@@ -9,11 +9,11 @@ Keying Material Exporters (RFC 5705) based key generation
the RFC5705 based key material generation to the current custom
OpenVPN PRF. This feature requires OpenSSL or mbed TLS 2.18+.
-Deprecated features
--------------------
-``inetd`` has been removed
- This was a very limited and not-well-tested way to run OpenVPN, on TCP
- and TAP mode only.
+Compatibility with OpenSSL in FIPS mode
+ OpenVPN will now work with OpenSSL in FIPS mode. Note, no effort
+ has been made to check or implement all the
+ requirements/recommendation of FIPS 140-2. This just allows OpenVPN
+ to be run on a system that be configured OpenSSL in FIPS mode.
Overview of changes in 2.5
@@ -699,4 +699,20 @@ const char *translate_cipher_name_from_openvpn(const char *cipher_name);
*/
const char *translate_cipher_name_to_openvpn(const char *cipher_name);
+
+/**
+ * Calculates the TLS 1.0-1.1 PRF function. For the exact specification of the
+ * function definition see the TLS RFCs like RFC 4346.
+ *
+ * @param seed seed to use
+ * @param seed_len length of the seed
+ * @param secret secret to use
+ * @param secret_len length of the secret
+ * @param output output destination
+ * @param output_len length of output/number of bytes to generate
+ *
+ * @return true if successful, false on any error
+ */
+bool ssl_tls1_PRF(const uint8_t *seed, int seed_len, const uint8_t *secret,
+ int secret_len, uint8_t *output, int output_len);
#endif /* CRYPTO_BACKEND_H_ */
@@ -54,6 +54,7 @@
#include <mbedtls/pem.h>
#include <mbedtls/entropy.h>
+#include <mbedtls/ssl.h>
/*
@@ -984,4 +985,138 @@ memcmp_constant_time(const void *a, const void *b, size_t size)
return diff;
}
+/* mbedtls-2.18.0 or newer */
+#ifdef HAVE_MBEDTLS_SSL_TLS_PRF
+bool ssl_tls1_PRF(const uint8_t *seed, int seed_len, const uint8_t *secret,
+ int secret_len, uint8_t *output, int output_len)
+{
+ return mbed_ok(mbedtls_ssl_tls_prf(MBEDTLS_SSL_TLS_PRF_TLS1, secret,
+ secret_len, "", seed, seed_len, output,
+ output_len));
+}
+#else
+/*
+ * Generate the hash required by for the \c tls1_PRF function.
+ *
+ * @param md_kt Message digest to use
+ * @param sec Secret to base the hash on
+ * @param sec_len Length of the secret
+ * @param seed Seed to hash
+ * @param seed_len Length of the seed
+ * @param out Output buffer
+ * @param olen Length of the output buffer
+ */
+static void
+tls1_P_hash(const md_kt_t *md_kt,
+ const uint8_t *sec,
+ int sec_len,
+ const uint8_t *seed,
+ int seed_len,
+ uint8_t *out,
+ int olen)
+{
+ struct gc_arena gc = gc_new();
+ uint8_t A1[MAX_HMAC_KEY_LENGTH];
+
+#ifdef ENABLE_DEBUG
+ const int olen_orig = olen;
+ const uint8_t *out_orig = out;
+#endif
+
+ hmac_ctx_t *ctx = hmac_ctx_new();
+ hmac_ctx_t *ctx_tmp = hmac_ctx_new();
+
+ dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash sec: %s", format_hex(sec, sec_len, 0, &gc));
+ dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash seed: %s", format_hex(seed, seed_len, 0, &gc));
+
+ int chunk = md_kt_size(md_kt);
+ unsigned int A1_len = md_kt_size(md_kt);
+
+ hmac_ctx_init(ctx, sec, sec_len, md_kt);
+ hmac_ctx_init(ctx_tmp, sec, sec_len, md_kt);
+
+ hmac_ctx_update(ctx,seed,seed_len);
+ hmac_ctx_final(ctx, A1);
+
+ for (;;)
+ {
+ hmac_ctx_reset(ctx);
+ hmac_ctx_reset(ctx_tmp);
+ hmac_ctx_update(ctx, A1, A1_len);
+ hmac_ctx_update(ctx_tmp, A1, A1_len);
+ hmac_ctx_update(ctx, seed, seed_len);
+
+ if (olen > chunk)
+ {
+ hmac_ctx_final(ctx, out);
+ out += chunk;
+ olen -= chunk;
+ hmac_ctx_final(ctx_tmp, A1); /* calc the next A1 value */
+ }
+ else /* last one */
+ {
+ hmac_ctx_final(ctx, A1);
+ memcpy(out, A1, olen);
+ break;
+ }
+ }
+ hmac_ctx_cleanup(ctx);
+ hmac_ctx_free(ctx);
+ hmac_ctx_cleanup(ctx_tmp);
+ hmac_ctx_free(ctx_tmp);
+ secure_memzero(A1, sizeof(A1));
+
+ dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash out: %s", format_hex(out_orig, olen_orig, 0, &gc));
+ gc_free(&gc);
+}
+
+/*
+ * Use the TLS PRF function for generating data channel keys.
