Remove support for OpenSSL without ECC.

As OpenSSL >= 1.0.0 is now required, ECDHE is now mandatory.  The group
has to be validated at runtime, because of RedHat lawyers (P224 support
is entirely missing in the OpenSSL RPM, but P256 is present and is the
default).

Resolves ticket #16140.

diff --git a/changes/ticket16140 b/changes/ticket16140
new file mode 100644 (file)
index 0000000..00c19f1
--- /dev/null
+++ b/changes/ticket16140
@@ -0,0 +1,6 @@
+  o Removed features:
+
+    - Tor no longer supports copies of OpenSSL that are missing support for
+      Elliptic Curve Cryptography.  In particular support for at least one of
+      P256 or P224 is now required, with manual configuration needed if only
+      P224 is available.

diff --git a/src/common/tortls.c b/src/common/tortls.c
index ca7b15fcd7803857b98b329b0423d44893aef967..57d5408ca87e592d66de5f4da152a8cca111e0a5 100644 (file)
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -49,6 +49,9 @@
 #if OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(1,0,0)
 #error "We require OpenSSL >= 1.0.0"
 #endif
+#ifdef OPENSSL_NO_EC
+#error "We require OpenSSL with ECC support"
+#endif
 
 #include <openssl/ssl.h>
 #include <openssl/ssl3.h>
@@ -475,7 +478,6 @@ tor_tls_init(void)
     SSL_load_error_strings();
 
 #if (SIZEOF_VOID_P >= 8 &&                              \
-     !defined(OPENSSL_NO_EC) &&                         \
      OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,0,1))
     long version = SSLeay();
 
@@ -1327,7 +1329,6 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
     SSL_CTX_set_tmp_dh(result->ctx, crypto_dh_get_dh_(dh));
     crypto_dh_free(dh);
   }
-#if !defined(OPENSSL_NO_EC)
   if (! is_client) {
     int nid;
     EC_KEY *ec_key;
@@ -1343,9 +1344,6 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
       SSL_CTX_set_tmp_ecdh(result->ctx, ec_key);
     EC_KEY_free(ec_key);
   }
-#else
-  (void)flags;
-#endif
   SSL_CTX_set_verify(result->ctx, SSL_VERIFY_PEER,
                      always_accept_verify_cb);
   /* let us realloc bufs that we're writing from */
@@ -2933,3 +2931,29 @@ tor_tls_init_bufferevent(tor_tls_t *tls, struct bufferevent *bufev_in,
 }
 #endif
 
+/** Check whether the ECC group requested is supported by the current OpenSSL
+ * library instance.  Return 1 if the group is supported, and 0 if not.
+ */
+int
+evaluate_ecgroup_for_tls(const char *ecgroup)
+{
+  EC_KEY *ec_key;
+  int nid;
+  int ret;
+
+  if (!ecgroup)
+    nid = NID_tor_default_ecdhe_group;
+  else if (!strcasecmp(ecgroup, "P256"))
+    nid = NID_X9_62_prime256v1;
+  else if (!strcasecmp(ecgroup, "P224"))
+    nid = NID_secp224r1;
+  else
+    return 0;
+
+  ec_key = EC_KEY_new_by_curve_name(nid);
+  ret = (ec_key != NULL);
+  EC_KEY_free(ec_key);
+
+  return ret;
+}
+

diff --git a/src/common/tortls.h b/src/common/tortls.h
index 083052f4b2bf5636641086fee4fff38c54197c98..9216e8315012badeb5e8f8fdee26e56683714456 100644 (file)
--- a/src/common/tortls.h
+++ b/src/common/tortls.h
@@ -139,5 +139,7 @@ int tor_tls_cert_is_valid(int severity,
                           int check_rsa_1024);
 const char *tor_tls_get_ciphersuite_name(tor_tls_t *tls);
 
+int evaluate_ecgroup_for_tls(const char *ecgroup);
+
 #endif
 

diff --git a/src/or/config.c b/src/or/config.c
index 1c04578893c53672ae9b07cfde75b01f4f847bc5..e4a2d1c5ae31ef328c4a84ca6ad2e45036a26e14 100644 (file)
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -2806,6 +2806,9 @@ options_validate(or_options_t *old_options, or_options_t *options,
     COMPLAIN("Unrecognized TLSECGroup: Falling back to the default.");
     tor_free(options->TLSECGroup);
   }
+  if (!evaluate_ecgroup_for_tls(options->TLSECGroup)) {
+    REJECT("Unsupported TLSECGroup.");
+  }
 
   if (options->ExcludeNodes && options->StrictNodes) {
     COMPLAIN("You have asked to exclude certain relays from all positions "

diff --git a/src/test/bench.c b/src/test/bench.c
index a74fc776fa77c50d14c00779f74afc32c12800c3..bc2b1f04d831790743fb86f56de9a621a2c706cf 100644 (file)
--- a/src/test/bench.c
+++ b/src/test/bench.c
@@ -19,11 +19,9 @@ const char tor_git_revision[] = "";
 #include "relay.h"
 #include <openssl/opensslv.h>
 #include <openssl/evp.h>
-#ifndef OPENSSL_NO_EC
 #include <openssl/ec.h>
 #include <openssl/ecdh.h>
 #include <openssl/obj_mac.h>
-#endif
 
 #include "config.h"
 #include "crypto_curve25519.h"
@@ -502,8 +500,6 @@ bench_dh(void)
          "      %f millisec each.\n", NANOCOUNT(start, end, iters)/1e6);
 }
 
-#if !defined(OPENSSL_NO_EC)
-#define HAVE_EC_BENCHMARKS
 static void
 bench_ecdh_impl(int nid, const char *name)
 {
@@ -553,7 +549,6 @@ bench_ecdh_p224(void)
 {
   bench_ecdh_impl(NID_secp224r1, "P-224");
 }
-#endif
 
 typedef void (*bench_fn)(void);
 
@@ -576,10 +571,8 @@ static struct benchmark_t benchmarks[] = {
   ENT(cell_aes),
   ENT(cell_ops),
   ENT(dh),
-#ifdef HAVE_EC_BENCHMARKS
   ENT(ecdh_p256),
   ENT(ecdh_p224),
-#endif
   {NULL,NULL,0}
 };