Merge release-20200810.0-48-gb9d87ae7a (automated)

5 files changed, 142 insertions, 12 deletions

diff --git a/pkg/sentry/fsimpl/proc/proc_state_autogen.go b/pkg/sentry/fsimpl/proc/proc_state_autogen.go
index eca33249c..a7e43b7a7 100644
--- a/pkg/sentry/fsimpl/proc/proc_state_autogen.go
+++ b/pkg/sentry/fsimpl/proc/proc_state_autogen.go
@@ -1199,6 +1199,35 @@ func (x *tcpRecoveryData) StateLoad(m state.Source) {
 	m.LoadWait(1, &x.stack)
 }
 
+func (x *tcpMemData) StateTypeName() string {
+	return "pkg/sentry/fsimpl/proc.tcpMemData"
+}
+
+func (x *tcpMemData) StateFields() []string {
+	return []string{
+		"DynamicBytesFile",
+		"dir",
+		"stack",
+	}
+}
+
+func (x *tcpMemData) beforeSave() {}
+
+func (x *tcpMemData) StateSave(m state.Sink) {
+	x.beforeSave()
+	m.Save(0, &x.DynamicBytesFile)
+	m.Save(1, &x.dir)
+	m.Save(2, &x.stack)
+}
+
+func (x *tcpMemData) afterLoad() {}
+
+func (x *tcpMemData) StateLoad(m state.Source) {
+	m.Load(0, &x.DynamicBytesFile)
+	m.Load(1, &x.dir)
+	m.LoadWait(2, &x.stack)
+}
+
 func init() {
 	state.Register((*FilesystemType)(nil))
 	state.Register((*subtasksInode)(nil))
@@ -1242,4 +1271,5 @@ func init() {
 	state.Register((*hostnameData)(nil))
 	state.Register((*tcpSackData)(nil))
 	state.Register((*tcpRecoveryData)(nil))
+	state.Register((*tcpMemData)(nil))
 }
diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go
index b71778128..6435385ef 100644
--- a/pkg/sentry/fsimpl/proc/tasks_sys.go
+++ b/pkg/sentry/fsimpl/proc/tasks_sys.go
@@ -25,10 +25,18 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
+type tcpMemDir int
+
+const (
+	tcpRMem tcpMemDir = iota
+	tcpWMem
+)
+
 // newSysDir returns the dentry corresponding to /proc/sys directory.
 func (fs *filesystem) newSysDir(root *auth.Credentials, k *kernel.Kernel) *kernfs.Dentry {
 	return kernfs.NewStaticDir(root, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), 0555, map[string]*kernfs.Dentry{
@@ -56,7 +64,9 @@ func (fs *filesystem) newSysNetDir(root *auth.Credentials, k *kernel.Kernel) *ke
 		contents = map[string]*kernfs.Dentry{
 			"ipv4": kernfs.NewStaticDir(root, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), 0555, map[string]*kernfs.Dentry{
 				"tcp_recovery": fs.newDentry(root, fs.NextIno(), 0644, &tcpRecoveryData{stack: stack}),
+				"tcp_rmem":     fs.newDentry(root, fs.NextIno(), 0644, &tcpMemData{stack: stack, dir: tcpRMem}),
 				"tcp_sack":     fs.newDentry(root, fs.NextIno(), 0644, &tcpSackData{stack: stack}),
+				"tcp_wmem":     fs.newDentry(root, fs.NextIno(), 0644, &tcpMemData{stack: stack, dir: tcpWMem}),
 
 				// The following files are simple stubs until they are implemented in
 				// netstack, most of these files are configuration related. We use the
@@ -181,10 +191,11 @@ func (d *tcpSackData) Generate(ctx context.Context, buf *bytes.Buffer) error {
 		// Tough luck.
 		val = "1\n"
 	}
-	buf.WriteString(val)
-	return nil
+	_, err := buf.WriteString(val)
+	return err
 }
 
+// Write implements vfs.WritableDynamicBytesSource.Write.
 func (d *tcpSackData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) {
 	if offset != 0 {
 		// No need to handle partial writes thus far.
@@ -200,7 +211,7 @@ func (d *tcpSackData) Write(ctx context.Context, src usermem.IOSequence, offset
 	var v int32
 	n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
 	if err != nil {
-		return n, err
+		return 0, err
 	}
 	if d.enabled == nil {
 		d.enabled = new(bool)
@@ -228,10 +239,11 @@ func (d *tcpRecoveryData) Generate(ctx context.Context, buf *bytes.Buffer) error
 		return err
 	}
 