+ * This code is based on the OpenSSL library.
+ *
+ * TLS generates keys as such:
+ *
+ * master_secret[48] = PRF(pre_master_secret[48], "master secret",
+ * ClientHello.random[32] + ServerHello.random[32])
+ *
+ * key_block[] = PRF(SecurityParameters.master_secret[48],
+ * "key expansion",
+ * SecurityParameters.server_random[32] +
+ * SecurityParameters.client_random[32]);
+ *
+ * Notes:
+ *
+ * (1) key_block contains a full set of 4 keys.
+ * (2) The pre-master secret is generated by the client.
+ */
+bool ssl_tls1_PRF(const uint8_t *label, int label_len, const uint8_t *sec,
+ int slen, uint8_t *out1, int olen)
+{
+ struct gc_arena gc = gc_new();
+ const md_kt_t *md5 = md_kt_get("MD5");
+ const md_kt_t *sha1 = md_kt_get("SHA1");
+
+ uint8_t *out2 = (uint8_t *) gc_malloc(olen, false, &gc);
+
+ int len = slen/2;
+ const uint8_t *S1 = sec;
+ const uint8_t *S2 = &(sec[len]);
+ len += (slen&1); /* add for odd, make longer */
+
+ tls1_P_hash(md5, S1, len, label, label_len, out1, olen);
+ tls1_P_hash(sha1, S2, len, label, label_len, out2, olen);
+
+ for (int i = 0; i<olen; i++)
+ {
+ out1[i] ^= out2[i];
+ }
+
+ secure_memzero(out2, olen);
+
+ dmsg(D_SHOW_KEY_SOURCE, "tls1_PRF out[%d]: %s", olen, format_hex(out1, olen, 0, &gc));
+
+ gc_free(&gc);
+ return true;
+}
+#endif
#endif /* ENABLE_CRYPTO_MBEDTLS */
@@ -50,6 +50,9 @@
#include <openssl/objects.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+#include <openssl/kdf.h>
+#endif
/*
* Check for key size creepage.
@@ -1124,4 +1127,196 @@ engine_load_key(const char *file, SSL_CTX *ctx)
#endif /* if HAVE_OPENSSL_ENGINE */
}
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+bool ssl_tls1_PRF(const uint8_t *seed, int seed_len, const uint8_t *secret,
+ int secret_len, uint8_t *output, int output_len)
+{
+ EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_TLS1_PRF, NULL);
+ if(!EVP_PKEY_derive_init(pctx))
+ {
+ return false;
+ }
+
+
+ if(!EVP_PKEY_CTX_set_tls1_prf_md(pctx, EVP_md5_sha1()))
+ {
+ return false;
+ }
+
+ if(!EVP_PKEY_CTX_set1_tls1_prf_secret(pctx, secret, secret_len))
+ {
+ return false;
+ }
+
+ if(!EVP_PKEY_CTX_add1_tls1_prf_seed(pctx, seed, seed_len))
+ {
+ return false;
+ }
+
+ size_t out_len = output_len;
+ if(!EVP_PKEY_derive(pctx, output, &out_len))
+ {
+ return false;
+ }
+ if (out_len != output_len)
+ {
+ return false;
+ }
+ return true;
+}
+#else
+/*
+ * Generate the hash required by for the \c tls1_PRF function.
+ *
+ * We cannot use our normal hmac_* function as they do not work
+ * in a FIPS environment (no MD5 allowed, which we need). Instead
+ * we need to directly use the EVP_MD_* API with the special
+ * EVP_MD_CTX_FLAG_NON_FIPS_ALLOW flag.
