extmod/modussl_mbedtls: Implement cert_reqs and cadata arguments.

Add cert_reqs and cadata keyword-args to ssl.wrap_socket() and
ssl.CERT_NONE, ssl.CERT_OPTIONAL, ssl.CERT_REQUIRED constants to allow
certificate validation.

CPython doesn't accept cadata in ssl.wrap_socket(), but it does in
SSLContext.load_verify_locations(), so we use this name to at least match
the same name in load_verify_locations().

Add docs for these new arguments, as well as docs for the existing
server_hostname argument which is important for certificate validation.

Tests are added as well.

Signed-off-by: Carlos Gil <carlosgilglez@gmail.com>

docs/library/ssl.rst

@@ -13,7 +13,7 @@ facilities for network sockets, both client-side and server-side.
 Functions
 ---------
 
-.. function:: ssl.wrap_socket(sock, server_side=False, keyfile=None, certfile=None, cert_reqs=CERT_NONE, ca_certs=None, do_handshake=True)
+.. function:: ssl.wrap_socket(sock, server_side=False, keyfile=None, certfile=None, cert_reqs=CERT_NONE, cadata=None, server_hostname=None, do_handshake=True)
 
    Takes a `stream` *sock* (usually socket.socket instance of ``SOCK_STREAM`` type),
    and returns an instance of ssl.SSLSocket, which wraps the underlying stream in
@@ -31,6 +31,17 @@ Functions
      until it completes. Note that in AXTLS the handshake can be deferred until the first
      read or write but it then blocks until completion.
 
+   - *cert_reqs* determines whether the peer (server or client) must present a valid certificate.
+     Note that for mbedtls based ports, ``ssl.CERT_NONE`` and ``ssl.CERT_OPTIONAL`` will not
+     validate any certificate, only ``ssl.CERT_REQUIRED`` will.
+
+   - *cadata* is a bytes object containing the CA certificate chain (in DER format) that will
+     validate the peer's certificate.  Currently only a single DER-encoded certificate is supported.
+
+   - *server_hostname* is for use as a client, and sets the hostname to check against the received
+     server certificate.  It also sets the name for Server Name Indication (SNI), allowing the server
+     to present the proper certificate.
+
    Depending on the underlying module implementation in a particular
    :term:`MicroPython port`, some or all keyword arguments above may be not supported.
 

extmod/modussl_mbedtls.c

@@ -63,6 +63,8 @@ struct ssl_args {
     mp_arg_val_t cert;
     mp_arg_val_t server_side;
     mp_arg_val_t server_hostname;
+    mp_arg_val_t cert_reqs;
+    mp_arg_val_t cadata;
     mp_arg_val_t do_handshake;
 };
 
@@ -191,7 +193,7 @@ STATIC mp_obj_ssl_socket_t *socket_new(mp_obj_t sock, struct ssl_args *args) {
         goto cleanup;
     }
 
-    mbedtls_ssl_conf_authmode(&o->conf, MBEDTLS_SSL_VERIFY_NONE);
+    mbedtls_ssl_conf_authmode(&o->conf, args->cert_reqs.u_int);
     mbedtls_ssl_conf_rng(&o->conf, mbedtls_ctr_drbg_random, &o->ctr_drbg);
     #ifdef MBEDTLS_DEBUG_C
     mbedtls_ssl_conf_dbg(&o->conf, mbedtls_debug, NULL);
@@ -237,6 +239,19 @@ STATIC mp_obj_ssl_socket_t *socket_new(mp_obj_t sock, struct ssl_args *args) {
         }
     }
 
