crypto: Add a simple API for [X]ChaCha20-Poly1035 on flat buffers.

This is a synchronous software API which wraps the existing software
implementation shared with OCF.  Note that this will not currently
use optimized backends (such as ossl(4)) but may be appropriate for
operations on small buffers.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D33524

2 files changed, 295 insertions, 0 deletions

diff --git a/sys/crypto/chacha20_poly1305.c b/sys/crypto/chacha20_poly1305.c
new file mode 100644
index 000000000000..938400c0feef
--- /dev/null
+++ b/sys/crypto/chacha20_poly1305.c
@@ -0,0 +1,241 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 The FreeBSD Foundation
+ *
+ * This software was developed by Ararat River Consulting, LLC under
+ * sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/endian.h>
+#include <crypto/chacha20_poly1305.h>
+#include <opencrypto/xform_enc.h>
+
+static const uint8_t zeroes[POLY1305_BLOCK_LEN];
+
+void
+chacha20_poly1305_encrypt(uint8_t *dst, const uint8_t *src,
+    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+    const uint8_t *nonce, const size_t nonce_len, const uint8_t *key)
+{
+	const struct enc_xform *exf;
+	void *ctx;
+	size_t resid, todo;
+	uint64_t lengths[2];
+
+	exf = &enc_xform_chacha20_poly1305;
+	ctx = __builtin_alloca(exf->ctxsize);
+	exf->setkey(ctx, key, CHACHA20_POLY1305_KEY);
+	exf->reinit(ctx, nonce, nonce_len);
+
+	exf->update(ctx, aad, aad_len);
+	if (aad_len % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - aad_len % POLY1305_BLOCK_LEN);
+
+	resid = src_len;
+	todo = rounddown2(resid, CHACHA20_NATIVE_BLOCK_LEN);
+	if (todo > 0) {
+		exf->encrypt_multi(ctx, src, dst, todo);
+		exf->update(ctx, dst, todo);
+		src += todo;
+		dst += todo;
+		resid -= todo;
+	}
+	if (resid > 0) {
+		exf->encrypt_last(ctx, src, dst, resid);
+		exf->update(ctx, dst, resid);
+		dst += resid;
+		if (resid % POLY1305_BLOCK_LEN != 0)
+			exf->update(ctx, zeroes,
+			    POLY1305_BLOCK_LEN - resid % POLY1305_BLOCK_LEN);
+	}
+
+	lengths[0] = htole64(aad_len);
+	lengths[1] = htole64(src_len);
+	exf->update(ctx, lengths, sizeof(lengths));
+	exf->final(dst, ctx);
+
+	explicit_bzero(ctx, exf->ctxsize);
+	explicit_bzero(lengths, sizeof(lengths));
+}
+
+bool
+chacha20_poly1305_decrypt(uint8_t *dst, const uint8_t *src,
+    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+    const uint8_t *nonce, const size_t nonce_len, const uint8_t *key)
+{
+	const struct enc_xform *exf;
+	void *ctx;
+	size_t resid, todo;
+	union {
+		uint64_t lengths[2];
+		char tag[POLY1305_HASH_LEN];
+	} u;
+	bool result;
+
+	if (src_len < POLY1305_HASH_LEN)
+		return (false);
+	resid = src_len - POLY1305_HASH_LEN;
+
+	exf = &enc_xform_chacha20_poly1305;
+	ctx = __builtin_alloca(exf->ctxsize);
+	exf->setkey(ctx, key, CHACHA20_POLY1305_KEY);
+	exf->reinit(ctx, nonce, nonce_len);
+
+	exf->update(ctx, aad, aad_len);
+	if (aad_len % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - aad_len % POLY1305_BLOCK_LEN);
+	exf->update(ctx, src, resid);
+	if (resid % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - resid % POLY1305_BLOCK_LEN);
+
+	u.lengths[0] = htole64(aad_len);
+	u.lengths[1] = htole64(resid);
+	exf->update(ctx, u.lengths, sizeof(u.lengths));
+	exf->final(u.tag, ctx);
+	result = (timingsafe_bcmp(u.tag, src + resid, POLY1305_HASH_LEN) == 0);
+	if (!result)
+		goto out;
+
+	todo = rounddown2(resid, CHACHA20_NATIVE_BLOCK_LEN);
+	if (todo > 0) {
+		exf->decrypt_multi(ctx, src, dst, todo);
+		src += todo;
+		dst += todo;
+		resid -= todo;
+	}
+	if (resid > 0)
+		exf->decrypt_last(ctx, src, dst, resid);
+
+out:
+	explicit_bzero(ctx, exf->ctxsize);
+	explicit_bzero(&u, sizeof(u));
+	return (result);
+}
+
+void
+xchacha20_poly1305_encrypt(uint8_t *dst, const uint8_t *src,
+    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+    const uint8_t *nonce, const uint8_t *key)
+{
+	const struct enc_xform *exf;
+	void *ctx;
