Reduce code size when mbedtls_x509_*_info() unused

Introduce MBEDTLS_X509_INFO to indicate the availability of the
mbedtls_x509_*_info() function and closely related APIs. When this is
not defined, also omit name and description from
mbedtls_oid_descriptor_t, and omit OID arrays, macros, and types that
are entirely unused. This saves several KB of code space.

Change-Id: I056312613379890e0d70e1d08c34171287c0aa17
diff --git a/library/debug.c b/library/debug.c
index 36510cd..158caf1 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -300,7 +300,7 @@
 }
 #endif /* MBEDTLS_BIGNUM_C */
 
-#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_X509_CRT_PARSE_C) && defined(MBEDTLS_X509_INFO)
 static void debug_print_pk( const mbedtls_ssl_context *ssl, int level,
                             const char *file, int line,
                             const char *text, const mbedtls_pk_context *pk )
@@ -395,7 +395,7 @@
         crt = crt->next;
     }
 }
-#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_X509_INFO */
 
 #if defined(MBEDTLS_ECDH_C)
 static void mbedtls_debug_printf_ecdh_internal( const mbedtls_ssl_context *ssl,
diff --git a/library/oid.c b/library/oid.c
index 33f437c..04918b9 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -51,6 +51,17 @@
 #define ADD_LEN(s)      s, MBEDTLS_OID_SIZE(s)
 
 /*
+ * Macro to generate mbedtls_oid_descriptor_t
+ */
+#if defined(MBEDTLS_X509_INFO)
+#define OID_DESCRIPTOR(s, name, description)  { ADD_LEN(s), name, description }
+#define NULL_OID_DESCRIPTOR                   { NULL, 0, NULL, NULL }
+#else
+#define OID_DESCRIPTOR(s, name, description)  { ADD_LEN(s) }
+#define NULL_OID_DESCRIPTOR                   { NULL, 0 }
+#endif
+
+/*
  * Macro to generate an internal function for oid_XXX_from_asn1() (used by
  * the other functions)
  */
@@ -73,6 +84,7 @@
         return( NULL );                                                 \
     }
 
+#if defined(MBEDTLS_X509_INFO)
 /*
  * Macro to generate a function for retrieving a single attribute from the
  * descriptor of an mbedtls_oid_descriptor_t wrapper.
@@ -85,6 +97,7 @@
     *ATTR1 = data->descriptor.ATTR1;                                    \
     return( 0 );                                                        \
 }
+#endif /* MBEDTLS_X509_INFO */
 