+    if (args->cadata.u_obj != mp_const_none) {
+        size_t cacert_len;
+        const byte *cacert = (const byte *)mp_obj_str_get_data(args->cadata.u_obj, &cacert_len);
+        // len should include terminating null
+        ret = mbedtls_x509_crt_parse(&o->cacert, cacert, cacert_len + 1);
+        if (ret != 0) {
+            ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA; // use general error for all cert errors
+            goto cleanup;
+        }
+
+        mbedtls_ssl_conf_ca_chain(&o->conf, &o->cacert, NULL);
+    }
+
     if (args->do_handshake.u_bool) {
         while ((ret = mbedtls_ssl_handshake(&o->ssl)) != 0) {
             if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
@@ -395,6 +410,8 @@ STATIC mp_obj_t mod_ssl_wrap_socket(size_t n_args, const mp_obj_t *pos_args, mp_
         { MP_QSTR_cert, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_server_side, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
         { MP_QSTR_server_hostname, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+        { MP_QSTR_cert_reqs, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = MBEDTLS_SSL_VERIFY_NONE}},
+        { MP_QSTR_cadata, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
         { MP_QSTR_do_handshake, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = true} },
     };
 
@@ -412,6 +429,9 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(mod_ssl_wrap_socket_obj, 1, mod_ssl_wrap_socke
 STATIC const mp_rom_map_elem_t mp_module_ssl_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_ussl) },
     { MP_ROM_QSTR(MP_QSTR_wrap_socket), MP_ROM_PTR(&mod_ssl_wrap_socket_obj) },
+    { MP_ROM_QSTR(MP_QSTR_CERT_NONE), MP_ROM_INT(MBEDTLS_SSL_VERIFY_NONE) },
+    { MP_ROM_QSTR(MP_QSTR_CERT_OPTIONAL), MP_ROM_INT(MBEDTLS_SSL_VERIFY_OPTIONAL) },
+    { MP_ROM_QSTR(MP_QSTR_CERT_REQUIRED), MP_ROM_INT(MBEDTLS_SSL_VERIFY_REQUIRED) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(mp_module_ssl_globals, mp_module_ssl_globals_table);

