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-rw-r--r--src/lib/tls/msg_cert_verify.cpp2
-rw-r--r--src/lib/tls/msg_certificate.cpp32
-rw-r--r--src/lib/tls/msg_client_kex.cpp4
-rw-r--r--src/lib/tls/msg_server_kex.cpp20
-rw-r--r--src/lib/tls/tls_ciphersuite.cpp5
-rw-r--r--src/lib/tls/tls_client.cpp1
-rw-r--r--src/lib/tls/tls_extensions.cpp1
-rw-r--r--src/lib/tls/tls_extensions.h1
-rw-r--r--src/lib/tls/tls_messages.h1
-rw-r--r--src/lib/tls/tls_policy.cpp69
-rw-r--r--src/lib/tls/tls_policy.h37
-rw-r--r--src/lib/tls/tls_record.cpp1
-rw-r--r--src/lib/tls/tls_session.h2
-rw-r--r--src/tests/unit_tls.cpp2
14 files changed, 120 insertions, 58 deletions
diff --git a/src/lib/tls/msg_cert_verify.cpp b/src/lib/tls/msg_cert_verify.cpp
index 2598255eb..6b59e703f 100644
--- a/src/lib/tls/msg_cert_verify.cpp
+++ b/src/lib/tls/msg_cert_verify.cpp
@@ -82,6 +82,8 @@ bool Certificate_Verify::verify(const X509_Certificate& cert,
{
std::unique_ptr<Public_Key> key(cert.subject_public_key());
+ policy.check_peer_key_acceptable(*key);
+
std::pair<std::string, Signature_Format> format =
state.parse_sig_format(*key.get(), m_hash_algo, m_sig_algo,
true, policy);
diff --git a/src/lib/tls/msg_certificate.cpp b/src/lib/tls/msg_certificate.cpp
index a83d32d11..10ee7c95f 100644
--- a/src/lib/tls/msg_certificate.cpp
+++ b/src/lib/tls/msg_certificate.cpp
@@ -31,7 +31,7 @@ Certificate::Certificate(Handshake_IO& io,
/**
* Deserialize a Certificate message
*/
-Certificate::Certificate(const std::vector<byte>& buf, const Policy &policy)
+Certificate::Certificate(const std::vector<byte>& buf, const Policy& /*policy_currently_unused*/)
{
if(buf.size() < 3)
throw Decoding_Error("Certificate: Message malformed");
@@ -54,35 +54,7 @@ Certificate::Certificate(const std::vector<byte>& buf, const Policy &policy)
throw Decoding_Error("Certificate: Message malformed");
DataSource_Memory cert_buf(&certs[3], cert_size);
- X509_Certificate cert(cert_buf);
-
- std::unique_ptr<Public_Key> cert_pub_key(cert.subject_public_key());
-
- const std::string algo_name = cert_pub_key->algo_name();
- const size_t keylength = cert_pub_key->max_input_bits();
- if(algo_name == "RSA")
- {
- const size_t expected_keylength = policy.minimum_rsa_bits();
- if(keylength < expected_keylength)
- throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
- "The peer sent RSA certificate of " +
- std::to_string(keylength) +
- " bits, policy requires at least " +
- std::to_string(expected_keylength));
- }
- else if(algo_name == "ECDH")
- {
- const size_t expected_keylength = policy.minimum_ecdh_group_size();
- if(keylength < expected_keylength)
- throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
- "The peer sent ECDH certificate of " +
- std::to_string(keylength) +
- " bits, policy requires at least " +
- std::to_string(expected_keylength));
-
- }
-
- m_certs.push_back(cert);
+ m_certs.push_back(X509_Certificate(cert_buf));
certs += cert_size + 3;
}
diff --git a/src/lib/tls/msg_client_kex.cpp b/src/lib/tls/msg_client_kex.cpp
index 192c774b8..bc4d33d52 100644
--- a/src/lib/tls/msg_client_kex.cpp
+++ b/src/lib/tls/msg_client_kex.cpp
@@ -110,6 +110,8 @@ Client_Key_Exchange::Client_Key_Exchange(Handshake_IO& io,
DH_PublicKey counterparty_key(group, Y);
+ policy.check_peer_key_acceptable(counterparty_key);
+
DH_PrivateKey priv_key(rng, group);
PK_Key_Agreement ka(priv_key, "Raw");
@@ -153,6 +155,8 @@ Client_Key_Exchange::Client_Key_Exchange(Handshake_IO& io,
ECDH_PublicKey counterparty_key(group, OS2ECP(ecdh_key, group.get_curve()));
+ policy.check_peer_key_acceptable(counterparty_key);
+
ECDH_PrivateKey priv_key(rng, group);
PK_Key_Agreement ka(priv_key, "Raw");
diff --git a/src/lib/tls/msg_server_kex.cpp b/src/lib/tls/msg_server_kex.cpp
