Previously we were representing socket addresses as an interface{},
which allowed any type which could be binary.Marshal()ed to be used as
a socket address. This is fine when the address is passed to userspace
via the linux ABI, but is problematic when used from within the sentry
such as by networking procfs files.
PiperOrigin-RevId: 262460640
Major differences from the current ("v1") sentry VFS:
- Path resolution is Filesystem-driven (FilesystemImpl methods call
vfs.ResolvingPath methods) rather than VFS-driven (fs package owns a
Dirent tree and calls fs.InodeOperations methods to populate it). This
drastically improves performance, primarily by reducing overhead from
inefficient synchronization and indirection. It also makes it possible
to implement remote filesystem protocols that translate FS system calls
into single RPCs, rather than having to make (at least) one RPC per path
component, significantly reducing the latency of remote filesystems
(especially during cold starts and for uncacheable shared filesystems).
- Mounts are correctly represented as a separate check based on
contextual state (current mount) rather than direct replacement in a
fs.Dirent tree. This makes it possible to support (non-recursive) bind
mounts and mount namespaces.
Included in this CL is fsimpl/memfs, an incomplete in-memory filesystem
that exists primarily to demonstrate intended filesystem implementation
patterns and for benchmarking:
BenchmarkVFS1TmpfsStat/1-6 3000000 497 ns/op
BenchmarkVFS1TmpfsStat/2-6 2000000 676 ns/op
BenchmarkVFS1TmpfsStat/3-6 2000000 904 ns/op
BenchmarkVFS1TmpfsStat/8-6 1000000 1944 ns/op
BenchmarkVFS1TmpfsStat/64-6 100000 14067 ns/op
BenchmarkVFS1TmpfsStat/100-6 50000 21700 ns/op
BenchmarkVFS2MemfsStat/1-6 10000000 197 ns/op
BenchmarkVFS2MemfsStat/2-6 5000000 233 ns/op
BenchmarkVFS2MemfsStat/3-6 5000000 268 ns/op
BenchmarkVFS2MemfsStat/8-6 3000000 477 ns/op
BenchmarkVFS2MemfsStat/64-6 500000 2592 ns/op
BenchmarkVFS2MemfsStat/100-6 300000 4045 ns/op
BenchmarkVFS1TmpfsMountStat/1-6 2000000 679 ns/op
BenchmarkVFS1TmpfsMountStat/2-6 2000000 912 ns/op
BenchmarkVFS1TmpfsMountStat/3-6 1000000 1113 ns/op
BenchmarkVFS1TmpfsMountStat/8-6 1000000 2118 ns/op
BenchmarkVFS1TmpfsMountStat/64-6 100000 14251 ns/op
BenchmarkVFS1TmpfsMountStat/100-6 100000 22397 ns/op
BenchmarkVFS2MemfsMountStat/1-6 5000000 317 ns/op
BenchmarkVFS2MemfsMountStat/2-6 5000000 361 ns/op
BenchmarkVFS2MemfsMountStat/3-6 5000000 387 ns/op
BenchmarkVFS2MemfsMountStat/8-6 3000000 582 ns/op
BenchmarkVFS2MemfsMountStat/64-6 500000 2699 ns/op
BenchmarkVFS2MemfsMountStat/100-6 300000 4133 ns/op
From this we can infer that, on this machine:
- Constant cost for tmpfs stat() is ~160ns in VFS2 and ~280ns in VFS1.
- Per-path-component cost is ~35ns in VFS2 and ~215ns in VFS1, a
difference of about 6x.
- The cost of crossing a mount boundary is about 80ns in VFS2
(MemfsMountStat/1 does approximately the same amount of work as
MemfsStat/2, except that it also crosses a mount boundary). This is an
inescapable cost of the separate mount lookup needed to support bind
mounts and mount namespaces.
PiperOrigin-RevId: 258853946
Addresses obvious typos, in the documentation only.
COPYBARA_INTEGRATE_REVIEW=https://github.com/google/gvisor/pull/443 from Pixep:fix/documentation-spelling 4d0688164eafaf0b3010e5f4824b35d1e7176d65
PiperOrigin-RevId: 255477779
We don't have the plumbing for btime yet, so that field is left off. The
returned mask indicates that btime is absent.
Fixes#343
PiperOrigin-RevId: 254575752
Adds simple introspection for syscall compatibility information to Linux/AMD64.
