Attention is currently required from: flichtenheld.
Hello flichtenheld,
I'd like you to reexamine a change. Please visit
http://gerrit.openvpn.net/c/openvpn/+/560?usp=email
to look at the new patch set (#2).
Change subject: Remove custom TLS 1.0 PRF implementation only used by
LibreSSL/wolfSSL
......................................................................
Remove custom TLS 1.0 PRF implementation only used by LibreSSL/wolfSSL
After the removal of the OpenSSL 1.0.2 support, LibreSSL/wolfSSL are the
only libraries that still needs the custom implementation.
Since our LibreSSL/wolfSSL support is always best effort, we can afford to
limit LibreSSL support in this way. If they want to support this, they
should expose the functionality as well.
Change-Id: I5bfa3630ad4dff2807705658bc877c4a429a39ce
Signed-off-by: Arne Schwabe <a...@rfc2549.org>
---
M src/openvpn/crypto_openssl.c
1 file changed, 5 insertions(+), 174 deletions(-)
git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/60/560/2
diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 64ad346..a86b1ab 100644
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -1372,7 +1372,7 @@
return ret;
}
-#elif !defined(LIBRESSL_VERSION_NUMBER)
+#elif !defined(LIBRESSL_VERSION_NUMBER) && !defined(ENABLE_CRYPTO_WOLFSSL)
bool
ssl_tls1_PRF(const uint8_t *seed, int seed_len, const uint8_t *secret,
int secret_len, uint8_t *output, int output_len)
@@ -1419,183 +1419,14 @@
return ret;
}
#else /* if defined(LIBRESSL_VERSION_NUMBER) */
-/*
- * 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
-bool
-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 = EVP_MAX_MD_SIZE;
- int ret = false;
-
- chunk = EVP_MD_size(md);
- OPENSSL_assert(chunk >= 0);
-
- ctx = md_ctx_new();
- ctx_tmp = md_ctx_new();
- ctx_init = md_ctx_new();
- 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)
- {
- j = olen;
- 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
- {
- A1_len = EVP_MAX_MD_SIZE;
- /* last one */
- if (!EVP_DigestSignFinal(ctx, A1, &A1_len))
- {
- goto err;
- }
- memcpy(out, A1, olen);
- break;
- }
- }
- ret = true;
-err:
- EVP_PKEY_free(mac_key);
- EVP_MD_CTX_free(ctx);
- EVP_MD_CTX_free(ctx_tmp);
- EVP_MD_CTX_free(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.
- */
+/* LibreSSL and wolfSSL do not expose a TLS 1.0/1.1 PRF via the same APIs as
+ * OpenSSL does. As result they will only be able to support
+ * peers that support TLS EKM like when running with OpenSSL 3.x FIPS */
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_get("MD5") fails otherwise in the unit test */
- const EVP_MD *md5 = EVP_md5();
- const EVP_MD *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;
+ return false;
}
#endif /* if LIBRESSL_VERSION_NUMBER */
#endif /* ENABLE_CRYPTO_OPENSSL */
--
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Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I5bfa3630ad4dff2807705658bc877c4a429a39ce
Gerrit-Change-Number: 560
Gerrit-PatchSet: 2
Gerrit-Owner: plaisthos <arne-open...@rfc2549.org>
Gerrit-Reviewer: flichtenheld <fr...@lichtenheld.com>
Gerrit-CC: openvpn-devel <openvpn-devel@lists.sourceforge.net>
Gerrit-Attention: flichtenheld <fr...@lichtenheld.com>
Gerrit-MessageType: newpatchset
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