index 99f0d0f09..10581fe45 100644
--- a/src/lib/tls/msg_server_kex.cpp
+++ b/src/lib/tls/msg_server_kex.cpp
@@ -147,7 +147,6 @@ Server_Key_Exchange::Server_Key_Exchange(Handshake_IO& io,
Server_Key_Exchange::Server_Key_Exchange(const std::vector<byte>& buf,
const std::string& kex_algo,
const std::string& sig_algo,
- const Policy& policy,
Protocol_Version version)
{
TLS_Data_Reader reader("ServerKeyExchange", buf);
@@ -166,18 +165,11 @@ Server_Key_Exchange::Server_Key_Exchange(const std::vector<byte>& buf,
if(kex_algo == "DH" || kex_algo == "DHE_PSK")
{
// 3 bigints, DH p, g, Y
- std::vector<byte> p = reader.get_range<byte>(2, 1, 65535);
- reader.get_range<byte>(2, 1, 65535);
- reader.get_range<byte>(2, 1, 65535);
-
- // protection against the LOGJAM attack
- int key_size = p.size() * 8;
- if(key_size < policy.minimum_dh_group_size())
- throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
- "Server sent DH group of " +
- std::to_string(key_size) +
- " bits, policy requires at least " +
- std::to_string(policy.minimum_dh_group_size()));
+
+ for(size_t i = 0; i != 3; ++i)
+ {
+ reader.get_range<byte>(2, 1, 65535);
+ }
}
else if(kex_algo == "ECDH" || kex_algo == "ECDHE_PSK")
{
@@ -244,6 +236,8 @@ bool Server_Key_Exchange::verify(const Public_Key& server_key,
const Handshake_State& state,
const Policy& policy) const
{
+ policy.check_peer_key_acceptable(server_key);
+
std::pair<std::string, Signature_Format> format =
state.parse_sig_format(server_key, m_hash_algo, m_sig_algo,
false, policy);
diff --git a/src/lib/tls/tls_ciphersuite.cpp b/src/lib/tls/tls_ciphersuite.cpp
index 1526c1059..0b575a6ca 100644
--- a/src/lib/tls/tls_ciphersuite.cpp
+++ b/src/lib/tls/tls_ciphersuite.cpp
@@ -102,8 +102,9 @@ bool Ciphersuite::ecc_ciphersuite() const
bool Ciphersuite::cbc_ciphersuite() const
{
- return (cipher_algo() == "3DES" || cipher_algo() == "AES-128" || cipher_algo() == "AES-256"
- || cipher_algo() == "Camellia-128" || cipher_algo() == "Camellia-256");
+ return (cipher_algo() == "3DES" || cipher_algo() == "SEED" ||
+ cipher_algo() == "AES-128" || cipher_algo() == "AES-256" ||
+ cipher_algo() == "Camellia-128" || cipher_algo() == "Camellia-256");
}
namespace {
diff --git a/src/lib/tls/tls_client.cpp b/src/lib/tls/tls_client.cpp
index 13dde99c4..bf7ccdf8c 100644
--- a/src/lib/tls/tls_client.cpp
+++ b/src/lib/tls/tls_client.cpp
@@ -387,7 +387,6 @@ void Client::process_handshake_msg(const Handshake_State* active_state,
new Server_Key_Exchange(contents,
state.ciphersuite().kex_algo(),
state.ciphersuite().sig_algo(),
- policy(),
state.version())
);
diff --git a/src/lib/tls/tls_extensions.cpp b/src/lib/tls/tls_extensions.cpp
index 49b7355ab..3dceb505a 100644
--- a/src/lib/tls/tls_extensions.cpp
+++ b/src/lib/tls/tls_extensions.cpp
@@ -1,6 +1,7 @@
/*
* TLS Extensions
* (C) 2011,2012,2015,2016 Jack Lloyd
+* 2016 Juraj Somorovsky
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
diff --git a/src/lib/tls/tls_extensions.h b/src/lib/tls/tls_extensions.h
index e273ae096..28c49f084 100644
--- a/src/lib/tls/tls_extensions.h
+++ b/src/lib/tls/tls_extensions.h
@@ -1,6 +1,7 @@
/*
* TLS Extensions
* (C) 2011,2012,2016 Jack Lloyd
+* 2016 Juraj Somorovsky
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
diff --git a/src/lib/tls/tls_messages.h b/src/lib/tls/tls_messages.h
index a5ababc0e..c6a65b658 100644
--- a/src/lib/tls/tls_messages.h
+++ b/src/lib/tls/tls_messages.h
@@ -499,7 +499,6 @@ class Server_Key_Exchange final : public Handshake_Message
Server_Key_Exchange(const std::vector<byte>& buf,
const std::string& kex_alg,
const std::string& sig_alg,
- const Policy& policy,
Protocol_Version version);
~Server_Key_Exchange();
diff --git a/src/lib/tls/tls_policy.cpp b/src/lib/tls/tls_policy.cpp
index fdc6ba862..592d4f572 100644
