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2020-05-05Update comments for synthetic gofer files in vfs2.Dean Deng
PiperOrigin-RevId: 309966538
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
2020-05-01Port netstack, hostinet, and netlink sockets to VFS2.Dean Deng
All three follow the same pattern: 1. Refactor VFS1 sockets into socketOpsCommon, so that most of the methods can be shared with VFS2. 2. Create a FileDescriptionImpl with the corresponding socket operations, rewriting the few that cannot be shared with VFS1. 3. Set up a VFS2 socket provider that creates a socket by setting up a dentry in the global Kernel.socketMount and connecting it with a new FileDescription. This mostly completes the work for porting sockets to VFS2, and many syscall tests can be enabled as a result. There are several networking-related syscall tests that are still not passing: 1. net gofer tests 2. socketpair gofer tests 2. sendfile tests (splice is not implemented in VFS2 yet) Updates #1478, #1484, #1485 PiperOrigin-RevId: 309457331
2020-04-30Add gofer.InternalFilesystemOptions.LeakConnection.Jamie Liu
PiperOrigin-RevId: 309317605
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
2020-04-24VFS2: Get HelloWorld image tests to pass with VFS2Zach Koopmans
This change includes: - Modifications to loader_test.go to get TestCreateMountNamespace to pass with VFS2. - Changes necessary to get TestHelloWorld in image tests to pass with VFS2. This means runsc can run the hello-world container with docker on VSF2. Note: Containers that use sockets will not run with these changes. See "//test/image/...". Any tests here with sockets currently fail (which is all of them but HelloWorld). PiperOrigin-RevId: 308363072
2020-04-23Add vfs.MkdirOptions.ForSyntheticMountpoint.Jamie Liu
PiperOrigin-RevId: 308143529
2020-04-23Factor fsimpl/gofer.host{Preadv,Pwritev} out of fsimpl/gofer.Jamie Liu
Also fix returning EOF when 0 bytes are read. PiperOrigin-RevId: 308089875
2020-04-21Update gofer.filesystem.BoundEndpointAt() to allow path resolution.Dean Deng
Even though BoundEndpointAt is not yet implemented for gofer fs, allow path resolution errors to be returned so that we can jump to tmpfs, where it is implemented. Updates #1476. PiperOrigin-RevId: 307718335
2020-04-21Remove filesystem structure from vfs.Dentry.Jamie Liu
This change: - Drastically simplifies the synchronization model: filesystem structure is both implementation-defined and implementation-synchronized. - Allows implementations of vfs.DentryImpl to use implementation-specific dentry types, reducing casts during path traversal. - Doesn't require dentries representing non-directory files to waste space on a map of children. - Allows dentry revalidation and mount lookup to be correctly ordered (fixed FIXME in fsimpl/gofer/filesystem.go). - Removes the need to have two separate maps in gofer.dentry (dentry.vfsd.children and dentry.negativeChildren) for positive and negative lookups respectively. //pkg/sentry/fsimpl/tmpfs/benchmark_test.go: name old time/op new time/op delta VFS2TmpfsStat/1-112 172ns ± 4% 165ns ± 3% -4.08% (p=0.002 n=9+9) VFS2TmpfsStat/2-112 199ns ± 3% 195ns ±10% ~ (p=0.132 n=8+9) VFS2TmpfsStat/3-112 230ns ± 2% 216ns ± 2% -6.15% (p=0.000 n=8+8) VFS2TmpfsStat/8-112 390ns ± 2% 358ns ± 4% -8.33% (p=0.000 n=9+8) VFS2TmpfsStat/64-112 2.20µs ± 3% 2.01µs ± 3% -8.48% (p=0.000 n=10+8) VFS2TmpfsStat/100-112 3.42µs ± 9% 3.08µs ± 2% -9.82% (p=0.000 n=9+8) VFS2TmpfsMountStat/1-112 278ns ± 1% 286ns ±15% ~ (p=0.712 n=8+10) VFS2TmpfsMountStat/2-112 311ns ± 4% 298ns ± 2% -4.27% (p=0.000 n=9+8) VFS2TmpfsMountStat/3-112 339ns ± 3% 330ns ± 9% ~ (p=0.070 n=8+9) VFS2TmpfsMountStat/8-112 503ns ± 3% 466ns ± 3% -7.38% (p=0.000 n=8+8) VFS2TmpfsMountStat/64-112 2.53µs ±16% 2.17µs ± 7% -14.19% (p=0.000 n=10+9) VFS2TmpfsMountStat/100-112 3.60µs ± 4% 3.30µs ± 8% -8.33% (p=0.001 n=8+9) Updates #1035 PiperOrigin-RevId: 307655892
