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2020-05-12Don't allow rename across different gofer or tmpfs mounts.Nicolas Lacasse
Fixes #2651. PiperOrigin-RevId: 311193661
2020-05-07Update privateunixsocket TODOs.Dean Deng
Synthetic sockets do not have the race condition issue in VFS2, and we will get rid of privateunixsocket as well. Fixes #1200. PiperOrigin-RevId: 310386474
2020-05-06Add maximum memory limit.Nicolas Lacasse
PiperOrigin-RevId: 310179277
2020-05-05Translate p9.NoUID/GID to OverflowUID/GID.Jamie Liu
p9.NoUID/GID (== uint32(-1) == auth.NoID) is not a valid auth.KUID/KGID; in particular, using it for file ownership causes capabilities to be ineffective since file capabilities require that the file's KUID and KGID are mapped into the capability holder's user namespace [1], and auth.NoID is not mapped into any user namespace. Map p9.NoUID/GID to a different, valid KUID/KGID; in the unlikely case that an application actually using the overflow KUID/KGID attempts an operation that is consequently permitted by client permission checks, the remote operation will still fail with EPERM. Since this changes the VFS2 gofer client to no longer ignore the invalid IDs entirely, this CL both permits and requires that we change synthetic mount point creation to use root credentials. [1] See fs.Inode.CheckCapability or vfs.GenericCheckPermissions. PiperOrigin-RevId: 309856455
2020-04-28Support pipes and sockets in VFS2 gofer fs.Dean Deng
Named pipes and sockets can be represented in two ways in gofer fs: 1. As a file on the remote filesystem. In this case, all file operations are passed through 9p. 2. As a synthetic file that is internal to the sandbox. In this case, the dentry stores an endpoint or VFSPipe for sockets and pipes respectively, which replaces interactions with the remote fs through the gofer. In gofer.filesystem.MknodAt, we attempt to call mknod(2) through 9p, and if it fails, fall back to the synthetic version. Updates #1200. PiperOrigin-RevId: 308828161
2020-04-27Import host sockets.Dean Deng
The FileDescription implementation for hostfs sockets uses the standard Unix socket implementation (unix.SocketVFS2), but is also tied to a hostfs dentry. Updates #1672, #1476 PiperOrigin-RevId: 308716426
2020-04-24Port SCM Rights to VFS2.Dean Deng
Fixes #1477. PiperOrigin-RevId: 308317511
2020-04-23Port devpts to VFS2.Nicolas Lacasse
PiperOrigin-RevId: 308164359
2020-04-22Move user home detection to its own library.Nicolas Lacasse
PiperOrigin-RevId: 307977689
2020-04-21Misc VFS2 fixesFabricio Voznika
- Fix defer operation ordering in kernfs.Filesystem.AccessAt() - Add AT_NULL entry in proc/pid/auvx - Fix line padding in /proc/pid/maps - Fix linux_dirent serialization for getdents(2) - Remove file creation flags from vfs.FileDescription.statusFlags() Updates #1193, #1035 PiperOrigin-RevId: 307704159
2020-04-21Sentry metrics updates.Dave Bailey
Sentry metrics with nanoseconds units are labeled as such, and non-cumulative sentry metrics are supported. PiperOrigin-RevId: 307621080
2020-04-13Remove obsolete TODOs for b/38173783Jon Budd
The comments in the ticket indicate that this behavior is fine and that the ticket should be closed, so we shouldn't need pointers to the ticket. PiperOrigin-RevId: 306266071
2020-04-10Use O_CLOEXEC when dup'ing FDsFabricio Voznika
The sentry doesn't allow execve, but it's a good defense in-depth measure. PiperOrigin-RevId: 305958737
2020-04-09Merge pull request #2253 from amscanne:nogogVisor bot
PiperOrigin-RevId: 305807868
2020-04-09Downgrade VFS1-specific FIXME to a NOTE.Jamie Liu
PiperOrigin-RevId: 305794509
2020-04-08Clean up TODOsFabricio Voznika
PiperOrigin-RevId: 305592245
2020-04-08Remove InodeOperations FIXMEs that will be obsoleted by VFS2.Dean Deng
PiperOrigin-RevId: 305588941
2020-04-08Handle utimes correctly for shared gofer filesystems.Dean Deng
Determine system time from within the sentry rather than relying on the remote filesystem to prevent inconsistencies. Resolve related TODOs; the time discrepancies in question don't exist anymore. PiperOrigin-RevId: 305557099
2020-04-08Enable SubprocessExited and SubprocessZombie for gVisorFabricio Voznika
Updates #164 PiperOrigin-RevId: 305544029
2020-04-08Fix all printf formatting errors.Adin Scannell
Updates #2243
2020-04-08Fix all copy locks violations.Adin Scannell
This required minor restructuring of how system call tables were saved and restored, but it makes way more sense this way. Updates #2243
2020-04-02Fix typo in TODO comments.Dean Deng
PiperOrigin-RevId: 304508083
2020-03-31Include original copyUp error in panic if cleanupUpper fails.Nicolas Lacasse
