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-rw-r--r--pkg/sentry/syscalls/linux/sys_file.go39
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/BUILD3
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/fd.go2
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/lock.go64
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/mount.go145
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/vfs2.go6
6 files changed, 226 insertions, 33 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index 35a98212a..8347617bd 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -998,9 +998,6 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
return 0, nil, err
}
- // The lock uid is that of the Task's FDTable.
- lockUniqueID := lock.UniqueID(t.FDTable().ID())
-
// These locks don't block; execute the non-blocking operation using the inode's lock
// context directly.
switch flock.Type {
@@ -1010,12 +1007,12 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
}
if cmd == linux.F_SETLK {
// Non-blocking lock, provide a nil lock.Blocker.
- if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.ReadLock, rng, nil) {
+ if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.ReadLock, rng, nil) {
return 0, nil, syserror.EAGAIN
}
} else {
// Blocking lock, pass in the task to satisfy the lock.Blocker interface.
- if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.ReadLock, rng, t) {
+ if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.ReadLock, rng, t) {
return 0, nil, syserror.EINTR
}
}
@@ -1026,18 +1023,18 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
}
if cmd == linux.F_SETLK {
// Non-blocking lock, provide a nil lock.Blocker.
- if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.WriteLock, rng, nil) {
+ if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.WriteLock, rng, nil) {
return 0, nil, syserror.EAGAIN
}
} else {
// Blocking lock, pass in the task to satisfy the lock.Blocker interface.
- if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.WriteLock, rng, t) {
+ if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.WriteLock, rng, t) {
return 0, nil, syserror.EINTR
}
}
return 0, nil, nil
case linux.F_UNLCK:
- file.Dirent.Inode.LockCtx.Posix.UnlockRegion(lockUniqueID, rng)
+ file.Dirent.Inode.LockCtx.Posix.UnlockRegion(t.FDTable(), rng)
return 0, nil, nil
default:
return 0, nil, syserror.EINVAL
@@ -2157,22 +2154,6 @@ func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
nonblocking := operation&linux.LOCK_NB != 0
operation &^= linux.LOCK_NB
- // flock(2):
- // Locks created by flock() are associated with an open file table entry. This means that
- // duplicate file descriptors (created by, for example, fork(2) or dup(2)) refer to the
- // same lock, and this lock may be modified or released using any of these descriptors. Furthermore,
- // the lock is released either by an explicit LOCK_UN operation on any of these duplicate
- // descriptors, or when all such descriptors have been closed.
- //
- // If a process uses open(2) (or similar) to obtain more than one descriptor for the same file,
- // these descriptors are treated independently by flock(). An attempt to lock the file using
- // one of these file descriptors may be denied by a lock that the calling process has already placed via
- // another descriptor.
- //
- // We use the File UniqueID as the lock UniqueID because it needs to reference the same lock across dup(2)
- // and fork(2).
- lockUniqueID := lock.UniqueID(file.UniqueID)
-
// A BSD style lock spans the entire file.
rng := lock.LockRange{
Start: 0,
@@ -2183,29 +2164,29 @@ func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
case linux.LOCK_EX:
if nonblocking {
// Since we're nonblocking we pass a nil lock.Blocker implementation.
- if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.WriteLock, rng, nil) {
+ if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.WriteLock, rng, nil) {
return 0, nil, syserror.EWOULDBLOCK
}
} else {
// Because we're blocking we will pass the task to satisfy the lock.Blocker interface.
- if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.WriteLock, rng, t) {
+ if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.WriteLock, rng, t) {
return 0, nil, syserror.EINTR
}
}
case linux.LOCK_SH:
if nonblocking {
// Since we're nonblocking we pass a nil lock.Blocker implementation.
- if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.ReadLock, rng, nil) {
+ if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.ReadLock, rng, nil) {
return 0, nil, syserror.EWOULDBLOCK
}
} else {
// Because we're blocking we will pass the task to satisfy the lock.Blocker interface.
