[KDF] Add KBKDF implementation for counter-mode HMAC

Implement SP800-108 section 5.1 with HMAC intended for use in Kerberos.
Add test vectors from RFC 8009.

Adds error codes PROV_R_INVALID_MAC and PROV_R_MISSING_MAC.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>

Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9924)

4 files changed, 307 insertions, 1 deletions

diff --git a/providers/common/include/internal/provider_algs.h b/providers/common/include/internal/provider_algs.h
index 4bbbbf61c5..3e23788698 100644
--- a/providers/common/include/internal/provider_algs.h
+++ b/providers/common/include/internal/provider_algs.h
@@ -212,6 +212,7 @@ extern const OSSL_DISPATCH kdf_hkdf_functions[];
 extern const OSSL_DISPATCH kdf_sshkdf_functions[];
 extern const OSSL_DISPATCH kdf_sskdf_functions[];
 extern const OSSL_DISPATCH kdf_x963_kdf_functions[];
+extern const OSSL_DISPATCH kdf_kbkdf_functions[];
 #ifndef OPENSSL_NO_CMS
 extern const OSSL_DISPATCH kdf_x942_kdf_functions[];
 #endif
diff --git a/providers/common/include/internal/providercommonerr.h b/providers/common/include/internal/providercommonerr.h
index 81e5931d84..a9f79762b5 100644
--- a/providers/common/include/internal/providercommonerr.h
+++ b/providers/common/include/internal/providercommonerr.h
@@ -69,6 +69,7 @@ int ERR_load_PROV_strings(void);
 # define PROV_R_INVALID_KEYLEN                            117
 # define PROV_R_INVALID_KEY_LEN                           124
 # define PROV_R_INVALID_KEY_LENGTH                        105
+# define PROV_R_INVALID_MAC                               151
 # define PROV_R_INVALID_MODE                              125
 # define PROV_R_INVALID_MODE_INT                          126
 # define PROV_R_INVALID_SALT_LENGTH                       112
@@ -76,6 +77,7 @@ int ERR_load_PROV_strings(void);
 # define PROV_R_INVALID_TAGLEN                            118
 # define PROV_R_MISSING_CEK_ALG                           144
 # define PROV_R_MISSING_KEY                               128
+# define PROV_R_MISSING_MAC                               150
 # define PROV_R_MISSING_MESSAGE_DIGEST                    129
 # define PROV_R_MISSING_PASS                              130
 # define PROV_R_MISSING_SALT                              131
diff --git a/providers/common/kdfs/build.info b/providers/common/kdfs/build.info
index a881fa00b9..8a723d488d 100644
--- a/providers/common/kdfs/build.info
+++ b/providers/common/kdfs/build.info
@@ -1,4 +1,4 @@
-$COMMON=tls1_prf.c hkdf.c pbkdf2.c sskdf.c
+$COMMON=tls1_prf.c hkdf.c kbkdf.c pbkdf2.c sskdf.c
 