tests/multi_net/ssl_cert_rsa.py

@@ -0,0 +1,152 @@
+# Simple test creating an SSL connection and transferring some data
+# This test won't run under CPython because CPython doesn't have key/cert
+
+try:
+    import ubinascii as binascii, usocket as socket, ussl as ssl
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+PORT = 8000
+
+
+# This self-signed key/cert pair is randomly generated and to be used for
+# testing/demonstration only.  You should always generate your own key/cert.
+
+# To generate a new self-signed key/cert pair with openssl do:
+# $ openssl req -x509 -newkey rsa:4096 -keyout rsa_key.pem -out rsa_cert.pem -days 365 -node
+#
+# Convert them to DER format:
+# $ openssl rsa -in rsa_key.pem -out rsa_key.der -outform DER
+# $ openssl x509 -in rsa_cert.pem -out rsa_key.der -outform DER
+#
+# Then convert to hex format, eg using binascii.hexlify(data).
+
+cert = binascii.unhexlify(
+    b"308205d7308203bfa003020102020900bc63b48a700c3d49300d06092a864886f70d01010b050030"
+    b"8181310b3009060355040613024155310c300a06035504080c03466f6f310c300a06035504070c03"
+    b"42617231143012060355040a0c0b4d6963726f507974686f6e310c300a060355040b0c03666f6f31"
+    b"16301406035504030c0d657370686f6d652e6c6f63616c311a301806092a864886f70d010901160b"
+    b"666f6f406261722e636f6d301e170d3232303731323138303031335a170d32333037313231383030"
+    b"31335a308181310b3009060355040613024155310c300a06035504080c03466f6f310c300a060355"
+    b"04070c0342617231143012060355040a0c0b4d6963726f507974686f6e310c300a060355040b0c03"
+    b"666f6f3116301406035504030c0d657370686f6d652e6c6f63616c311a301806092a864886f70d01"
+    b"0901160b666f6f406261722e636f6d30820222300d06092a864886f70d01010105000382020f0030"
+    b"82020a0282020100ce3c0f730ab34432ce605ab44d4ac0aafd8a6243133eab0dcc9d444ab7d9ff66"
+    b"a6815a101d2d3cbd72140afc34f8c3caedce16e9528350f3e0e56343f248507d82e41b51abb515cb"
+    b"f60e5a619f2dbca8684d174c3b0951e2c7ba576c7fb06453a3597755810a6a4c45eb0925c855ab53"
+    b"7785df46bf29145871330ff0641a101a24f0830c20bae865ba8bb32606caac4555812acf19f59553"
+    b"349ce70fb7ff63512f0444f8f41b973183eabf9679903087c6cd69dc3adcbe754dd0207ea57c50e9"
+    b"2d800bce6258d1618bb749d3fc01239b6d1af6d3f9cada3acbb312a1d85a59cfabd28b2e572c56a4"
+    b"818ce170ca2b781a04749c6239206c64ad9e057484143a4c52bdef6189c46405c1a9642489cb640a"
+    b"937adfc2687578dfa2b40ebafa05213642a1ccbc265557cd40de53324cff1bfba6f5c215f657b8f9"
+    b"f2260ab6293625d0e203bba975bc7ac6dff3e604c9b0d2a2a4ba5941c0dc8d2e0e9439c56447b404"
+    b"8c0e6cfb03517742ff6f7c2140a05954aa1e29247d1ae8bfd7db0db8dd45d095710fb78284ede285"
