Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 112 insertions, 0 deletions

diff --git a/pkg/sentry/syscalls/linux/timespec.go b/pkg/sentry/syscalls/linux/timespec.go
new file mode 100644
index 000000000..e865c6fc0
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/timespec.go
@@ -0,0 +1,112 @@
+// Copyright 2018 Google Inc.
+//
+// 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 linux
+
+import (
+	"syscall"
+	"time"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// copyTimespecIn copies a Timespec from the untrusted app range to the kernel.
+func copyTimespecIn(t *kernel.Task, addr usermem.Addr) (linux.Timespec, error) {
+	switch t.Arch().Width() {
+	case 8:
+		ts := linux.Timespec{}
+		in := t.CopyScratchBuffer(16)
+		_, err := t.CopyInBytes(addr, in)
+		if err != nil {
+			return ts, err
+		}
+		ts.Sec = int64(usermem.ByteOrder.Uint64(in[0:]))
+		ts.Nsec = int64(usermem.ByteOrder.Uint64(in[8:]))
+		return ts, nil
+	default:
+		return linux.Timespec{}, syserror.ENOSYS
+	}
+}
+
+// copyTimespecOut copies a Timespec to the untrusted app range.
+func copyTimespecOut(t *kernel.Task, addr usermem.Addr, ts *linux.Timespec) error {
+	switch t.Arch().Width() {
+	case 8:
+		out := t.CopyScratchBuffer(16)
+		usermem.ByteOrder.PutUint64(out[0:], uint64(ts.Sec))
+		usermem.ByteOrder.PutUint64(out[8:], uint64(ts.Nsec))
+		_, err := t.CopyOutBytes(addr, out)
+		return err
+	default:
+		return syserror.ENOSYS
+	}
+}
+
+// copyTimevalIn copies a Timeval from the untrusted app range to the kernel.
+func copyTimevalIn(t *kernel.Task, addr usermem.Addr) (linux.Timeval, error) {
+	switch t.Arch().Width() {
+	case 8:
+		tv := linux.Timeval{}
+		in := t.CopyScratchBuffer(16)
+		_, err := t.CopyInBytes(addr, in)
+		if err != nil {
+			return tv, err
+		}
+		tv.Sec = int64(usermem.ByteOrder.Uint64(in[0:]))
+		tv.Usec = int64(usermem.ByteOrder.Uint64(in[8:]))
+		return tv, nil
+	default:
+		return linux.Timeval{}, syscall.ENOSYS
+	}
+}
+
+// copyTimevalOut copies a Timeval to the untrusted app range.
+func copyTimevalOut(t *kernel.Task, addr usermem.Addr, tv *linux.Timeval) error {
+	switch t.Arch().Width() {
+	case 8:
+		out := t.CopyScratchBuffer(16)
+		usermem.ByteOrder.PutUint64(out[0:], uint64(tv.Sec))
+		usermem.ByteOrder.PutUint64(out[8:], uint64(tv.Usec))
+		_, err := t.CopyOutBytes(addr, out)
+		return err
+	default:
+		return syscall.ENOSYS
+	}
+}
+
+// copyTimespecInToDuration copies a Timespec from the untrusted app range,
+// validates it and converts it to a Duration.
+//
+// If the Timespec is larger than what can be represented in a Duration, the
+// returned value is the maximum that Duration will allow.
+//
+// If timespecAddr is NULL, the returned value is negative.
+func copyTimespecInToDuration(t *kernel.Task, timespecAddr usermem.Addr) (time.Duration, error) {
+	// Use a negative Duration to indicate "no timeout".
+	timeout := time.Duration(-1)
+	if timespecAddr != 0 {
+		timespec, err := copyTimespecIn(t, timespecAddr)
+		if err != nil {
+			return 0, err
+		}
+		if !timespec.Valid() {
+			return 0, syscall.EINVAL
+		}
+		timeout = time.Duration(timespec.ToNsecCapped())
+	}
+	return timeout, nil
+}