diff --git a/appl/rcp/util.c b/appl/rcp/util.c
index 8d19f67d2..638c42a80 100644
--- a/appl/rcp/util.c
+++ b/appl/rcp/util.c
@@ -136,6 +136,7 @@ allocbuf(bp, fd, blksize)
 {
 	struct stat stb;
 	size_t size;
+	char *p;
 
 	if (fstat(fd, &stb) < 0) {
 		run_err("fstat: %s", strerror(errno));
@@ -146,11 +147,16 @@ allocbuf(bp, fd, blksize)
 		size = blksize;
 	if (bp->cnt >= size)
 		return (bp);
-	if ((bp->buf = realloc(bp->buf, size)) == NULL) {
+	if ((p = realloc(bp->buf, size)) == NULL) {
+		if (bp->buf)
+			free(bp->buf);
+		bp->buf = NULL;
 		bp->cnt = 0;
 		run_err("%s", strerror(errno));
 		return (0);
 	}
+	memset(p, 0, size);
+	bp->buf = p;
 	bp->cnt = size;
 	return (bp);
 }