+ *
+ *
+ * The function below is adapted from OpenSSL 1.0.2t
+ *
+ * @param md_kt Message digest to use
+ * @param sec Secret to base the hash on
+ * @param sec_len Length of the secret
+ * @param seed Seed to hash
+ * @param seed_len Length of the seed
+ * @param out Output buffer
+ * @param olen Length of the output buffer
+ */
+static
+int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
+ int sec_len,
+ const void *seed, int seed_len,
+ unsigned char *out, int olen)
+{
+ int chunk;
+ size_t j;
+ EVP_MD_CTX ctx, ctx_tmp, ctx_init;
+ EVP_PKEY *mac_key;
+ unsigned char A1[EVP_MAX_MD_SIZE];
+ size_t A1_len;
+ int ret = 0;
+
+ chunk = EVP_MD_size(md);
+ OPENSSL_assert(chunk >= 0);
+
+ EVP_MD_CTX_init(&ctx);
+ EVP_MD_CTX_init(&ctx_tmp);
+ EVP_MD_CTX_init(&ctx_init);
+ EVP_MD_CTX_set_flags(&ctx_init, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
+ mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
+ if (!mac_key)
+ goto err;
+ if (!EVP_DigestSignInit(&ctx_init, NULL, md, NULL, mac_key))
+ goto err;
+ if (!EVP_MD_CTX_copy_ex(&ctx, &ctx_init))
+ goto err;
+ if (!EVP_DigestSignUpdate(&ctx, seed, seed_len))
+ goto err;
+ if (!EVP_DigestSignFinal(&ctx, A1, &A1_len))
+ goto err;
+
+ for (;;) {
+ /* Reinit mac contexts */
+ if (!EVP_MD_CTX_copy_ex(&ctx, &ctx_init))
+ goto err;
+ if (!EVP_DigestSignUpdate(&ctx, A1, A1_len))
+ goto err;
+ if (olen > chunk && !EVP_MD_CTX_copy_ex(&ctx_tmp, &ctx))
+ goto err;
+ if (!EVP_DigestSignUpdate(&ctx, seed, seed_len))
+ goto err;
+
+ if (olen > chunk)
+ {
+ if (!EVP_DigestSignFinal(&ctx, out, &j))
+ goto err;
+ out += j;
+ olen -= j;
+ /* calc the next A1 value */
+ if (!EVP_DigestSignFinal(&ctx_tmp, A1, &A1_len))
+ goto err;
+ }
+ else
+ {
+ /* last one */
+
+ if (!EVP_DigestSignFinal(&ctx, A1, &A1_len))
+ goto err;
+ memcpy(out, A1, olen);
+ break;
+ }
+ }
+ ret = 1;
+err:
+ EVP_PKEY_free(mac_key);
+ EVP_MD_CTX_cleanup(&ctx);
+ EVP_MD_CTX_cleanup(&ctx_tmp);
+ EVP_MD_CTX_cleanup(&ctx_init);
+ OPENSSL_cleanse(A1, sizeof(A1));
+ return ret;
+}
+
+
+/*
+ * Use the TLS PRF function for generating data channel keys.
+ * This code is based on the OpenSSL library.
+ *
+ * TLS generates keys as such:
+ *
+ * master_secret[48] = PRF(pre_master_secret[48], "master secret",
+ * ClientHello.random[32] + ServerHello.random[32])
+ *
+ * key_block[] = PRF(SecurityParameters.master_secret[48],
+ * "key expansion",
+ * SecurityParameters.server_random[32] +
+ * SecurityParameters.client_random[32]);
+ *
+ * Notes:
+ *
+ * (1) key_block contains a full set of 4 keys.
+ * (2) The pre-master secret is generated by the client.