--- a/src/lib/tls/tls_policy.cpp
+++ b/src/lib/tls/tls_policy.cpp
@@ -1,6 +1,7 @@
/*
* Policies for TLS
* (C) 2004-2010,2012,2015,2016 Jack Lloyd
+* 2016 Christian Mainka
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
@@ -119,23 +120,73 @@ std::string Policy::choose_curve(const std::vector<std::string>& curve_names) co
std::string Policy::dh_group() const
{
+ // We offer 2048 bit DH because we can
return "modp/ietf/2048";
}
size_t Policy::minimum_dh_group_size() const
{
+ // Many servers still send 1024 bit
return 1024;
}
-size_t Policy::minimum_ecdh_group_size() const
+size_t Policy::minimum_ecdsa_group_size() const
{
- return 159;
+ // Here we are at the mercy of whatever the CA signed, but most certs should be 256 bit by now
+ return 256;
}
+size_t Policy::minimum_ecdh_group_size() const
+ {
+ // P-256 is smallest curve currently supplrted for TLS key exchange (after 1.11.29)
+ return 256;
+ }
size_t Policy::minimum_rsa_bits() const
{
- return 1000; // Not 1024, since some certificates use, e.g., only 1023 bits
+ /* Default assumption is all end-entity certificates should
+ be at least 2048 bits these days.
+
+ If you are connecting to arbitrary servers on the Internet
+ (ie as a web browser or SMTP client) you'll probably have to reduce this
+ to 1024 bits, or perhaps even lower.
+ */
+ return 2048;
+ }
+
+void Policy::check_peer_key_acceptable(const Public_Key& public_key) const
+ {
+ const std::string algo_name = public_key.algo_name();
+
+ // FIXME this is not really the right way to do this
+ size_t keylength = public_key.max_input_bits();
+ size_t expected_keylength = 0;
+
+ if(algo_name == "RSA")
+ {
+ expected_keylength = minimum_rsa_bits();
+ keylength += 1; // fixup for use of max_input_bits above
+ }
+ else if(algo_name == "DH")
+ {
+ expected_keylength = minimum_dh_group_size();
+ }
+ else if(algo_name == "ECDH")
+ {
+ expected_keylength = minimum_ecdh_group_size();
+ }
+ else if(algo_name == "ECDSA")
+ {
+ expected_keylength = minimum_ecdsa_group_size();
+ }
+ // else some other algo, so leave expected_keylength as zero and the check is a no-op
+
+ if(keylength < expected_keylength)
+ throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
+ "Peer sent " +
+ std::to_string(keylength) + " bit " + algo_name + " key"
+ ", policy requires at least " +
+ std::to_string(expected_keylength));
}
/*
@@ -158,13 +209,13 @@ bool Policy::send_fallback_scsv(Protocol_Version version) const
bool Policy::acceptable_protocol_version(Protocol_Version version) const
{
- // Uses boolean optimization:
- // First check the current version (left part), then if it is allowed
- // (right part)
- // checks are ordered according to their probability
- return (
- ( ( version == Protocol_Version::TLS_V10) && allow_tls10() ) ||
+ // Uses boolean optimization:
+ // First check the current version (left part), then if it is allowed
+ // (right part)
+ // checks are ordered according to their probability
+ return (
( ( version == Protocol_Version::TLS_V12) && allow_tls12() ) ||
+ ( ( version == Protocol_Version::TLS_V10) && allow_tls10() ) ||
( ( version == Protocol_Version::TLS_V11) && allow_tls11() ) ||
( ( version == Protocol_Version::DTLS_V12) && allow_dtls12() ) ||
( ( version == Protocol_Version::DTLS_V10) && allow_dtls10() )
diff --git a/src/lib/tls/tls_policy.h b/src/lib/tls/tls_policy.h
index 3a09a1747..76e80ddde 100644
--- a/src/lib/tls/tls_policy.h
+++ b/src/lib/tls/tls_policy.h
@@ -131,18 +131,47 @@ class BOTAN_DLL Policy
/**
* Return the minimum DH group size we're willing to use
+ * Default is currently 1024 (insecure), should be 2048
*/
virtual size_t minimum_dh_group_size() const;
/**
+ * For ECDSA authenticated ciphersuites, the smallest key size the
+ * client will accept.