 LIBS=../../../libcrypto
 SOURCE[../../../libcrypto]=$COMMON
diff --git a/providers/common/kdfs/kbkdf.c b/providers/common/kdfs/kbkdf.c
new file mode 100644
index 0000000000..77cee258e8
--- /dev/null
+++ b/providers/common/kdfs/kbkdf.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2019 Red Hat, Inc.
+ *
+ * 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
+ */
+
+/*
+ * This implements https://csrc.nist.gov/publications/detail/sp/800-108/final
+ * section 5.1 ("counter mode") in HMAC only.  That document does not name the
+ * KDFs it defines; the name is derived from
+ * https://csrc.nist.gov/Projects/Cryptographic-Algorithm-Validation-Program/Key-Derivation
+ *
+ * Note that sections 5.2 ("feedback mode") and 5.3 ("double-pipeline mode")
+ * are not implemented, though it would be possible to do so in the future.
+ * CMAC mode is also not implemented; some plumbing would be required.
+ *
+ * These versions all assume the counter is used.  It would be relatively
+ * straightforward to expose a configuration handle should the need arise.
+ *
+ * Variable names attempt to match those of SP800-108.
+ */
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openssl/core_names.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/kdf.h>
+#include <openssl/params.h>
+
+#include "internal/cryptlib.h"
+#include "internal/evp_int.h"
+#include "internal/numbers.h"
+#include "internal/provider_algs.h"
+#include "internal/provider_ctx.h"
+#include "internal/provider_util.h"
+#include "internal/providercommonerr.h"
+
+#include "e_os.h"
+
+#define MIN(a, b) ((a) < (b)) ? (a) : (b)
+
+/* Our context structure. */
+typedef struct {
+    void *provctx;
+    EVP_MAC_CTX *ctx_init;
+
+    /* Names are lowercased versions of those found in SP800-108. */
+    unsigned char *ki;
+    size_t ki_len;
+    unsigned char *label;
+    size_t label_len;
+    unsigned char *context;
+    size_t context_len;
+} KBKDF;
+
+/* Definitions needed for typechecking. */
+static OSSL_OP_kdf_newctx_fn kbkdf_new;
+static OSSL_OP_kdf_freectx_fn kbkdf_free;
+static OSSL_OP_kdf_reset_fn kbkdf_reset;
+static OSSL_OP_kdf_derive_fn kbkdf_derive;
+static OSSL_OP_kdf_settable_ctx_params_fn kbkdf_settable_ctx_params;
+static OSSL_OP_kdf_set_ctx_params_fn kbkdf_set_ctx_params;
+
+/* Not all platforms have htobe32(). */
+static uint32_t be32(uint32_t host)
+{
+    uint32_t big = 0;
+    const union {
+        long one;
+        char little;
+    } is_endian = { 1 };
+
+    if (!is_endian.little)
+        return host;
+
+    big |= (host & 0xff000000) >> 24;
+    big |= (host & 0x00ff0000) >> 8;
+    big |= (host & 0x0000ff00) << 8;
+    big |= (host & 0x000000ff) << 24;
+    return big;
+}
+
+static void *kbkdf_new(void *provctx)
+{
+    KBKDF *ctx;
+
+    ctx = OPENSSL_zalloc(sizeof(*ctx));
+    if (ctx == NULL) {
+        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+
+    ctx->provctx = provctx;
+    return ctx;
+}
+
+static void kbkdf_free(void *vctx)
+{
+    KBKDF *ctx = (KBKDF *)vctx;
+
+    kbkdf_reset(ctx);
+    OPENSSL_free(ctx);
+}
+
+static void kbkdf_reset(void *vctx)
+{
+    KBKDF *ctx = (KBKDF *)vctx;
+
+    EVP_MAC_CTX_free(ctx->ctx_init);
+    OPENSSL_clear_free(ctx->context, ctx->context_len);
+    OPENSSL_clear_free(ctx->label, ctx->label_len);
+    OPENSSL_clear_free(ctx->ki, ctx->ki_len);
+    memset(ctx, 0, sizeof(*ctx));
+}
+
+/* SP800-108 section 5.1. */
+static int kbkdf_derive_counter(EVP_MAC_CTX *ctx_init,
+                                unsigned char *label, size_t label_len,
+                                unsigned char *context, size_t context_len,
+                                unsigned char *k_i, size_t h, uint32_t l,
+                                unsigned char *ko, size_t ko_len)
+{
+    int ret = 0;
+    EVP_MAC_CTX *ctx = NULL;
+    size_t written = 0, to_write;
+    const unsigned char zero = 0;
+    uint32_t counter, i;
+
+    for (counter = 1; written < ko_len; counter++) {
+        i = be32(counter);
+
+        ctx = EVP_MAC_CTX_dup(ctx_init);
+        if (ctx == NULL)
+            goto done;
+
+        if (!EVP_MAC_update(ctx, (unsigned char *)&i, 4)
+            || !EVP_MAC_update(ctx, label, label_len)
+            || !EVP_MAC_update(ctx, &zero, 1)
+            || !EVP_MAC_update(ctx, context, context_len)
+            || !EVP_MAC_update(ctx, (unsigned char *)&l, 4)
+            || !EVP_MAC_final(ctx, k_i, NULL, h))
+            goto done;
+
+        to_write = ko_len - written;
+        memcpy(ko + written, k_i, MIN(to_write, h));
+        written += h;
+
+        EVP_MAC_CTX_free(ctx);
+        ctx = NULL;
+    }
+
+    ret = 1;
+done:
+    EVP_MAC_CTX_free(ctx);
+    return ret;
+}
+
+static int kbkdf_derive(void *vctx, unsigned char *key, size_t keylen)
+{
+    KBKDF *ctx = (KBKDF *)vctx;