- if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.ReadLock, rng, t) {
+ if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.ReadLock, rng, t) {
return 0, nil, syserror.EINTR
}
}
case linux.LOCK_UN:
- file.Dirent.Inode.LockCtx.BSD.UnlockRegion(lockUniqueID, rng)
+ file.Dirent.Inode.LockCtx.BSD.UnlockRegion(file, rng)
default:
// flock(2): EINVAL operation is invalid.
return 0, nil, syserror.EINVAL
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD
index 9c8b44f64..9f93f4354 100644
--- a/pkg/sentry/syscalls/linux/vfs2/BUILD
+++ b/pkg/sentry/syscalls/linux/vfs2/BUILD
@@ -14,8 +14,10 @@ go_library(
"getdents.go",
"inotify.go",
"ioctl.go",
+ "lock.go",
"memfd.go",
"mmap.go",
+ "mount.go",
"path.go",
"pipe.go",
"poll.go",
@@ -41,6 +43,7 @@ go_library(
"//pkg/fspath",
"//pkg/gohacks",
"//pkg/sentry/arch",
+ "//pkg/sentry/fs/lock",
"//pkg/sentry/fsbridge",
"//pkg/sentry/fsimpl/eventfd",
"//pkg/sentry/fsimpl/pipefs",
diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go
index ca0f7fd1e..6006758a5 100644
--- a/pkg/sentry/syscalls/linux/vfs2/fd.go
+++ b/pkg/sentry/syscalls/linux/vfs2/fd.go
@@ -168,7 +168,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
err := tmpfs.AddSeals(file, args[2].Uint())
return 0, nil, err
default:
- // TODO(gvisor.dev/issue/1623): Everything else is not yet supported.
+ // TODO(gvisor.dev/issue/2920): Everything else is not yet supported.
return 0, nil, syserror.EINVAL
}
}
diff --git a/pkg/sentry/syscalls/linux/vfs2/lock.go b/pkg/sentry/syscalls/linux/vfs2/lock.go
new file mode 100644
index 000000000..bf19028c4
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/vfs2/lock.go
@@ -0,0 +1,64 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vfs2
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/fs/lock"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// Flock implements linux syscall flock(2).
+func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ operation := args[1].Int()
+
+ file := t.GetFileVFS2(fd)
+ if file == nil {
+ // flock(2): EBADF fd is not an open file descriptor.
+ return 0, nil, syserror.EBADF
+ }
+ defer file.DecRef()
+
+ nonblocking := operation&linux.LOCK_NB != 0
+ operation &^= linux.LOCK_NB
+
+ var blocker lock.Blocker
+ if !nonblocking {
+ blocker = t
+ }
+
+ switch operation {
+ case linux.LOCK_EX:
+ if err := file.LockBSD(t, lock.WriteLock, blocker); err != nil {
+ return 0, nil, err
+ }
+ case linux.LOCK_SH:
+ if err := file.LockBSD(t, lock.ReadLock, blocker); err != nil {
+ return 0, nil, err
+ }
+ case linux.LOCK_UN:
+ if err := file.UnlockBSD(t); err != nil {
+ return 0, nil, err
+ }
+ default:
+ // flock(2): EINVAL operation is invalid.
+ return 0, nil, syserror.EINVAL
+ }
+
+ return 0, nil, nil
+}
diff --git a/pkg/sentry/syscalls/linux/vfs2/mount.go b/pkg/sentry/syscalls/linux/vfs2/mount.go
new file mode 100644
index 000000000..adeaa39cc
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/vfs2/mount.go
@@ -0,0 +1,145 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vfs2
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// Mount implements Linux syscall mount(2).
+func Mount(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ sourceAddr := args[0].Pointer()
+ targetAddr := args[1].Pointer()
+ typeAddr := args[2].Pointer()
+ flags := args[3].Uint64()
+ dataAddr := args[4].Pointer()
+
+ // For null-terminated strings related to mount(2), Linux copies in at most
+ // a page worth of data. See fs/namespace.c:copy_mount_string().
+ fsType, err := t.CopyInString(typeAddr, usermem.PageSize)
+ if err != nil {
+ return 0, nil, err
+ }
+ source, err := t.CopyInString(sourceAddr, usermem.PageSize)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ targetPath, err := copyInPath(t, targetAddr)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ data := ""
+ if dataAddr != 0 {
+ // In Linux, a full page is always copied in regardless of null
+ // character placement, and the address is passed to each file system.
+ // Most file systems always treat this data as a string, though, and so
+ // do all of the ones we implement.
+ data, err = t.CopyInString(dataAddr, usermem.PageSize)
+ if err != nil {
+ return 0, nil, err
+ }
+ }
+
+ // Ignore magic value that was required before Linux 2.4.
