Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 184 insertions, 0 deletions

diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c
new file mode 100644
index 000000000..c70d163c1
--- /dev/null
+++ b/crypto/ghash-generic.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GHASH: hash function for GCM (Galois/Counter Mode).
+ *
+ * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
+ * Copyright (c) 2009 Intel Corp.
+ *   Author: Huang Ying <ying.huang@intel.com>
+ */
+
+/*
+ * GHASH is a keyed hash function used in GCM authentication tag generation.
+ *
+ * The original GCM paper [1] presents GHASH as a function GHASH(H, A, C) which
+ * takes a 16-byte hash key H, additional authenticated data A, and a ciphertext
+ * C.  It formats A and C into a single byte string X, interprets X as a
+ * polynomial over GF(2^128), and evaluates this polynomial at the point H.
+ *
+ * However, the NIST standard for GCM [2] presents GHASH as GHASH(H, X) where X
+ * is the already-formatted byte string containing both A and C.
+ *
+ * "ghash" in the Linux crypto API uses the 'X' (pre-formatted) convention,
+ * since the API supports only a single data stream per hash.  Thus, the
+ * formatting of 'A' and 'C' is done in the "gcm" template, not in "ghash".
+ *
+ * The reason "ghash" is separate from "gcm" is to allow "gcm" to use an
+ * accelerated "ghash" when a standalone accelerated "gcm(aes)" is unavailable.
+ * It is generally inappropriate to use "ghash" for other purposes, since it is
+ * an "ε-almost-XOR-universal hash function", not a cryptographic hash function.
+ * It can only be used securely in crypto modes specially designed to use it.
+ *
+ * [1] The Galois/Counter Mode of Operation (GCM)
+ *     (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.694.695&rep=rep1&type=pdf)
+ * [2] Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC
+ *     (https://csrc.nist.gov/publications/detail/sp/800-38d/final)
+ */
+
+#include <crypto/algapi.h>
+#include <crypto/gf128mul.h>
+#include <crypto/ghash.h>
+#include <crypto/internal/hash.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+static int ghash_init(struct shash_desc *desc)
+{
+	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+
+	memset(dctx, 0, sizeof(*dctx));
+
+	return 0;
+}
+
+static int ghash_setkey(struct crypto_shash *tfm,
+			const u8 *key, unsigned int keylen)
+{
+	struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
+	be128 k;
+
+	if (keylen != GHASH_BLOCK_SIZE)
+		return -EINVAL;
+
+	if (ctx->gf128)
+		gf128mul_free_4k(ctx->gf128);
+
+	BUILD_BUG_ON(sizeof(k) != GHASH_BLOCK_SIZE);
+	memcpy(&k, key, GHASH_BLOCK_SIZE); /* avoid violating alignment rules */
+	ctx->gf128 = gf128mul_init_4k_lle(&k);
+	memzero_explicit(&k, GHASH_BLOCK_SIZE);
+
+	if (!ctx->gf128)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int ghash_update(struct shash_desc *desc,
+			 const u8 *src, unsigned int srclen)
+{
+	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+	u8 *dst = dctx->buffer;
+
+	if (dctx->bytes) {
+		int n = min(srclen, dctx->bytes);
+		u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+		dctx->bytes -= n;
+		srclen -= n;
+
+		while (n--)
+			*pos++ ^= *src++;
+
+		if (!dctx->bytes)
+			gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+	}
+
+	while (srclen >= GHASH_BLOCK_SIZE) {
+		crypto_xor(dst, src, GHASH_BLOCK_SIZE);
+		gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+		src += GHASH_BLOCK_SIZE;
+		srclen -= GHASH_BLOCK_SIZE;
+	}
+
+	if (srclen) {
+		dctx->bytes = GHASH_BLOCK_SIZE - srclen;
+		while (srclen--)
+			*dst++ ^= *src++;
+	}
+
+	return 0;
+}
+
+static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
+{
+	u8 *dst = dctx->buffer;
+
+	if (dctx->bytes) {
+		u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
+
+		while (dctx->bytes--)
+			*tmp++ ^= 0;
+
+		gf128mul_4k_lle((be128 *)dst, ctx->gf128);
+	}
+
+	dctx->bytes = 0;
+}
+
+static int ghash_final(struct shash_desc *desc, u8 *dst)
+{
+	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
+	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
+	u8 *buf = dctx->buffer;
+
+	ghash_flush(ctx, dctx);
+	memcpy(dst, buf, GHASH_BLOCK_SIZE);
+
+	return 0;
+}
+
+static void ghash_exit_tfm(struct crypto_tfm *tfm)
+{
+	struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
+	if (ctx->gf128)
+		gf128mul_free_4k(ctx->gf128);
+}
+
+static struct shash_alg ghash_alg = {
+	.digestsize	= GHASH_DIGEST_SIZE,
+	.init		= ghash_init,
+	.update		= ghash_update,
+	.final		= ghash_final,
+	.setkey		= ghash_setkey,
+	.descsize	= sizeof(struct ghash_desc_ctx),
+	.base		= {
+		.cra_name		= "ghash",
+		.cra_driver_name	= "ghash-generic",
+		.cra_priority		= 100,
+		.cra_blocksize		= GHASH_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct ghash_ctx),
+		.cra_module		= THIS_MODULE,
+		.cra_exit		= ghash_exit_tfm,
+	},
+};
+
+static int __init ghash_mod_init(void)
+{
+	return crypto_register_shash(&ghash_alg);
+}
+
+static void __exit ghash_mod_exit(void)
+{
+	crypto_unregister_shash(&ghash_alg);
+}
+
+subsys_initcall(ghash_mod_init);
+module_exit(ghash_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("GHASH hash function");
+MODULE_ALIAS_CRYPTO("ghash");
+MODULE_ALIAS_CRYPTO("ghash-generic");