Test and fix x509_oid functions
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 03caa74..ef9a331 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -802,3 +802,27 @@
 X509 CRT parse path #4 (two certs, one non-cert)
 depends_on:POLARSSL_SHA1_C:POLARSSL_RSA_C:POLARSSL_SHA256_C:POLARSSL_ECDSA_C:POLARSSL_ECP_DP_SECP384R1_ENABLED
 x509_crt_parse_path:"data_files/dir3":1:2
+
+X509 OID description #1
+x509_oid_desc:"2B06010505070301":"TLS Web Server Authentication"
+
+X509 OID description #2
+x509_oid_desc:"2B0601050507030f":"notfound"
+
+X509 OID description #3
+x509_oid_desc:"2B0601050507030100":"notfound"
+
+X509 OID numstring #1 (wide buffer)
+x509_oid_numstr:"2B06010505070301":"1.3.6.1.5.5.7.3.1":20:17
+
+X509 OID numstring #2 (buffer just fits)
+x509_oid_numstr:"2B06010505070301":"1.3.6.1.5.5.7.3.1":18:17
+
+X509 OID numstring #3 (buffer too small)
+x509_oid_numstr:"2B06010505070301":"1.3.6.1.5.5.7.3.1":17:POLARSSL_ERR_OID_BUF_TOO_SMALL
+
+X509 OID numstring #4 (larger number)
+x509_oid_numstr:"2A864886F70D":"1.2.840.113549":15:14
+
+X509 OID numstring #5 (arithmetic overflow)
+x509_oid_numstr:"2A8648F9F8F7F6F5F4F3F2F1F001":"":100:POLARSSL_ERR_OID_BUF_TOO_SMALL
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index 8638235..effa4cc 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -265,6 +265,57 @@
 }
 /* END_CASE */
 
+/* BEGIN_CASE */
+void x509_oid_desc( char *oid_str, char *ref_desc )
+{
+    x509_buf oid;
+    const char *desc;
+    unsigned char buf[20];
+
+    memset( buf, 0, sizeof buf );
+
+    oid.tag = ASN1_OID;
+    oid.len = unhexify( buf, oid_str );
+    oid.p   = buf;
+
+    desc = x509_oid_get_description( &oid );
+
+    if( strcmp( ref_desc, "notfound" ) == 0 )
+        TEST_ASSERT( desc == NULL );
+    else
+    {
+        TEST_ASSERT( desc != NULL );
+        TEST_ASSERT( strcmp( desc, ref_desc ) == 0 );
+    }
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void x509_oid_numstr( char *oid_str, char *numstr, int blen, int ret )
+{
+    x509_buf oid;
+    unsigned char oid_buf[20];
+    char num_buf[100];
+
+    memset( oid_buf, 0x00, sizeof oid_buf );
+    memset( num_buf, 0x2a, sizeof num_buf );
+
+    oid.tag = ASN1_OID;
+    oid.len = unhexify( oid_buf, oid_str );
+    oid.p   = oid_buf;
+
+    TEST_ASSERT( (size_t) blen <= sizeof num_buf );
+
+    TEST_ASSERT( x509_oid_get_numeric_string( num_buf, blen, &oid ) == ret );
+
+    if( ret >= 0 )
+    {
+        TEST_ASSERT( num_buf[ret] == 0 );
+        TEST_ASSERT( strcmp( num_buf, numstr ) == 0 );
+    }
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:POLARSSL_X509_CRT_PARSE_C:POLARSSL_SELF_TEST */
 void x509_selftest()
 {