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path: root/pkg/sentry/kernel/kernel.go
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2021-04-12Don't grab TaskSet mu recursively when reading task state.Rahat Mahmood
Reported-by: syzbot+a6ef0f95a2c9e7da26f3@syzkaller.appspotmail.com Reported-by: syzbot+2eaf8a9f115edec468fe@syzkaller.appspotmail.com PiperOrigin-RevId: 368093861
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
2021-02-24Add 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
2021-01-26Implement error on pointersTamir Duberstein
This improves type-assertion safety. PiperOrigin-RevId: 353931228
2021-01-12Fix simple mistakes identified by goreportcard.Adin Scannell
These are primarily simplification and lint mistakes. However, minor fixes are also included and tests added where appropriate. PiperOrigin-RevId: 351425971
2020-12-14Do not check for reference leaks after saving.Dean Deng
We should not assert that all resources are dropped after saving. PiperOrigin-RevId: 347420131
2020-11-12Fix misuses of kernel.Task as context.Context.Jamie Liu
kernel.Task can only be used as context.Context by that Task's task goroutine. This is violated in at least two places: - In any case where one thread accesses the /proc/[tid] of any other thread, passing the kernel.Task for [tid] as the context.Context is incorrect. - Task.rebuildTraceContext() may be called by Kernel.RebuildTraceContexts() outside the scope of any task goroutine. Fix these (as well as a data race on Task.traceContext discovered during the course of finding the latter). PiperOrigin-RevId: 342174404
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
2020-10-23Support VFS2 save/restore.Jamie Liu
Inode number consistency checks are now skipped in save/restore tests for reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename. They pass in VFS1 due to the bug described in new test case SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs. Fixes #1663 PiperOrigin-RevId: 338776148
2020-10-19[vfs2] Fix fork reference leaks.Dean Deng
PiperOrigin-RevId: 337919424
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
2020-10-13Don't leak VDSO mappings.Dean Deng
PiperOrigin-RevId: 336822021
2020-10-12[vfs2] Don't leak disconnected mounts.Dean Deng
PiperOrigin-RevId: 336694658
2020-09-29Merge pull request #3875 from btw616:fix/issue-3874gVisor bot
PiperOrigin-RevId: 334428344
2020-09-24Add basic stateify annotations.Adin Scannell
Updates #1663 PiperOrigin-RevId: 333539293
2020-09-24Fix socket record leak in VFS2Tiwei Bie
VFS2 socket record is not removed from the system-wide socket table when the socket is released, which will lead to a memory leak. This patch fixes this issue. Fixes: #3874 Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
2020-09-24Rename kernel.SocketEntry to kernel.SocketRecordTiwei Bie
SocketEntry can be confusing with the template types as the 'Entry' is usually used as a suffix for list element types, e.g. socketEntry in the same package. Suggested by Dean (@dean-deng). Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
2020-09-08Fix the use after nil check on args.MountNamespaceVFS2Tiwei Bie
The args.MountNamespaceVFS2 is used again after the nil check, instead, mntnsVFS2 which holds the expected reference should be used. This patch fixes this issue. Fixes: #3855 Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
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
2020-08-20Consistent precondition formattingMichael Pratt
Our "Preconditions:" blocks are very useful to determine the input invariants, but they are bit inconsistent throughout the codebase, which makes them harder to read (particularly cases with 5+ conditions in a single paragraph). I've reformatted all of the cases to fit in simple rules: 1. Cases with a single condition are placed on a single line. 2. Cases with multiple conditions are placed in a bulleted list. This format has been added to the style guide. I've also mentioned "Postconditions:", though those are much less frequently used, and all uses already match this style. PiperOrigin-RevId: 327687465
2020-08-03Add callbacks to support lazy loading/restoring thread statesAndrei Vagin
PiperOrigin-RevId: 324748508
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
2020-07-23Add AfterFunc to tcpip.ClockSam Balana
Changes the API of tcpip.Clock to also provide a method for scheduling and rescheduling work after a specified duration. This change also implements the AfterFunc method for existing implementations of tcpip.Clock. This is the groundwork required to mock time within tests. All references to CancellableTimer has been replaced with the tcpip.Job interface, allowing for custom implementations of scheduling work. This is a BREAKING CHANGE for clients that implement their own tcpip.Clock or use tcpip.CancellableTimer. Migration plan: 1. Add AfterFunc(d, f) to tcpip.Clock 2. Replace references of tcpip.CancellableTimer with tcpip.Job 3. Replace calls to tcpip.CancellableTimer#StopLocked with tcpip.Job#Cancel 4. Replace calls to tcpip.CancellableTimer#Reset with tcpip.Job#Schedule 5. Replace calls to tcpip.NewCancellableTimer with tcpip.NewJob. PiperOrigin-RevId: 322906897
2020-07-09Gate FUSE behind a runsc flagRidwan Sharif
This change gates all FUSE commands (by gating /dev/fuse) behind a runsc flag. In order to use FUSE commands, use the --fuse flag with the --vfs2 flag. Check if FUSE is enabled by running dmesg in the sandbox.
