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krb5/SOURCES/Use-OpenSSL-s-KBKDF-and-KRB...

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From 21e3b9a4463f1d1aeb71de8a27c298f1307d186b Mon Sep 17 00:00:00 2001
From: Robbie Harwood <rharwood@redhat.com>
Date: Fri, 4 Oct 2019 14:49:29 -0400
Subject: [PATCH] Use OpenSSL's KBKDF and KRB5KDF for deriving long-term keys
If supported, use OpenSSL-provided KBKDF (aes-sha2 and camellia) and
KRB5KDF (3des and aes-sha1). We already use OpenSSL's PBKDF2 where
appropriate. OpenSSL added support for these KDFs in 3.0.
OpenSSL's restrictions to use KRB5KDF in FIPS mode are bypassed in case
AES SHA-1 HMAC encryption types are allowed by the crypto policy.
(cherry picked from commit ef8d11f6fb1232201c9efd2ae2ed567023fb85d2)
[rharwood@redhat.com: 3des removal]
---
src/lib/crypto/krb/derive.c | 409 ++++++++++++++++++++++++++++--------
1 file changed, 324 insertions(+), 85 deletions(-)
diff --git a/src/lib/crypto/krb/derive.c b/src/lib/crypto/krb/derive.c
index 6707a7308..8e474b38e 100644
--- a/src/lib/crypto/krb/derive.c
+++ b/src/lib/crypto/krb/derive.c
@@ -27,6 +27,12 @@
#include "crypto_int.h"
+#ifdef HAVE_EVP_KDF_FETCH
+#include <openssl/core_names.h>
+#include <openssl/evp.h>
+#include <openssl/kdf.h>
+#endif
+
static krb5_key
find_cached_dkey(struct derived_key *list, const krb5_data *constant)
{
@@ -77,55 +83,251 @@ cleanup:
return ENOMEM;
}
+#ifdef HAVE_EVP_KDF_FETCH
static krb5_error_code
-derive_random_rfc3961(const struct krb5_enc_provider *enc,
- krb5_key inkey, krb5_data *outrnd,
- const krb5_data *in_constant)
+openssl_kbdkf_counter_hmac(const struct krb5_hash_provider *hash,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *label, const krb5_data *context)
{
- size_t blocksize, keybytes, n;
krb5_error_code ret;
- krb5_data block = empty_data();
+ EVP_KDF *kdf = NULL;
+ EVP_KDF_CTX *kctx = NULL;
+ OSSL_PARAM params[6];
+ size_t i = 0;
+ char *digest;
- blocksize = enc->block_size;
- keybytes = enc->keybytes;
+ /* On NULL hash, preserve default behavior for pbkdf2_string_to_key(). */
+ if (hash == NULL || !strcmp(hash->hash_name, "SHA1")) {
+ digest = "SHA1";
+ } else if (!strcmp(hash->hash_name, "SHA-256")) {
+ digest = "SHA256";
+ } else if (!strcmp(hash->hash_name, "SHA-384")) {
+ digest = "SHA384";
+ } else {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
- if (blocksize == 1)
- return KRB5_BAD_ENCTYPE;
- if (inkey->keyblock.length != enc->keylength || outrnd->length != keybytes)
+ kdf = EVP_KDF_fetch(NULL, "KBKDF", NULL);
+ if (!kdf) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ kctx = EVP_KDF_CTX_new(kdf);
+ if (!kctx) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_DIGEST,
+ digest, 0);
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_MAC,
+ "HMAC", 0);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
+ inkey->keyblock.contents,
+ inkey->keyblock.length);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_INFO,
+ context->data,
+ context->length);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
+ label->data,
+ label->length);
+ params[i] = OSSL_PARAM_construct_end();
+ if (EVP_KDF_derive(kctx, (unsigned char *)outrnd->data, outrnd->length,
+ params) <= 0) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ ret = 0;
+done:
+ if (ret)
+ zap(outrnd->data, outrnd->length);
+ EVP_KDF_free(kdf);
+ EVP_KDF_CTX_free(kctx);
+ return ret;
+}
+
+static krb5_error_code
