted ELF loader to use fsbridge - Added VFS2 types to FSContext - Added vfs.MountNamespace to ThreadGroup Updates #1623 PiperOrigin-RevId: 295183950
2020-01-28Add vfs.FileDescription to FD tableFabricio Voznika
FD table now holds both VFS1 and VFS2 types and uses the correct one based on what's set. Parts of this CL are just initial changes (e.g. sys_read.go, runsc/main.go) to serve as a template for the remaining changes. Updates #1487 Updates #1623 PiperOrigin-RevId: 292023223
2020-01-27Update package locations.Adin Scannell
Because the abi will depend on the core types for marshalling (usermem, context, safemem, safecopy), these need to be flattened from the sentry directory. These packages contain no sentry-specific details. PiperOrigin-RevId: 291811289
2020-01-09New sync package.Ian Gudger
* Rename syncutil to sync. * Add aliases to sync types. * Replace existing usage of standard library sync package. This will make it easier to swap out synchronization primitives. For example, this will allow us to use primitives from github.com/sasha-s/go-deadlock to check for lock ordering violations. Updates #1472 PiperOrigin-RevId: 289033387
2020-01-06Implement rseq(2)Michael Pratt
PiperOrigin-RevId: 288342928
2019-12-06Add runtime tracing.Adin Scannell
This adds meaningful annotations to the trace generated by the runtime/trace package. PiperOrigin-RevId: 284290115
2019-11-21Import and structure cleanup.Adin Scannell
PiperOrigin-RevId: 281795269
2019-10-29Fix grammar in comment.Dean Deng
Missing "for". PiperOrigin-RevId: 277358513
2019-10-28Update commentMichael Pratt
FDTable.GetFile doesn't exist. PiperOrigin-RevId: 277089842
2019-09-18Signalfd supportAdin Scannell
Note that the exact semantics for these signalfds are slightly different from Linux. These signalfds are bound to the process at creation time. Reads, polls, etc. are all associated with signals directed at that task. In Linux, all signalfd operations are associated with current, regardless of where the signalfd originated. In practice, this should not be an issue given how signalfds are used. In order to fix this however, we will need to plumb the context through all the event APIs. This gets complicated really quickly, because the waiter APIs are all netstack-specific, and not generally exposed to the context. Probably not worthwhile fixing immediately. PiperOrigin-RevId: 269901749
2019-07-02Remove map from fd_map, change to fd_table.Adin Scannell
This renames FDMap to FDTable and drops the kernel.FD type, which had an entire package to itself and didn't serve much use (it was freely cast between types, and served as more of an annoyance than providing any protection.) Based on BenchmarkFDLookupAndDecRef-12, we can expect 5-10 ns per lookup operation, and 10-15 ns per concurrent lookup operation of savings. This also fixes two tangential usage issues with the FDMap. Namely, non-atomic use of NewFDFrom and associated calls to Remove (that are both racy and fail to drop the reference on the underlying file.) PiperOrigin-RevId: 256285890
2019-06-25gvisor: lockless read access for task credentialsAndrei Vagin
Credentials are immutable and even before these changes we could read them without locks, but we needed to take a task lock to get a credential object from a task object. It is possible to avoid this lock, if we will guarantee that a credential object will not be changed after setting it on a task. PiperOrigin-RevId: 254989492
2019-06-21kernel: call t.mu.Unlock() explicitly in WithMuLockedAndrei Vagin
defer here doesn't improve readability, but we know it slower that the explicit call. PiperOrigin-RevId: 254441473
2019-06-19Add MountNamespace to task.Nicolas Lacasse
This allows tasks to have distinct mount namespace, instead of all sharing the kernel's root mount namespace. Currently, the only way for a task to get a different mount namespace than the kernel's root is by explicitly setting a different MountNamespace in CreateProcessArgs, and nothing does this (yet). In a follow-up CL, we will set CreateProcessArgs.MountNamespace when creating a new container inside runsc. Note that "MountNamespace" is a poor term for this thing. It's more like a distinct VFS tree. When we get around to adding real mount namespaces, this will need a better naem. PiperOrigin-RevId: 254009310
2019-06-13Update canonical repository.Adin Scannell
This can be merged after: https://github.com/google/gvisor-website/pull/77 or https://github.com/google/gvisor-website/pull/78 PiperOrigin-RevId: 253132620
