From 43c24b8da93e1b75517913a547e3790671849b3d Mon Sep 17 00:00:00 2001
From: Hanno Becker <hanno.becker@arm.com>
Date: Wed, 1 May 2019 09:45:57 +0100
Subject: [PATCH] Fix missing compile-time guards around CID-only constants

---
 library/ssl_tls.c                    | 24 ++++++++++++++----------
 tests/suites/test_suite_ssl.function | 11 +++++++++++
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 405cda4a6..53055c2a8 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2074,14 +2074,12 @@ static void ssl_extract_add_data_from_record( unsigned char* add_data,
 
 #if defined(MBEDTLS_SSL_CID)
     memcpy( add_data + 11, rec->cid, rec->cid_len );
-#endif /* MBEDTLS_SSL_CID */
-
     add_data[11 + rec->cid_len + 0] = ( rec->data_len >> 8 ) & 0xFF;
     add_data[11 + rec->cid_len + 1] = ( rec->data_len >> 0 ) & 0xFF;
-
-#if defined(MBEDTLS_SSL_CID)
     *add_data_len = 13 + rec->cid_len;
-#else
+#else /* MBEDTLS_SSL_CID */
+    add_data[11 + 0] = ( rec->data_len >> 8 ) & 0xFF;
+    add_data[11 + 1] = ( rec->data_len >> 0 ) & 0xFF;
     *add_data_len = 13;
 #endif /* MBEDTLS_SSL_CID */
 }
@@ -2122,11 +2120,14 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "no transform provided to encrypt_buf" ) );
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
-    if( rec == NULL                     ||
-        rec->buf == NULL                ||
-        rec->buf_len < rec->data_offset ||
-        rec->buf_len - rec->data_offset < rec->data_len ||
-        rec->cid_len != 0 )
+    if( rec == NULL
+        || rec->buf == NULL
+        || rec->buf_len < rec->data_offset
+        || rec->buf_len - rec->data_offset < rec->data_len
+#if defined(MBEDTLS_SSL_CID)
+        || rec->cid_len != 0
+#endif
+        )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad record structure provided to encrypt_buf" ) );
         return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
@@ -4149,7 +4150,10 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush )
                                        ssl->conf->transport, rec.ver );
             rec.type = ssl->out_msgtype;
 
+#if defined(MBEDTLS_SSL_CID)
+            /* The CID is set by mbedtls_ssl_encrypt_buf(). */
             rec.cid_len = 0;
+#endif /* MBEDTLS_SSL_CID */
 
             if( ( ret = mbedtls_ssl_encrypt_buf( ssl, ssl->transform_out, &rec,
                                          ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 0640779a8..9f80b1e50 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -38,11 +38,16 @@ static int build_transforms( mbedtls_ssl_transform *t_in,
     unsigned char *key0 = NULL, *key1 = NULL;
     unsigned char iv_enc[16], iv_dec[16];
 
+#if defined(MBEDTLS_SSL_CID)
     unsigned char cid0[ SSL_CID_LEN_MIN ];
     unsigned char cid1[ SSL_CID_LEN_MIN ];
 
     rnd_std_rand( NULL, cid0, sizeof( cid0 ) );
     rnd_std_rand( NULL, cid1, sizeof( cid1 ) );
+#else
+    ((void) cid0_len);
+    ((void) cid1_len);
+#endif /* MBEDTLS_SSL_CID */
 
     maclen = 0;
 
@@ -241,6 +246,7 @@ static int build_transforms( mbedtls_ssl_transform *t_in,
     memcpy( &t_out->iv_dec, iv_enc, sizeof( iv_enc ) );
     memcpy( &t_out->iv_enc, iv_dec, sizeof( iv_dec ) );
 
+#if defined(MBEDTLS_SSL_CID)
     /* Add CID */
     memcpy( &t_in->in_cid,  cid0, cid0_len );
     memcpy( &t_in->out_cid, cid1, cid1_len );
@@ -250,6 +256,7 @@ static int build_transforms( mbedtls_ssl_transform *t_in,
     memcpy( &t_out->out_cid, cid0, cid0_len );
     t_out->in_cid_len = cid1_len;
     t_out->out_cid_len = cid0_len;
+#endif /* MBEDTLS_SSL_CID */
 
 cleanup:
 
@@ -372,7 +379,9 @@ void ssl_crypt_record( int cipher_type, int hash_id,
         rec.type    = 42;
         rec.ver[0]  = num_records;
         rec.ver[1]  = num_records;
+#if defined(MBEDTLS_SSL_CID)
         rec.cid_len = 0;
+#endif /* MBEDTLS_SSL_CID */
 
         rec.buf     = buf;
         rec.buf_len = buflen;
@@ -490,7 +499,9 @@ void ssl_crypt_record_small( int cipher_type, int hash_id,
             rec.ver[1]  = offset;
             rec.buf     = buf;
             rec.buf_len = buflen;
+#if defined(MBEDTLS_SSL_CID)
             rec.cid_len = 0;
+#endif /* MBEDTLS_SSL_CID */
 
             switch( mode )
             {