Merge release-20201030.0-39-g29683f359 (automated)

3 files changed, 30 insertions, 0 deletions

diff --git a/pkg/sentry/hostfd/hostfd_linux.go b/pkg/sentry/hostfd/hostfd_linux.go
new file mode 100644
index 000000000..1cabc848f
--- /dev/null
+++ b/pkg/sentry/hostfd/hostfd_linux.go
@@ -0,0 +1,18 @@
+// 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 hostfd
+
+// maxIov is the maximum permitted size of a struct iovec array.
+const maxIov = 1024 // UIO_MAXIOV
diff --git a/pkg/sentry/hostfd/hostfd_linux_state_autogen.go b/pkg/sentry/hostfd/hostfd_linux_state_autogen.go
new file mode 100644
index 000000000..9033424d5
--- /dev/null
+++ b/pkg/sentry/hostfd/hostfd_linux_state_autogen.go
@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package hostfd
diff --git a/pkg/sentry/hostfd/hostfd_unsafe.go b/pkg/sentry/hostfd/hostfd_unsafe.go
index cd4dc67fb..694371b1c 100644
--- a/pkg/sentry/hostfd/hostfd_unsafe.go
+++ b/pkg/sentry/hostfd/hostfd_unsafe.go
@@ -20,6 +20,7 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/safemem"
 )
 
@@ -44,6 +45,10 @@ func Preadv2(fd int32, dsts safemem.BlockSeq, offset int64, flags uint32) (uint6
 		}
 	} else {
 		iovs := safemem.IovecsFromBlockSeq(dsts)
+		if len(iovs) > maxIov {
+			log.Debugf("hostfd.Preadv2: truncating from %d iovecs to %d", len(iovs), maxIov)
+			iovs = iovs[:maxIov]
+		}
 		n, _, e = syscall.Syscall6(unix.SYS_PREADV2, uintptr(fd), uintptr((unsafe.Pointer)(&iovs[0])), uintptr(len(iovs)), uintptr(offset), 0 /* pos_h */, uintptr(flags))
 	}
 	if e != 0 {
@@ -76,6 +81,10 @@ func Pwritev2(fd int32, srcs safemem.BlockSeq, offset int64, flags uint32) (uint
 		}
 	} else {
 		iovs := safemem.IovecsFromBlockSeq(srcs)
+		if len(iovs) > maxIov {
+			log.Debugf("hostfd.Preadv2: truncating from %d iovecs to %d", len(iovs), maxIov)
+			iovs = iovs[:maxIov]
+		}
 		n, _, e = syscall.Syscall6(unix.SYS_PWRITEV2, uintptr(fd), uintptr((unsafe.Pointer)(&iovs[0])), uintptr(len(iovs)), uintptr(offset), 0 /* pos_h */, uintptr(flags))
 	}
 	if e != 0 {