2019-06-06"Implement" mbind(2).Jamie Liu
We still only advertise a single NUMA node, and ignore mempolicy accordingly, but mbind() at least now succeeds and has effects reflected by get_mempolicy(). Also fix handling of nodemasks: round sizes to unsigned long (as documented and done by Linux), and zero trailing bits when copying them out. PiperOrigin-RevId: 251950859
2019-04-29Change copyright notice to "The gVisor Authors"Michael Pratt
Based on the guidelines at https://opensource.google.com/docs/releasing/authors/. 1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./' 2. Manual fixup of "Google Inc" references. 3. Add AUTHORS file. Authors may request to be added to this file. 4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS. Fixes #209 PiperOrigin-RevId: 245823212 Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
2019-04-17Use FD limit and file size limit from hostFabricio Voznika
FD limit and file size limit is read from the host, instead of using hard-coded defaults, given that they effect the sandbox process. Also limit the direct cache to use no more than half if the available FDs. PiperOrigin-RevId: 244050323 Change-Id: I787ad0fdf07c49d589e51aebfeae477324fe26e6
2019-03-29Use kernel.Task.CopyScratchBuffer in syscalls/linux where possible.Jamie Liu
PiperOrigin-RevId: 241072126 Change-Id: Ib4d9f58f550732ac4c5153d3cf159a5b1a9749da
2019-03-22Implement PTRACE_SEIZE, PTRACE_INTERRUPT, and PTRACE_LISTEN.Jamie Liu
PiperOrigin-RevId: 239803092 Change-Id: I42d612ed6a889e011e8474538958c6de90c6fcab
2019-03-14Decouple filemem from platform and move it to pgalloc.MemoryFile.Jamie Liu
This is in preparation for improved page cache reclaim, which requires greater integration between the page cache and page allocator. PiperOrigin-RevId: 238444706 Change-Id: Id24141b3678d96c7d7dc24baddd9be555bffafe4
2019-01-31Move package sync to third_partyMichael Pratt
PiperOrigin-RevId: 231889261 Change-Id: I482f1df055bcedf4edb9fe3fe9b8e9c80085f1a0
2018-11-20Fix recursive read lock taken on TaskSetFabricio Voznika
SyncSyscallFiltersToThreadGroup and Task.TheadID() both acquired TaskSet RWLock in R mode and could deadlock if a writer comes in between. PiperOrigin-RevId: 222313551 Change-Id: I4221057d8d46fec544cbfa55765c9a284fe7ebfa
2018-10-20Add more unimplemented syscall eventsFabricio Voznika
Added events for *ctl syscalls that may have multiple different commands. For runsc, each syscall event is only logged once. For *ctl syscalls, use the cmd as identifier, not only the syscall number. PiperOrigin-RevId: 218015941 Change-Id: Ie3c19131ae36124861e9b492a7dbe1765d9e5e59
2018-10-19Use correct company name in copyright headerIan Gudger
PiperOrigin-RevId: 217951017 Change-Id: Ie08bf6987f98467d07457bcf35b5f1ff6e43c035
2018-10-15Merge host.endpoint into host.ConnectedEndpointIan Gudger
host.endpoint contained duplicated logic from the sockerpair implementation and host.ConnectedEndpoint. Remove host.endpoint in favor of a host.ConnectedEndpoint wrapped in a socketpair end. PiperOrigin-RevId: 217240096 Change-Id: I4a3d51e3fe82bdf30e2d0152458b8499ab4c987c
2018-09-27Implement 'runsc kill --all'Fabricio Voznika
In order to implement kill --all correctly, the Sentry needs to track all tasks that belong to a given container. This change introduces ContainerID to the task, that gets inherited by all children. 'kill --all' then iterates over all tasks comparing the ContainerID field to find all processes that need to be signalled. PiperOrigin-RevId: 214841768 Change-Id: I693b2374be8692d88cc441ef13a0ae34abf73ac6
2018-09-14Fix interaction between rt_sigtimedwait and ignored signals.Jamie Liu
PiperOrigin-RevId: 213011782 Change-Id: I716c6ea3c586b0c6c5a892b6390d2d11478bc5af
2018-08-31Document more task-goroutine-owned fields in kernel.Task.Jamie Liu
Task.creds can only be changed by the task's own set*id and execve syscalls, and Task namespaces can only be changed by the task's own unshare/setns syscalls. PiperOrigin-RevId: 211156279 Change-Id: I94d57105d34e8739d964400995a8a5d76306b2a0
2018-08-31Disintegrate kernel.TaskResources.Jamie Liu
This allows us to call kernel.FDMap.DecRef without holding mutexes cleanly. PiperOrigin-RevId: 211139657 Change-Id: Ie59d5210fb9282e1950e2e40323df7264a01bcec
2018-08-31Delete the long-obsolete kernel.TaskMaybe interface.Jamie Liu
PiperOrigin-RevId: 211131855 Change-Id: Ia7799561ccd65d16269e0ae6f408ab53749bca37