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2020-10-23Check for verity file/Merkle file when reopenChong Cai
Even if the child dentry has been cached, we should still check whether the file and the corresponding Merkle tree file exist as expected. This ensures that we can detect deletion/renaming of files that have been previous enabled and opened. Also make all verification failures to return EIO. This helps to test verify failures. PiperOrigin-RevId: 338709055
2020-10-23Support getsockopt for SO_ACCEPTCONN.Nayana Bidari
The SO_ACCEPTCONN option is used only on getsockopt(). When this option is specified, getsockopt() indicates whether socket listening is enabled for the socket. A value of zero indicates that socket listening is disabled; non-zero that it is enabled. PiperOrigin-RevId: 338703206
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
2020-10-21Check for nil in kernel.FSContext functions.Dean Deng
Reported-by: syzbot+c0e175d2b10708314eb3@syzkaller.appspotmail.com PiperOrigin-RevId: 338386575
2020-10-21Merge pull request #4535 from lubinszARM:pr_kvm_exec_binary_1gVisor bot
PiperOrigin-RevId: 338321125
2020-10-20Merge pull request #4524 from lemin9538:lemin_arm64gVisor bot
PiperOrigin-RevId: 338126491
2020-10-19loader/elf: validate file offsetAndrei Vagin
Reported-by: syzbot+7406eef8247cb5a20855@syzkaller.appspotmail.com PiperOrigin-RevId: 337974474
2020-10-19Fix reference counting on kcov mappings.Dean Deng
Reported-by: syzbot+078580ce5dd6d607fcd8@syzkaller.appspotmail.com Reported-by: syzbot+2096681f6891e7bf8aed@syzkaller.appspotmail.com PiperOrigin-RevId: 337973519
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
2020-10-19[vfs2] Fix fork reference leaks.Dean Deng
PiperOrigin-RevId: 337919424
2020-10-19splice: return EINVAL is len is negativeAndrei Vagin
Reported-by: syzbot+0268cc591c0f517a1de0@syzkaller.appspotmail.com PiperOrigin-RevId: 337901664
2020-10-19pgalloc: Do not hold MemoryFile.mu while calling mincore.Ayush Ranjan
This change makes the following changes: - Unlocks MemoryFile.mu while calling mincore (checkCommitted) because mincore can take a really long time. Accordingly looks up the segment in the tree tree again and handles changes to the segment. - MemoryFile.UpdateUsage() can now only be called at frequency at most 100Hz. 100 Hz = linux.CLOCKS_PER_SEC. Co-authored-by: Jamie Liu <jamieliu@google.com> PiperOrigin-RevId: 337865250
2020-10-18arm64 kvm: handle exception from accessing undefined instructionBin Lu
Consistent with the linux approach, we will produce a sigill to handle el0_undef. After applying this patch, exec_binary_test_runsc_kvm will be passed on Arm64. Signed-off-by: Bin Lu <bin.lu@arm.com>
2020-10-16Merge pull request #4387 from lubinszARM:pr_tls_host_sentry_1gVisor bot
PiperOrigin-RevId: 337544656
2020-10-15sockets: ignore io.EOF from view.ReadAtAndrei Vagin
Reported-by: syzbot+5466463b7604c2902875@syzkaller.appspotmail.com PiperOrigin-RevId: 337451896
2020-10-15Change verity isEnable to be a member of dentryChong Cai
PiperOrigin-RevId: 337384146
2020-10-15arm64: the ASID offset of TTBR register is 48Min Le
Signed-off-by: Min Le <lemin.lm@antgroup.com>
2020-10-14Fix SCM Rights reference leaks.Dean Deng
Control messages should be released on Read (which ignores the control message) or zero-byte Send. Otherwise, open fds sent through the control messages will be leaked. PiperOrigin-RevId: 337110774
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
2020-10-13Merge pull request #4482 from lemin9538:lemin_arm64gVisor bot
PiperOrigin-RevId: 336976081
2020-10-13Merge pull request #4386 from lubinszARM:pr_testutil_tls_usrgVisor bot
PiperOrigin-RevId: 336970511
2020-10-13Merge pull request #4374 from lubinszARM:pr_ffmpeg_kvm_01gVisor bot
PiperOrigin-RevId: 336962937
2020-10-13Don't read beyond EOF when inserting into sentry page cache.Jamie Liu
The sentry page cache stores file contents at page granularity; this is necessary for memory mappings. Thus file offset ranges passed to fsutil.FileRangeSet.Fill() must be page-aligned. If the read callback passed to Fill() returns (partial read, nil error) when reading up to EOF (which is the case for p9.ClientFile.ReadAt() since 9P's Rread cannot convey both a partial read and EOF), Fill() will re-invoke the read callback to try to read from EOF to the end of the containing page, which is harmless but needlessly expensive. Fix this by handling file size explicitly in fsutil.FileRangeSet.Fill(). PiperOrigin-RevId: 336934075
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
2020-10-13Avoid excessive Tgkill and wait operations.Adin Scannell
The required states may simply not be observed by the thread running bounce, so track guest and user generations to ensure that at least one of the desired state transitions happens. Fixes #3532 PiperOrigin-RevId: 336908216
2020-10-13[vfs2] Destroy all tmpfs files when the filesystem is released.Dean Deng
In addition to fixing reference leaks, this change also releases memory used by regular tmpfs files once the containing filesystem is released. PiperOrigin-RevId: 336833111
2020-10-13[vfs2] Add FilesystemType.Release to avoid reference leaks.Dean Deng
Singleton filesystem like devpts and devtmpfs have a single filesystem shared among all mounts, so they acquire a "self-reference" when initialized that must be released when the entire virtual filesystem is released at sandbox exit. PiperOrigin-RevId: 336828852
2020-10-13Don't leak VDSO mappings.Dean Deng
PiperOrigin-RevId: 336822021
