From: Tobias Brunner <tobias@strongswan.org>
Date: Mon, 25 Jun 2012 14:04:40 +0000 (+0200)
Subject: Check rng return value when generating secrets and IVs in libtls
X-Git-Tag: 5.0.1~327
X-Git-Url: https://git.strongswan.org/?p=strongswan.git;a=commitdiff_plain;h=126eb2af591b56039ecf3d5d985c978eba62d88f

Check rng return value when generating secrets and IVs in libtls
---

diff --git a/src/libtls/tls_peer.c b/src/libtls/tls_peer.c
index 068dd3a..65072d0 100644
--- a/src/libtls/tls_peer.c
+++ b/src/libtls/tls_peer.c
@@ -709,13 +709,15 @@ static status_t send_client_hello(private_tls_peer_t *this,
 
 	htoun32(&this->client_random, time(NULL));
 	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
-	if (!rng)
+	if (!rng ||
+		!rng->get_bytes(rng, sizeof(this->client_random) - 4,
+						this->client_random + 4))
 	{
-		DBG1(DBG_TLS, "no suitable RNG found to generate client random");
+		DBG1(DBG_TLS, "failed to generate client random");
 		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		DESTROY_IF(rng);
 		return NEED_MORE;
 	}
-	rng->get_bytes(rng, sizeof(this->client_random) - 4, this->client_random + 4);
 	rng->destroy(rng);
 
 	/* TLS version */
@@ -903,13 +905,13 @@ static status_t send_key_exchange_encrypt(private_tls_peer_t *this,
 	chunk_t encrypted;
 
 	rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
-	if (!rng)
+	if (!rng || !rng->get_bytes(rng, sizeof(premaster) - 2, premaster + 2))
 	{
-		DBG1(DBG_TLS, "no suitable RNG found for TLS premaster secret");
+		DBG1(DBG_TLS, "failed to generate TLS premaster secret");
 		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		DESTROY_IF(rng);
 		return NEED_MORE;
 	}
-	rng->get_bytes(rng, sizeof(premaster) - 2, premaster + 2);
 	rng->destroy(rng);
 	htoun16(premaster, TLS_1_2);
 
diff --git a/src/libtls/tls_protection.c b/src/libtls/tls_protection.c
index 7120ca8..a92e902 100644
--- a/src/libtls/tls_protection.c
+++ b/src/libtls/tls_protection.c
@@ -243,14 +243,14 @@ METHOD(tls_protection_t, build, status_t,
 				}
 				else
 				{	/* TLSv1.1 uses random IVs, prepended to record */
-					if (!this->rng)
+					iv.len = this->crypter_out->get_iv_size(this->crypter_out);
+					if (!this->rng ||
+						!this->rng->allocate_bytes(this->rng, iv.len, &iv))
 					{
-						DBG1(DBG_TLS, "no RNG supported to generate TLS IV");
+						DBG1(DBG_TLS, "failed to generate TLS IV");
 						free(data->ptr);
 						return FAILED;
 					}
-					iv.len = this->crypter_out->get_iv_size(this->crypter_out);
-					this->rng->allocate_bytes(this->rng, iv.len, &iv);
 				}
 
 				*data = chunk_cat("mmcc", *data, mac, padding,
diff --git a/src/libtls/tls_server.c b/src/libtls/tls_server.c
index 8d6a933..c8fa276 100644
--- a/src/libtls/tls_server.c
+++ b/src/libtls/tls_server.c
@@ -266,13 +266,15 @@ static status_t process_client_hello(private_tls_server_t *this,
 
 	htoun32(&this->server_random, time(NULL));
 	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
-	if (!rng)
+	if (!rng ||
+		!rng->get_bytes(rng, sizeof(this->server_random) - 4,
+						this->server_random + 4))
 	{
-		DBG1(DBG_TLS, "no suitable RNG found to generate server random");
+		DBG1(DBG_TLS, "failed to generate server random");
 		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		DESTROY_IF(rng);
 		return NEED_MORE;
 	}
-	rng->get_bytes(rng, sizeof(this->server_random) - 4, this->server_random + 4);
 	rng->destroy(rng);
 
 	if (!this->tls->set_version(this->tls, version))
@@ -407,13 +409,13 @@ static status_t process_key_exchange_encrypted(private_tls_server_t *this,
 	htoun16(premaster, this->client_version);
 	/* pre-randomize premaster for failure cases */
 	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
-	if (!rng)
+	if (!rng || !rng->get_bytes(rng, sizeof(premaster) - 2, premaster + 2))
 	{
-		DBG1(DBG_TLS, "creating RNG failed");
+		DBG1(DBG_TLS, "failed to generate premaster secret");
 		this->alert->add(this->alert, TLS_FATAL, TLS_INTERNAL_ERROR);
+		DESTROY_IF(rng);
 		return NEED_MORE;
 	}
-	rng->get_bytes(rng, sizeof(premaster) - 2, premaster + 2);
 	rng->destroy(rng);
 
 	if (this->private &&