diff -up openssh-7.4p1/pam_ssh_agent_auth-0.10.3/iterate_ssh_agent_keys.c.psaa-seteuid openssh-7.4p1/pam_ssh_agent_auth-0.10.3/iterate_ssh_agent_keys.c

--- openssh-7.4p1/pam_ssh_agent_auth-0.10.3/iterate_ssh_agent_keys.c.psaa-seteuid	2017-02-13 17:51:29.790005199 +0100

+++ openssh-7.4p1/pam_ssh_agent_auth-0.10.3/iterate_ssh_agent_keys.c	2017-02-13 17:52:53.640919947 +0100

@@ -238,17 +238,25 @@ ssh_get_authentication_socket_for_uid(ui

 	}

 	errno = 0; 

-	seteuid(uid); /* To ensure a race condition is not used to circumvent the stat

-	             above, we will temporarily drop UID to the caller */

-	if (connect(sock, (struct sockaddr *)&sunaddr, sizeof sunaddr) < 0) {

+	/* To ensure a race condition is not used to circumvent the stat

+	   above, we will temporarily drop UID to the caller */

+	if (seteuid(uid) == -1) {

 		close(sock);

-        if(errno == EACCES)

-		fatal("MAJOR SECURITY WARNING: uid %lu made a deliberate and malicious attempt to open an agent socket owned by another user", (unsigned long) uid);

+		error("seteuid(%lu) failed with error: %s", (unsigned long) uid, strerror(errno));

 		return -1;

 	}

+	if (connect(sock, (struct sockaddr *)&sunaddr, sizeof sunaddr) < 0) {

+		close(sock);

+		sock = -1;

+		if(errno == EACCES)

+			fatal("MAJOR SECURITY WARNING: uid %lu made a deliberate and malicious attempt to open an agent socket owned by another user", (unsigned long) uid);

+	}

-	seteuid(0); /* we now continue the regularly scheduled programming */

-

+	/* we now continue the regularly scheduled programming */

+	if (0 != seteuid(0)) {

+	fatal("setuid(0) failed with error: %s", strerror(errno));

+	return -1;

+	}

 	return sock;

 }