+    b"0fc0c21235406af83e6044addf9385316403e2a25442b9ffbfc7b01c6c9292e5a3531e6a48496c01"
+    b"6de1373334a52f01b7c6a0ece1261936788d2161c53a8985a0946d6d319225b230d96d055ea4692f"
+    b"eb71fdaf4b775ac9fbc38e1b943e6617cf61d33e930ab288a3ea4730b4f2784a8018e0dfc8a11e73"
+    b"0203010001a350304e301d0603551d0e04160414bc6048fe3cd278257e8b7c90dedbbce8369b20b8"
+    b"301f0603551d23041830168014bc6048fe3cd278257e8b7c90dedbbce8369b20b8300c0603551d13"
+    b"040530030101ff300d06092a864886f70d01010b0500038202010009238354b43379a3d2b56e928c"
+    b"ac8ea28e2c01cf8148e54c0bbd4055e2e57d578697d1e2c392f1fe3bc9211d4f27ed1be631e7547a"
+    b"6390d7f121a9e20a195fdda73f755188b16cf39714924a9686dd7cc749421335038c0640c2c6b15d"
+    b"f44d74d94a97285ee2a7b075ccc9d9d632e2a5906030cf59bde14ab10660b7cf47ec9d7ae2f35963"
+    b"454f76735a3dac12a4a4c907183e9ccf3e07d59484c182e67edc7c35ce15c7e1072fae8c9965a126"
+    b"1a1f31147d4af8d1ebf8ee7c142badfe67e31fb324a79a29bc94e89370b70d8cf7cd2b2aa427a49f"
+    b"77849891e7c4d5911f6fda52733a3c169b0188c2d9918f296dd8e234f8962f0db5e47c6159448045"
+    b"4e2d9a5850d4c696a0fb3b66534a4591c49dda8cc6f1b0008c625aa5e0091ecfbd51d9715c60b85e"
+    b"4e89d4a6cfabb2acdf81518eb61403b8f8767c5c00216f730e08f22959dff695a081cc726c4ab35a"
+    b"e3f6538a231f831a6e91206f3b691a94bdf95343ec02ef7aac42da2a70846cd5f13dd2955a5f1737"
+    b"a4c3c6c03b041d334c1dadd1e305f07c83b4b4e0509ec1d23e95f820290942eaaf8bea304cd5a505"
+    b"8fc0d4624ff1ffe1348e7bc54c756a12acb258eb5e7426fb062a82b88ec274c9c13b3eff8b010947"
+    b"62e166f490cd25b14e762db708785859a337d8fd0008fe602a90e2933cded3359e98ce3fbc041208"
+    b"66bd4d96d6b6f7f53def854d40021196b7a06b"
+)
+
+key = binascii.unhexlify(
+    b"308209290201000282020100ce3c0f730ab34432ce605ab44d4ac0aafd8a6243133eab0dcc9d444a"
+    b"b7d9ff66a6815a101d2d3cbd72140afc34f8c3caedce16e9528350f3e0e56343f248507d82e41b51"
+    b"abb515cbf60e5a619f2dbca8684d174c3b0951e2c7ba576c7fb06453a3597755810a6a4c45eb0925"
+    b"c855ab537785df46bf29145871330ff0641a101a24f0830c20bae865ba8bb32606caac4555812acf"
+    b"19f59553349ce70fb7ff63512f0444f8f41b973183eabf9679903087c6cd69dc3adcbe754dd0207e"
+    b"a57c50e92d800bce6258d1618bb749d3fc01239b6d1af6d3f9cada3acbb312a1d85a59cfabd28b2e"
+    b"572c56a4818ce170ca2b781a04749c6239206c64ad9e057484143a4c52bdef6189c46405c1a96424"
+    b"89cb640a937adfc2687578dfa2b40ebafa05213642a1ccbc265557cd40de53324cff1bfba6f5c215"
+    b"f657b8f9f2260ab6293625d0e203bba975bc7ac6dff3e604c9b0d2a2a4ba5941c0dc8d2e0e9439c5"
