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2020-10-23Rewrite reference leak checker without finalizers.Dean Deng
Our current reference leak checker uses finalizers to verify whether an object has reached zero references before it is garbage collected. There are multiple problems with this mechanism, so a rewrite is in order. With finalizers, there is no way to guarantee that a finalizer will run before the program exits. When an unreachable object with a finalizer is garbage collected, its finalizer will be added to a queue and run asynchronously. The best we can do is run garbage collection upon sandbox exit to make sure that all finalizers are enqueued. Furthermore, if there is a chain of finalized objects, e.g. A points to B points to C, garbage collection needs to run multiple times before all of the finalizers are enqueued. The first GC run will register the finalizer for A but not free it. It takes another GC run to free A, at which point B's finalizer can be registered. As a result, we need to run GC as many times as the length of the longest such chain to have a somewhat reliable leak checker. Finally, a cyclical chain of structs pointing to one another will never be garbage collected if a finalizer is set. This is a well-known issue with Go finalizers (https://github.com/golang/go/issues/7358). Using leak checking on filesystem objects that produce cycles will not work and even result in memory leaks. The new leak checker stores reference counted objects in a global map when leak check is enabled and removes them once they are destroyed. At sandbox exit, any remaining objects in the map are considered as leaked. This provides a deterministic way of detecting leaks without relying on the complexities of finalizers and garbage collection. This approach has several benefits over the former, including: - Always detects leaks of objects that should be destroyed very close to sandbox exit. The old checker very rarely detected these leaks, because it relied on garbage collection to be run in a short window of time. - Panics if we forgot to enable leak check on a ref-counted object (we will try to remove it from the map when it is destroyed, but it will never have been added). - Can store extra logging information in the map values without adding to the size of the ref count struct itself. With the size of just an int64, the ref count object remains compact, meaning frequent operations like IncRef/DecRef are more cache-efficient. - Can aggregate leak results in a single report after the sandbox exits. Instead of having warnings littered in the log, which were non-deterministically triggered by garbage collection, we can print all warning messages at once. Note that this could also be a limitation--the sandbox must exit properly for leaks to be detected. Some basic benchmarking indicates that this change does not significantly affect performance when leak checking is enabled, which is understandable since registering/unregistering is only done once for each filesystem object. Updates #1486. PiperOrigin-RevId: 338685972
2020-10-22Load spec during "runsc start" to process flag overridesFabricio Voznika
Subcontainers are only configured when the container starts, however because start doesn't load the spec, flag annotations that may override flags were not getting applied to the configuration. Updates #3494 PiperOrigin-RevId: 338610953
2020-10-21Merge pull request #3957 from workato:auto-cgroupgVisor bot
PiperOrigin-RevId: 338372736
2020-10-20Do not even try forcing cgroups in testsKonstantin Baranov
2020-10-20Add /dev to mandatory mounts testFabricio Voznika
PiperOrigin-RevId: 338072845
2020-10-19Fix runsc tests on VFS2 overlay.Jamie Liu
- Check the sticky bit in overlay.filesystem.UnlinkAt(). Fixes StickyTest.StickyBitPermDenied. - When configuring a VFS2 overlay in runsc, copy the lower layer's root owner/group/mode to the upper layer's root (as in the VFS1 equivalent, boot.addOverlay()). This makes the overlay root owned by UID/GID 65534 with mode 0755 rather than owned by UID/GID 0 with mode 01777. Fixes CreateTest.CreateFailsOnUnpermittedDir, which assumes that the test cannot create files in /. - MknodTest.UnimplementedTypesReturnError assumes that the creation of device special files is not supported. However, while the VFS2 gofer client still doesn't support device special files, VFS2 tmpfs does, and in the overlay test dimension mknod() targets a tmpfs upper layer. The test initially has all capabilities, including CAP_MKNOD, so its creation of these files succeeds. Constrain these tests to VFS1. - Rename overlay.nonDirectoryFD to overlay.regularFileFD and only use it for regular files, using the original FD for pipes and device special files. This is more consistent with Linux (which gets the original inode_operations, and therefore file_operations, for these file types from ovl_fill_inode() => init_special_inode()) and fixes remaining mknod and pipe tests. - Read/write 1KB at a time in PipeTest.Streaming, rather than 4 bytes. This isn't strictly necessary, but it makes the test less obnoxiously slow on ptrace. Fixes #4407 PiperOrigin-RevId: 337971042