+ if flags&linux.MS_MGC_MSK == linux.MS_MGC_VAL {
+ flags = flags &^ linux.MS_MGC_MSK
+ }
+
+ // Must have CAP_SYS_ADMIN in the current mount namespace's associated user
+ // namespace.
+ creds := t.Credentials()
+ if !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, t.MountNamespaceVFS2().Owner) {
+ return 0, nil, syserror.EPERM
+ }
+
+ const unsupportedOps = linux.MS_REMOUNT | linux.MS_BIND |
+ linux.MS_SHARED | linux.MS_PRIVATE | linux.MS_SLAVE |
+ linux.MS_UNBINDABLE | linux.MS_MOVE
+
+ // Silently allow MS_NOSUID, since we don't implement set-id bits
+ // anyway.
+ const unsupportedFlags = linux.MS_NODEV |
+ linux.MS_NODIRATIME | linux.MS_STRICTATIME
+
+ // Linux just allows passing any flags to mount(2) - it won't fail when
+ // unknown or unsupported flags are passed. Since we don't implement
+ // everything, we fail explicitly on flags that are unimplemented.
+ if flags&(unsupportedOps|unsupportedFlags) != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ var opts vfs.MountOptions
+ if flags&linux.MS_NOATIME == linux.MS_NOATIME {
+ opts.Flags.NoATime = true
+ }
+ if flags&linux.MS_NOEXEC == linux.MS_NOEXEC {
+ opts.Flags.NoExec = true
+ }
+ if flags&linux.MS_RDONLY == linux.MS_RDONLY {
+ opts.ReadOnly = true
+ }
+ opts.GetFilesystemOptions.Data = data
+
+ target, err := getTaskPathOperation(t, linux.AT_FDCWD, targetPath, disallowEmptyPath, nofollowFinalSymlink)
+ if err != nil {
+ return 0, nil, err
+ }
+ defer target.Release()
+
+ return 0, nil, t.Kernel().VFS().MountAt(t, creds, source, &target.pop, fsType, &opts)
+}
+
+// Umount2 implements Linux syscall umount2(2).
+func Umount2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ addr := args[0].Pointer()
+ flags := args[1].Int()
+
+ // Must have CAP_SYS_ADMIN in the mount namespace's associated user
+ // namespace.
+ //
+ // Currently, this is always the init task's user namespace.
+ creds := t.Credentials()
+ if !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, t.MountNamespaceVFS2().Owner) {
+ return 0, nil, syserror.EPERM
+ }
+
+ const unsupported = linux.MNT_FORCE | linux.MNT_EXPIRE
+ if flags&unsupported != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ path, err := copyInPath(t, addr)
+ if err != nil {
+ return 0, nil, err
+ }
+ tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, nofollowFinalSymlink)
+ if err != nil {
+ return 0, nil, err
+ }
+ defer tpop.Release()
+
+ opts := vfs.UmountOptions{
+ Flags: uint32(flags),
+ }
+
+ return 0, nil, t.Kernel().VFS().UmountAt(t, creds, &tpop.pop, &opts)
+}
diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
index ef8358b8a..954c82f97 100644
--- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go
+++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
@@ -62,7 +62,7 @@ func Override() {
s.Table[55] = syscalls.Supported("getsockopt", GetSockOpt)
s.Table[59] = syscalls.Supported("execve", Execve)
s.Table[72] = syscalls.Supported("fcntl", Fcntl)
- delete(s.Table, 73) // flock
+ s.Table[73] = syscalls.Supported("fcntl", Flock)
s.Table[74] = syscalls.Supported("fsync", Fsync)
s.Table[75] = syscalls.Supported("fdatasync", Fdatasync)
s.Table[76] = syscalls.Supported("truncate", Truncate)
@@ -90,8 +90,8 @@ func Override() {
s.Table[138] = syscalls.Supported("fstatfs", Fstatfs)
s.Table[161] = syscalls.Supported("chroot", Chroot)
s.Table[162] = syscalls.Supported("sync", Sync)
- delete(s.Table, 165) // mount
- delete(s.Table, 166) // umount2
+ s.Table[165] = syscalls.Supported("mount", Mount)
+ s.Table[166] = syscalls.Supported("umount2", Umount2)
delete(s.Table, 187) // readahead
s.Table[188] = syscalls.Supported("setxattr", Setxattr)
s.Table[189] = syscalls.Supported("lsetxattr", Lsetxattr)
generated by cgit v1.2.3 (git 2.39.1) at 2025-03-07 04:52:39 +0000