Commit Graph

25 Commits

Author SHA1 Message Date
Dean Deng ce19497c1c Fix Unix socket permissions.
Enforce write permission checks in BoundEndpointAt, which corresponds to the
permission checks in Linux (net/unix/af_unix.c:unix_find_other).
Also, create bound socket files with the correct permissions in VFS2.

Fixes #2324.

PiperOrigin-RevId: 308949084
2020-04-28 20:13:01 -07:00
Dean Deng f3ca5ca82a Support pipes and sockets in VFS2 gofer fs.
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
2020-04-28 08:34:00 -07:00
Dean Deng 632b104aff Plumb context.Context into kernfs.Inode.Open().
PiperOrigin-RevId: 308304793
2020-04-24 12:37:49 -07:00
Fabricio Voznika 2cc0fd42f4 Fixes for procfs
- Return ENOENT for /proc/[pid]/task if task is zoombied or terminated
- Allow directory to be Seek() to the end
- Construct synthetic files for /proc/[pid]/ns/*
- Changed GenericDirectoryFD.Init to not register with FileDescription,
  otherwise other implementation cannot change behavior.

Updates #1195,1193

PiperOrigin-RevId: 308294649
2020-04-24 11:45:19 -07:00
Nicolas Lacasse 696feaf10c Port devpts to VFS2.
PiperOrigin-RevId: 308164359
2020-04-23 17:34:29 -07:00
Fabricio Voznika 37e01fd2ea Misc VFS2 fixes
- 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
2020-04-21 16:31:53 -07:00
Jamie Liu 9b5e305e05 Remove filesystem structure from vfs.Dentry.
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
2020-04-21 12:18:07 -07:00
Dean Deng 09ddb5a426 Port extended attributes to VFS2.
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
2020-04-10 19:02:55 -07:00
Fabricio Voznika 6dd5a1f3fe Clean up TODOs
PiperOrigin-RevId: 305592245
2020-04-08 17:58:13 -07:00
Jamie Liu dd98fdd5be Correctly implement magic symlinks in VFS2 procfs.
Updates #1195

PiperOrigin-RevId: 305143567
2020-04-06 16:32:37 -07:00
Fabricio Voznika dd3bc49997 Add NAME_MAX checks and update file times
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
2020-04-02 19:39:03 -07:00
Dean Deng 76a7ace751 Add BoundEndpointAt filesystem operation.
BoundEndpointAt() is needed to support Unix sockets bound at a
file path, corresponding to BoundEndpoint() in VFS1.

Updates #1476.

PiperOrigin-RevId: 303258251
2020-03-26 21:52:24 -07:00
Fabricio Voznika 2a6c4369be Enforce file size rlimits in VFS2
Updates #1035

PiperOrigin-RevId: 301255357
2020-03-16 16:00:49 -07:00
Fabricio Voznika 0f60799a4f Add calls to vfs.CheckSetStat to fsimpls
Only gofer filesystem was calling vfs.CheckSetStat for
vfs.FilesystemImpl.SetStatAt and vfs.FileDescriptionImpl.SetStat.

Updates #1193, #1672, #1197

PiperOrigin-RevId: 301226522
2020-03-16 13:29:12 -07:00
Dean Deng 2e38408f20 Implement access/faccessat for VFS2.
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
2020-03-13 11:41:08 -07:00
Dean Deng 960f6a975b Add plumbing for importing fds in VFS2, along with non-socket, non-TTY impl.
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
2020-03-06 12:59:49 -08:00
gVisor bot 4075de11be Plumb VFS2 inside the Sentry
- 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
2020-02-14 11:12:47 -08:00
gVisor bot a6024f7f5f Add FileExec flag to OpenOptions
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
2020-02-13 17:57:36 -08:00
Fabricio Voznika bfa0bba72a Redirect FIXME to gvisor.dev
PiperOrigin-RevId: 294272755
2020-02-10 12:04:38 -08:00
Adin Scannell 0e2f1b7abd Update package locations.
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
2020-01-27 15:31:32 -08:00
Fabricio Voznika 3dd3275da7 Add more files to /proc/[pid]/*
Files not implemented require VFSv2 plumbing into the kernel.
Also, cgroup is not implemented yet.

Updates #1195

PiperOrigin-RevId: 290129176
2020-01-16 14:10:05 -08:00
Fabricio Voznika 574e988f2b Fix deadlock in kernfs.Filesystem.revalidateChildLocked
It was calling Dentry.InsertChild with the dentry's mutex
already locked.

Updates #1035

PiperOrigin-RevId: 286962742
2019-12-23 17:32:46 -08:00
Jamie Liu f45df7505b Clean up vfs.FilesystemImpl methods that operate on parent directories.
- Make FilesystemImpl methods that operate on parent directories require
  !rp.Done() (i.e. there is at least one path component to resolve) as
  precondition and postcondition (in cases where they do not finish path
  resolution due to mount boundary / absolute symlink), and require that they
  do not need to follow the last path component (the file being created /
  deleted) as a symlink. Check for these in VFS.

- Add FilesystemImpl.GetParentDentryAt(), which is required to obtain the old
  parent directory for VFS.RenameAt(). (Passing the Dentry to be renamed
  instead has the wrong semantics if the file named by the old path is a mount
  point since the Dentry will be on the wrong Mount.)

- Update memfs to implement these methods correctly (?), including RenameAt.

- Change fspath.Parse() to allow empty paths (to simplify implementation of
  AT_EMPTY_PATH).

- Change vfs.PathOperation to take a fspath.Path instead of a raw pathname;
  non-test callers will need to fspath.Parse() pathnames themselves anyway in
  order to detect absolute paths and select PathOperation.Start accordingly.

PiperOrigin-RevId: 286934941
2019-12-23 13:18:39 -08:00
Jamie Liu 744401297a Add VFS2 plumbing for extended attributes.
PiperOrigin-RevId: 286281274
2019-12-18 15:48:45 -08:00
Rahat Mahmood 007707a072 Implement kernfs.
PiperOrigin-RevId: 285231002
2019-12-12 11:20:47 -08:00