When copyUp fails, we attempt to clean up the upper filesystem by removing any files that have already been copied-up. If the cleanup fails, we panic because the "overlay filesystem is in an inconsistent state". This CL adds the original copy-up error to the panic information, to hopefully make it easier to track down how the overlay filesystem got into the inconsistent state. PiperOrigin-RevId: 304053370
2020-03-26Use host-defined file owner and mode, when possible, for imported fds.Dean Deng
Using the host-defined file owner matches VFS1. It is more correct to use the host-defined mode, since the cached value may become out of date. However, kernfs.Inode.Mode() does not return an error--other filesystems on kernfs are in-memory so retrieving mode should not fail. Therefore, if the host syscall fails, we rely on a cached value instead. Updates #1672. PiperOrigin-RevId: 303220864
2020-03-19Remove the "frozen" bit from dirents.Zach Koopmans
Frozen was to lock down changes to the host filesystem for hostFS. Now that hostFS is gone, it can be removed. PiperOrigin-RevId: 301907923
2020-03-18Port imported TTY fds to vfs2.Dean Deng
Refactor fs/host.TTYFileOperations so that the relevant functionality can be shared with VFS2 (fsimpl/host.ttyFD). Incorporate host.defaultFileFD into the default host.fileDescription. This way, there is no need for a separate default_file.go. As in vfs1, the TTY file implementation can be built on top of this default and override operations as necessary (PRead/Read/PWrite/Write, Release, Ioctl). Note that these changes still need to be plumbed into runsc, which refers to imported TTYs in control/proc.go:ExecAsync. Updates #1672. PiperOrigin-RevId: 301718157
2020-03-17Remove HostFS from Sentry.Zach Koopmans
PiperOrigin-RevId: 301402181
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
2020-03-13Fix 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
2020-03-09Move /proc/net to /proc/PID/net, and make /proc/net -> /proc/self/net.Ting-Yu Wang
Issue #1833 PiperOrigin-RevId: 299998105
2020-03-06Add plumbing for importing fds in VFS2, along with non-socket, non-TTY impl.Dean Deng
In VFS2, imported file descriptors are stored in a kernfs-based filesystem. Upon calling ImportFD, the host fd can be accessed in two ways: 1. a FileDescription that can be added to the FDTable, and 2. a Dentry in the host.filesystem mount, which we will want to access through magic symlinks in /proc/[pid]/fd/. An implementation of the kernfs.Inode interface stores a unique host fd. This inode can be inserted into file descriptions as well as dentries. This change also plumbs in three FileDescriptionImpls corresponding to fds for sockets, TTYs, and other files (only the latter is implemented here). These implementations will mostly make corresponding syscalls to the host. Where possible, the logic is ported over from pkg/sentry/fs/host. Updates #1672 PiperOrigin-RevId: 299417263
2020-03-06Prevent memory leaks in ilistTamir Duberstein
When list elements are removed from a list but not discarded, it becomes important to invalidate the references they hold to their former neighbors to prevent memory leaks. PiperOrigin-RevId: 299412421
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
2020-03-02Take write lock when removing xattrMichael Pratt
PiperOrigin-RevId: 298380654
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
2020-02-25Fix DATA RACE in fs.MayDelete.Adin Scannell
MayDelete must lock the directory also, otherwise concurrent renames may race. Note that this also changes the methods to be aligned with the actual Remove and RemoveDirectory methods to minimize confusion when reading the code. (It was hard to see that resolution was correct.) PiperOrigin-RevId: 297258304
2020-02-25Fix mount refcount issue.Adin Scannell
Each mount is holds a reference on a root Dirent, but the mount itself may live beyond it's own reference. This means that a call to Root() can come after the associated reference has been dropped. Instead of introducing a separate layer of references for mount objects, we simply change the Root() method to use TryIncRef() and allow it to return nil if the mount is already gone. This requires updating a small number of callers and minimizes the change (since VFSv2 will replace this code shortly). PiperOrigin-RevId: 297174230
2020-02-21Implement tap/tun device in vfs.Ting-Yu Wang
PiperOrigin-RevId: 296526279
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
2020-02-11Ensure fsimpl/gofer.dentryPlatformFile.hostFileMapper is initialized.gVisor bot
Fixes #1812. (The more direct cause of the deadlock is panic unsafety because the historically high cost of defer means that we avoid it in hot paths, including much of MM; defer is much cheaper as of Go 1.14, but still a measurable overhead.) PiperOrigin-RevId: 294560316
2020-02-11Prevent DATA RACE in UnstableAttr.Adin Scannell