+	size_t resid, todo;
+	uint64_t lengths[2];
+
+	exf = &enc_xform_xchacha20_poly1305;
+	ctx = __builtin_alloca(exf->ctxsize);
+	exf->setkey(ctx, key, XCHACHA20_POLY1305_KEY);
+	exf->reinit(ctx, nonce, XCHACHA20_POLY1305_IV_LEN);
+
+	exf->update(ctx, aad, aad_len);
+	if (aad_len % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - aad_len % POLY1305_BLOCK_LEN);
+
+	resid = src_len;
+	todo = rounddown2(resid, CHACHA20_NATIVE_BLOCK_LEN);
+	if (todo > 0) {
+		exf->encrypt_multi(ctx, src, dst, todo);
+		exf->update(ctx, dst, todo);
+		src += todo;
+		dst += todo;
+		resid -= todo;
+	}
+	if (resid > 0) {
+		exf->encrypt_last(ctx, src, dst, resid);
+		exf->update(ctx, dst, resid);
+		dst += resid;
+		if (resid % POLY1305_BLOCK_LEN != 0)
+			exf->update(ctx, zeroes,
+			    POLY1305_BLOCK_LEN - resid % POLY1305_BLOCK_LEN);
+	}
+
+	lengths[0] = htole64(aad_len);
+	lengths[1] = htole64(src_len);
+	exf->update(ctx, lengths, sizeof(lengths));
+	exf->final(dst, ctx);
+
+	explicit_bzero(ctx, exf->ctxsize);
+	explicit_bzero(lengths, sizeof(lengths));
+}
+
+bool
+xchacha20_poly1305_decrypt(uint8_t *dst, const uint8_t *src,
+    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+    const uint8_t *nonce, const uint8_t *key)
+{
+	const struct enc_xform *exf;
+	void *ctx;
+	size_t resid, todo;
+	union {
+		uint64_t lengths[2];
+		char tag[POLY1305_HASH_LEN];
+	} u;
+	bool result;
+
+	if (src_len < POLY1305_HASH_LEN)
+		return (false);
+	resid = src_len - POLY1305_HASH_LEN;
+
+	exf = &enc_xform_xchacha20_poly1305;
+	ctx = __builtin_alloca(exf->ctxsize);
+	exf->setkey(ctx, key, XCHACHA20_POLY1305_KEY);
+	exf->reinit(ctx, nonce, XCHACHA20_POLY1305_IV_LEN);
+
+	exf->update(ctx, aad, aad_len);
+	if (aad_len % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - aad_len % POLY1305_BLOCK_LEN);
+	exf->update(ctx, src, resid);
+	if (resid % POLY1305_BLOCK_LEN != 0)
+		exf->update(ctx, zeroes,
+		    POLY1305_BLOCK_LEN - resid % POLY1305_BLOCK_LEN);
+
+	u.lengths[0] = htole64(aad_len);
+	u.lengths[1] = htole64(resid);
+	exf->update(ctx, u.lengths, sizeof(u.lengths));
+	exf->final(u.tag, ctx);
+	result = (timingsafe_bcmp(u.tag, src + resid, POLY1305_HASH_LEN) == 0);
+	if (!result)
+		goto out;
+
+	todo = rounddown2(resid, CHACHA20_NATIVE_BLOCK_LEN);
+	if (todo > 0) {
+		exf->decrypt_multi(ctx, src, dst, todo);
+		src += todo;
+		dst += todo;
+		resid -= todo;
+	}
+	if (resid > 0)
+		exf->decrypt_last(ctx, src, dst, resid);
+
+out:
+	explicit_bzero(ctx, exf->ctxsize);
+	explicit_bzero(&u, sizeof(u));
+	return (result);
+}
diff --git a/sys/crypto/chacha20_poly1305.h b/sys/crypto/chacha20_poly1305.h
new file mode 100644
index 000000000000..505a5ef9d6f0
--- /dev/null
+++ b/sys/crypto/chacha20_poly1305.h
@@ -0,0 +1,54 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2021 The FreeBSD Foundation
+ *
+ * This software was developed by Ararat River Consulting, LLC under
+ * sponsorship from the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __CRYPTO_CHACHA20_POLY1305_H__
+#define	__CRYPTO_CHACHA20_POLY1305_H__
+
+#include <sys/types.h>
+
+/* The Poly1305 tag is appended to the cipher text. */
+
+void	chacha20_poly1305_encrypt(uint8_t *dst, const uint8_t *src,
+	    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+	    const uint8_t *nonce, const size_t nonce_len, const uint8_t *key);
+
+bool	chacha20_poly1305_decrypt(uint8_t *dst, const uint8_t *src,
+	    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+	    const uint8_t *nonce, const size_t nonce_len, const uint8_t *key);
+
+void	xchacha20_poly1305_encrypt(uint8_t *dst, const uint8_t *src,
+	    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+	    const uint8_t *nonce, const uint8_t *key);
+
+bool	xchacha20_poly1305_decrypt(uint8_t *dst, const uint8_t *src,
+	    const size_t src_len, const uint8_t *aad, const size_t aad_len,
+	    const uint8_t *nonce, const uint8_t *key);
+
+#endif /* !__CRYPTO_CHACHA20_POLY1305_H__ */