diff --git a/crypto/openssh/buffer.c b/crypto/openssh/buffer.c
index 8ff8c2f48b4f..9c9ca6431709 100644
--- a/crypto/openssh/buffer.c
+++ b/crypto/openssh/buffer.c
@@ -23,8 +23,11 @@ RCSID("$OpenBSD: buffer.c,v 1.17 2003/09/16 03:03:47 deraadt Exp $");
 void
 buffer_init(Buffer *buffer)
 {
-	buffer->alloc = 4096;
-	buffer->buf = xmalloc(buffer->alloc);
+	const u_int len = 4096;
+
+	buffer->alloc = 0;
+	buffer->buf = xmalloc(len);
+	buffer->alloc = len;
 	buffer->offset = 0;
 	buffer->end = 0;
 }
@@ -34,8 +37,10 @@ buffer_init(Buffer *buffer)
 void
 buffer_free(Buffer *buffer)
 {
-	memset(buffer->buf, 0, buffer->alloc);
-	xfree(buffer->buf);
+	if (buffer->alloc > 0) {
+		memset(buffer->buf, 0, buffer->alloc);
+		xfree(buffer->buf);
+	}
 }
 
 /*