2020-04-10Port extended attributes to VFS2.Dean Deng
As in VFS1, we only support the user.* namespace. Plumbing is added to tmpfs and goferfs. Note that because of the slightly different order of checks between VFS2 and Linux, one of the xattr tests needs to be relaxed slightly. Fixes #2363. PiperOrigin-RevId: 305985121
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
2020-04-07Make unlink tests pass with goferfsFabricio Voznika
Required directory checks were being skipped when there was no child cached. Now the code always loads the child file before unlinking it. Updates #1198 PiperOrigin-RevId: 305382323
2020-04-07Make gofer.dentry.destroyLocked idempotentFabricio Voznika
gofer operations accumulate dentries touched in a slice to call checkCachingLocked on them when the operation is over. In case the same dentry is touched multiple times during the operation, checkCachingLocked, and consequently destroyLocked, may be called more than once for the same dentry. Updates #1198 PiperOrigin-RevId: 305276819
2020-04-02Add NAME_MAX checks and update file timesFabricio Voznika
NAME_MAX should be enforced per filesystem implementation because other file systems may not have the same restriction. Gofer filesystem now keeps a reference to the kernel clock to avoid lookup in the Context on file access to update atime. Update access, modification, and status change times in tmpfs. Updates #1197, #1198. PiperOrigin-RevId: 304527148
2020-03-27Add FilesystemType.Name method, and FilesystemType field to Filesystem struct.Nicolas Lacasse
Both have analogues in Linux: * struct file_system_type has a char *name field. * struct super_block keeps a pointer to the file_system_type. These fields are necessary to support the `filesystem type` field in /proc/[pid]/mountinfo. PiperOrigin-RevId: 303434063
2020-03-26Add BoundEndpointAt filesystem operation.Dean Deng
BoundEndpointAt() is needed to support Unix sockets bound at a file path, corresponding to BoundEndpoint() in VFS1. Updates #1476. PiperOrigin-RevId: 303258251
2020-03-26Combine file mode and isDir argumentsFabricio Voznika
Updates #1035 PiperOrigin-RevId: 303021328
2020-03-25Misc fixes to make stat_test pass (almost)Fabricio Voznika
The only test failing now requires socket which is not available in VFS2 yet. Updates #1198 PiperOrigin-RevId: 302976572
2020-03-16Enforce file size rlimits in VFS2Fabricio Voznika
Updates #1035 PiperOrigin-RevId: 301255357
2020-03-13Implement access/faccessat for VFS2.Dean Deng
Note that the raw faccessat system call does not actually take a flags argument; according to faccessat(2), the glibc wrapper implements the flags by using fstatat(2). Remove the flag argument that we try to extract from vfs1, which would just be a garbage value. Updates #1965 Fixes #2101 PiperOrigin-RevId: 300796067
2020-03-03Update cached file size when cache is skippedFabricio Voznika
gofer.dentryReadWriter.WriteFromBlocks was not updating gofer.dentry.size after a write operation that skips the cache. Updates #1198 PiperOrigin-RevId: 298708646
2020-02-28Change dup2 call to dup3Fabricio Voznika
We changed syscalls to allow dup3 for ARM64. Updates #1198 PiperOrigin-RevId: 297870816
2020-02-14Allow vfs.IterDirentsCallback.Handle() to return an error.gVisor bot
This is easier than storing errors from e.g. CopyOut in the callback. PiperOrigin-RevId: 295230021
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
2020-02-13Add FileExec flag to OpenOptionsgVisor bot
This allow callers to say whether the file is being opened to be executed, so that the proper checks can be done from FilesystemImpl.OpenAt() Updates #1623 PiperOrigin-RevId: 295042595
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
2020-02-10Add contextual note.Adin Scannell
PiperOrigin-RevId: 294285723
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