+    b"6447b4048c0e6cfb03517742ff6f7c2140a05954aa1e29247d1ae8bfd7db0db8dd45d095710fb782"
+    b"84ede2850fc0c21235406af83e6044addf9385316403e2a25442b9ffbfc7b01c6c9292e5a3531e6a"
+    b"48496c016de1373334a52f01b7c6a0ece1261936788d2161c53a8985a0946d6d319225b230d96d05"
+    b"5ea4692feb71fdaf4b775ac9fbc38e1b943e6617cf61d33e930ab288a3ea4730b4f2784a8018e0df"
+    b"c8a11e73020301000102820201008efa0e8fe81c2e2cb6ed10152dfca4242750581d3e6b54f56524"
+    b"a6a2d2613cf2727efcec6cfddebd4c285f1148bc2a2936c28919cb0da502dea8c92fe2f9856bee61"
+    b"ac1aebdac838b5e66f7c7c799df07716f30ef362dbb5485884a180c8ce5539cb1db35699dce5f217"
+    b"27295d811f1ce7a115111c1823b5c90ce880f5352872a7a76282f6f1fd8a015136ab274c3d30783d"
+    b"eb6ad7096e33d826eafdf7c70398d5eab4d28f91cd3913c69c7a7ade9ef692b9f8292959be64dec4"
+    b"6ab2c291b41a6464004b5ddd4b93bfe41b37eedeef4ba2d16dcbb9c28b96f57fb96c20ed4a9471ff"
+    b"ae643b254f100f8c9702b5f67af6369e8d887f285e5d520c5aa5d3a79e5de96432e6d2e3dea68e58"
+    b"208c075fb119c6d3d4149b7e1247208d6b337c70272befc41d57f278618f1a82de337173346dc135"
+    b"4d80a7c9075af99dbb2a14733c06b71600c6677a6bb28c0e4fc63db622228047a2cb7474dc8141c3"
+    b"5f3a597c3e2bca9911d28eb9fd1a0c915e9f9c1cfd643d4fd8cac867f215380168ec37b8cfa28564"
+    b"e6288ab04a7d67ca44b4c8375214a7ffaa1e6be92c4b138fcfd6beaba251b31a50a6e2ef241c9554"
+    b"a1dc710b4acb63e749f5849e53d3f4915c6eb2a9a009bab04e932841ab34ae29eb000a08777d6399"
+    b"169c2dc3d7952df5bc2d06e90a32139c6a2793d3817e4feadac2ccac554d383a8d41569140c29168"
+    b"89220d3a5e410282010100fd603d18feef7aac61bda3b674a57ab38748bcde5c3efdba2279638f8e"
+    b"a413cc26b9dda0375c116a8798a295b2c283aaaad7cca0dbd9bb3322a9a815f6d0aa5fc4f9aff8fb"
+    b"da8ff914091ede7aefdb07a119c9b2e2b2bda776ac497060b8e88a82eb20c62f26f343566697726e"
+    b"71aa46fd4efad6f42fc8a478856324d72cbf5eb3918317162d6fc2cfd775969a2077759fa2c8220d"
+    b"acdc2ebb03ec39feed3f2b415449cbf40a7126bcf01d1068e3a45ec01181f2c68d7e05b4720bfe4a"
+    b"308e1648123c91214a5f8dfce58727c4cd9396a8b403b733a717449b2f1970db97a3b8467271ffa6"
+    b"e8c7cc9e2e1c0f789284ae9efe77eaac01131463c9c1329a1ba3530282010100d05ed6ab9b9fbdf7"
+    b"a0f5f91f68dc3bac5789332d6ece46103fb1ef109fc972fdc99edf3107a23d66d1cdfe6bdddfd1bb"
+    b"3952ccd10b5c20ad1b3e0aa6a51271ecf3a7ef2a65e029f5d77f238d1235b52a9dca3451c165d70a"
+    b"99cbaea5c610e5455979696db769191e7cf2db21f641959e4ba1c5c0aae260c724962b6ac2621d92"
+    b"e9df7adeb82b522d37b42cb454003bbe60d9915bf7737aeccf88c7ed1263a22f431a734e61fe7173"
+    b"a937ddf76ad2a79994c05238defc15f6846858e9edf27ae2a567c7c5c735ea5d2fbef65a2195bc05"
