--- /dev/null
+From 6efeaa2e4462bc10f395d8aceed363c3e77b35a3 Mon Sep 17 00:00:00 2001
+From: Adriaan de Jong <dejong@fox-it.com>
+Date: Mon, 2 Apr 2012 09:28:02 +0200
+Subject: [PATCH] Added support for new PolarSSL 1.1 RNG
+
+This patch, while retaining PolarSSL 1.0 support, introduces the PolarSSL 1.1 DRBG.
+This RNG adds a number of features, including support for personalisation strings
+and multiple entropy sources.
+
+Personalisation strings have been implemented, based on PID, program name, place
+within memory, and a hash of the user's certificate.
+
+The entropy sources used are the platform default ones. Which ones these are
+depends on how PolarSSL was built, but usually this includes:
+
+ - /dev/urandom or the Windows CryptoAPI RNG
+ - the HAVEGE RNG
+ - the output of PolarSSL's hardclock() call (usually RDTSC)
+
+Finally, this patch moves to only one instance of the RNG per OpenVPN instance,
+instead of one per keystate
+
+Signed-off-by: Adriaan de Jong <dejong@fox-it.com>
+Signed-off-by: Eelse-jan Stutvoet <stutvoet@fox-it.com>
+Acked-by: James Yonan <james@openvpn.net>
+Message-Id: 1333351687-3732-1-git-send-email-dejong@fox-it.com
+URL: http://article.gmane.org/gmane.network.openvpn.devel/6210
+Signed-off-by: David Sommerseth <davids@redhat.com>
+---
+ crypto_polarssl.c | 84 ++++++++++++++++++++++++++++++++++++-----
+ crypto_polarssl.h | 25 ++++++++++++
+ ssl.c | 5 ++
+ ssl_backend.h | 10 +++++
+ ssl_polarssl.c | 44 ++++++++++++++++-----
+ ssl_polarssl.h | 2 -
+ 6 files changed, 148 insertions(+), 22 deletions(-)
+
+--- a/crypto_polarssl.c
++++ b/crypto_polarssl.c
+@@ -36,12 +36,18 @@
+ #include "buffer.h"
+ #include "integer.h"
+ #include "crypto_backend.h"
++#include "otime.h"
++#include "misc.h"
+
+ #include <polarssl/des.h>
+ #include <polarssl/md5.h>
+ #include <polarssl/cipher.h>
+ #include <polarssl/havege.h>
+
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++#include <polarssl/entropy.h>
++#endif
++
+ /*
+ *
+ * Hardware engine support. Allows loading/unloading of engines.
+@@ -143,7 +149,6 @@ show_available_engines ()
+ "available\n");
+ }
+
+-
+ /*
+ *
+ * Random number functions, used in cases where we want
+@@ -153,29 +158,88 @@ show_available_engines ()
+ *
+ */
+
+-int
+-rand_bytes (uint8_t *output, int len)
++/*
++ * Initialise the given ctr_drbg context, using a personalisation string and an
++ * entropy gathering function.
++ */
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ctr_drbg_context * rand_ctx_get()
++{
++ static entropy_context ec = {0};
++ static ctr_drbg_context cd_ctx = {0};
++ static bool rand_initialised = false;
++
++ if (!rand_initialised)
++ {
++ struct gc_arena gc = gc_new();
++ struct buffer pers_string = alloc_buf_gc(100, &gc);
++
++ /*
++ * Personalisation string, should be as unique as possible (see NIST
++ * 800-90 section 8.7.1). We have very little information at this stage.
++ * Include Program Name, memory address of the context and PID.