 /*
  * Macro to generate a function for retrieving a single attribute from an
@@ -167,83 +180,83 @@
 static const oid_x520_attr_t oid_x520_attr_type[] =
 {
     {
-        { ADD_LEN( MBEDTLS_OID_AT_CN ),          "id-at-commonName",               "Common Name" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_CN,          "id-at-commonName",               "Common Name" ),
         "CN",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_COUNTRY ),     "id-at-countryName",              "Country" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_COUNTRY,     "id-at-countryName",              "Country" ),
         "C",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_LOCALITY ),    "id-at-locality",                 "Locality" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_LOCALITY,    "id-at-locality",                 "Locality" ),
         "L",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_STATE ),       "id-at-state",                    "State" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_STATE,       "id-at-state",                    "State" ),
         "ST",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_ORGANIZATION ),"id-at-organizationName",         "Organization" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_ORGANIZATION,"id-at-organizationName",         "Organization" ),
         "O",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_ORG_UNIT ),    "id-at-organizationalUnitName",   "Org Unit" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_ORG_UNIT,    "id-at-organizationalUnitName",   "Org Unit" ),
         "OU",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS9_EMAIL ),    "emailAddress",                   "E-mail address" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS9_EMAIL,    "emailAddress",                   "E-mail address" ),
         "emailAddress",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_SERIAL_NUMBER ),"id-at-serialNumber",            "Serial number" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_SERIAL_NUMBER,"id-at-serialNumber",            "Serial number" ),
         "serialNumber",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_POSTAL_ADDRESS ),"id-at-postalAddress",          "Postal address" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_POSTAL_ADDRESS,"id-at-postalAddress",          "Postal address" ),
         "postalAddress",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_POSTAL_CODE ), "id-at-postalCode",               "Postal code" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_POSTAL_CODE, "id-at-postalCode",               "Postal code" ),
         "postalCode",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_SUR_NAME ),    "id-at-surName",                  "Surname" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_SUR_NAME,    "id-at-surName",                  "Surname" ),
         "SN",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_GIVEN_NAME ),  "id-at-givenName",                "Given name" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_GIVEN_NAME,  "id-at-givenName",                "Given name" ),
         "GN",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_INITIALS ),    "id-at-initials",                 "Initials" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_INITIALS,    "id-at-initials",                 "Initials" ),
         "initials",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_GENERATION_QUALIFIER ), "id-at-generationQualifier", "Generation qualifier" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_GENERATION_QUALIFIER, "id-at-generationQualifier", "Generation qualifier" ),
         "generationQualifier",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_TITLE ),       "id-at-title",                    "Title" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_TITLE,       "id-at-title",                    "Title" ),
         "title",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_DN_QUALIFIER ),"id-at-dnQualifier",              "Distinguished Name qualifier" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_DN_QUALIFIER,"id-at-dnQualifier",              "Distinguished Name qualifier" ),
         "dnQualifier",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_PSEUDONYM ),   "id-at-pseudonym",                "Pseudonym" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_PSEUDONYM,   "id-at-pseudonym",                "Pseudonym" ),
         "pseudonym",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_DOMAIN_COMPONENT ), "id-domainComponent",           "Domain component" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DOMAIN_COMPONENT, "id-domainComponent",           "Domain component" ),
         "DC",
     },
     {
-        { ADD_LEN( MBEDTLS_OID_AT_UNIQUE_IDENTIFIER ), "id-at-uniqueIdentifier",    "Unique Identifier" },
+        OID_DESCRIPTOR( MBEDTLS_OID_AT_UNIQUE_IDENTIFIER, "id-at-uniqueIdentifier",    "Unique Identifier" ),
         "uniqueIdentifier",
     },
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         NULL,
     }
 };
@@ -262,27 +275,27 @@
 static const oid_x509_ext_t oid_x509_ext[] =
 {
     {
-        { ADD_LEN( MBEDTLS_OID_BASIC_CONSTRAINTS ),    "id-ce-basicConstraints",   "Basic Constraints" },
+        OID_DESCRIPTOR( MBEDTLS_OID_BASIC_CONSTRAINTS,    "id-ce-basicConstraints",   "Basic Constraints" ),
         MBEDTLS_X509_EXT_BASIC_CONSTRAINTS,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_KEY_USAGE ),            "id-ce-keyUsage",           "Key Usage" },
+        OID_DESCRIPTOR( MBEDTLS_OID_KEY_USAGE,            "id-ce-keyUsage",           "Key Usage" ),
         MBEDTLS_X509_EXT_KEY_USAGE,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_EXTENDED_KEY_USAGE ),   "id-ce-extKeyUsage",        "Extended Key Usage" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EXTENDED_KEY_USAGE, "id-ce-extKeyUsage", "Extended Key Usage" ),
         MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_SUBJECT_ALT_NAME ),     "id-ce-subjectAltName",     "Subject Alt Name" },
+        OID_DESCRIPTOR( MBEDTLS_OID_SUBJECT_ALT_NAME, "id-ce-subjectAltName", "Subject Alt Name" ),
         MBEDTLS_X509_EXT_SUBJECT_ALT_NAME,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_NS_CERT_TYPE ),         "id-netscape-certtype",     "Netscape Certificate Type" },
+        OID_DESCRIPTOR( MBEDTLS_OID_NS_CERT_TYPE, "id-netscape-certtype", "Netscape Certificate Type" ),
         MBEDTLS_X509_EXT_NS_CERT_TYPE,
     },
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         0,
     },
 };
@@ -290,19 +303,22 @@
 FN_OID_TYPED_FROM_ASN1(oid_x509_ext_t, x509_ext, oid_x509_ext)
 FN_OID_GET_ATTR1(mbedtls_oid_get_x509_ext_type, oid_x509_ext_t, x509_ext, int, ext_type)
 