The slaveInodeOperations is currently copying the object when truncate is called (which is a no-op). This may result in a (unconsequential) data race when being modified concurrently. PiperOrigin-RevId: 294484276
2020-02-10Add context to comments.Adin Scannell
PiperOrigin-RevId: 294295852
2020-02-07Support listxattr and removexattr syscalls.Dean Deng
Note that these are only implemented for tmpfs, and other impls will still return EOPNOTSUPP. PiperOrigin-RevId: 293899385
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
2020-02-04VFS2 gofer clientJamie Liu
Updates #1198 Opening host pipes (by spinning in fdpipe) and host sockets is not yet complete, and will be done in a future CL. Major differences from VFS1 gofer client (sentry/fs/gofer), with varying levels of backportability: - "Cache policies" are replaced by InteropMode, which control the behavior of timestamps in addition to caching. Under InteropModeExclusive (analogous to cacheAll) and InteropModeWritethrough (analogous to cacheAllWritethrough), client timestamps are *not* written back to the server (it is not possible in 9P or Linux for clients to set ctime, so writing back client-authoritative timestamps results in incoherence between atime/mtime and ctime). Under InteropModeShared (analogous to cacheRemoteRevalidating), client timestamps are not used at all (remote filesystem clocks are authoritative). cacheNone is translated to InteropModeShared + new option filesystemOptions.specialRegularFiles. - Under InteropModeShared, "unstable attribute" reloading for permission checks, lookup, and revalidation are fused, which is feasible in VFS2 since gofer.filesystem controls path resolution. This results in a ~33% reduction in RPCs for filesystem operations compared to cacheRemoteRevalidating. For example, consider stat("/foo/bar/baz") where "/foo/bar/baz" fails revalidation, resulting in the instantiation of a new dentry: VFS1 RPCs: getattr("/") // fs.MountNamespace.FindLink() => fs.Inode.CheckPermission() => gofer.inodeOperations.check() => gofer.inodeOperations.UnstableAttr() walkgetattr("/", "foo") = fid1 // fs.Dirent.walk() => gofer.session.Revalidate() => gofer.cachePolicy.Revalidate() clunk(fid1) getattr("/foo") // CheckPermission walkgetattr("/foo", "bar") = fid2 // Revalidate clunk(fid2) getattr("/foo/bar") // CheckPermission walkgetattr("/foo/bar", "baz") = fid3 // Revalidate clunk(fid3) walkgetattr("/foo/bar", "baz") = fid4 // fs.Dirent.walk() => gofer.inodeOperations.Lookup getattr("/foo/bar/baz") // linux.stat() => gofer.inodeOperations.UnstableAttr() VFS2 RPCs: getattr("/") // gofer.filesystem.walkExistingLocked() walkgetattr("/", "foo") = fid1 // gofer.filesystem.stepExistingLocked() clunk(fid1) // No getattr: walkgetattr already updated metadata for permission check walkgetattr("/foo", "bar") = fid2 clunk(fid2) walkgetattr("/foo/bar", "baz") = fid3 // No clunk: fid3 used for new gofer.dentry // No getattr: walkgetattr already updated metadata for stat() - gofer.filesystem.unlinkAt() does not require instantiation of a dentry that represents the file to be deleted. Updates #898. - gofer.regularFileFD.OnClose() skips Tflushf for regular files under InteropModeExclusive, as it's nonsensical to request a remote file flush without flushing locally-buffered writes to that remote file first. - Symlink targets are cached when InteropModeShared is not in effect. - p9.QID.Path (which is already required to be unique for each file within a server, and is accordingly already synthesized from device/inode numbers in all known gofers) is used as-is for inode numbers, rather than being mapped along with attr.RDev in the client to yet another synthetic inode number. - Relevant parts of fsutil.CachingInodeOperations are inlined directly into gofer package code. This avoids having to duplicate part of its functionality in fsutil.HostMappable. PiperOrigin-RevId: 293190213
2020-02-04Add support for sentry internal pipe for gofer mountsFabricio Voznika
Internal pipes are supported similarly to how internal UDS is done. It is also controlled by the same flag. Fixes #1102 PiperOrigin-RevId: 293150045
2020-01-31Internal change.gVisor bot
PiperOrigin-RevId: 292587459
2020-01-30Enforce splice offset limitsMichael Pratt
Splice must not allow negative offsets. Writes also must not allow offset + size to overflow int64. Reads are similarly broken, but not just in splice (b/148095030). Reported-by: syzbot+0e1ff0b95fb2859b4190@syzkaller.appspotmail.com PiperOrigin-RevId: 292361208
2020-01-28fs/splice: don't report partial errors for special filesAndrei Vagin
Special files can have additional requirements for granularity. For example, read from eventfd returns EINVAL if a size is less 8 bytes. Reported-by: syzbot+3905f5493bec08eb7b02@syzkaller.appspotmail.com PiperOrigin-RevId: 292002926
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