Allow ssl_client2/ssl_server2 to use HMAC DRBG instead of CTR DRBG
So far, ssl_client2 and ssl_server2 were relying on MBEDTLS_CTR_DRBG_C
being set. This commit adapts them to use HMAC DRBG in case CTR DRBG
is disabled in the configuration.
Note that disabling CTR DRBG in favor of HMAC DRBG can be useful on
constrained systems because Mbed TLS' HMAC DRBG is slightly smaller,
and moreover needed anyway as part of deterministic ECDSA.
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 2aa4950..cd02fcb 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -43,13 +43,16 @@
#endif
#if !defined(MBEDTLS_ENTROPY_C) || \
- !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
- !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_CTR_DRBG_C)
+ !defined(MBEDTLS_SSL_TLS_C) || \
+ !defined(MBEDTLS_SSL_CLI_C) || \
+ !defined(MBEDTLS_NET_C) || \
+ !( defined(MBEDTLS_CTR_DRBG_C) || defined(MBEDTLS_HMAC_DRBG_C) )
int main( void )
{
mbedtls_printf("MBEDTLS_ENTROPY_C and/or "
"MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_CLI_C and/or "
- "MBEDTLS_NET_C and/or MBEDTLS_CTR_DRBG_C and/or not defined.\n");
+ "MBEDTLS_NET_C not defined, or "
+ "neither MBEDTLS_CTR_DRBG_C nor MBEDTLS_HMAC_DRBG_C defined.\n");
return( 0 );
}
#else
@@ -59,6 +62,7 @@
#include "mbedtls/ssl_ciphersuites.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
+#include "mbedtls/hmac_drbg.h"
#include "mbedtls/certs.h"
#include "mbedtls/x509.h"
#include "mbedtls/error.h"
@@ -701,8 +705,9 @@
return( 0 );
}
-#if !defined(MBEDTLS_SSL_CONF_SINGLE_HASH)
-static int ssl_sig_hashes_for_test[] = {
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+static int available_hashes[] = {
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_MD_SHA512,
MBEDTLS_MD_SHA384,
@@ -717,8 +722,6 @@
#endif
MBEDTLS_MD_NONE
};
-#endif /* !MBEDTLS_SSL_CONF_SINGLE_HASH */
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
/*
* Wait for an event from the underlying transport or the timer
@@ -892,14 +895,23 @@
#if defined(MBEDTLS_SSL_CONF_RNG)
int rng_wrap( void *ctx, unsigned char *dst, size_t len );
+#if defined(MBEDTLS_CTR_DRBG_C)
mbedtls_ctr_drbg_context *rng_ctx_global = NULL;
+#else
+mbedtls_hmac_drbg_context *rng_ctx_global = NULL;
+#endif /* MBEDTLS_CTR_DRBG_C */
+
int rng_wrap( void *ctx, unsigned char *dst, size_t len )
{
/* We expect the NULL parameter here. */
if( ctx != NULL )
return( -1 );
+#if defined(MBEDTLS_CTR_DRBG_C)
return( mbedtls_ctr_drbg_random( rng_ctx_global, dst, len ) );
+#else
+ return( mbedtls_hmac_drbg_random( rng_ctx_global, dst, len ) );
+#endif
}
#endif /* MBEDTLS_SSL_CONF_RNG */
@@ -941,7 +953,11 @@
mbedtls_x509_crt_profile crt_profile_for_test = mbedtls_x509_crt_profile_default;
#endif
mbedtls_entropy_context entropy;
+#if defined(MBEDTLS_CTR_DRBG_C)
mbedtls_ctr_drbg_context ctr_drbg;
+#else
+ mbedtls_hmac_drbg_context hmac_drbg;
+#endif
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_ssl_session saved_session;
@@ -970,7 +986,11 @@
mbedtls_ssl_init( &ssl );
mbedtls_ssl_config_init( &conf );
memset( &saved_session, 0, sizeof( mbedtls_ssl_session ) );
+#if defined(MBEDTLS_CTR_DRBG_C)
mbedtls_ctr_drbg_init( &ctr_drbg );
+#else
+ mbedtls_hmac_drbg_init( &hmac_drbg );
+#endif /* MBEDTLS_CTR_DRBG_C */
#if defined(MBEDTLS_X509_CRT_PARSE_C)
mbedtls_x509_crt_init( &cacert );
mbedtls_x509_crt_init( &clicert );
@@ -1664,6 +1684,7 @@
fflush( stdout );
mbedtls_entropy_init( &entropy );
+#if defined(MBEDTLS_CTR_DRBG_C)
if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,
&entropy, (const unsigned char *) pers,
strlen( pers ) ) ) != 0 )
@@ -1672,6 +1693,19 @@
-ret );
goto exit;
}
+#else /* MBEDTLS_CTR_DRBG_C */
+ if( ( ret = mbedtls_hmac_drbg_seed( &hmac_drbg,
+ mbedtls_md_info_from_type(
+ available_hashes[0] ),
+ mbedtls_entropy_func,
+ &entropy, (const unsigned char *) pers,
+ strlen( pers ) ) ) != 0 )
+ {
+ mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned -0x%x\n",
+ -ret );
+ goto exit;
+ }
+#endif /* MBEDTLS_CTR_DRBG */
mbedtls_printf( " ok\n" );
@@ -1851,7 +1885,7 @@
crt_profile_for_test.allowed_mds |= MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA1 );
mbedtls_ssl_conf_cert_profile( &conf, &crt_profile_for_test );
#if !defined(MBEDTLS_SSL_CONF_SINGLE_HASH)
- mbedtls_ssl_conf_sig_hashes( &conf, ssl_sig_hashes_for_test );
+ mbedtls_ssl_conf_sig_hashes( &conf, available_hashes );
#endif
}
@@ -1953,11 +1987,19 @@
}
#endif
+#if defined(MBEDTLS_CTR_DRBG_C)
#if !defined(MBEDTLS_SSL_CONF_RNG)
mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
#else
rng_ctx_global = &ctr_drbg;
#endif
+#else /* MBEDTLS_CTR_DRBG_C */
+#if !defined(MBEDTLS_SSL_CONF_RNG)
+ mbedtls_ssl_conf_rng( &conf, mbedtls_hmac_drbg_random, &hmac_drbg );
+#else
+ rng_ctx_global = &hmac_drbg;
+#endif
+#endif /* MBEDTLS_CTR_DRBG_C */
#if defined(MBEDTLS_DEBUG_C)
mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
@@ -2871,7 +2913,11 @@
mbedtls_ssl_session_free( &saved_session );
mbedtls_ssl_free( &ssl );
mbedtls_ssl_config_free( &conf );
+#if defined(MBEDTLS_CTR_DRBG_C)
mbedtls_ctr_drbg_free( &ctr_drbg );
+#else
+ mbedtls_hmac_drbg_free( &hmac_drbg );
+#endif
mbedtls_entropy_free( &entropy );
if( session_data != NULL )
mbedtls_platform_zeroize( session_data, session_data_len );
@@ -2895,4 +2941,4 @@
}
#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C &&
- MBEDTLS_CTR_DRBG_C MBEDTLS_TIMING_C */
+ ( MBEDTLS_CTR_DRBG_C || MBEDTLS_HMAC_DRBG_C ) && MBEDTLS_TIMING_C */