2020-10-19Remove legacy bazel configurations.Adin Scannell
Using the newer bazel rules necessitates a transition from proto1 to proto2. In order to resolve the incompatibility between proto2 and gogoproto, the cri runtimeoptions proto must be vendored. Further, some of the semantics of bazel caching changed during the transition. It is now necessary to: - Ensure that :gopath depends only on pure library targets, as the propagation of go_binary build attributes (pure, static) will affected the generated files (though content remains the same, there are conflicts with respect to the gopath). - Update bazel.mk to include the possibility of binaries in the bazel-out directory, as it will now put runsc and others there. This required some refinements to the mechanism of extracting paths, since some the existing regex resulted in false positives. - Change nogo rules to prevent escape generation on binary targets. For some reason, the newer version of bazel attempted to run the nogo analysis on the binary targets, which fails due to the fact that objdump does not work on the final binary. This must be due to a change in the semantics of aspects in bazel3. PiperOrigin-RevId: 337958324
2020-10-19Fixes to cgroupsFabricio Voznika
There were a few problems with cgroups: - cleanup loop what breaking too early - parse of /proc/[pid]/cgroups was skipping "name=systemd" because "name=" was not being removed from name. - When no limits are specified, fillFromAncestor was not being called, causing a failure to set cpuset.mems Updates #4536 PiperOrigin-RevId: 337947356
2020-10-15`runsc do` fallback to internal network on failureFabricio Voznika
In case setting up network fails, log a warning and fallback to internal network. Closes #4498 PiperOrigin-RevId: 337442632
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
2020-10-12[vfs2] Don't leak disconnected mounts.Dean Deng
PiperOrigin-RevId: 336694658
2020-10-07Add staticcheck and staticstyle analyzers.Adin Scannell
This change also adds support to go_stateify for detecting an appropriate receiver name, avoiding a large number of false positives. PiperOrigin-RevId: 335994587
2020-10-06Ignore errors in rootless and test modesKonstantin Baranov
2020-10-06Merge pull request #4355 from majek:marek/swallow-SO_RCVBUFFORCE-errorgVisor bot
PiperOrigin-RevId: 335714100
2020-10-06Implement membarrier(2) commands other than *_SYNC_CORE.Jamie Liu
Updates #267 PiperOrigin-RevId: 335713923
2020-10-05Fix gofer monitor prematurely destroying containerFabricio Voznika
When all container tasks finish, they release the mount which in turn will close the 9P session to the gofer. The gofer exits when the connection closes, triggering the gofer monitor. The gofer monitor will _think_ that the gofer died prematurely and destroy the container. Then when the caller attempts to wait for the container, e.g. to get the exit code, wait fails saying the container doesn't exist. Gofer monitor now just SIGKILLs the container, and let the normal teardown process to happen, which will evetually destroy the container at the right time. Also, fixed an issue with exec racing with container's init process exiting. Closes #1487 PiperOrigin-RevId: 335537350
2020-10-05Merge pull request #3970 from benbuzbee:gomaxprocsgVisor bot
PiperOrigin-RevId: 335516972
2020-10-05Enable more VFS2 testsFabricio Voznika
Updates #1487 PiperOrigin-RevId: 335516732
2020-10-02Treat absent "linux" section is empty "cgroupsPath" tooKonstantin Baranov
2020-09-30Use consistent thread configuration for sandbox go runtimeBen Buzbee
With cgroups configured NumCPU is correct, however GOMAXPROCS is still derived from total host core count and ignores cgroup restrictions. This can lead to different and undesired behavior across different hosts. For example, the total number of threads in the guest process will be larger on machines with more cores. This change configures the go runtime for the sandbox to only use the number of threads consistent with its restrictions.