Syscalls registered in the syscall table now have associated metadata like
name, support level, notes, and URLs to relevant issues.
Syscall information can be exported as a table, JSON, or CSV using the new
'runsc help syscalls' command. Users can use this info to debug and get info
on the compatibility of the version of runsc they are running or to generate
documentation.
PiperOrigin-RevId: 252558304
We still only advertise a single NUMA node, and ignore mempolicy
accordingly, but mbind() at least now succeeds and has effects reflected
by get_mempolicy().
Also fix handling of nodemasks: round sizes to unsigned long (as
documented and done by Linux), and zero trailing bits when copying them
out.
PiperOrigin-RevId: 251950859
This is necessary for implementing network diagnostic interfaces like
/proc/net/{tcp,udp,unix} and sock_diag(7).
For pass-through endpoints such as hostinet, we obtain the socket
state from the backend. For netstack, we add explicit tracking of TCP
states.
PiperOrigin-RevId: 251934850
We don't actually support core dumps, but some applications want to
get/set dumpability, which still has an effect in procfs.
Lack of support for set-uid binaries or fs creds simplifies things a
bit.
As-is, processes started via CreateProcess (i.e., init and sentryctl
exec) have normal dumpability. I'm a bit torn on whether sentryctl exec
tasks should be dumpable, but at least since they have no parent normal
UID/GID checks should protect them.
PiperOrigin-RevId: 251712714
Pipe internals are made more efficient by avoiding garbage collection.
A pool is now used that can be shared by all pipes, and buffers are
chained via an intrusive list. The documentation for pipe structures
and methods is also simplified and clarified.
The pipe tests are now parameterized, so that they are run on all
different variants (named pipes, small buffers, default buffers).
The pipe buffer sizes are exposed by fcntl, which is now supported
by this change. A size change test has been added to the suite.
These new tests uncovered a bug regarding the semantics of open
named pipes with O_NONBLOCK, which is also fixed by this CL. This
fix also addresses the lack of the O_LARGEFILE flag for named pipes.
PiperOrigin-RevId: 249375888
Change-Id: I48e61e9c868aedb0cadda2dff33f09a560dee773
This does not actually implement an efficient splice or sendfile. Rather, it
adds a generic plumbing to the file internals so that this can be added. All
file implementations use the stub fileutil.NoSplice implementation, which
causes sendfile and splice to fall back to an internal copy.
A basic splice system call interface is added, along with a test.
PiperOrigin-RevId: 249335960
Change-Id: Ic5568be2af0a505c19e7aec66d5af2480ab0939b
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
Only emit unimplemented syscall events for setting SO_OOBINLINE and SO_LINGER
when attempting to set unsupported values.
PiperOrigin-RevId: 244229675
Change-Id: Icc4562af8f733dd75a90404621711f01a32a9fc1
The previous implementation revolved around runes instead of bytes, which caused
weird behavior when converting between the two. For example, peekRune would read
the byte 0xff from a buffer, convert it to a rune, then return it. As rune is an
alias of int32, 0xff was 0-padded to int32(255), which is the hex code point for
?. However, peekRune also returned the length of the byte (1). When calling
utf8.EncodeRune, we only allocated 1 byte, but tried the write the 2-byte
character ?.
tl;dr: I apparently didn't understand runes when I wrote this.
PiperOrigin-RevId: 241789081
Change-Id: I14c788af4d9754973137801500ef6af7ab8a8727
Memfds are simply anonymous tmpfs files with no associated
mounts. Also implementing file seals, which Linux only implements for
memfds at the moment.
PiperOrigin-RevId: 240450031
Change-Id: I31de78b950101ae8d7a13d0e93fe52d98ea06f2f
It is Implemented without the priority inheritance part given
that gVisor defers scheduling decisions to Go runtime and doesn't
have control over it.
PiperOrigin-RevId: 236989545
Change-Id: I714c8ca0798743ecf3167b14ffeb5cd834302560
CopyObjectOut grows its destination byte slice incrementally, causing
many small slice allocations on the heap. This leads to increased GC and
noticeably slower stat calls.
PiperOrigin-RevId: 233140904
Change-Id: Ieb90295dd8dd45b3e56506fef9d7f86c92e97d97
Also includes a few fixes for IPv4 multicast support. IPv6 support is coming in
a followup CL.
PiperOrigin-RevId: 233008638
Change-Id: If7dae6222fef43fda48033f0292af77832d95e82
Nothing reads them and they can simply get stale.
