From 338694cf0d2ff38a00bab7103081ffa3db2cbeca Mon Sep 17 00:00:00 2001
From: jsing <>
Date: Thu, 17 Jan 2019 06:32:12 +0000
Subject: Provide an extensible buffer implementation that uses a read
 callback.

The read callback returns a TLS13_IO_* value on EOF, failure, want pollin
or want pollout, or a positive value indicating the number of bytes read.

This will be used by upcoming TLSv1.3 handshake message and record
processing code, both of which need the ability to read a fixed size
header, before extending the buffer to the number of bytes specified in the
header.

ok beck@ tb@
---
 src/lib/libssl/tls13_buffer.c | 125 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 src/lib/libssl/tls13_buffer.c

(limited to 'src/lib/libssl/tls13_buffer.c')

diff --git a/src/lib/libssl/tls13_buffer.c b/src/lib/libssl/tls13_buffer.c
new file mode 100644
index 0000000000..1b490c8b46
--- /dev/null
+++ b/src/lib/libssl/tls13_buffer.c
@@ -0,0 +1,125 @@
+/* $OpenBSD: tls13_buffer.c,v 1.1 2019/01/17 06:32:12 jsing Exp $ */
+/*
+ * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "ssl_locl.h"
+
+#include "bytestring.h"
+#include "tls13_internal.h"
+
+struct tls13_buffer {
+	size_t capacity;
+	uint8_t *data;
+	size_t len;
+	size_t offset;
+};
+
+static int tls13_buffer_resize(struct tls13_buffer *buf, size_t capacity);
+
+struct tls13_buffer *
+tls13_buffer_new(size_t init_size)
+{
+	struct tls13_buffer *buf = NULL;
+
+	if ((buf = calloc(1, sizeof(struct tls13_buffer))) == NULL)
+		goto err;
+
+	if (!tls13_buffer_resize(buf, init_size))
+		goto err;
+
+	return buf;
+
+ err:
+	tls13_buffer_free(buf);
+
+	return NULL;
+}
+
+void
+tls13_buffer_free(struct tls13_buffer *buf)
+{
+	if (buf == NULL)
+		return;
+
+	freezero(buf->data, buf->capacity);
+	freezero(buf, sizeof(struct tls13_buffer));
+}
+
+static int
+tls13_buffer_resize(struct tls13_buffer *buf, size_t capacity)
+{
+	uint8_t *data;
+
+	if (buf->capacity == capacity)
+		return 1;
+
+	if ((data = recallocarray(buf->data, buf->capacity, capacity, 1)) == NULL)
+		return 0;
+
+	buf->data = data;
+	buf->capacity = capacity;
+
+	return 1;
+}
+
+ssize_t
+tls13_buffer_extend(struct tls13_buffer *buf, size_t len,
+    tls13_read_cb read_cb, void *cb_arg)
+{
+	ssize_t ret;
+
+	if (len == buf->len)
+		return buf->len;
+
+	if (len < buf->len)
+		return TLS13_IO_FAILURE;
+
+	if (!tls13_buffer_resize(buf, len))
+		return TLS13_IO_FAILURE;
+
+	for (;;) {
+		if ((ret = read_cb(&buf->data[buf->len],
+		    buf->capacity - buf->len, cb_arg)) <= 0)
+			return ret;
+
+		buf->len += ret;
+
+		if (buf->len == buf->capacity)
+			return buf->len;
+	}
+}
+
+void
+tls13_buffer_cbs(struct tls13_buffer *buf, CBS *cbs)
+{
+	CBS_init(cbs, buf->data, buf->len);
+}
+
+int
+tls13_buffer_finish(struct tls13_buffer *buf, uint8_t **out, size_t *out_len)
+{
+	if (out == NULL || out_len == NULL)
+		return 0;
+
+	*out = buf->data;
+	*out_len = buf->len;
+
+	buf->capacity = 0;
+	buf->data = NULL;
+	buf->len = 0;
+
+	return 1;
+}
-- 
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