+openssl_kbkdf_feedback_cmac(const struct krb5_enc_provider *enc,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *in_constant)
+{
+ krb5_error_code ret;
+ EVP_KDF *kdf = NULL;
+ EVP_KDF_CTX *kctx = NULL;
+ OSSL_PARAM params[7];
+ size_t i = 0;
+ char *cipher;
+ static unsigned char zeroes[16];
+
+ memset(zeroes, 0, sizeof(zeroes));
+
+ if (!memcmp(enc, &krb5int_enc_camellia128, sizeof(*enc))) {
+ cipher = "CAMELLIA-128-CBC";
+ } else if (!memcmp(enc, &krb5int_enc_camellia256, sizeof(*enc))) {
+ cipher = "CAMELLIA-256-CBC";
+ } else {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ kdf = EVP_KDF_fetch(NULL, "KBKDF", NULL);
+ if (!kdf) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ kctx = EVP_KDF_CTX_new(kdf);
+ if (!kctx) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_MODE,
+ "FEEDBACK", 0);
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_MAC,
+ "CMAC", 0);
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_CIPHER,
+ cipher, 0);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
+ inkey->keyblock.contents,
+ inkey->keyblock.length);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SALT,
+ in_constant->data,
+ in_constant->length);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_SEED,
+ zeroes, sizeof(zeroes));
+ params[i] = OSSL_PARAM_construct_end();
+ if (EVP_KDF_derive(kctx, (unsigned char *)outrnd->data, outrnd->length,
+ params) <= 0) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ ret = 0;
+done:
+ if (ret)
+ zap(outrnd->data, outrnd->length);
+ EVP_KDF_free(kdf);
+ EVP_KDF_CTX_free(kctx);
+ return ret;
+}
+
+static krb5_error_code
+openssl_krb5kdf(const struct krb5_enc_provider *enc, krb5_key inkey,
+ krb5_data *outrnd, const krb5_data *in_constant)
+{
+ krb5_error_code ret;
+ EVP_KDF *kdf = NULL;
+ EVP_KDF_CTX *kctx = NULL;
+ OSSL_PARAM params[4];
+ size_t i = 0;
+ char *cipher;
+
+ if (inkey->keyblock.length != enc->keylength ||
+ outrnd->length != enc->keybytes) {
+ return KRB5_CRYPTO_INTERNAL;
+ }
+
+ if (!memcmp(enc, &krb5int_enc_aes128, sizeof(*enc))) {
+ cipher = "AES-128-CBC";
+ } else if (!memcmp(enc, &krb5int_enc_aes256, sizeof(*enc))) {
+ cipher = "AES-256-CBC";
+ } else {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ kdf = EVP_KDF_fetch(NULL, "KRB5KDF", "-fips");
+ if (kdf == NULL) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ kctx = EVP_KDF_CTX_new(kdf);
+ if (kctx == NULL) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ params[i++] = OSSL_PARAM_construct_utf8_string(OSSL_KDF_PARAM_CIPHER,
+ cipher, 0);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_KEY,
+ inkey->keyblock.contents,
+ inkey->keyblock.length);
+ params[i++] = OSSL_PARAM_construct_octet_string(OSSL_KDF_PARAM_CONSTANT,
+ in_constant->data,
+ in_constant->length);
+ params[i] = OSSL_PARAM_construct_end();
+ if (EVP_KDF_derive(kctx, (unsigned char *)outrnd->data, outrnd->length,
+ params) <= 0) {
+ ret = KRB5_CRYPTO_INTERNAL;
+ goto done;
+ }
+
+ ret = 0;
+done:
+ if (ret)
+ zap(outrnd->data, outrnd->length);
+ EVP_KDF_free(kdf);
+ EVP_KDF_CTX_free(kctx);
+ return ret;
+}
+
+#else /* HAVE_EVP_KDF_FETCH */
+
+/*
+ * NIST SP800-108 KDF in counter mode (section 5.1).
+ * Parameters:
+ * - HMAC (with hash as the hash provider) is the PRF.
+ * - A block counter of four bytes is used.
+ * - Four bytes are used to encode the output length in the PRF input.
+ *
+ * There are no uses requiring more than a single PRF invocation.
