Add Argon2 KDF demo.

Signed-off-by: Milan Broz <gmazyland@gmail.com>

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20531)

2 files changed, 156 insertions, 2 deletions

diff --git a/demos/kdf/Makefile b/demos/kdf/Makefile
index 0aa5113105..364a104d79 100644
--- a/demos/kdf/Makefile
+++ b/demos/kdf/Makefile
@@ -7,7 +7,7 @@ CFLAGS = -I../../include -g
 LDFLAGS = -L../..
 LDLIBS = -lcrypto
 
-all: hkdf pbkdf2 scrypt
+all: hkdf pbkdf2 scrypt argon2
 
 %.o: %.c
 	$(CC) $(CFLAGS) -c $<
@@ -19,4 +19,4 @@ scrypt: scrypt.o
 test: ;
 
 clean:
-	$(RM) *.o hkdf pbkdf2 scrypt
+	$(RM) *.o hkdf pbkdf2 scrypt argon2
diff --git a/demos/kdf/argon2.c b/demos/kdf/argon2.c
new file mode 100644
index 0000000000..b6a1590328
--- /dev/null
+++ b/demos/kdf/argon2.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include <openssl/core_names.h>
+#include <openssl/crypto.h>
+#include <openssl/kdf.h>
+#include <openssl/params.h>
+#include <openssl/thread.h>
+
+/*
+ * Example showing how to use Argon2 KDF.
+ * See man EVP_KDF-ARGON2 for more information.
+ *
+ * test vector from
+ * https://datatracker.ietf.org/doc/html/rfc9106
+ */
+
+/*
+ * Hard coding a password into an application is very bad.
+ * It is done here solely for educational purposes.
+ */
+static unsigned char password[] = {
+    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01
+};
+
+/*
+ * The salt is better not being hard coded too.  Each password should have a
+ * different salt if possible.  The salt is not considered secret information
+ * and is safe to store with an encrypted password.
+ */
+static unsigned char salt[] = {
+    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
+    0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02
+};
+
+/*
+ * Optional secret for KDF
+ */
+static unsigned char secret[] = {
+    0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03
+};
+
+/*
+ * Optional additional data
+ */
+static unsigned char ad[] = {
+    0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
+    0x04, 0x04, 0x04, 0x04
+};
+
+/*
+ * Argon2 cost parameters
+ */
+static uint32_t memory_cost    = 32;
+static uint32_t iteration_cost =  3;
+static uint32_t parallel_cost  =  4;
+
+static const unsigned char expected_output[] = {
+   0x0d, 0x64, 0x0d, 0xf5, 0x8d, 0x78, 0x76, 0x6c,
+   0x08, 0xc0, 0x37, 0xa3, 0x4a, 0x8b, 0x53, 0xc9,
+   0xd0, 0x1e, 0xf0, 0x45, 0x2d, 0x75, 0xb6, 0x5e,
+   0xb5, 0x25, 0x20, 0xe9, 0x6b, 0x01, 0xe6, 0x59
+};
+
+int main(int argc, char **argv)
+{
+    int rv = EXIT_FAILURE;
+    EVP_KDF *kdf = NULL;
+    EVP_KDF_CTX *kctx = NULL;
+    unsigned char out[32];
+    OSSL_PARAM params[9], *p = params;
+    OSSL_LIB_CTX *library_context = NULL;
+    unsigned int threads;
+
+    library_context = OSSL_LIB_CTX_new();
+    if (library_context == NULL) {
+        fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
+        goto end;
+    }
+
+    /* Fetch the key derivation function implementation */
+    kdf = EVP_KDF_fetch(library_context, "argon2id", NULL);
+    if (kdf == NULL) {
+        fprintf(stderr, "EVP_KDF_fetch() returned NULL\n");
+        goto end;
+    }
+
+    /* Create a context for the key derivation operation */
+    kctx = EVP_KDF_CTX_new(kdf);
+    if (kctx == NULL) {
+        fprintf(stderr, "EVP_KDF_CTX_new() returned NULL\n");
+        goto end;
+    }
+
+    /*
+     * Thread support can be turned off; use serialization if we cannot
+     * set requested number of threads.
+     */
+    threads = parallel_cost;
+    if (OSSL_set_max_threads(library_context, parallel_cost) != 1) {
+        uint64_t max_threads = OSSL_get_max_threads(library_context);
+
+        if (max_threads == 0)
+            threads = 1;
+        else if (max_threads < parallel_cost)
+            threads = max_threads;
+    }
+
+    /* Set password */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_PASSWORD, password, sizeof(password));
+    /* Set salt */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT, salt, sizeof(salt));
+    /* Set optional additional data */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_ARGON2_AD, ad, sizeof(ad));
+    /* Set optional secret */
+    *p++ = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SECRET, secret, sizeof(secret));
+    /* Set iteration count */
+    *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ITER, &iteration_cost);
+    /* Set threads performing derivation (can be decreased) */
+    *p++ = OSSL_PARAM_construct_uint(OSSL_KDF_PARAM_THREADS, &threads);
+    /* Set parallel cost */
+    *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_LANES, &parallel_cost);
+    /* Set memory requirement */
+    *p++ = OSSL_PARAM_construct_uint32(OSSL_KDF_PARAM_ARGON2_MEMCOST, &memory_cost);
+    *p = OSSL_PARAM_construct_end();
+
+    /* Derive the key */
+    if (EVP_KDF_derive(kctx, out, sizeof(out), params) != 1) {
+        fprintf(stderr, "EVP_KDF_derive() failed\n");
+        goto end;
+    }
+
+    if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
+        fprintf(stderr, "Generated key does not match expected value\n");
+        goto end;
+    }
+
+    rv = EXIT_SUCCESS;
+end:
+    EVP_KDF_CTX_free(kctx);
+    EVP_KDF_free(kdf);
+    OSSL_LIB_CTX_free(library_context);
+    return rv;
+}