Add libcbor; an implementation of the Concise Binary Object

Representation (CBOR) encoding format defined in RFC7049.

This is a dependency of libfido2, that we'll use for U2F/FIDO
support in OpenSSH.

feedback and "Looks good enough to me" deraadt@

1 files changed, 112 insertions, 0 deletions

diff --git a/lib/libcbor/src/cbor/internal/encoders.c b/lib/libcbor/src/cbor/internal/encoders.c
new file mode 100644
index 00000000000..478b3885cb1
--- /dev/null
+++ b/lib/libcbor/src/cbor/internal/encoders.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2014-2017 Pavel Kalvoda <me@pavelkalvoda.com>
+ *
+ * libcbor is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+
+#include "encoders.h"
+
+#if HAVE_ENDIAN_H
+#include <endian.h>
+#endif
+
+size_t _cbor_encode_uint8(uint8_t value, unsigned char *buffer, size_t buffer_size, uint8_t offset)
+{
+	if (value <= 23) {
+		if (buffer_size >= 1) {
+			buffer[0] = value + offset;
+			return 1;
+		}
+	} else {
+		if (buffer_size >= 2) {
+			buffer[0] = 0x18 + offset;
+			buffer[1] = value;
+			return 2;
+		}
+	}
+	return 0;
+}
+
+size_t _cbor_encode_uint16(uint16_t value, unsigned char *buffer, size_t buffer_size, uint8_t offset)
+{
+	if (buffer_size >= 3) {
+		buffer[0] = 0x19 + offset;
+
+#ifdef HAVE_ENDIAN_H
+		*(uint16_t *) &buffer[1] = htobe16(value);
+#else
+	#ifdef IS_BIG_ENDIAN
+			*(uint16_t *) &buffer[1] = value;
+	#else
+			buffer[1] = value >> 8;
+			buffer[2] = value;
+	#endif
+#endif
+
+		return 3;
+	} else
+		return 0;
+}
+
+size_t _cbor_encode_uint32(uint32_t value, unsigned char *buffer, size_t buffer_size, uint8_t offset)
+{
+	if (buffer_size >= 5) {
+		buffer[0] = 0x1A + offset;
+
+#ifdef HAVE_ENDIAN_H
+		*(uint32_t *) &buffer[1] = htobe32(value);
+#else
+	#ifdef IS_BIG_ENDIAN
+			*(uint32_t *) &buffer[1] = value;
+	#else
+			buffer[1] = value >> 24;
+			buffer[2] = value >> 16;
+			buffer[3] = value >> 8;
+			buffer[4] = value;
+	#endif
+#endif
+
+		return 5;
+	} else
+		return 0;
+}
+
+size_t _cbor_encode_uint64(uint64_t value, unsigned char *buffer, size_t buffer_size, uint8_t offset)
+{
+	if (buffer_size >= 9) {
+		buffer[0] = 0x1B + offset;
+
+#ifdef HAVE_ENDIAN_H
+		*(uint64_t *) &buffer[1] = htobe64(value);
+#else
+		#ifdef IS_BIG_ENDIAN
+			*(uint64_t *) &buffer[1] = value;
+		#else
+			buffer[1] = value >> 56;
+			buffer[2] = value >> 48;
+			buffer[3] = value >> 40;
+			buffer[4] = value >> 32;
+			buffer[5] = value >> 24;
+			buffer[6] = value >> 16;
+			buffer[7] = value >> 8;
+			buffer[8] = value;
+		#endif
+#endif
+
+		return 9;
+	} else
+		return 0;
+}
+
+size_t _cbor_encode_uint(uint64_t value, unsigned char *buffer, size_t buffer_size, uint8_t offset)
+{
+	if (value <= UINT16_MAX) if (value <= UINT8_MAX)
+		return _cbor_encode_uint8((uint8_t) value, buffer, buffer_size, offset);
+	else
+		return _cbor_encode_uint16((uint16_t) value, buffer, buffer_size, offset);
+	else if (value <= UINT32_MAX)
+		return _cbor_encode_uint32((uint32_t) value, buffer, buffer_size, offset);
+	else
+		return _cbor_encode_uint64((uint64_t) value, buffer, buffer_size, offset);
+}