+ */
+static krb5_error_code
+builtin_sp800_108_counter_hmac(const struct krb5_hash_provider *hash,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *label,
+ const krb5_data *context)
+{
+ krb5_crypto_iov iov[5];
+ krb5_error_code ret;
+ krb5_data prf;
+ unsigned char ibuf[4], lbuf[4];
+
+ if (hash == NULL || outrnd->length > hash->hashsize)
return KRB5_CRYPTO_INTERNAL;
/* Allocate encryption data buffer. */
- ret = alloc_data(&block, blocksize);
+ ret = alloc_data(&prf, hash->hashsize);
if (ret)
return ret;
- /* Initialize the input block. */
- if (in_constant->length == blocksize) {
- memcpy(block.data, in_constant->data, blocksize);
- } else {
- krb5int_nfold(in_constant->length * 8,
- (unsigned char *) in_constant->data,
- blocksize * 8, (unsigned char *) block.data);
- }
+ /* [i]2: four-byte big-endian binary string giving the block counter (1) */
+ iov[0].flags = KRB5_CRYPTO_TYPE_DATA;
+ iov[0].data = make_data(ibuf, sizeof(ibuf));
+ store_32_be(1, ibuf);
+ /* Label */
+ iov[1].flags = KRB5_CRYPTO_TYPE_DATA;
+ iov[1].data = *label;
+ /* 0x00: separator byte */
+ iov[2].flags = KRB5_CRYPTO_TYPE_DATA;
+ iov[2].data = make_data("", 1);
+ /* Context */
+ iov[3].flags = KRB5_CRYPTO_TYPE_DATA;
+ iov[3].data = *context;
+ /* [L]2: four-byte big-endian binary string giving the output length */
+ iov[4].flags = KRB5_CRYPTO_TYPE_DATA;
+ iov[4].data = make_data(lbuf, sizeof(lbuf));
+ store_32_be(outrnd->length * 8, lbuf);
- /* Loop encrypting the blocks until enough key bytes are generated. */
- n = 0;
- while (n < keybytes) {
- ret = encrypt_block(enc, inkey, &block);
- if (ret)
- goto cleanup;
-
- if ((keybytes - n) <= blocksize) {
- memcpy(outrnd->data + n, block.data, (keybytes - n));
- break;
- }
-
- memcpy(outrnd->data + n, block.data, blocksize);
- n += blocksize;
- }
-
-cleanup:
- zapfree(block.data, blocksize);
+ ret = krb5int_hmac(hash, inkey, iov, 5, &prf);
+ if (!ret)
+ memcpy(outrnd->data, prf.data, outrnd->length);
+ zapfree(prf.data, prf.length);
return ret;
}
@@ -139,9 +341,9 @@ cleanup:
* - Four bytes are used to encode the output length in the PRF input.
*/
static krb5_error_code
-derive_random_sp800_108_feedback_cmac(const struct krb5_enc_provider *enc,
- krb5_key inkey, krb5_data *outrnd,
- const krb5_data *in_constant)
+builtin_sp800_108_feedback_cmac(const struct krb5_enc_provider *enc,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *in_constant)
{
size_t blocksize, keybytes, n;
krb5_crypto_iov iov[6];
@@ -204,56 +406,94 @@ cleanup:
return ret;
}
-/*
- * NIST SP800-108 KDF in counter mode (section 5.1).
- * Parameters:
- * - HMAC (with hash as the hash provider) is the PRF.
- * - A block counter of four bytes is used.
- * - Four bytes are used to encode the output length in the PRF input.
- *
- * There are no uses requiring more than a single PRF invocation.