+ * This policy is currently only enforced on the server by the client.
+ */
+ virtual size_t minimum_ecdsa_group_size() const;
+
+ /**
* Return the minimum ECDH group size we're willing to use
+ * for key exchange
+ *
+ * Default 256, allowing P-256 and larger
+ * P-256 is the smallest curve we will negotiate
*/
virtual size_t minimum_ecdh_group_size() const;
/**
- * Return the minimum RSA bit size we're willing to use
+ * Return the minimum bit size we're willing to accept for RSA
+ * key exchange or server signatures.
+ *
+ * It does not place any requirements on the size of any RSA signature(s)
+ * which were used to check the server certificate. This is only
+ * concerned with the server's public key.
+ *
+ * Default is 2048 which is smallest RSA key size still secure
+ * for medium term security.
*/
virtual size_t minimum_rsa_bits() const;
+
+ /**
+ * Throw an exception if you don't like the peer's key.
+ * Default impl checks the key size against minimum_rsa_bits, minimum_ecdsa_group_size,
+ * or minimum_ecdh_group_size depending on the key's type.
+ * Override if you'd like to perform some other kind of test on
+ * (or logging of) the peer's keys.
+ */
+ virtual void check_peer_key_acceptable(const Public_Key& public_key) const;
/**
* If this function returns false, unknown SRP/PSK identifiers
@@ -352,6 +381,12 @@ class BOTAN_DLL Text_Policy : public Policy
std::string dh_group() const override
{ return get_str("dh_group", Policy::dh_group()); }
+ size_t minimum_ecdh_group_size() const override
+ { return get_len("minimum_ecdh_group_size", Policy::minimum_ecdh_group_size()); }
+
+ size_t minimum_ecdsa_group_size() const override
+ { return get_len("minimum_ecdsa_group_size", Policy::minimum_ecdsa_group_size()); }
+
size_t minimum_dh_group_size() const override
{ return get_len("minimum_dh_group_size", Policy::minimum_dh_group_size()); }
diff --git a/src/lib/tls/tls_record.cpp b/src/lib/tls/tls_record.cpp
index 16dfecc6a..c273a1546 100644
--- a/src/lib/tls/tls_record.cpp
+++ b/src/lib/tls/tls_record.cpp
@@ -1,6 +1,7 @@
/*
* TLS Record Handling
* (C) 2012,2013,2014,2015 Jack Lloyd
+* (C) 2016 Juraj Somorovsky
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
diff --git a/src/lib/tls/tls_session.h b/src/lib/tls/tls_session.h
index 15e79b811..643b79ac6 100644
--- a/src/lib/tls/tls_session.h
+++ b/src/lib/tls/tls_session.h
@@ -184,7 +184,7 @@ class BOTAN_DLL Session
const Server_Information& server_info() const { return m_server_info; }
private:
- enum { TLS_SESSION_PARAM_STRUCT_VERSION = 20160103 };
+ enum { TLS_SESSION_PARAM_STRUCT_VERSION = 20160812};
std::chrono::system_clock::time_point m_start_time;
diff --git a/src/tests/unit_tls.cpp b/src/tests/unit_tls.cpp
index 91eca0d5a..1dbc20273 100644
--- a/src/tests/unit_tls.cpp
+++ b/src/tests/unit_tls.cpp
@@ -666,6 +666,8 @@ class Test_Policy : public Botan::TLS::Text_Policy
size_t dtls_initial_timeout() const override { return 1; }
size_t dtls_maximum_timeout() const override { return 8; }
+
+ size_t minimum_rsa_bits() const { return 1024; }
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 17:28:53 +0000