-	buf.WriteString(fmt.Sprintf("%d\n", recovery))
-	return nil
+	_, err = buf.WriteString(fmt.Sprintf("%d\n", recovery))
+	return err
 }
 
+// Write implements vfs.WritableDynamicBytesSource.Write.
 func (d *tcpRecoveryData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) {
 	if offset != 0 {
 		// No need to handle partial writes thus far.
@@ -254,3 +266,91 @@ func (d *tcpRecoveryData) Write(ctx context.Context, src usermem.IOSequence, off
 	}
 	return n, nil
 }
+
+// tcpMemData implements vfs.WritableDynamicBytesSource for
+// /proc/sys/net/ipv4/tcp_rmem and /proc/sys/net/ipv4/tcp_wmem.
+//
+// +stateify savable
+type tcpMemData struct {
+	kernfs.DynamicBytesFile
+
+	dir   tcpMemDir
+	stack inet.Stack `state:"wait"`
+
+	// mu protects against concurrent reads/writes to FDs based on the dentry
+	// backing this byte source.
+	mu sync.Mutex `state:"nosave"`
+}
+
+var _ vfs.WritableDynamicBytesSource = (*tcpMemData)(nil)
+
+// Generate implements vfs.DynamicBytesSource.
+func (d *tcpMemData) Generate(ctx context.Context, buf *bytes.Buffer) error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	size, err := d.readSizeLocked()
+	if err != nil {
+		return err
+	}
+	_, err = buf.WriteString(fmt.Sprintf("%d\t%d\t%d\n", size.Min, size.Default, size.Max))
+	return err
+}
+
+// Write implements vfs.WritableDynamicBytesSource.Write.
+func (d *tcpMemData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) {
+	if offset != 0 {
+		// No need to handle partial writes thus far.
+		return 0, syserror.EINVAL
+	}
+	if src.NumBytes() == 0 {
+		return 0, nil
+	}
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	// Limit the amount of memory allocated.
+	src = src.TakeFirst(usermem.PageSize - 1)
+	size, err := d.readSizeLocked()
+	if err != nil {
+		return 0, err
+	}
+	buf := []int32{int32(size.Min), int32(size.Default), int32(size.Max)}
+	n, err := usermem.CopyInt32StringsInVec(ctx, src.IO, src.Addrs, buf, src.Opts)
+	if err != nil {
+		return 0, err
+	}
+	newSize := inet.TCPBufferSize{
+		Min:     int(buf[0]),
+		Default: int(buf[1]),
+		Max:     int(buf[2]),
+	}
+	if err := d.writeSizeLocked(newSize); err != nil {
+		return 0, err
+	}
+	return n, nil
+}
+
+// Precondition: d.mu must be locked.
+func (d *tcpMemData) readSizeLocked() (inet.TCPBufferSize, error) {
+	switch d.dir {
+	case tcpRMem:
+		return d.stack.TCPReceiveBufferSize()
+	case tcpWMem:
+		return d.stack.TCPSendBufferSize()
+	default:
+		panic(fmt.Sprintf("unknown tcpMemFile type: %v", d.dir))
+	}
+}
+
+// Precondition: d.mu must be locked.
+func (d *tcpMemData) writeSizeLocked(size inet.TCPBufferSize) error {
+	switch d.dir {
+	case tcpRMem:
+		return d.stack.SetTCPReceiveBufferSize(size)
+	case tcpWMem:
+		return d.stack.SetTCPSendBufferSize(size)
+	default:
+		panic(fmt.Sprintf("unknown tcpMemFile type: %v", d.dir))
+	}
+}
diff --git a/pkg/sentry/fsimpl/tmpfs/inode_refs.go b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
index 175dc3409..3245ede1f 100644
--- a/pkg/sentry/fsimpl/tmpfs/inode_refs.go
+++ b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
@@ -1,11 +1,11 @@
 package tmpfs
 
 import (
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
+	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/platform/ring0/defs_impl_arm64.go b/pkg/sentry/platform/ring0/defs_impl_arm64.go
index eda1e1484..424b66f76 100644
--- a/pkg/sentry/platform/ring0/defs_impl_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_impl_arm64.go
@@ -1,13 +1,13 @@
 package ring0
 
 import (
-	"fmt"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"io"
-	"reflect"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/usermem"
+	"io"
+	"reflect"
 )
 
 // Useful bits.
diff --git a/pkg/sentry/socket/unix/socket_refs.go b/pkg/sentry/socket/unix/socket_refs.go
index 090395057..6ed7b1151 100644
--- a/pkg/sentry/socket/unix/socket_refs.go
+++ b/pkg/sentry/socket/unix/socket_refs.go
@@ -1,11 +1,11 @@
 package unix
 
 import (
-	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
+	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so