Factor out the TLSv1.3 code that handles content from TLS records.

Currently, the plaintext content from opened TLS records is handled via
the rbuf code in the TLSv1.3 record layer. Factor this out and provide a
separate struct tls_content, which knows how to track and manipulate the
content.

This makes the TLSv1.3 code cleaner, however it will also soon also be used
to untangle parts of the legacy record layer.

ok beck@ tb@

1 files changed, 149 insertions, 0 deletions

diff --git a/src/lib/libssl/tls_content.c b/src/lib/libssl/tls_content.c
new file mode 100644
index 0000000000..ede178f84c
--- /dev/null
+++ b/src/lib/libssl/tls_content.c
@@ -0,0 +1,149 @@
+/* $OpenBSD: tls_content.c,v 1.1 2021/09/04 16:26:12 jsing Exp $ */
+/*
+ * Copyright (c) 2020 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 <stdlib.h>
+#include <string.h>
+
+#include "tls_content.h"
+
+/* Content from a TLS record. */
+struct tls_content {
+        uint8_t type;
+        uint16_t epoch;
+
+        const uint8_t *data;
+        size_t len;
+        CBS cbs;
+};
+
+struct tls_content *
+tls_content_new(void)
+{
+        return calloc(1, sizeof(struct tls_content));
+}
+
+void
+tls_content_clear(struct tls_content *content)
+{
+        freezero((void *)content->data, content->len);
+        memset(content, 0, sizeof(*content));
+}
+
+void
+tls_content_free(struct tls_content *content)
+{
+        if (content == NULL)
+                return;
+
+        tls_content_clear(content);
+
+        freezero(content, sizeof(struct tls_content));
+}
+
+CBS *
+tls_content_cbs(struct tls_content *content)
+{
+        return &content->cbs;
+}
+
+int
+tls_content_equal(struct tls_content *content, const uint8_t *buf, size_t n)
+{
+        return CBS_mem_equal(&content->cbs, buf, n);
+}
+
+size_t
+tls_content_remaining(struct tls_content *content)
+{
+        return CBS_len(&content->cbs);
+}
+
+uint8_t
+tls_content_type(struct tls_content *content)
+{
+        return content->type;
+}
+
+int
+tls_content_dup_data(struct tls_content *content, uint8_t type,
+    const uint8_t *data, size_t data_len)
+{
+        uint8_t *dup;
+
+        if ((dup = calloc(1, data_len)) == NULL)
+                return 0;
+        memcpy(dup, data, data_len);
+
+        tls_content_set_data(content, type, dup, data_len);
+
+        return 1;
+}
+
+uint16_t
+tls_content_epoch(struct tls_content *content)
+{
+        return content->epoch;
+}
+
+void
+tls_content_set_epoch(struct tls_content *content, uint16_t epoch)
+{
+        content->epoch = epoch;
+}
+
+void
+tls_content_set_data(struct tls_content *content, uint8_t type,
+    const uint8_t *data, size_t data_len)
+{
+        tls_content_clear(content);
+
+        content->type = type;
+        content->data = data;
+        content->len = data_len;
+
+        CBS_init(&content->cbs, content->data, content->len);
+}
+
+static ssize_t
+tls_content_read_internal(struct tls_content *content, uint8_t *buf, size_t n,
+    int peek)
+{
+        if (n > CBS_len(&content->cbs))
+                n = CBS_len(&content->cbs);
+
+        /* XXX - CBS_memcpy? CBS_copy_bytes? */
+        memcpy(buf, CBS_data(&content->cbs), n);
+
+        if (!peek) {
+                if (!CBS_skip(&content->cbs, n))
+                        return -1;
+        }
+
+        return n;
+}
+
+ssize_t
+tls_content_peek(struct tls_content *content, uint8_t *buf, size_t n)
+{
+        return tls_content_read_internal(content, buf, n, 1);
+}
+
+ssize_t
+tls_content_read(struct tls_content *content, uint8_t *buf, size_t n)
+{
+        return tls_content_read_internal(content, buf, n, 0);
+}