+    b"d82cbf06a477b29c84c92e8054c2bb25d8c6f19d43ef5fd1fce13c2cdbc361c39baec37b399200b3"
+    b"2d4a6798ba0b546102820101008e41492c4e7daff7368d1d6c64034067a94dca5461a0301e201add"
+    b"2e0d5ccb8cb435685bfa98e362572cf8236a10d191b187a568aee688b6c60050d1bc181d7fd57c86"
+    b"33195bf5b7576b637c6fb358dae8b52ccc15815affb99e334137dcb91a833475db2f4004164b5d20"
+    b"2c6c1bbf094a50dc7e70ec9f0ed067bb6944b1e7e3c897aaecfc53984add1c4ff5b525034cf3ca95"
+    b"e8a09aeba804f1c7e02be391b2bc641166c3e654eef5e72dba37d98f406f3fa520e41f2ea10f5574"
+    b"ac5984f75145378fefbfac1d07fff3f234fec698d55e746b1da18f6f7de24ec84ed7cb446d428820"
+    b"bef33c00693e6a0ef114b5d66e9fefa8ee059238df1ac37c87e7841ae7028201000721a7d139c34e"
+    b"da21cd295894db2cc3aa3f4cdc1a35bf1a2143f2bdabea56202f7d5b802f15b36a4875f76633b2cc"
+    b"57cf0f71691a2d6e04deb0d1e68031d06a5eb079b406c6944910b60e3e6ec81dca369a4c0e1c4363"
+    b"07bed9c4c171b4f453da4b187ba3d25a04bc1c07b9f2d6adcb3c256e4238d7049eec36a387c4dd5c"
+    b"cbc16b5fa62dc175cf8c5f83442cb7d153a3b6ee8daa3b6e929a4bc123f1042df1d6271a992d2b6b"
+    b"309d33074ac7822c304a72069e61ab590915e10862013dd24cdd825ec8fb17724cfc2c59fc1db825"
+    b"3641fece0ee9241b9dd5c198f0d575d0b7ebe26b3489b5b09edc3bcd366fd3110e83ce886c383d31"
+    b"feefe6e302cc2345210282010008f77a33d0081e9be3c1b1ac8b8e0eebb72df2eb69b95d2ed74935"
+    b"b9dab8e17023cc38465354023c5183b51a6a20288fbb2181172be1c2fdb8b444419454e5b37f7f3b"
+    b"df11e28cf4746b25534eb62f7e87bbbf28eda37024368b3897fbc661b40a93e04a183db9219c04a8"
+    b"7643edf5d8b5dbfe3d424e91d558d5e3e2fa02ce1984ee69fb8518470eee2e7db0e1df5ac4571f78"
+    b"a7a2529bc1fef5e32d46994869a8d8cc47869e174d84e7976be8ebb88f2ccb71a603a8bdb06af3eb"
+    b"2ddbd62082f40d7987e47f2e321eb5eb2a28fefab263409f89dc97ebc723a1b751418cdd3ea684ba"
+    b"8b17a330a306a6fbcf51ba83563aed85a4f886fff1a22423748d83798c"
+)
+
+# Server
+def instance0():
+    multitest.globals(IP=multitest.get_network_ip())
+    s = socket.socket()
+    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    s.bind(socket.getaddrinfo("0.0.0.0", PORT)[0][-1])
+    s.listen(1)
+    multitest.next()
+    s2, _ = s.accept()
+    s2 = ssl.wrap_socket(s2, server_side=True, key=key, cert=cert)
+    print(s2.read(16))
+    s2.write(b"server to client")
+    s2.close()
+    s.close()
+
+
+# Client
+def instance1():
+    multitest.next()
+    s = socket.socket()
+    s.connect(socket.getaddrinfo(IP, PORT)[0][-1])
+    s = ssl.wrap_socket(s, cert_reqs=ssl.CERT_REQUIRED, cadata=cert)
+    s.write(b"client to server")
+    print(s.read(16))
+    s.close()

