Index: share/man/man4/unix.4
===================================================================
--- share/man/man4/unix.4
+++ share/man/man4/unix.4
@@ -28,7 +28,7 @@
 .\"     @(#)unix.4	8.1 (Berkeley) 6/9/93
 .\" $FreeBSD$
 .\"
-.Dd August 3, 2020
+.Dd October 30, 2020
 .Dt UNIX 4
 .Os
 .Sh NAME
@@ -287,6 +287,14 @@
 Therefore, a message accompanied by a particular
 .Fa sc_euid
 value should not be trusted as being from that user.
+.It Dv LOCAL_PASSCRED
+This option is similar to
+.Dv LOCAL_CREDS ,
+except that socket credentials are passed on every read from a
+.Dv SOCK_STREAM
+or
+.Dv SOCK_SEQPACKET
+socket, instead of just the first read.
 .It Dv LOCAL_CONNWAIT
 Used with
 .Dv SOCK_STREAM
Index: sys/kern/uipc_usrreq.c
===================================================================
--- sys/kern/uipc_usrreq.c
+++ sys/kern/uipc_usrreq.c
@@ -1040,7 +1040,7 @@
 			break;
 		}
 
-		if (unp2->unp_flags & UNP_WANTCRED)
+		if (unp2->unp_flags & UNP_WANTCRED_MASK)
 			control = unp_addsockcred(td, control);
 		if (unp->unp_addr != NULL)
 			from = (struct sockaddr *)unp->unp_addr;
@@ -1094,10 +1094,11 @@
 			break;
 		}
 		SOCKBUF_LOCK(&so2->so_rcv);
-		if (unp2->unp_flags & UNP_WANTCRED) {
+		if (unp2->unp_flags & UNP_WANTCRED_MASK) {
 			/*
 			 * Credentials are passed only once on SOCK_STREAM
-			 * and SOCK_SEQPACKET.
+			 * and SOCK_SEQPACKET (LOCAL_CREDS => WANTCRED), or
+			 * forever (LOCAL_PASSCRED => WANTCRED_ALWAYS).
 			 */
 			unp2->unp_flags &= ~UNP_WANTCRED;
 			control = unp_addsockcred(td, control);
@@ -1409,6 +1410,12 @@
 			error = sooptcopyout(sopt, &optval, sizeof(optval));
 			break;
 
+		case LOCAL_PASSCRED:
+			/* Unlocked read. */
+			optval = unp->unp_flags & UNP_WANTCRED_ALWAYS ? 1 : 0;
+			error = sooptcopyout(sopt, &optval, sizeof(optval));
+			break;
+
 		case LOCAL_CONNWAIT:
 			/* Unlocked read. */
 			optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
@@ -1424,6 +1431,7 @@
 	case SOPT_SET:
 		switch (sopt->sopt_name) {
 		case LOCAL_CREDS:
+		case LOCAL_PASSCRED:
 		case LOCAL_CONNWAIT:
 			error = sooptcopyin(sopt, &optval, sizeof(optval),
 					    sizeof(optval));
@@ -1433,9 +1441,9 @@
 #define	OPTSET(bit) do {						\
 	UNP_PCB_LOCK(unp);						\
 	if (optval)							\
-		unp->unp_flags |= bit;					\
+		unp->unp_flags |= (bit);					\
 	else								\
-		unp->unp_flags &= ~bit;					\
+		unp->unp_flags &= ~(bit);					\
 	UNP_PCB_UNLOCK(unp);						\
 } while (0)
 
@@ -1444,6 +1452,10 @@
 				OPTSET(UNP_WANTCRED);
 				break;
 
+			case LOCAL_PASSCRED:
+				OPTSET(UNP_WANTCRED_ALWAYS);
+				break;
+
 			case LOCAL_CONNWAIT:
 				OPTSET(UNP_CONNWAIT);
 				break;
@@ -1651,8 +1663,7 @@
 	memcpy(&server_unp->unp_peercred, &listen_unp->unp_peercred,
 	    sizeof(server_unp->unp_peercred));
 	server_unp->unp_flags |= UNP_HAVEPC;
-	if (listen_unp->unp_flags & UNP_WANTCRED)
-		client_unp->unp_flags |= UNP_WANTCRED;
+	client_unp->unp_flags |= (listen_unp->unp_flags & UNP_WANTCRED_MASK);
 }
 
 static int
@@ -2853,6 +2864,10 @@
 		db_printf("%sUNP_HAVEPC", comma ? ", " : "");
 		comma = 1;
 	}
+	if (unp_flags & UNP_WANTCRED_ALWAYS) {
+		db_printf("%sUNP_WANTCRED_ALWAYS", comma ? ", " : "");
+		comma = 1;
+	}
 	if (unp_flags & UNP_WANTCRED) {
 		db_printf("%sUNP_WANTCRED", comma ? ", " : "");
 		comma = 1;
Index: sys/sys/un.h
===================================================================
--- sys/sys/un.h
+++ sys/sys/un.h
@@ -67,6 +67,7 @@
 /* Socket options. */
 #define	LOCAL_PEERCRED		1	/* retrieve peer credentials */
 #define	LOCAL_CREDS		2	/* pass credentials to receiver */
+#define	LOCAL_PASSCRED		3	/* pass credentials to receiver */
 #define	LOCAL_CONNWAIT		4	/* connects block until accepted */
 
 /* Start of reserved space for third-party socket options. */
Index: sys/sys/unpcb.h
===================================================================
--- sys/sys/unpcb.h
+++ sys/sys/unpcb.h
@@ -107,10 +107,13 @@
  * to determine whether the contents should be sent to the user or
  * not.
  */
-#define UNP_HAVEPC			0x001
-#define	UNP_WANTCRED			0x004	/* credentials wanted */
+#define	UNP_HAVEPC			0x001
+#define	UNP_WANTCRED_ALWAYS		0x002	/* credentials wanted always */
+#define	UNP_WANTCRED			0x004	/* credentials wanted once */
 #define	UNP_CONNWAIT			0x008	/* connect blocks until accepted */
 
+#define	UNP_WANTCRED_MASK			(UNP_WANTCRED | UNP_WANTCRED_ALWAYS)
+
 /*
  * These flags are used to handle non-atomicity in connect() and bind()
  * operations on a socket: in particular, to avoid races between multiple