+#if defined(MBEDTLS_X509_INFO)
 static const mbedtls_oid_descriptor_t oid_ext_key_usage[] =
 {
-    { ADD_LEN( MBEDTLS_OID_SERVER_AUTH ),      "id-kp-serverAuth",      "TLS Web Server Authentication" },
-    { ADD_LEN( MBEDTLS_OID_CLIENT_AUTH ),      "id-kp-clientAuth",      "TLS Web Client Authentication" },
-    { ADD_LEN( MBEDTLS_OID_CODE_SIGNING ),     "id-kp-codeSigning",     "Code Signing" },
-    { ADD_LEN( MBEDTLS_OID_EMAIL_PROTECTION ), "id-kp-emailProtection", "E-mail Protection" },
-    { ADD_LEN( MBEDTLS_OID_TIME_STAMPING ),    "id-kp-timeStamping",    "Time Stamping" },
-    { ADD_LEN( MBEDTLS_OID_OCSP_SIGNING ),     "id-kp-OCSPSigning",     "OCSP Signing" },
-    { NULL, 0, NULL, NULL },
+    OID_DESCRIPTOR( MBEDTLS_OID_SERVER_AUTH,      "id-kp-serverAuth",      "TLS Web Server Authentication" ),
+    OID_DESCRIPTOR( MBEDTLS_OID_CLIENT_AUTH,      "id-kp-clientAuth",      "TLS Web Client Authentication" ),
+    OID_DESCRIPTOR( MBEDTLS_OID_CODE_SIGNING,     "id-kp-codeSigning",     "Code Signing" ),
+    OID_DESCRIPTOR( MBEDTLS_OID_EMAIL_PROTECTION, "id-kp-emailProtection", "E-mail Protection" ),
+    OID_DESCRIPTOR( MBEDTLS_OID_TIME_STAMPING,    "id-kp-timeStamping",    "Time Stamping" ),
+    OID_DESCRIPTOR( MBEDTLS_OID_OCSP_SIGNING,     "id-kp-OCSPSigning",     "OCSP Signing" ),
+    NULL_OID_DESCRIPTOR,
 };
 
 FN_OID_TYPED_FROM_ASN1(mbedtls_oid_descriptor_t, ext_key_usage, oid_ext_key_usage)
 FN_OID_GET_ATTR1(mbedtls_oid_get_extended_key_usage, mbedtls_oid_descriptor_t, ext_key_usage, const char *, description)
+#endif /* MBEDTLS_X509_INFO */
+
 #endif /* MBEDTLS_X509_USE_C || MBEDTLS_X509_CREATE_C */
 