- */
+static krb5_error_code
+builtin_derive_random_rfc3961(const struct krb5_enc_provider *enc,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *in_constant)
+{
+ size_t blocksize, keybytes, n;
+ krb5_error_code ret;
+ krb5_data block = empty_data();
+
+ blocksize = enc->block_size;
+ keybytes = enc->keybytes;
+
+ if (blocksize == 1)
+ return KRB5_BAD_ENCTYPE;
+ if (inkey->keyblock.length != enc->keylength || outrnd->length != keybytes)
+ return KRB5_CRYPTO_INTERNAL;
+
+ /* Allocate encryption data buffer. */
+ ret = alloc_data(&block, blocksize);
+ if (ret)
+ return ret;
+
+ /* Initialize the input block. */
+ if (in_constant->length == blocksize) {
+ memcpy(block.data, in_constant->data, blocksize);
+ } else {
+ krb5int_nfold(in_constant->length * 8,
+ (unsigned char *) in_constant->data,
+ blocksize * 8, (unsigned char *) block.data);
+ }
+
+ /* Loop encrypting the blocks until enough key bytes are generated. */
+ n = 0;
+ while (n < keybytes) {
+ ret = encrypt_block(enc, inkey, &block);
+ if (ret)
+ goto cleanup;
+
+ if ((keybytes - n) <= blocksize) {
+ memcpy(outrnd->data + n, block.data, (keybytes - n));
+ break;
+ }
+
+ memcpy(outrnd->data + n, block.data, blocksize);
+ n += blocksize;
+ }
+
+cleanup:
+ zapfree(block.data, blocksize);
+ return ret;
+}
+#endif /* HAVE_EVP_KDF_FETCH */
+
krb5_error_code
k5_sp800_108_counter_hmac(const struct krb5_hash_provider *hash,
krb5_key inkey, krb5_data *outrnd,
const krb5_data *label, const krb5_data *context)
{
- krb5_crypto_iov iov[5];
- krb5_error_code ret;
- krb5_data prf;
- unsigned char ibuf[4], lbuf[4];
+#ifdef HAVE_EVP_KDF_FETCH
+ return openssl_kbdkf_counter_hmac(hash, inkey, outrnd, label, context);
+#else
+ return builtin_sp800_108_counter_hmac(hash, inkey, outrnd, label,
+ context);
+#endif
+}
- if (hash == NULL || outrnd->length > hash->hashsize)
- return KRB5_CRYPTO_INTERNAL;
+static krb5_error_code
+sp800_108_feedback_cmac(const struct krb5_enc_provider *enc,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *in_constant)
+{
+#ifdef HAVE_EVP_KDF_FETCH
+ return openssl_kbkdf_feedback_cmac(enc, inkey, outrnd, in_constant);
+#else
+ return builtin_sp800_108_feedback_cmac(enc, inkey, outrnd, in_constant);
+#endif
+}
- /* Allocate encryption data buffer. */
- ret = alloc_data(&prf, hash->hashsize);
- if (ret)
- return ret;
-
- /* [i]2: four-byte big-endian binary string giving the block counter (1) */
- iov[0].flags = KRB5_CRYPTO_TYPE_DATA;
- iov[0].data = make_data(ibuf, sizeof(ibuf));
- store_32_be(1, ibuf);
- /* Label */
- iov[1].flags = KRB5_CRYPTO_TYPE_DATA;
- iov[1].data = *label;
- /* 0x00: separator byte */
- iov[2].flags = KRB5_CRYPTO_TYPE_DATA;
- iov[2].data = make_data("", 1);
- /* Context */
- iov[3].flags = KRB5_CRYPTO_TYPE_DATA;
- iov[3].data = *context;
- /* [L]2: four-byte big-endian binary string giving the output length */
- iov[4].flags = KRB5_CRYPTO_TYPE_DATA;
- iov[4].data = make_data(lbuf, sizeof(lbuf));
- store_32_be(outrnd->length * 8, lbuf);
-
- ret = krb5int_hmac(hash, inkey, iov, 5, &prf);
- if (!ret)
- memcpy(outrnd->data, prf.data, outrnd->length);
- zapfree(prf.data, prf.length);
- return ret;
+static krb5_error_code
+derive_random_rfc3961(const struct krb5_enc_provider *enc,
+ krb5_key inkey, krb5_data *outrnd,
+ const krb5_data *in_constant)
+{
+#ifdef HAVE_EVP_KDF_FETCH
+ return openssl_krb5kdf(enc, inkey, outrnd, in_constant);
+#else
+ return builtin_derive_random_rfc3961(enc, inkey, outrnd, in_constant);
+#endif
}
krb5_error_code
@@ -268,8 +508,7 @@ krb5int_derive_random(const struct krb5_enc_provider *enc,
case DERIVE_RFC3961:
return derive_random_rfc3961(enc, inkey, outrnd, in_constant);
case DERIVE_SP800_108_CMAC:
- return derive_random_sp800_108_feedback_cmac(enc, inkey, outrnd,
- in_constant);
+ return sp800_108_feedback_cmac(enc, inkey, outrnd, in_constant);
case DERIVE_SP800_108_HMAC:
return k5_sp800_108_counter_hmac(hash, inkey, outrnd, in_constant,
&empty);