Generated with:
$ sed -i "s/licenses(\(.*\)).*/licenses(\1)/" **/BUILD
PiperOrigin-RevId: 231818945
Change-Id: Ibc3f9838546b7e94f13f217060d31f4ada9d4bf0
More helper structs have been added to the fsutil package to make it easier to
implement fs.InodeOperations and fs.FileOperations.
PiperOrigin-RevId: 229305982
Change-Id: Ib6f8d3862f4216745116857913dbfa351530223b
Using linux.Errno as an error doesn't work very well as none of the sentry code
expects error to contain a linux.Errno.
This moves using syserr.Error.ToLinux as an error in a syscall handler from a
runtime error to a compile error.
PiperOrigin-RevId: 227744312
Change-Id: Iea63108a5b198296c908614e09c01733dd684da0
Within gVisor, plumb new socket options to netstack.
Within netstack, fix GetSockOpt and SetSockOpt return value logic.
PiperOrigin-RevId: 226532229
Change-Id: If40734e119eed633335f40b4c26facbebc791c74
Implement pwritev2 and associated unit tests.
Clean up preadv2 unit tests.
Tag RWF_ flags in both preadv2 and pwritev2 with associated bug tickets.
PiperOrigin-RevId: 226222119
Change-Id: Ieb22672418812894ba114bbc88e67f1dd50de620
Currently mlock() and friends do nothing whatsoever. However, mlocking
is directly application-visible in a number of ways; for example,
madvise(MADV_DONTNEED) and msync(MS_INVALIDATE) both fail on mlocked
regions. We handle this inconsistently: MADV_DONTNEED is too important
to not work, but MS_INVALIDATE is rejected.
Change MM to track mlocked regions in a manner consistent with Linux.
It still will not actually pin pages into host physical memory, but:
- mlock() will now cause sentry memory management to precommit mlocked
pages.
- MADV_DONTNEED and MS_INVALIDATE will interact with mlocked pages as
described above.
PiperOrigin-RevId: 225861605
Change-Id: Iee187204979ac9a4d15d0e037c152c0902c8d0ee
Unlike FlagSet, order doesn't matter here, so it can simply be a map.
PiperOrigin-RevId: 224377910
Change-Id: I15810c698a7f02d8614bf09b59583ab73cba0514
RET_KILL_THREAD doesn't work well for Go because it will
kill only the offending thread and leave the process hanging.
RET_TRAP can be masked out and it's not guaranteed to kill
the process. RET_KILL_PROCESS is available since 4.14.
For older kernel, continue to use RET_TRAP as this is the
best option (likely to kill process, easy to debug).
PiperOrigin-RevId: 222357867
Change-Id: Icc1d7d731274b16c2125b7a1ba4f7883fbdb2cbd
sync_file_range - sync a file segment with disk
In Linux, sync_file_range() accepts three flags:
SYNC_FILE_RANGE_WAIT_BEFORE
Wait upon write-out of all pages in the specified range that
have already been submitted to the device driver for write-out
before performing any write.
SYNC_FILE_RANGE_WRITE
Initiate write-out of all dirty pages in the specified range
which are not presently submitted write-out. Note that even
this may block if you attempt to write more than request queue
size.
SYNC_FILE_RANGE_WAIT_AFTER
Wait upon write-out of all pages in the range after performing
any write.
In this implementation:
SYNC_FILE_RANGE_WAIT_BEFORE without SYNC_FILE_RANGE_WAIT_AFTER isn't
supported right now.
SYNC_FILE_RANGE_WRITE is skipped. It should initiate write-out of all
dirty pages, but it doesn't wait, so it should be safe to do nothing
while nobody uses SYNC_FILE_RANGE_WAIT_BEFORE.
SYNC_FILE_RANGE_WAIT_AFTER is equal to fdatasync(). In Linux,
sync_file_range() doesn't writes out the file's meta-data, but
fdatasync() does if a file size is changed.
PiperOrigin-RevId: 220730840
Change-Id: Iae5dfb23c2c916967d67cf1a1ad32f25eb3f6286
Rahat Mahmood
Ian Lewis
Kevin Krakauer
Jamie Liu
Ayush Ranjan
Adin Scannell
Michael Pratt
Nicolas Lacasse
Fabricio Voznika
Ian Gudger
Googler
Zach Koopmans
Bin Lu
Andrei Vagin