tests/multi_net/ssl_cert_rsa.py.exp

@@ -0,0 +1,4 @@
+--- instance0 ---
+b'client to server'
+--- instance1 ---
+b'server to client'

tests/net_inet/ssl_cert.py

@@ -0,0 +1,68 @@
+import ubinascii as binascii
+import usocket as socket
+import ussl as ssl
+
+
+# This certificate was obtained from micropython.org using openssl:
+# $ openssl s_client -showcerts -connect micropython.org:443 </dev/null 2>/dev/null
+# The certificate is from Let's Encrypt:
+# 1 s:/C=US/O=Let's Encrypt/CN=R3
+#   i:/C=US/O=Internet Security Research Group/CN=ISRG Root X1
+# Validity
+#            Not Before: Sep  4 00:00:00 2020 GMT
+#            Not After : Sep 15 16:00:00 2025 GMT
+# Copy PEM content to a file (certmpy.pem) and convert to DER e.g.
+# $ openssl x509 -in certmpy.pem -out certmpy.der -outform DER
+# Then convert to hex format, eg using binascii.hexlify(data).
+
+ca_cert_chain = binascii.unhexlify(
+    b"30820516308202fea003020102021100912b084acf0c18a753f6d62e25a75f5a300d06092a864886"
+    b"f70d01010b0500304f310b300906035504061302555331293027060355040a1320496e7465726e65"
+    b"742053656375726974792052657365617263682047726f7570311530130603550403130c49535247"
+    b"20526f6f74205831301e170d3230303930343030303030305a170d3235303931353136303030305a"
+    b"3032310b300906035504061302555331163014060355040a130d4c6574277320456e637279707431"
+    b"0b300906035504031302523330820122300d06092a864886f70d01010105000382010f003082010a"
+    b"0282010100bb021528ccf6a094d30f12ec8d5592c3f882f199a67a4288a75d26aab52bb9c54cb1af"
+    b"8e6bf975c8a3d70f4794145535578c9ea8a23919f5823c42a94e6ef53bc32edb8dc0b05cf35938e7"
+    b"edcf69f05a0b1bbec094242587fa3771b313e71cace19befdbe43b45524596a9c153ce34c852eeb5"
+    b"aeed8fde6070e2a554abb66d0e97a540346b2bd3bc66eb66347cfa6b8b8f572999f830175dba726f"
+    b"fb81c5add286583d17c7e709bbf12bf786dcc1da715dd446e3ccad25c188bc60677566b3f118f7a2"
+    b"5ce653ff3a88b647a5ff1318ea9809773f9d53f9cf01e5f5a6701714af63a4ff99b3939ddc53a706"
+    b"fe48851da169ae2575bb13cc5203f5ed51a18bdb150203010001a382010830820104300e0603551d"
+    b"0f0101ff040403020186301d0603551d250416301406082b0601050507030206082b060105050703"
+    b"0130120603551d130101ff040830060101ff020100301d0603551d0e04160414142eb317b75856cb"
+    b"ae500940e61faf9d8b14c2c6301f0603551d2304183016801479b459e67bb6e5e40173800888c81a"
+    b"58f6e99b6e303206082b0601050507010104263024302206082b060105050730028616687474703a"
+    b"2f2f78312e692e6c656e63722e6f72672f30270603551d1f0420301e301ca01aa018861668747470"
+    b"3a2f2f78312e632e6c656e63722e6f72672f30220603551d20041b30193008060667810c01020130"
+    b"0d060b2b0601040182df13010101300d06092a864886f70d01010b0500038202010085ca4e473ea3"
+    b"f7854485bcd56778b29863ad754d1e963d336572542d81a0eac3edf820bf5fccb77000b76e3bf65e"
+    b"94dee4209fa6ef8bb203e7a2b5163c91ceb4ed3902e77c258a47e6656e3f46f4d9f0ce942bee54ce"
+    b"12bc8c274bb8c1982fa2afcd71914a08b7c8b8237b042d08f908573e83d904330a472178098227c3"
+    b"2ac89bb9ce5cf264c8c0be79c04f8e6d440c5e92bb2ef78b10e1e81d4429db5920ed63b921f81226"
+    b"949357a01d6504c10a22ae100d4397a1181f7ee0e08637b55ab1bd30bf876e2b2aff214e1b05c3f5"
+    b"1897f05eacc3a5b86af02ebc3b33b9ee4bdeccfce4af840b863fc0554336f668e136176a8e99d1ff"
+    b"a540a734b7c0d063393539756ef2ba76c89302e9a94b6c17ce0c02d9bd81fb9fb768d40665b3823d"
+    b"7753f88e7903ad0a3107752a43d8559772c4290ef7c45d4ec8ae468430d7f2855f18a179bbe75e70"
+    b"8b07e18693c3b98fdc6171252aafdfed255052688b92dce5d6b5e3da7dd0876c842131ae82f5fbb9"
+    b"abc889173de14ce5380ef6bd2bbd968114ebd5db3d20a77e59d3e2f858f95bb848cdfe5c4f1629fe"
+    b"1e5523afc811b08dea7c9390172ffdaca20947463ff0e9b0b7ff284d6832d6675e1e69a393b8f59d"
+    b"8b2f0bd25243a66f3257654d3281df3853855d7e5d6629eab8dde495b5cdb5561242cdc44ec62538"
+    b"44506decce005518fee94964d44eca979cb45bc073a8abb847c2"
+)
+
+
+def main(use_stream=True):
+    s = socket.socket()
+    ai = socket.getaddrinfo("micropython.org", 443)
+    addr = ai[0][-1]
+    s.connect(addr)
+    s = ssl.wrap_socket(
+        s, cert_reqs=ssl.CERT_REQUIRED, cadata=ca_cert_chain, server_hostname="micropython.org"
+    )
+    s.write(b"GET / HTTP/1.0\r\n\r\n")
+    print(s.read(17))
+    s.close()
+
+
+main()

tests/net_inet/ssl_cert.py.exp

@@ -0,0 +1 @@
+b'HTTP/1.1 200 OK\r\n'