 #if defined(MBEDTLS_MD_C)
@@ -320,51 +336,51 @@
 #if defined(MBEDTLS_RSA_C)
 #if defined(MBEDTLS_MD2_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_MD2 ),        "md2WithRSAEncryption",     "RSA with MD2" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_MD2,        "md2WithRSAEncryption",     "RSA with MD2" ),
         MBEDTLS_MD_MD2,      MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_MD2_C */
 #if defined(MBEDTLS_MD4_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_MD4 ),        "md4WithRSAEncryption",     "RSA with MD4" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_MD4,        "md4WithRSAEncryption",     "RSA with MD4" ),
         MBEDTLS_MD_MD4,      MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_MD4_C */
 #if defined(MBEDTLS_MD5_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_MD5 ),        "md5WithRSAEncryption",     "RSA with MD5" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_MD5,        "md5WithRSAEncryption",     "RSA with MD5" ),
         MBEDTLS_MD_MD5,      MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_MD5_C */
 #if defined(MBEDTLS_SHA1_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_SHA1 ),       "sha-1WithRSAEncryption",   "RSA with SHA1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_SHA1,       "sha-1WithRSAEncryption",   "RSA with SHA1" ),
         MBEDTLS_MD_SHA1,     MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_SHA1_C */
 #if defined(MBEDTLS_SHA256_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_SHA224 ),     "sha224WithRSAEncryption",  "RSA with SHA-224" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_SHA224,     "sha224WithRSAEncryption",  "RSA with SHA-224" ),
         MBEDTLS_MD_SHA224,   MBEDTLS_PK_RSA,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_SHA256 ),     "sha256WithRSAEncryption",  "RSA with SHA-256" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_SHA256,     "sha256WithRSAEncryption",  "RSA with SHA-256" ),
         MBEDTLS_MD_SHA256,   MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_SHA256_C */
 #if defined(MBEDTLS_SHA512_C)
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_SHA384 ),     "sha384WithRSAEncryption",  "RSA with SHA-384" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_SHA384,     "sha384WithRSAEncryption",  "RSA with SHA-384" ),
         MBEDTLS_MD_SHA384,   MBEDTLS_PK_RSA,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_SHA512 ),     "sha512WithRSAEncryption",  "RSA with SHA-512" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_SHA512,     "sha512WithRSAEncryption",  "RSA with SHA-512" ),
         MBEDTLS_MD_SHA512,   MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_SHA512_C */
 #if defined(MBEDTLS_SHA1_C)
     {
-        { ADD_LEN( MBEDTLS_OID_RSA_SHA_OBS ),      "sha-1WithRSAEncryption",   "RSA with SHA1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_RSA_SHA_OBS,      "sha-1WithRSAEncryption",   "RSA with SHA1" ),
         MBEDTLS_MD_SHA1,     MBEDTLS_PK_RSA,
     },
 #endif /* MBEDTLS_SHA1_C */
@@ -372,45 +388,49 @@
 #if defined(MBEDTLS_ECDSA_C)
 #if defined(MBEDTLS_SHA1_C)
     {
-        { ADD_LEN( MBEDTLS_OID_ECDSA_SHA1 ),       "ecdsa-with-SHA1",      "ECDSA with SHA1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_ECDSA_SHA1,       "ecdsa-with-SHA1",      "ECDSA with SHA1" ),
         MBEDTLS_MD_SHA1,     MBEDTLS_PK_ECDSA,
     },
 #endif /* MBEDTLS_SHA1_C */
 #if defined(MBEDTLS_SHA256_C)
     {
-        { ADD_LEN( MBEDTLS_OID_ECDSA_SHA224 ),     "ecdsa-with-SHA224",    "ECDSA with SHA224" },
+        OID_DESCRIPTOR( MBEDTLS_OID_ECDSA_SHA224,     "ecdsa-with-SHA224",    "ECDSA with SHA224" ),
         MBEDTLS_MD_SHA224,   MBEDTLS_PK_ECDSA,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_ECDSA_SHA256 ),     "ecdsa-with-SHA256",    "ECDSA with SHA256" },
+        OID_DESCRIPTOR( MBEDTLS_OID_ECDSA_SHA256,     "ecdsa-with-SHA256",    "ECDSA with SHA256" ),
         MBEDTLS_MD_SHA256,   MBEDTLS_PK_ECDSA,
     },
 #endif /* MBEDTLS_SHA256_C */
 #if defined(MBEDTLS_SHA512_C)
     {
-        { ADD_LEN( MBEDTLS_OID_ECDSA_SHA384 ),     "ecdsa-with-SHA384",    "ECDSA with SHA384" },
+        OID_DESCRIPTOR( MBEDTLS_OID_ECDSA_SHA384,     "ecdsa-with-SHA384",    "ECDSA with SHA384" ),
         MBEDTLS_MD_SHA384,   MBEDTLS_PK_ECDSA,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_ECDSA_SHA512 ),     "ecdsa-with-SHA512",    "ECDSA with SHA512" },
+        OID_DESCRIPTOR( MBEDTLS_OID_ECDSA_SHA512,     "ecdsa-with-SHA512",    "ECDSA with SHA512" ),
         MBEDTLS_MD_SHA512,   MBEDTLS_PK_ECDSA,
     },
 #endif /* MBEDTLS_SHA512_C */
 #endif /* MBEDTLS_ECDSA_C */
 #if defined(MBEDTLS_RSA_C)
     {
-        { ADD_LEN( MBEDTLS_OID_RSASSA_PSS ),        "RSASSA-PSS",           "RSASSA-PSS" },
+        OID_DESCRIPTOR( MBEDTLS_OID_RSASSA_PSS,        "RSASSA-PSS",           "RSASSA-PSS" ),
         MBEDTLS_MD_NONE,     MBEDTLS_PK_RSASSA_PSS,
     },
 #endif /* MBEDTLS_RSA_C */
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_MD_NONE, MBEDTLS_PK_NONE,
     },
 };
 