+ */
+bool ssl_tls1_PRF(const uint8_t *label, int label_len, const uint8_t *sec,
+ int slen, uint8_t *out1, int olen)
+{
+ bool ret = true;
+ struct gc_arena gc = gc_new();
+ /* For some reason our md_kt_get("MD5") fails otherwise in the unit test */
+ const md_kt_t *md5 = EVP_md5();
+ const md_kt_t *sha1 = EVP_sha1();
+
+ uint8_t *out2 = (uint8_t *) gc_malloc(olen, false, &gc);
+
+ int len = slen/2;
+ const uint8_t *S1 = sec;
+ const uint8_t *S2 = &(sec[len]);
+ len += (slen&1); /* add for odd, make longer */
+
+ if(!tls1_P_hash(md5,S1,len,label,label_len,out1,olen))
+ {
+ ret = false;
+ goto done;
+ }
+
+ if(!tls1_P_hash(sha1,S2,len,label,label_len,out2,olen))
+ {
+ ret = false;
+ goto done;
+ }
+
+ for (int i = 0; i<olen; i++)
+ {
+ out1[i] ^= out2[i];
+ }
+
+ secure_memzero(out2, olen);
+
+ dmsg(D_SHOW_KEY_SOURCE, "tls1_PRF out[%d]: %s", olen, format_hex(out1, olen, 0, &gc));
+done:
+ gc_free(&gc);
+ return ret;
+}
+#endif
#endif /* ENABLE_CRYPTO_OPENSSL */
@@ -1580,135 +1580,7 @@ key_source2_print(const struct key_source2 *k)
key_source_print(&k->server, "Server");
}
-/*
- * Generate the hash required by for the \c tls1_PRF function.
- *
- * @param md_kt Message digest to use
- * @param sec Secret to base the hash on
- * @param sec_len Length of the secret
- * @param seed Seed to hash
- * @param seed_len Length of the seed
- * @param out Output buffer
- * @param olen Length of the output buffer
- */
-static void
-tls1_P_hash(const md_kt_t *md_kt,
- const uint8_t *sec,
- int sec_len,
- const uint8_t *seed,
- int seed_len,
- uint8_t *out,
- int olen)
-{
- struct gc_arena gc = gc_new();
- uint8_t A1[MAX_HMAC_KEY_LENGTH];
-
-#ifdef ENABLE_DEBUG
- const int olen_orig = olen;
- const uint8_t *out_orig = out;
-#endif
-
- hmac_ctx_t *ctx = hmac_ctx_new();
- hmac_ctx_t *ctx_tmp = hmac_ctx_new();
-
- dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash sec: %s", format_hex(sec, sec_len, 0, &gc));
- dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash seed: %s", format_hex(seed, seed_len, 0, &gc));
-
- int chunk = md_kt_size(md_kt);
- unsigned int A1_len = md_kt_size(md_kt);
-
- hmac_ctx_init(ctx, sec, sec_len, md_kt);
- hmac_ctx_init(ctx_tmp, sec, sec_len, md_kt);
-
- hmac_ctx_update(ctx,seed,seed_len);
- hmac_ctx_final(ctx, A1);
-
- for (;; )
- {
- hmac_ctx_reset(ctx);
- hmac_ctx_reset(ctx_tmp);
- hmac_ctx_update(ctx,A1,A1_len);
- hmac_ctx_update(ctx_tmp,A1,A1_len);
- hmac_ctx_update(ctx,seed,seed_len);
-
- if (olen > chunk)
- {
- hmac_ctx_final(ctx, out);
- out += chunk;
- olen -= chunk;
- hmac_ctx_final(ctx_tmp, A1); /* calc the next A1 value */
- }
- else /* last one */
- {
- hmac_ctx_final(ctx, A1);
- memcpy(out,A1,olen);
- break;
- }
- }
- hmac_ctx_cleanup(ctx);
- hmac_ctx_free(ctx);
- hmac_ctx_cleanup(ctx_tmp);
- hmac_ctx_free(ctx_tmp);
- secure_memzero(A1, sizeof(A1));
-
- dmsg(D_SHOW_KEY_SOURCE, "tls1_P_hash out: %s", format_hex(out_orig, olen_orig, 0, &gc));
- gc_free(&gc);
-}
-
-/*
- * Use the TLS PRF function for generating data channel keys.
- * This code is based on the OpenSSL library.
- *
- * TLS generates keys as such:
- *
- * master_secret[48] = PRF(pre_master_secret[48], "master secret",
- * ClientHello.random[32] + ServerHello.random[32])
- *
- * key_block[] = PRF(SecurityParameters.master_secret[48],
- * "key expansion",
- * SecurityParameters.server_random[32] +
- * SecurityParameters.client_random[32]);
- *
- * Notes:
- *
- * (1) key_block contains a full set of 4 keys.
- * (2) The pre-master secret is generated by the client.
