[bind] Return EINVAL for under sized address

...and EAFNOSUPPORT for unexpected address family.

To comply with Linux.

Updates #6021, #6575.

PiperOrigin-RevId: 396893590

pkg/sentry/socket/netstack/netstack.go

@@ -419,6 +419,27 @@ func bytesToIPAddress(addr []byte) tcpip.Address {
 	return tcpip.Address(addr)
 }
 
+// minSockAddrLen returns the minimum length in bytes of a socket address for
+// the socket's family.
+func (s *socketOpsCommon) minSockAddrLen() int {
+	const addressFamilySize = 2
+
+	switch s.family {
+	case linux.AF_UNIX:
+		return addressFamilySize
+	case linux.AF_INET:
+		return sockAddrInetSize
+	case linux.AF_INET6:
+		return sockAddrInet6Size
+	case linux.AF_PACKET:
+		return sockAddrLinkSize
+	case linux.AF_UNSPEC:
+		return addressFamilySize
+	default:
+		panic(fmt.Sprintf("s.family unrecognized = %d", s.family))
+	}
+}
+
 func (s *socketOpsCommon) isPacketBased() bool {
 	return s.skType == linux.SOCK_DGRAM || s.skType == linux.SOCK_SEQPACKET || s.skType == linux.SOCK_RDM || s.skType == linux.SOCK_RAW
 }
@@ -545,16 +566,21 @@ func (s *socketOpsCommon) Readiness(mask waiter.EventMask) waiter.EventMask {
 	return s.Endpoint.Readiness(mask)
 }
 
-func (s *socketOpsCommon) checkFamily(family uint16, exact bool) *syserr.Error {
+// checkFamily returns true iff the specified address family may be used with
+// the socket.
+//
+// If exact is true, then the specified address family must be an exact match
+// with the socket's family.
+func (s *socketOpsCommon) checkFamily(family uint16, exact bool) bool {
 	if family == uint16(s.family) {
-		return nil
+		return true
 	}
 	if !exact && family == linux.AF_INET && s.family == linux.AF_INET6 {
 		if !s.Endpoint.SocketOptions().GetV6Only() {
-			return nil
+			return true
 		}
 	}
-	return syserr.ErrInvalidArgument
+	return false
 }
 
 // mapFamily maps the AF_INET ANY address to the IPv4-mapped IPv6 ANY if the
@@ -587,8 +613,8 @@ func (s *socketOpsCommon) Connect(t *kernel.Task, sockaddr []byte, blocking bool
 		return syserr.TranslateNetstackError(err)
 	}
 
-	if err := s.checkFamily(family, false /* exact */); err != nil {
-		return err
+	if !s.checkFamily(family, false /* exact */) {
+		return syserr.ErrInvalidArgument
 	}
 	addr = s.mapFamily(addr, family)
 
@@ -655,14 +681,18 @@ func (s *socketOpsCommon) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
 			Addr: tcpip.Address(a.HardwareAddr[:header.EthernetAddressSize]),
 		}
 	} else {
+		if s.minSockAddrLen() > len(sockaddr) {
+			return syserr.ErrInvalidArgument
+		}
+
 		var err *syserr.Error
 		addr, family, err = socket.AddressAndFamily(sockaddr)
 		if err != nil {
 			return err
 		}
 
-		if err = s.checkFamily(family, true /* exact */); err != nil {
-			return err
+		if !s.checkFamily(family, true /* exact */) {
+			return syserr.ErrAddressFamilyNotSupported
 		}
 
 		addr = s.mapFamily(addr, family)
@@ -2872,8 +2902,8 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b
 		if err != nil {
 			return 0, err
 		}
-		if err := s.checkFamily(family, false /* exact */); err != nil {
-			return 0, err
+		if !s.checkFamily(family, false /* exact */) {
+			return 0, syserr.ErrInvalidArgument
 		}
 		addrBuf = s.mapFamily(addrBuf, family)