++ */
++ buf_printf(&pers_string, "OpenVPN %0u %p %s", getpid(), &cd_ctx, time_string(0, 0, 0, &gc));
++
++ /* Initialise PolarSSL RNG, and built-in entropy sources */
++ entropy_init(&ec);
++
++ if (0 != ctr_drbg_init(&cd_ctx, entropy_func, &ec, BPTR(&pers_string), BLEN(&pers_string)))
++ msg (M_FATAL, "Failed to initialize random generator");
++
++ gc_free(&gc);
++ rand_initialised = true;
++ }
++
++ return &cd_ctx;
++}
++
++#else /* (POLARSSL_VERSION_NUMBER < 0x01010000) */
++
++havege_state * rand_ctx_get()
+ {
+ static havege_state hs = {0};
+- static bool hs_initialised = false;
+- const int int_size = sizeof(int);
++ static bool rand_initialised = false;
+
+- if (!hs_initialised)
++ if (!rand_initialised)
+ {
+ /* Initialise PolarSSL RNG */
+ havege_init(&hs);
+- hs_initialised = true;
++ rand_initialised = true;
+ }
+
++ return &hs;
++}
++
++#endif /* (POLARSSL_VERSION_NUMBER >= 0x01010000) */
++
++int
++rand_bytes (uint8_t *output, int len)
++{
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ ctr_drbg_context *rng_ctx = rand_ctx_get();
++#else /* (POLARSSL_VERSION_NUMBER >= 0x01010000) */
++ havege_state *rng_ctx = rand_ctx_get();
++#endif /* (POLARSSL_VERSION_NUMBER >= 0x01010000) */
++
+ while (len > 0)
+ {
+- const int blen = min_int (len, int_size);
+- const int rand_int = havege_rand(&hs);
+-
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ const size_t blen = min_int (len, CTR_DRBG_MAX_REQUEST);
++ if (0 != ctr_drbg_random(rng_ctx, output, blen))
++ return 0;
++
++#else /* (POLARSSL_VERSION_NUMBER >= 0x01010000) */
++ const size_t blen = min_int (len, sizeof(int));
++ const int rand_int = havege_rand(rng_ctx);
+ memcpy (output, &rand_int, blen);
++
++#endif /* (POLARSSL_VERSION_NUMBER >= 0x01010000) */
++
+ output += blen;
+ len -= blen;
+ }
++
+ return 1;
+ }
+
+--- a/crypto_polarssl.h
++++ b/crypto_polarssl.h
+@@ -30,9 +30,16 @@
+ #ifndef CRYPTO_POLARSSL_H_
+ #define CRYPTO_POLARSSL_H_
+
++#include <polarssl/version.h>
+ #include <polarssl/cipher.h>
+ #include <polarssl/md.h>
+
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++# include <polarssl/ctr_drbg.h>
++#else
++# include <polarssl/havege.h>
++#endif
++
+ /** Generic cipher key type %context. */
+ typedef cipher_info_t cipher_kt_t;
+
+@@ -71,4 +78,22 @@ typedef md_context_t hmac_ctx_t;
+ #define SHA_DIGEST_LENGTH 20
+ #define DES_KEY_LENGTH 8
+
++/**
++ * Returns a singleton instance of the PolarSSL random number generator.
++ *
++ * For PolarSSL 1.0, this is the HAVEGE random number generator.
++ *
++ * For PolarSSL 1.1+, this is the CTR_DRBG random number generator. If it
++ * hasn't been initialised yet, the RNG will be initialised using the default
++ * entropy sources. Aside from the default platform entropy sources, an
++ * additional entropy source, the HAVEGE random number generator will also be
++ * added. During initialisation, a personalisation string will be added based
++ * on the time, the PID, and a pointer to the random context.
++ */
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ctr_drbg_context * rand_ctx_get();
++#else
++havege_state * rand_ctx_get();
++#endif
++
+ #endif /* CRYPTO_POLARSSL_H_ */
+--- a/ssl.c
++++ b/ssl.c
+@@ -385,6 +385,11 @@ init_ssl (const struct options *options,
+ tls_ctx_restrict_ciphers(new_ctx, options->cipher_list);
+ }
+
++#ifdef ENABLE_CRYPTO_POLARSSL
++ /* Fox-IT hardening: Personalise the random by mixing in the certificate */
++ tls_ctx_personalise_random (new_ctx);
++#endif
++
+ tls_clear_error ();
+ return;
+
+--- a/ssl_backend.h
++++ b/ssl_backend.h
+@@ -272,6 +272,16 @@ void tls_ctx_load_extra_certs (struct tl
+ #endif
+ );
+
++#ifdef ENABLE_CRYPTO_POLARSSL
++/**
++ * Add a personalisation string to the PolarSSL RNG, based on the certificate
++ * loaded into the given context.