- */
-static void
-tls1_PRF(const uint8_t *label,
- int label_len,
- const uint8_t *sec,
- int slen,
- uint8_t *out1,
- int olen)
-{
- struct gc_arena gc = gc_new();
- const md_kt_t *md5 = md_kt_get("MD5");
- const md_kt_t *sha1 = md_kt_get("SHA1");
-
- uint8_t *out2 = (uint8_t *) gc_malloc(olen, false, &gc);
-
- int len = slen/2;
- const uint8_t *S1 = sec;
- const uint8_t *S2 = &(sec[len]);
- len += (slen&1); /* add for odd, make longer */
-
- tls1_P_hash(md5,S1,len,label,label_len,out1,olen);
- tls1_P_hash(sha1,S2,len,label,label_len,out2,olen);
-
- for (int i = 0; i<olen; i++)
- {
- out1[i] ^= out2[i];
- }
-
- secure_memzero(out2, olen);
-
- dmsg(D_SHOW_KEY_SOURCE, "tls1_PRF out[%d]: %s", olen, format_hex(out1, olen, 0, &gc));
-
- gc_free(&gc);
-}
-
-static void
+static bool
openvpn_PRF(const uint8_t *secret,
int secret_len,
const char *label,
@@ -1721,6 +1593,7 @@ openvpn_PRF(const uint8_t *secret,
uint8_t *output,
int output_len)
{
+ bool ret = true;
/* concatenate seed components */
struct buffer seed = alloc_buf(strlen(label)
@@ -1742,12 +1615,16 @@ openvpn_PRF(const uint8_t *secret,
}
/* compute PRF */
- tls1_PRF(BPTR(&seed), BLEN(&seed), secret, secret_len, output, output_len);
+ if (!ssl_tls1_PRF(BPTR(&seed), BLEN(&seed), secret, secret_len, output, output_len))
+ {
+ ret = false;
+ }
buf_clear(&seed);
free_buf(&seed);
VALGRIND_MAKE_READABLE((void *)output, output_len);
+ return ret;
}
static void
@@ -1782,8 +1659,8 @@ generate_key_expansion_tls_export(struct tls_session *session, struct key2 *key2
return true;
}
-static struct key2
-generate_key_expansion_openvpn_prf(const struct tls_session *session)
+static bool
+generate_key_expansion_openvpn_prf(const struct tls_session *session, struct key2 *key2)
{
uint8_t master[48] = { 0 };
@@ -1799,33 +1676,40 @@ generate_key_expansion_openvpn_prf(const struct tls_session *session)
key_source2_print(key_src);
/* compute master secret */
- openvpn_PRF(key_src->client.pre_master,
- sizeof(key_src->client.pre_master),
- KEY_EXPANSION_ID " master secret",
- key_src->client.random1,
- sizeof(key_src->client.random1),
- key_src->server.random1,
- sizeof(key_src->server.random1),
- NULL,
- NULL,
- master,
- sizeof(master));
+ if(!openvpn_PRF(key_src->client.pre_master,
+ sizeof(key_src->client.pre_master),
+ KEY_EXPANSION_ID " master secret",
+ key_src->client.random1,
+ sizeof(key_src->client.random1),
+ key_src->server.random1,
+ sizeof(key_src->server.random1),
+ NULL,
+ NULL,
+ master,
+ sizeof(master)))
+ {
+ return false;
+ }
- struct key2 key2;
/* compute key expansion */
- openvpn_PRF(master,
- sizeof(master),
- KEY_EXPANSION_ID " key expansion",
- key_src->client.random2,
- sizeof(key_src->client.random2),
- key_src->server.random2,
- sizeof(key_src->server.random2),
- client_sid,
- server_sid,
- (uint8_t *)key2.keys,
- sizeof(key2.keys));
+ if (!openvpn_PRF(master,
+ sizeof(master),
+ KEY_EXPANSION_ID " key expansion",
+ key_src->client.random2,
+ sizeof(key_src->client.random2),
+ key_src->server.random2,
+ sizeof(key_src->server.random2),
+ client_sid,
+ server_sid,
+ (uint8_t *)key2->keys,
+ sizeof(key2->keys)))
+ {
+ return false;
+ }
secure_memzero(&master, sizeof(master));
+
+
/*
* fixup_key only correctly sets DES parity bits if the cipher is a
* DES variant.