 FN_OID_TYPED_FROM_ASN1(oid_sig_alg_t, sig_alg, oid_sig_alg)
+
+#if defined(MBEDTLS_X509_INFO)
 FN_OID_GET_DESCRIPTOR_ATTR1(mbedtls_oid_get_sig_alg_desc, oid_sig_alg_t, sig_alg, const char *, description)
+#endif
+
 FN_OID_GET_ATTR2(mbedtls_oid_get_sig_alg, oid_sig_alg_t, sig_alg, mbedtls_md_type_t, md_alg, mbedtls_pk_type_t, pk_alg)
 FN_OID_GET_OID_BY_ATTR2(mbedtls_oid_get_oid_by_sig_alg, oid_sig_alg_t, oid_sig_alg, mbedtls_pk_type_t, pk_alg, mbedtls_md_type_t, md_alg)
 #endif /* MBEDTLS_MD_C */
@@ -426,19 +446,19 @@
 static const oid_pk_alg_t oid_pk_alg[] =
 {
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS1_RSA ),      "rsaEncryption",   "RSA" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS1_RSA,      "rsaEncryption",   "RSA" ),
         MBEDTLS_PK_RSA,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_EC_ALG_UNRESTRICTED ),  "id-ecPublicKey",   "Generic EC key" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_ALG_UNRESTRICTED,  "id-ecPublicKey",   "Generic EC key" ),
         MBEDTLS_PK_ECKEY,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_EC_ALG_ECDH ),          "id-ecDH",          "EC key for ECDH" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_ALG_ECDH,          "id-ecDH",          "EC key for ECDH" ),
         MBEDTLS_PK_ECKEY_DH,
     },
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_PK_NONE,
     },
 };
@@ -460,72 +480,72 @@
 {
 #if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP192R1 ), "secp192r1",    "secp192r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP192R1, "secp192r1",    "secp192r1" ),
         MBEDTLS_ECP_DP_SECP192R1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP192R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP224R1 ), "secp224r1",    "secp224r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP224R1, "secp224r1",    "secp224r1" ),
         MBEDTLS_ECP_DP_SECP224R1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP224R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP256R1 ), "secp256r1",    "secp256r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP256R1, "secp256r1",    "secp256r1" ),
         MBEDTLS_ECP_DP_SECP256R1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP256R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP384R1 ), "secp384r1",    "secp384r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP384R1, "secp384r1",    "secp384r1" ),
         MBEDTLS_ECP_DP_SECP384R1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP384R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP521R1 ), "secp521r1",    "secp521r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP521R1, "secp521r1",    "secp521r1" ),
         MBEDTLS_ECP_DP_SECP521R1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP521R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP192K1 ), "secp192k1",    "secp192k1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP192K1, "secp192k1",    "secp192k1" ),
         MBEDTLS_ECP_DP_SECP192K1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP192K1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP224K1 ), "secp224k1",    "secp224k1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP224K1, "secp224k1",    "secp224k1" ),
         MBEDTLS_ECP_DP_SECP224K1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP224K1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_SECP256K1 ), "secp256k1",    "secp256k1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_SECP256K1, "secp256k1",    "secp256k1" ),
         MBEDTLS_ECP_DP_SECP256K1,
     },
 #endif /* MBEDTLS_ECP_DP_SECP256K1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_BP256R1 ),   "brainpoolP256r1","brainpool256r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_BP256R1,   "brainpoolP256r1","brainpool256r1" ),
         MBEDTLS_ECP_DP_BP256R1,
     },
 #endif /* MBEDTLS_ECP_DP_BP256R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_BP384R1 ),   "brainpoolP384r1","brainpool384r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_BP384R1,   "brainpoolP384r1","brainpool384r1" ),
         MBEDTLS_ECP_DP_BP384R1,
     },
 #endif /* MBEDTLS_ECP_DP_BP384R1_ENABLED */
 #if defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
     {
-        { ADD_LEN( MBEDTLS_OID_EC_GRP_BP512R1 ),   "brainpoolP512r1","brainpool512r1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_EC_GRP_BP512R1,   "brainpoolP512r1","brainpool512r1" ),
         MBEDTLS_ECP_DP_BP512R1,
     },
 #endif /* MBEDTLS_ECP_DP_BP512R1_ENABLED */
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_ECP_DP_NONE,
     },
 };
@@ -547,15 +567,15 @@
 static const oid_cipher_alg_t oid_cipher_alg[] =
 {
     {
-        { ADD_LEN( MBEDTLS_OID_DES_CBC ),              "desCBC",       "DES-CBC" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DES_CBC,              "desCBC",       "DES-CBC" ),
         MBEDTLS_CIPHER_DES_CBC,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_DES_EDE3_CBC ),         "des-ede3-cbc", "DES-EDE3-CBC" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DES_EDE3_CBC,         "des-ede3-cbc", "DES-EDE3-CBC" ),
         MBEDTLS_CIPHER_DES_EDE3_CBC,
     },
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_CIPHER_NONE,
     },
 };
@@ -577,50 +597,50 @@