2020-06-23Support for saving pointers to fields in the state package.Adin Scannell
Previously, it was not possible to encode/decode an object graph which contained a pointer to a field within another type. This was because the encoder was previously unable to disambiguate a pointer to an object and a pointer within the object. This CL remedies this by constructing an address map tracking the full memory range object occupy. The encoded Refvalue message has been extended to allow references to children objects within another object. Because the encoding process may learn about object structure over time, we cannot encode any objects under the entire graph has been generated. This CL also updates the state package to use standard interfaces intead of reflection-based dispatch in order to improve performance overall. This includes a custom wire protocol to significantly reduce the number of allocations and take advantage of structure packing. As part of these changes, there are a small number of minor changes in other places of the code base: * The lists used during encoding are changed to use intrusive lists with the objectEncodeState directly, which required that the ilist Len() method is updated to work properly with the ElementMapper mechanism. * A bug is fixed in the list code wherein Remove() called on an element that is already removed can corrupt the list (removing the element if there's only a single element). Now the behavior is correct. * Standard error wrapping is introduced. * Compressio was updated to implement the new wire.Reader and wire.Writer inteface methods directly. The lack of a ReadByte and WriteByte caused issues not due to interface dispatch, but because underlying slices for a Read or Write call through an interface would always escape to the heap! * Statify has been updated to support the new APIs. See README.md for a description of how the new mechanism works. PiperOrigin-RevId: 318010298
2020-06-16Port aio to VFS2.Nicolas Lacasse
In order to make sure all aio goroutines have stopped during S/R, a new WaitGroup was added to TaskSet, analagous to runningGoroutines. This WaitGroup is incremented with each aio goroutine, and waited on during kernel.Pause. The old VFS1 aio code was changed to use this new WaitGroup, rather than fs.Async. The only uses of fs.Async are now inode and mount Release operations, which do not call fs.Async recursively. This fixes a lock-ordering violation that can cause deadlocks. Updates #1035. PiperOrigin-RevId: 316689380
2020-06-16Miscellaneous VFS2 fixes.Jamie Liu
PiperOrigin-RevId: 316627764
2020-06-09Implement flock(2) in VFS2Fabricio Voznika
LockFD is the generic implementation that can be embedded in FileDescriptionImpl implementations. Unique lock ID is maintained in vfs.FileDescription and is created on demand. Updates #1480 PiperOrigin-RevId: 315604825
2020-05-14Port memfd_create to vfs2 and finish implementation of file seals.Nicolas Lacasse
Closes #2612. PiperOrigin-RevId: 311548074
2020-05-07Allocate device numbers for VFS2 filesystems.Jamie Liu
Updates #1197, #1198, #1672 PiperOrigin-RevId: 310432006
2020-05-07Move pkg/sentry/vfs/{eventfd,timerfd} to new packages in pkg/sentry/fsimpl.Nicolas Lacasse
They don't depend on anything in VFS2, so they should be their own packages. PiperOrigin-RevId: 310416807
2020-04-24Move hostfs mount to Kernel struct.Dean Deng
This is needed to set up host fds passed through a Unix socket. Note that the host package depends on kernel, so we cannot set up the hostfs mount directly in Kernel.Init as we do for sockfs and pipefs. Also, adjust sockfs to make its setup look more like hostfs's and pipefs's. PiperOrigin-RevId: 308274053
2020-04-16Implement pipe(2) and pipe2(2) for VFS2.Jamie Liu
Updates #1035 PiperOrigin-RevId: 306968644
2020-04-06Port timerfd to VFS2.Nicolas Lacasse
PiperOrigin-RevId: 305067208
2020-04-04Record VFS2 sockets in global socket map.Dean Deng
Updates #1476, #1478, #1484, #1485. PiperOrigin-RevId: 304845354
2020-04-03Refactor software GSO code.Bhasker Hariharan
Software GSO implementation currently has a complicated code path with implicit assumptions that all packets to WritePackets carry same Data and it does this to avoid allocations on the path etc. But this makes it hard to reuse the WritePackets API. This change breaks all such assumptions by introducing a new Vectorised View API ReadToVV which can be used to cleanly split a VV into multiple independent VVs. Further this change also makes packet buffers linkable to form an intrusive list. This allows us to get rid of the array of packet buffers that are passed in the WritePackets API call and replace it with a list of packet buffers. While this code does introduce some more allocations in the benchmarks it doesn't cause any degradation. Updates #231 PiperOrigin-RevId: 304731742
2020-03-31Add socket filesystem and global disconnected socket mount for VFS2.Dean Deng
A socket mount where anonymous sockets will reside is added to the VirtualFilesystem. Socketfs is built on top of kernfs. Updates #1476, #1478, #1484, #1485. PiperOrigin-RevId: 304095251
2020-03-14Plumb VFS2 imported fds into virtual filesystem.Dean Deng
- When setting up the virtual filesystem, mount a host.filesystem to contain all files that need to be imported. - Make read/preadv syscalls to the host in cases where preadv2 may not be supported yet (likewise for writing). - Make save/restore functions in kernel/kernel.go return early if vfs2 is enabled. PiperOrigin-RevId: 300922353
2020-02-28Hide /dev/net/tun when using hostinet.Ting-Yu Wang
/dev/net/tun does not currently work with hostinet. This has caused some program starts failing because it thinks the feature exists. PiperOrigin-RevId: 297876196
2020-02-25Add option to skip stuck tasks waiting for address spaceFabricio Voznika
PiperOrigin-RevId: 297192390
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
2020-02-14Synchronize signalling with S/RgVisor bot
This is to fix a data race between sending an external signal to a ThreadGroup and kernel saving state for S/R. PiperOrigin-RevId: 295244281
2020-02-14Inline vfs.VirtualFilesystem in Kernel structgVisor bot
This saves one pointer dereference per VFS access. Updates #1623 PiperOrigin-RevId: 295216176
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
2020-02-05Add notes to relevant tests.Adin Scannell
These were out-of-band notes that can help provide additional context and simplify automated imports. PiperOrigin-RevId: 293525915
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
2019-12-26Initial procfs implementation in VFSv2Fabricio Voznika
Updates #1195 PiperOrigin-RevId: 287227722
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