relayd: use ibuf_get_string() and ibuf_get_data() to read imsg payloads

Drop the local get_string() and read variable-length string and binary
payloads through the ibuf getters instead of the raw imsg->data pointer.

ibuf_get_string() no longer trims the input at the first non-printable
byte like the old get_string() did; the payloads come from the parent
over privsep imsg.

idea and ok claudio

usr.sbin/relayd/config.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.52 2026/06/14 08:48:04 rsadowski Exp $	*/
+/*	$OpenBSD: config.c,v 1.53 2026/06/14 08:54:21 rsadowski Exp $	*/
 
 /*
  * Copyright (c) 2011 - 2014 Reyk Floeter <reyk@openbsd.org>
@@ -361,8 +361,8 @@ config_gettable(struct relayd *env, struct imsg *imsg)
 		return (-1);
 	}
 	if ((sb = ibuf_size(&ibuf)) > 0) {
-		if ((tb->sendbuf = get_string(ibuf_data(&ibuf), sb)) == NULL) {
-			log_warn("%s: get_string", __func__);
+		if ((tb->sendbuf = ibuf_get_string(&ibuf, sb)) == NULL) {
+			log_warn("%s: ibuf_get_string", __func__);
 			free(tb);
 			return (-1);
 		}
@@ -732,9 +732,9 @@ config_getproto(struct relayd *env, struct imsg *imsg)
 	}
 	if ((s = ibuf_size(&ibuf)) > 0) {
 		proto->style = NULL;
-		if ((proto->style = get_string(ibuf_data(&ibuf), s - 1))
+		if ((proto->style = ibuf_get_string(&ibuf, s - 1))
 		    == NULL) {
-			log_warn("%s: get_string", __func__);
+			log_warn("%s: ibuf_get_string", __func__);
 			free(proto);
 			return (-1);
 		}
@@ -790,11 +790,7 @@ config_getrule(struct relayd *env, struct imsg *imsg)
 		/* Also accept "empty" 0-length strings */		\
 		if (ibuf_size(&ibuf) < (size_t)len ||			\
 		    (rule->rule_kv[_n].kv_##_f =			\
-		    get_string(ibuf_data(&ibuf), len)) == NULL) {	\
-			free(rule);					\
-			return (-1);					\
-		}							\
-		if (len > 0 && ibuf_skip(&ibuf, len) == -1) {		\
+		    ibuf_get_string(&ibuf, len)) == NULL) {		\
 			free(rule);					\
 			return (-1);					\
 		}							\
@@ -1104,8 +1100,7 @@ config_getrelay(struct relayd *env, struct imsg *imsg)
 		goto fail;
 	}
 	if (s > 0) {
-		if ((rlay->rl_tls_cakey = get_data(ibuf_data(&ibuf), s))
-		    == NULL)
+		if ((rlay->rl_tls_cakey = get_data(&ibuf, s)) == NULL)
 			goto fail;
 	}
 

usr.sbin/relayd/relayd.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: relayd.c,v 1.200 2026/06/14 08:51:11 rsadowski Exp $	*/
+/*	$OpenBSD: relayd.c,v 1.201 2026/06/14 08:54:21 rsadowski Exp $	*/
 
 /*
  * Copyright (c) 2007 - 2016 Reyk Floeter <reyk@openbsd.org>
@@ -437,8 +437,8 @@ parent_dispatch_pfe(int fd, struct privsep_proc *p, struct imsg *imsg)
 	case IMSG_CTL_RELOAD:
 		if (imsg_get_ibuf(imsg, &ibuf) != -1 &&
 		    (s = ibuf_size(&ibuf)) > 0) {
-			if ((str = get_string(ibuf_data(&ibuf), s)) == NULL) {
-				log_warn("%s: get_string", __func__);
+			if ((str = ibuf_get_string(&ibuf, s)) == NULL) {
+				log_warn("%s: ibuf_get_string", __func__);
 				return (-1);
 			}
 		}
@@ -1787,28 +1787,21 @@ socket_rlimit(int maxfd)
 		fatal("%s: failed to set resource limit", __func__);
 }
 
-char *
-get_string(u_int8_t *ptr, size_t len)
-{
-	size_t	 i;
-
-	for (i = 0; i < len; i++)
-		if (!(isprint((unsigned char)ptr[i]) ||
-		    isspace((unsigned char)ptr[i])))
-			break;
-
-	return strndup(ptr, i);
-}
-
 void *
-get_data(u_int8_t *ptr, size_t len)
+get_data(struct ibuf *ibuf, size_t len)
 {
 	u_int8_t	*data;
 
+	if (len == 0)
+		return (NULL);
+
 	if ((data = malloc(len)) == NULL)
 		return (NULL);
-	memcpy(data, ptr, len);
 
+	if (ibuf_get(ibuf, data, len) == -1) {
+		free(data);
+		return (NULL);
+	}
 	return (data);
 }
 

usr.sbin/relayd/relayd.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: relayd.h,v 1.284 2026/06/14 08:52:16 rsadowski Exp $	*/
+/*	$OpenBSD: relayd.h,v 1.285 2026/06/14 08:54:21 rsadowski Exp $	*/
 
 /*
  * Copyright (c) 2006 - 2016 Reyk Floeter <reyk@openbsd.org>
@@ -1336,8 +1336,7 @@ void		 imsg_event_add(struct imsgev *);
 int		 imsg_compose_event(struct imsgev *, u_int16_t, u_int32_t,
 		    pid_t, int, void *, u_int16_t);
 void		 socket_rlimit(int);
-char		*get_string(u_int8_t *, size_t);
-void		*get_data(u_int8_t *, size_t);
+void		*get_data(struct ibuf *, size_t);
 int		 sockaddr_cmp(struct sockaddr *, struct sockaddr *, int);
 struct in6_addr *prefixlen2mask6(u_int8_t, u_int32_t *);
 u_int32_t	 prefixlen2mask(u_int8_t);