 {
 #if defined(MBEDTLS_MD2_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_MD2 ),       "id-md2",       "MD2" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_MD2,       "id-md2",       "MD2" ),
         MBEDTLS_MD_MD2,
     },
 #endif /* MBEDTLS_MD2_C */
 #if defined(MBEDTLS_MD4_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_MD4 ),       "id-md4",       "MD4" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_MD4,       "id-md4",       "MD4" ),
         MBEDTLS_MD_MD4,
     },
 #endif /* MBEDTLS_MD4_C */
 #if defined(MBEDTLS_MD5_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_MD5 ),       "id-md5",       "MD5" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_MD5,       "id-md5",       "MD5" ),
         MBEDTLS_MD_MD5,
     },
 #endif /* MBEDTLS_MD5_C */
 #if defined(MBEDTLS_SHA1_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_SHA1 ),      "id-sha1",      "SHA-1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_SHA1,      "id-sha1",      "SHA-1" ),
         MBEDTLS_MD_SHA1,
     },
 #endif /* MBEDTLS_SHA1_C */
 #if defined(MBEDTLS_SHA256_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_SHA224 ),    "id-sha224",    "SHA-224" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_SHA224,    "id-sha224",    "SHA-224" ),
         MBEDTLS_MD_SHA224,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_SHA256 ),    "id-sha256",    "SHA-256" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_SHA256,    "id-sha256",    "SHA-256" ),
         MBEDTLS_MD_SHA256,
     },
 #endif /* MBEDTLS_SHA256_C */
 #if defined(MBEDTLS_SHA512_C)
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_SHA384 ),    "id-sha384",    "SHA-384" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_SHA384,    "id-sha384",    "SHA-384" ),
         MBEDTLS_MD_SHA384,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_DIGEST_ALG_SHA512 ),    "id-sha512",    "SHA-512" },
+        OID_DESCRIPTOR( MBEDTLS_OID_DIGEST_ALG_SHA512,    "id-sha512",    "SHA-512" ),
         MBEDTLS_MD_SHA512,
     },
 #endif /* MBEDTLS_SHA512_C */
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_MD_NONE,
     },
 };
@@ -641,32 +661,32 @@
 {
 #if defined(MBEDTLS_SHA1_C)
     {
-        { ADD_LEN( MBEDTLS_OID_HMAC_SHA1 ),      "hmacSHA1",      "HMAC-SHA-1" },
+        OID_DESCRIPTOR( MBEDTLS_OID_HMAC_SHA1,      "hmacSHA1",      "HMAC-SHA-1" ),
         MBEDTLS_MD_SHA1,
     },
 #endif /* MBEDTLS_SHA1_C */
 #if defined(MBEDTLS_SHA256_C)
     {
-        { ADD_LEN( MBEDTLS_OID_HMAC_SHA224 ),    "hmacSHA224",    "HMAC-SHA-224" },
+        OID_DESCRIPTOR( MBEDTLS_OID_HMAC_SHA224,    "hmacSHA224",    "HMAC-SHA-224" ),
         MBEDTLS_MD_SHA224,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_HMAC_SHA256 ),    "hmacSHA256",    "HMAC-SHA-256" },
+        OID_DESCRIPTOR( MBEDTLS_OID_HMAC_SHA256,    "hmacSHA256",    "HMAC-SHA-256" ),
         MBEDTLS_MD_SHA256,
     },
 #endif /* MBEDTLS_SHA256_C */
 #if defined(MBEDTLS_SHA512_C)
     {
-        { ADD_LEN( MBEDTLS_OID_HMAC_SHA384 ),    "hmacSHA384",    "HMAC-SHA-384" },
+        OID_DESCRIPTOR( MBEDTLS_OID_HMAC_SHA384,    "hmacSHA384",    "HMAC-SHA-384" ),
         MBEDTLS_MD_SHA384,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_HMAC_SHA512 ),    "hmacSHA512",    "HMAC-SHA-512" },
+        OID_DESCRIPTOR( MBEDTLS_OID_HMAC_SHA512,    "hmacSHA512",    "HMAC-SHA-512" ),
         MBEDTLS_MD_SHA512,
     },
 #endif /* MBEDTLS_SHA512_C */
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_MD_NONE,
     },
 };
@@ -688,15 +708,15 @@
 static const oid_pkcs12_pbe_alg_t oid_pkcs12_pbe_alg[] =
 {
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS12_PBE_SHA1_DES3_EDE_CBC ), "pbeWithSHAAnd3-KeyTripleDES-CBC", "PBE with SHA1 and 3-Key 3DES" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS12_PBE_SHA1_DES3_EDE_CBC, "pbeWithSHAAnd3-KeyTripleDES-CBC", "PBE with SHA1 and 3-Key 3DES" ),
         MBEDTLS_MD_SHA1,      MBEDTLS_CIPHER_DES_EDE3_CBC,
     },
     {
-        { ADD_LEN( MBEDTLS_OID_PKCS12_PBE_SHA1_DES2_EDE_CBC ), "pbeWithSHAAnd2-KeyTripleDES-CBC", "PBE with SHA1 and 2-Key 3DES" },
+        OID_DESCRIPTOR( MBEDTLS_OID_PKCS12_PBE_SHA1_DES2_EDE_CBC, "pbeWithSHAAnd2-KeyTripleDES-CBC", "PBE with SHA1 and 2-Key 3DES" ),
         MBEDTLS_MD_SHA1,      MBEDTLS_CIPHER_DES_EDE_CBC,
     },
     {
-        { NULL, 0, NULL, NULL },
+        NULL_OID_DESCRIPTOR,
         MBEDTLS_MD_NONE, MBEDTLS_CIPHER_NONE,
     },
 };
diff --git a/library/version_features.c b/library/version_features.c
index fc0b1f8..a1beb13 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -540,6 +540,9 @@
 #if defined(MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE)
     "MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE",
 #endif /* MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE */
+#if defined(MBEDTLS_X509_INFO)
+    "MBEDTLS_X509_INFO",
+#endif /* MBEDTLS_X509_INFO */
 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
     "MBEDTLS_X509_RSASSA_PSS_SUPPORT",
 #endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
diff --git a/library/x509.c b/library/x509.c
index a562df7..1dae6cb 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -836,6 +836,7 @@
     return( (int) ( size - n ) );
 }
 
