Add certificate policy of type any policy id

Add a function for getting the certificate policy. Currently only
"Any Policy" is supported.
diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index 65e626e..342ef75 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -168,6 +168,11 @@
 #define MBEDTLS_OID_FRESHEST_CRL                MBEDTLS_OID_ID_CE "\x2E" /**< id-ce-freshestCRL OBJECT IDENTIFIER ::=  { id-ce 46 } */
 
 /*
+ * Certificate policies
+ */
+#define MBEDTLS_OID_ANY_POLICY              MBEDTLS_OID_CERTIFICATE_POLICIES "\x00" /**< anyPolicy OBJECT IDENTIFIER ::= { id-ce-certificatePolicies 0 } */
+
+/*
  * Netscape certificate extensions
  */
 #define MBEDTLS_OID_NS_CERT                 MBEDTLS_OID_NETSCAPE "\x01"
@@ -577,6 +582,16 @@
 int mbedtls_oid_get_extended_key_usage( const mbedtls_asn1_buf *oid, const char **desc );
 
 /**
+ * \brief          Translate certificate policies OID into description
+ *
+ * \param oid      OID to use
+ * \param desc     place to store string pointer
+ *
+ * \return         0 if successful, or MBEDTLS_ERR_OID_NOT_FOUND
+ */
+int mbedtls_oid_get_certificate_policies( const mbedtls_asn1_buf *oid, const char **desc );
+
+/**
  * \brief          Translate md_type into hash algorithm OID
  *
  * \param md_alg   message digest algorithm
diff --git a/library/oid.c b/library/oid.c
index 294bbd6..4e10f8a 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -296,6 +296,15 @@
 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)
 
+static const mbedtls_oid_descriptor_t oid_certificate_policies[] =
+{
+    { ADD_LEN( MBEDTLS_OID_ANY_POLICY ),      "anyPolicy",       "Any Policy" },
+    { NULL, 0, NULL, NULL },
+};
+
+FN_OID_TYPED_FROM_ASN1(mbedtls_oid_descriptor_t, certificate_policies, oid_certificate_policies)
+FN_OID_GET_ATTR1(mbedtls_oid_get_certificate_policies, mbedtls_oid_descriptor_t, certificate_policies, const char *, description)
+
 #if defined(MBEDTLS_MD_C)
 /*
  * For SignatureAlgorithmIdentifier
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a8e7523..1b7ea78 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -116,6 +116,7 @@
 add_test_suite(memory_buffer_alloc)
 add_test_suite(mpi)
 add_test_suite(nist_kw)
+add_test_suite(oid)
 add_test_suite(pem)
 add_test_suite(pkcs1_v15)
 add_test_suite(pkcs1_v21)
diff --git a/tests/suites/test_suite_oid.data b/tests/suites/test_suite_oid.data
new file mode 100644
index 0000000..759a010
--- /dev/null
+++ b/tests/suites/test_suite_oid.data
@@ -0,0 +1,8 @@
+OID get Any Policy certificate policy
+oid_get_certificate_policies:"551D2000":"Any Policy"
+
+OID get certificate policy invalid oid
+oid_get_certificate_policies:"5533445566":""
+
+OID get certificate policy wrong oid - id-ce-authorityKeyIdentifier
+oid_get_certificate_policies:"551D23":""
diff --git a/tests/suites/test_suite_oid.function b/tests/suites/test_suite_oid.function
new file mode 100644
index 0000000..e95e48d
--- /dev/null
+++ b/tests/suites/test_suite_oid.function
@@ -0,0 +1,34 @@
+/* BEGIN_HEADER */
+#include "mbedtls/oid.h"
+#include "mbedtls/asn1.h"
+#include "mbedtls/asn1write.h"
+#include "string.h"
+/* END_HEADER */
+
+/* BEGIN_DEPENDENCIES
+ * depends_on:MBEDTLS_OID_C
+ * END_DEPENDENCIES
+ */
+
+/* BEGIN_CASE depends_on:MBEDTLS_ASN1_WRITE_C*/
+void oid_get_certificate_policies( data_t * oid, char * result_str )
+{
+    mbedtls_asn1_buf asn1_buf = { 0, 0, NULL };
+    int ret;
+    const char *desc;
+
+    asn1_buf.tag = MBEDTLS_ASN1_OID;
+    asn1_buf.p = oid->x;
+    asn1_buf.len = oid->len;
+
+    ret = mbedtls_oid_get_certificate_policies( &asn1_buf, &desc );
+    if( strlen( result_str ) == 0 )
+    {
+        TEST_ASSERT( ret == MBEDTLS_ERR_OID_NOT_FOUND );
+    }
+    else
+    {
+        TEST_ASSERT( strcmp( ( char* )desc, result_str ) == 0 );
+    }
+}
+/* END_CASE */