2020-10-12Change verity mu to be per file systemChong Cai
verity Mu should be per file system instead of global, so that enabling and verifying in different file systems won't block each other. Also Lock verity Mu in PRead. PiperOrigin-RevId: 336779356
2020-10-12Change Merkle tree library to use ReaderAtChong Cai
Merkle tree library was originally using Read/Seek to access data and tree, since the parameters are io.ReadSeeker. This could cause race conditions if multiple threads accesses the same fd to read. Here we change to use ReaderAt, and implement it with PRead to make it thread safe. PiperOrigin-RevId: 336779260
2020-10-12[vfs] kernfs: Fix inode memory leak issue.Ayush Ranjan
This change aims to fix the memory leak issue reported inĀ #3933. Background: VFS2 kernfs kept accumulating invalid dentries if those dentries were not walked on. After substantial consideration of the problem by our team, we decided to have an LRU cache solution. This change is the first part to that solution, where we don't cache anything. The LRU cache can be added on top of this. What has changed: - Introduced the concept of an inode tree in kernfs.OrderedChildren. This is helpful is cases where the lifecycle of an inode is different from that of a dentry. - OrderedChildren now deals with initialized inodes instead of initialized dentries. It now implements Lookup() where it constructs a new dentry using the inode. - OrderedChildren holds a ref on all its children inodes. With this change, now an inode can "outlive" a dentry pointing to it. See comments in kernfs.OrderedChildren. - The kernfs dentry tree is solely maintained by kernfs only. Inode implementations can not modify the dentry tree. - Dentries that reach ref count 0 are removed from the dentry tree. - revalidateChildLocked now defer-DecRefs the newly created dentry from Inode.Lookup(), limiting its life to the current filesystem operation. If refs are picked on the dentry during the FS op (via an FD or something), then it will stick around and will be removed when the FD is closed. So there is essentially _no caching_ for Look()ed up dentries. - kernfs.DecRef does not have the precondition that fs.mu must be locked. Fixes #3933 PiperOrigin-RevId: 336768576
2020-10-12Merge pull request #4072 from adamliyi:droppt_fixgVisor bot
PiperOrigin-RevId: 336719900
2020-10-12[vfs2] Don't leak disconnected mounts.Dean Deng
PiperOrigin-RevId: 336694658
2020-10-11arm64 kvm: add tls-usr supportBin Lu
The tls of guest-el1-sentry and host-el0-sentry may be different on Arm64. I added a solution for it. Signed-off-by: Bin Lu <bin.lu@arm.com>
2020-10-10arm64: set DZE bit to make EL0 can use DC ZVAMin Le
Signed-off-by: Min Le <lemin.lm@antgroup.com>
2020-10-09Include stat in Verity hashChong Cai
PiperOrigin-RevId: 336395445
2020-10-09platform/kvm: remove the unused fieldAndrei Vagin
PiperOrigin-RevId: 336366624
2020-10-09Merge pull request #4040 from lemin9538:lemin_arm64gVisor bot
PiperOrigin-RevId: 336362818
2020-10-09Reduce the cost of sysinfo(2).Jamie Liu
- sysinfo(2) does not actually require a fine-grained breakdown of memory usage. Accordingly, instead of calling pgalloc.MemoryFile.UpdateUsage() to update the sentry's fine-grained memory accounting snapshot, just use pgalloc.MemoryFile.TotalUsage() (which is a single fstat(), and therefore far cheaper). - Use the number of threads in the root PID namespace (i.e. globally) rather than in the task's PID namespace for consistency with Linux (which just reads global variable nr_threads), and add a new method to kernel.PIDNamespace to allow this to be read directly from an underlying map rather than requiring the allocation and population of an intermediate slice. PiperOrigin-RevId: 336353100
2020-10-09Automated rollback of changelist 336304024Ghanan Gowripalan
PiperOrigin-RevId: 336339194
2020-10-09syscalls: Don't leak a file on the error pathAndrei Vagin
Reported-by: syzbot+bb82fb556d5d0a43f632@syzkaller.appspotmail.com PiperOrigin-RevId: 336324720
2020-10-09Automated rollback of changelist 336185457Bhasker Hariharan
PiperOrigin-RevId: 336304024
2020-10-08Implement MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ.Jamie Liu
cf. 2a36ab717e8f "rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ" PiperOrigin-RevId: 336186795
2020-10-08Do not resolve routes immediatelyGhanan Gowripalan
When a response needs to be sent to an incoming packet, the stack should consult its neighbour table to determine the remote address's link address. When an entry does not exist in the stack's neighbor table, the stack should queue the packet while link resolution completes. See comments. PiperOrigin-RevId: 336185457
2020-10-08arm64: the mair_el1 value is wrongMin Le
the correct value needed is 0xbbff440c0400 but the const defined is 0x000000000000ffc0 due to the operator error in _MT_EL1_INIT, both kernel and user space memory attribute should be Normal memory not DEVICE_nGnRE Signed-off-by: Min Le <lemin.lm@antgroup.com>
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
2020-10-07Merge pull request #4376 from lubinszARM:pr_usr_tls_newgVisor bot
PiperOrigin-RevId: 335930035
2020-10-07Add precise synchronization to KVM.Adin Scannell
By using TSC scaling as a hack, we can trick the kernel into setting an offset of exactly zero. Huzzah! PiperOrigin-RevId: 335922019
2020-10-06Implement membarrier(2) commands other than *_SYNC_CORE.Jamie Liu
Updates #267 PiperOrigin-RevId: 335713923
2020-10-06[vfs2] Don't leak reference from Mountnamespace.Root().Dean Deng
PiperOrigin-RevId: 335583637