1 files changed, 65 insertions, 66 deletions

diff --git a/pkg/sentry/strace/socket.go b/pkg/sentry/strace/socket.go
index f4aab25b0..b164d9107 100644
--- a/pkg/sentry/strace/socket.go
+++ b/pkg/sentry/strace/socket.go
@@ -161,12 +161,10 @@ var controlMessageType = map[int32]string{
 	linux.SO_TIMESTAMP:    "SO_TIMESTAMP",
 }
 
-func unmarshalControlMessageRights(src []byte) linux.ControlMessageRights {
+func unmarshalControlMessageRights(src []byte) []primitive.Int32 {
 	count := len(src) / linux.SizeOfControlMessageRight
-	cmr := make(linux.ControlMessageRights, count)
-	for i, _ := range cmr {
-		cmr[i] = int32(hostarch.ByteOrder.Uint32(src[i*linux.SizeOfControlMessageRight:]))
-	}
+	cmr := make([]primitive.Int32, count)
+	primitive.UnmarshalUnsafeInt32Slice(cmr, src)
 	return cmr
 }
 
@@ -182,14 +180,14 @@ func cmsghdr(t *kernel.Task, addr hostarch.Addr, length uint64, maxBytes uint64)
 
 	var strs []string
 
-	for i := 0; i < len(buf); {
-		if i+linux.SizeOfControlMessageHeader > len(buf) {
+	for len(buf) > 0 {
+		if linux.SizeOfControlMessageHeader > len(buf) {
 			strs = append(strs, "{invalid control message (too short)}")
 			break
 		}
 
 		var h linux.ControlMessageHeader
-		h.UnmarshalUnsafe(buf[i : i+linux.SizeOfControlMessageHeader])
+		buf = h.UnmarshalUnsafe(buf)
 
 		var skipData bool
 		level := "SOL_SOCKET"
@@ -204,7 +202,9 @@ func cmsghdr(t *kernel.Task, addr hostarch.Addr, length uint64, maxBytes uint64)
 			typ = fmt.Sprint(h.Type)
 		}
 
-		if h.Length > uint64(len(buf)-i) {
+		width := t.Arch().Width()
+		length := int(h.Length) - linux.SizeOfControlMessageHeader
+		if length > len(buf) {
 			strs = append(strs, fmt.Sprintf(
 				"{level=%s, type=%s, length=%d, content extends beyond buffer}",
 				level,
@@ -214,9 +214,6 @@ func cmsghdr(t *kernel.Task, addr hostarch.Addr, length uint64, maxBytes uint64)
 			break
 		}
 
-		i += linux.SizeOfControlMessageHeader
-		width := t.Arch().Width()
-		length := int(h.Length) - linux.SizeOfControlMessageHeader
 		if length < 0 {
 			strs = append(strs, fmt.Sprintf(
 				"{level=%s, type=%s, length=%d, content too short}",
@@ -229,78 +226,80 @@ func cmsghdr(t *kernel.Task, addr hostarch.Addr, length uint64, maxBytes uint64)
 
 		if skipData {
 			strs = append(strs, fmt.Sprintf("{level=%s, type=%s, length=%d}", level, typ, h.Length))
-			i += bits.AlignUp(length, width)
-			continue
-		}
-
-		switch h.Type {
-		case linux.SCM_RIGHTS:
-			rightsSize := bits.AlignDown(length, linux.SizeOfControlMessageRight)
-			fds := unmarshalControlMessageRights(buf[i : i+rightsSize])
-			rights := make([]string, 0, len(fds))
-			for _, fd := range fds {
-				rights = append(rights, fmt.Sprint(fd))
-			}
+		} else {
+			switch h.Type {
+			case linux.SCM_RIGHTS:
+				rightsSize := bits.AlignDown(length, linux.SizeOfControlMessageRight)
+				fds := unmarshalControlMessageRights(buf[:rightsSize])
+				rights := make([]string, 0, len(fds))
+				for _, fd := range fds {
+					rights = append(rights, fmt.Sprint(fd))
+				}
 
-			strs = append(strs, fmt.Sprintf(
-				"{level=%s, type=%s, length=%d, content: %s}",
-				level,
-				typ,
-				h.Length,
-				strings.Join(rights, ","),
-			))
-
-		case linux.SCM_CREDENTIALS:
-			if length < linux.SizeOfControlMessageCredentials {
 				strs = append(strs, fmt.Sprintf(
-					"{level=%s, type=%s, length=%d, content too short}",
+					"{level=%s, type=%s, length=%d, content: %s}",
 					level,
 					typ,
 					h.Length,
+					strings.Join(rights, ","),
 				))
-				break
-			}
 
-			var creds linux.ControlMessageCredentials
-			creds.UnmarshalUnsafe(buf[i : i+linux.SizeOfControlMessageCredentials])
+			case linux.SCM_CREDENTIALS:
+				if length < linux.SizeOfControlMessageCredentials {
+					strs = append(strs, fmt.Sprintf(
+						"{level=%s, type=%s, length=%d, content too short}",
+						level,
+						typ,
+						h.Length,
+					))
+					break
+				}
 
-			strs = append(strs, fmt.Sprintf(
-				"{level=%s, type=%s, length=%d, pid: %d, uid: %d, gid: %d}",
-				level,
-				typ,
-				h.Length,
-				creds.PID,
-				creds.UID,
-				creds.GID,
-			))
+				var creds linux.ControlMessageCredentials
+				creds.UnmarshalUnsafe(buf)
 
-		case linux.SO_TIMESTAMP:
-			if length < linux.SizeOfTimeval {
 				strs = append(strs, fmt.Sprintf(
-					"{level=%s, type=%s, length=%d, content too short}",
+					"{level=%s, type=%s, length=%d, pid: %d, uid: %d, gid: %d}",
 					level,
 					typ,
 					h.Length,
+					creds.PID,
+					creds.UID,
+					creds.GID,
 				))
-				break
-			}
 
-			var tv linux.Timeval
-			tv.UnmarshalUnsafe(buf[i : i+linux.SizeOfTimeval])
+			case linux.SO_TIMESTAMP:
+				if length < linux.SizeOfTimeval {
+					strs = append(strs, fmt.Sprintf(
+						"{level=%s, type=%s, length=%d, content too short}",
+						level,
+						typ,
+						h.Length,
+					))
+					break
+				}
 
-			strs = append(strs, fmt.Sprintf(
-				"{level=%s, type=%s, length=%d, Sec: %d, Usec: %d}",
-				level,
-				typ,
-				h.Length,
-				tv.Sec,
-				tv.Usec,
-			))
+				var tv linux.Timeval
+				tv.UnmarshalUnsafe(buf)
 
-		default:
-			panic("unreachable")
+				strs = append(strs, fmt.Sprintf(
+					"{level=%s, type=%s, length=%d, Sec: %d, Usec: %d}",
+					level,
+					typ,
+					h.Length,
+					tv.Sec,
+					tv.Usec,
+				))
+
+			default:
+				panic("unreachable")
+			}
+		}
+		if shift := bits.AlignUp(length, width); shift > len(buf) {
+			buf = buf[:0]
+		} else {
+			buf = buf[shift:]
 		}
-		i += bits.AlignUp(length, width)
 	}
 
 	return fmt.Sprintf("%#x %s", addr, strings.Join(strs, ", "))