++ *
++ * @param ctx TLS context to use
++ */
++void tls_ctx_personalise_random(struct tls_root_ctx *ctx);
++#endif
++
+ /* **************************************
+ *
+ * Key-state specific functions
+--- a/ssl_polarssl.c
++++ b/ssl_polarssl.c
+@@ -38,6 +38,9 @@
+ #include "manage.h"
+ #include "ssl_common.h"
+
++#include <polarssl/sha2.h>
++#include <polarssl/havege.h>
++
+ #include "ssl_verify_polarssl.h"
+ #include <polarssl/pem.h>
+
+@@ -79,9 +82,6 @@ tls_ctx_server_new(struct tls_root_ctx *
+ ASSERT(NULL != ctx);
+ CLEAR(*ctx);
+
+- ALLOC_OBJ_CLEAR(ctx->hs, havege_state);
+- havege_init(ctx->hs);
+-
+ ALLOC_OBJ_CLEAR(ctx->dhm_ctx, dhm_context);
+ ALLOC_OBJ_CLEAR(ctx->priv_key, rsa_context);
+
+@@ -97,12 +97,8 @@ void
+ tls_ctx_client_new(struct tls_root_ctx *ctx)
+ {
+ ASSERT(NULL != ctx);
+-
+ CLEAR(*ctx);
+
+- ALLOC_OBJ_CLEAR(ctx->hs, havege_state);
+- havege_init(ctx->hs);
+-
+ ALLOC_OBJ_CLEAR(ctx->dhm_ctx, dhm_context);
+ ALLOC_OBJ_CLEAR(ctx->priv_key, rsa_context);
+
+@@ -137,8 +133,6 @@ tls_ctx_free(struct tls_root_ctx *ctx)
+ }
+ #endif
+
+- free(ctx->hs);
+-
+ if (ctx->allowed_ciphers)
+ free(ctx->allowed_ciphers);
+
+@@ -496,6 +490,30 @@ static void my_debug( void *ctx, int lev
+ }
+ }
+
++/*
++ * Further personalise the RNG using a hash of the public key
++ */
++void tls_ctx_personalise_random(struct tls_root_ctx *ctx)
++{
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ static char old_sha256_hash[32] = {0};
++ char sha256_hash[32] = {0};
++ ctr_drbg_context *cd_ctx = rand_ctx_get();
++
++ if (NULL != ctx->crt_chain)
++ {
++ x509_cert *cert = ctx->crt_chain;
++
++ sha2(cert->tbs.p, cert->tbs.len, sha256_hash, false);
++ if ( 0 != memcmp(old_sha256_hash, sha256_hash, sizeof(sha256_hash)))
++ {
++ ctr_drbg_update(cd_ctx, sha256_hash, 32);
++ memcpy(old_sha256_hash, sha256_hash, sizeof(old_sha256_hash));
++ }
++ }
++#endif /* POLARSSL_VERSION_NUMBER >= 0x01010000 */
++}
++
+ void key_state_ssl_init(struct key_state_ssl *ks_ssl,
+ const struct tls_root_ctx *ssl_ctx, bool is_server, void *session)
+ {
+@@ -509,7 +527,13 @@ void key_state_ssl_init(struct key_state
+ /* Initialise SSL context */
+ ssl_set_dbg (ks_ssl->ctx, my_debug, NULL);
+ ssl_set_endpoint (ks_ssl->ctx, ssl_ctx->endpoint);
+- ssl_set_rng (ks_ssl->ctx, havege_rand, ssl_ctx->hs);
++
++#if (POLARSSL_VERSION_NUMBER >= 0x01010000)
++ ssl_set_rng (ks_ssl->ctx, ctr_drbg_random, rand_ctx_get());
++#else /* POLARSSL_VERSION_NUMBER >= 0x01010000 */
++ ssl_set_rng (ks_ssl->ctx, havege_rand, rand_ctx_get());
++#endif /* POLARSSL_VERSION_NUMBER >= 0x01010000 */
++
+ ALLOC_OBJ_CLEAR (ks_ssl->ssn, ssl_session);
+ ssl_set_session (ks_ssl->ctx, 0, 0, ks_ssl->ssn );
+ if (ssl_ctx->allowed_ciphers)
+--- a/ssl_polarssl.h
++++ b/ssl_polarssl.h
+@@ -30,7 +30,6 @@
+ #ifndef SSL_POLARSSL_H_
+ #define SSL_POLARSSL_H_
+
+-#include <polarssl/havege.h>
+ #include <polarssl/ssl.h>
+ #include "config.h"
+
+@@ -63,7 +62,6 @@ struct tls_root_ctx {
+
+ int endpoint; /**< Whether or not this is a server or a client */
+
+- havege_state *hs; /**< HAVEGE random number state */
+ dhm_context *dhm_ctx; /**< Diffie-Helmann-Merkle context */
+ x509_cert *crt_chain; /**< Local Certificate chain */
+ x509_cert *ca_chain; /**< CA chain for remote verification */
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