2020-09-28Support creating protocol instances with Stack refGhanan Gowripalan
Network or transport protocols may want to reach the stack. Support this by letting the stack create the protocol instances so it can pass a reference to itself at protocol creation time. Note, protocols do not yet use the stack in this CL but later CLs will make use of the stack from protocols. PiperOrigin-RevId: 334260210
2020-09-25Add openat() to list of permitted syscalls in gotsan runs.Bhasker Hariharan
PiperOrigin-RevId: 333853498
2020-09-25Swallow SO_RCVBUFFORCE and SO_SNDBUFFORCE errors on SOCK_RAW socketsMarek Majkowski
In --network=sandbox mode, we create SOCK_RAW sockets on the given network device. The code tries to force-set 4MiB rcv and snd buffers on it, but in certain situations it might fail. There is no reason for refusing the sandbox startup in such case - we should bump the buffers to max availabe size and just move on.
2020-09-25fix seccomp test for ARM64Howard Zhang
As open syscall is not support on ARM64, change syscall from 'open' to 'openat' in no_match_name_allow Signed-off-by: Howard Zhang <howard.zhang@arm.com>
2020-09-25fix TestUserLog for multi-archHoward Zhang
based on arch, apply different syscall number for sched_rr_get_interval Signed-off-by: Howard Zhang <howard.zhang@arm.com>
2020-09-22Allow CLONE_SETTLS for Go 1.16Michael Pratt
https://go.googlesource.com/go/+/0941fc3 switches the Go runtime (on amd64) from using arch_prctl(ARCH_SET_FS) to CLONE_SETTLS to set the TLS. PiperOrigin-RevId: 333100550
2020-09-22Force clone parent_tidptr and child_tidptr to zeroMichael Pratt
Neither CLONE_PARENT_SETTID nor CLONE_CHILD_SETTID are used, so these arguments will always be NULL. PiperOrigin-RevId: 333085326
2020-09-18Drop ARCH_GET_FSMichael Pratt
Go does not call arch_prctl(ARCH_GET_FS), nor am I sure it ever did. Drop the filter. PiperOrigin-RevId: 332470532
2020-09-17Remove option to panic goferFabricio Voznika
Gofer panics are suppressed by p9 server and an error is returned to the caller, making it effectively the same as returning EROFS. PiperOrigin-RevId: 332282959
2020-09-17Add VFS2 overlay support in runscFabricio Voznika
All tests under runsc are passing with overlay enabled. Updates #1487, #1199 PiperOrigin-RevId: 332181267
2020-09-16Refactor removed default test dimensionFabricio Voznika
ptrace was always selected as a dimension before, but not anymore. Some tests were specifying "overlay" expecting that to be in addition to the default. PiperOrigin-RevId: 332004111
2020-09-15Add support for OCI seccomp filters in the sandbox.Ian Lewis
OCI configuration includes support for specifying seccomp filters. In runc, these filter configurations are converted into seccomp BPF programs and loaded into the kernel via libseccomp. runsc needs to be a static binary so, for runsc, we cannot rely on a C library and need to implement the functionality in Go. The generator added here implements basic support for taking OCI seccomp configuration and converting it into a seccomp BPF program with the same behavior as a program generated by libseccomp. - New conditional operations were added to pkg/seccomp to support operations available in OCI. - AllowAny and AllowValue were renamed to MatchAny and EqualTo to better reflect that syscalls matching the conditionals result in the provided action not simply SCMP_RET_ALLOW. - BuildProgram in pkg/seccomp no longer panics if provided an empty list of rules. It now builds a program with the architecture sanity check only. - ProgramBuilder now allows adding labels that are unused. However, backwards jumps are still not permitted. Fixes #510 PiperOrigin-RevId: 331938697
2020-09-15Use container ID as cgroup name if not providedKonstantin Baranov
Useful when you want to run multiple containers with the same config. And runc does that too.