+    int ret = 0;
+    unsigned char *k_i = NULL;
+    uint32_t l = be32(keylen * 8);
+    size_t h = 0;
+
+    /* Label and Context are permitted to be empty. Check everything else. */
+    if (ctx->ctx_init == NULL) {
+        if (ctx->ki_len == 0 || ctx->ki == NULL) {
+            ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
+            return 0;
+        }
+        /* Could either be missing MAC or missing message digest -
+         * arbitrarily, I pick this one. */
+        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_MAC);
+        return 0;
+    }
+
+    h = EVP_MAC_size(ctx->ctx_init);
+    if (h == 0)
+        goto done;
+
+    k_i = OPENSSL_zalloc(h);
+    if (k_i == NULL)
+        goto done;
+
+    ret = kbkdf_derive_counter(
+        ctx->ctx_init, ctx->label, ctx->label_len, ctx->context,
+        ctx->context_len, k_i, h, l, key, keylen);
+done:
+    if (ret != 1)
+        OPENSSL_cleanse(key, keylen);
+    OPENSSL_clear_free(k_i, h);
+    return ret;
+}
+
+static int kbkdf_set_buffer(unsigned char **out, size_t *out_len,
+                            const OSSL_PARAM *p)
+{
+    if (p->data == NULL || p->data_size == 0)
+        return 1;
+
+    OPENSSL_clear_free(*out, *out_len);
+    *out = NULL;
+    return OSSL_PARAM_get_octet_string(p, (void **)out, 0, out_len);
+}
+
+static int kbkdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
+{
+    KBKDF *ctx = (KBKDF *)vctx;
+    OPENSSL_CTX *libctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
+    const OSSL_PARAM *p;
+    OSSL_PARAM mparams[2];
+
+    if (!ossl_prov_macctx_load_from_params(&ctx->ctx_init, params, NULL,
+                                           NULL, NULL, libctx))
+        return 0;
+    else if (ctx->ctx_init != NULL
+        && !EVP_MAC_is_a(EVP_MAC_CTX_mac(ctx->ctx_init),
+                         OSSL_MAC_NAME_HMAC)) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_MAC);
+        return 0;
+    }
+
+    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY);
+    if (p != NULL && !kbkdf_set_buffer(&ctx->ki, &ctx->ki_len, p))
+        return 0;
+
+    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT);
+    if (p != NULL && !kbkdf_set_buffer(&ctx->label, &ctx->label_len, p))
+        return 0;
+
+    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_INFO);
+    if (p != NULL && !kbkdf_set_buffer(&ctx->context, &ctx->context_len, p))
+        return 0;
+
+    /* Set up digest context, if we can. */
+    if (ctx->ctx_init != NULL && ctx->ki_len != 0) {
+        mparams[0] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
+                                                       ctx->ki, ctx->ki_len);
+        mparams[1] = OSSL_PARAM_construct_end();
+
+        if (!EVP_MAC_CTX_set_params(ctx->ctx_init, mparams)
+            || !EVP_MAC_init(ctx->ctx_init))
+            return 0;
+    }
+
+    return 1;
+}
+
+static const OSSL_PARAM *kbkdf_settable_ctx_params(void)
+{
+    static const OSSL_PARAM known_settable_ctx_params[] = {
+        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_INFO, NULL, 0),
+        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
+        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
+        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_DIGEST, NULL, 0),
+        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_MAC, NULL, 0),
+
+        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
+        OSSL_PARAM_END,
+    };
+    return known_settable_ctx_params;
+}
+
+static int kbkdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
+{
+    OSSL_PARAM *p;
+
+    p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE);
+    if (p == NULL)
+        return -2;
+
+    /* KBKDF can produce results as large as you like. */
+    return OSSL_PARAM_set_size_t(p, SIZE_MAX);
+}
+
+static const OSSL_PARAM *kbkdf_gettable_ctx_params(void)
+{
+    static const OSSL_PARAM known_gettable_ctx_params[] =
+        { OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL), OSSL_PARAM_END };
+    return known_gettable_ctx_params;
+}
+
+const OSSL_DISPATCH kdf_kbkdf_functions[] = {
+    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kbkdf_new },
+    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kbkdf_free },
+    { OSSL_FUNC_KDF_RESET, (void(*)(void))kbkdf_reset },
+    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kbkdf_derive },
+    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
+      (void(*)(void))kbkdf_settable_ctx_params },
+    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kbkdf_set_ctx_params },
+    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
+      (void(*)(void))kbkdf_gettable_ctx_params },
+    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kbkdf_get_ctx_params },
+    { 0, NULL },
+};