@@ -1840,11 +1724,11 @@ generate_key_expansion_openvpn_prf(const struct tls_session *session)
*/
for (int i = 0; i < 2; ++i)
{
- fixup_key(&key2.keys[i], &session->opt->key_type);
+ fixup_key(&key2->keys[i], &session->opt->key_type);
}
- key2.n = 2;
+ key2->n = 2;
- return key2;
+ return true;
}
/*
@@ -1876,7 +1760,11 @@ generate_key_expansion(struct key_ctx_bi *key,
}
else
{
- key2 = generate_key_expansion_openvpn_prf(session);
+ if (!generate_key_expansion_openvpn_prf(session, &key2))
+ {
+ msg(D_TLS_ERRORS, "TLS Error: PRF calcuation failed");
+ goto exit;
+ }
}
key2_print(&key2, &session->opt->key_type,
@@ -38,6 +38,7 @@
#include <cmocka.h>
#include "crypto.h"
+#include "ssl_backend.h"
#include "mock_msg.h"
@@ -136,12 +137,43 @@ crypto_translate_cipher_names(void **state)
test_cipher_names("id-aes256-GCM", "AES-256-GCM");
}
+
+static uint8_t good_prf[32] = {0xd9, 0x8c, 0x85, 0x18, 0xc8, 0x5e, 0x94, 0x69,
+ 0x27, 0x91, 0x6a, 0xcf, 0xc2, 0xd5, 0x92, 0xfb,
+ 0xb1, 0x56, 0x7e, 0x4b, 0x4b, 0x14, 0x59, 0xe6,
+ 0xa9, 0x04, 0xac, 0x2d, 0xda, 0xb7, 0x2d, 0x67};
+static void
+crypto_test_tls_prf(void **state)
+{
+ const char *seedstr = "Quis aute iure reprehenderit in voluptate "
+ "velit esse cillum dolore";
+ const unsigned char *seed = (const unsigned char *) seedstr;
+ const size_t seed_len = strlen(seedstr);
+
+
+
+
+ const char* ipsumlorem = "Lorem ipsum dolor sit amet, consectetur "
+ "adipisici elit, sed eiusmod tempor incidunt ut "
+ "labore et dolore magna aliqua.";
+
+ const unsigned char *secret = (const unsigned char *) ipsumlorem;
+ size_t secret_len = strlen((const char *)secret);
+
+
+ uint8_t out[32];
+ ssl_tls1_PRF(seed, seed_len, secret, secret_len, out, sizeof(out));
+
+ assert_memory_equal(good_prf, out, sizeof(out));
+}
+
int
main(void)
{
const struct CMUnitTest tests[] = {
cmocka_unit_test(crypto_pem_encode_decode_loopback),
cmocka_unit_test(crypto_translate_cipher_names),
+ cmocka_unit_test(crypto_test_tls_prf)
};
#if defined(ENABLE_CRYPTO_OPENSSL)
This moves from using our own copy of the TLS1 PRF function to using TLS library provided function where possible. This includes currently OpenSSL 1.1.0+ and mbed TLS 2.18+. For the libraries where it is not possible to use the library's own function, we still use our own implementation. mbed TLS will continue to use our own old PRF function while for OpenSSL we will use a adapted version from OpenSSL 1.0.2t code. The version allows to be used in a FIPS enabled environment. The old OpenSSL and mbed TLS implementation could have shared some more code but as we will eventually drop support for older TLS libraries, the separation makes it easier it remove that code invdidually. In FIPS mode MD5 is normally forbidden, the TLS1 PRF1 function we use, makes uses of MD5, which in the past has caused OpenVPN to segfault. The new implementation for OpenSSL version of our custom implementation has added the special flags that tell OpenSSL that this specific use of MD5 is allowed in FIPS mode. No FIPS conformitiy testing etc has been done, this is only about allowing OpenVPN on a system where FIPS mode has been enabled system wide (e.g. on RHEL derivates). Patch v4: Handle the unlikely case that PRF generation fails. More formatting fixes. Signed-off-by: Arne Schwabe <arne@rfc2549.org> --- Changes.rst | 10 +- src/openvpn/crypto_backend.h | 16 ++ src/openvpn/crypto_mbedtls.c | 135 ++++++++++++++++ src/openvpn/crypto_openssl.c | 195 +++++++++++++++++++++++ src/openvpn/ssl.c | 206 ++++++------------------- tests/unit_tests/openvpn/test_crypto.c | 32 ++++ 6 files changed, 430 insertions(+), 164 deletions(-)