2020-09-08Honor readonly flag for root mountFabricio Voznika
Updates #1487 PiperOrigin-RevId: 330580699
2020-09-08Improve type safety for transport protocol optionsGhanan Gowripalan
The existing implementation for TransportProtocol.{Set}Option take arguments of an empty interface type which all types (implicitly) implement; any type may be passed to the functions. This change introduces marker interfaces for transport protocol options that may be set or queried which transport protocol option types implement to ensure that invalid types are caught at compile time. Different interfaces are used to allow the compiler to enforce read-only or set-only socket options. RELNOTES: n/a PiperOrigin-RevId: 330559811
2020-09-04Simplify FD handling for container start/execFabricio Voznika
VFS1 and VFS2 host FDs have different dupping behavior, making error prone to code for both. Change the contract so that FDs are released as they are used, so the caller can simple defer a block that closes all remaining files. This also addresses handling of partial failures. With this fix, more VFS2 tests can be enabled. Updates #1487 PiperOrigin-RevId: 330112266
2020-09-02Merge pull request #3822 from btw616:fix/issue-3821gVisor bot
PiperOrigin-RevId: 329710371
2020-09-01Implement setattr+clunk in 9PFabricio Voznika
This is to cover the common pattern: open->read/write->close, where SetAttr needs to be called to update atime/mtime before the file is closed. Benchmark results: BM_OpenReadClose/10240 CPU setattr+clunk: 63783 ns VFS2: 68109 ns VFS1: 72507 ns Updates #1198 PiperOrigin-RevId: 329628461
2020-09-01Refactor tty codebase to use master-replica terminology.Ayush Ranjan
Updates #2972 PiperOrigin-RevId: 329584905
2020-09-01Let flags be overriden from OCI annotationsFabricio Voznika
This allows runsc flags to be set per sandbox instance. For example, K8s pod annotations can be used to enable --debug for a single pod, making troubleshoot much easier. Similarly, features like --vfs2 can be enabled for experimentation without affecting other pods in the node. Closes #3494 PiperOrigin-RevId: 329542815
2020-09-01Dup stdio FDs for VFS2 when starting a child containerTiwei Bie
Currently the stdio FDs are not dupped and will be closed unexpectedly in VFS2 when starting a child container. This patch fixes this issue. Fixes: #3821 Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
2020-08-28Improve type safety for network protocol optionsGhanan Gowripalan
The existing implementation for NetworkProtocol.{Set}Option take arguments of an empty interface type which all types (implicitly) implement; any type may be passed to the functions. This change introduces marker interfaces for network protocol options that may be set or queried which network protocol option types implement to ensure that invalid types are caught at compile time. Different interfaces are used to allow the compiler to enforce read-only or set-only socket options. PiperOrigin-RevId: 328980359
2020-08-26Make flag propagation automaticFabricio Voznika
Use reflection and tags to provide automatic conversion from Config to flags. This makes adding new flags less error-prone, skips flags using default values (easier to read), and makes tests correctly use default flag values for test Configs. Updates #3494 PiperOrigin-RevId: 328662070
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
2020-08-25Include shim in individual released binaries.Adin Scannell
The debian rules are also moved to the top-level, since they apply to binaries outside the //runsc directory. Fixes #3665 PiperOrigin-RevId: 328379709
2020-08-21[vfs] Allow mountpoint to be an existing non-directory.Ayush Ranjan
Unlike linux mount(2), OCI spec allows mounting on top of an existing non-directory file. PiperOrigin-RevId: 327914342
2020-08-21Make mounts ReadWrite first, then later change to ReadOnly.Nicolas Lacasse
This lets us create "synthetic" mountpoint directories in ReadOnly mounts during VFS setup. Also add context.WithMountNamespace, as some filesystems (like overlay) require a MountNamespace on ctx to handle vfs.Filesystem Operations. PiperOrigin-RevId: 327874971
2020-08-20[vfs] Create recursive dir creation util.Ayush Ranjan
Refactored the recursive dir creation util in runsc/boot/vfs.go to be more flexible. PiperOrigin-RevId: 327719100
2020-08-19Move boot.Config to its own packageFabricio Voznika
Updates #3494 PiperOrigin-RevId: 327548511
2020-08-19Remove path walk from localFile.MknodFabricio Voznika
Replace mknod call with mknodat equivalent to protect against symlink attacks. Also added Mknod tests. Remove goferfs reliance on gofer to check for file existence before creating a synthetic entry. Updates #2923 PiperOrigin-RevId: 327544516