+#if defined(MBEDTLS_X509_INFO)
 /*
  * Helper for writing signature algorithms
  */
@@ -880,6 +881,7 @@
 
     return( (int)( size - n ) );
 }
+#endif /* MBEDTLS_X509_INFO */
 
 /*
  * Helper for writing "RSA key size", "EC key size", etc
diff --git a/library/x509_crl.c b/library/x509_crl.c
index 00f8545..6fa0825 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -619,6 +619,7 @@
 }
 #endif /* MBEDTLS_FS_IO */
 
+#if defined(MBEDTLS_X509_INFO)
 /*
  * Return an informational string about the certificate.
  */
@@ -698,6 +699,7 @@
 
     return( (int) ( size - n ) );
 }
+#endif /* MBEDTLS_X509_INFO */
 
 /*
  * Initialize a CRL chain
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 9d498ea..a1ecaa2 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1413,6 +1413,7 @@
 }
 #endif /* MBEDTLS_FS_IO */
 
+#if defined(MBEDTLS_X509_INFO)
 static int x509_info_subject_alt_name( char **buf, size_t *size,
                                        const mbedtls_x509_sequence *subject_alt_name )
 {
@@ -1735,6 +1736,7 @@
 
     return( (int) ( size - n ) );
 }
+#endif /* MBEDTLS_X509_INFO */
 
 #if defined(MBEDTLS_X509_CHECK_KEY_USAGE)
 int mbedtls_x509_crt_check_key_usage( const mbedtls_x509_crt *crt,
diff --git a/library/x509_csr.c b/library/x509_csr.c
index c8c08c8..859be38 100644
--- a/library/x509_csr.c
+++ b/library/x509_csr.c
@@ -328,6 +328,7 @@
 }
 #endif /* MBEDTLS_FS_IO */
 
+#if defined(MBEDTLS_X509_INFO)
 #define BEFORE_COLON    14
 #define BC              "14"
 /*
@@ -372,6 +373,7 @@
 
     return( (int) ( size - n ) );
 }
+#endif /* MBEDTLS_X509_INFO */
 
 /*
  * Initialize a CSR