zephyr-cp: working TCP sockets and TLS on the Pico W boards

ports/zephyr-cp/boards/raspberrypi/rpi_pico2_w_zephyr/board.conf

@@ -3,6 +3,12 @@ CONFIG_NET_IPV4=y
 CONFIG_NET_DHCPV4=y
 CONFIG_NET_SOCKETS=y
 
+# TCP. Nothing in the port or the SoC defaults turns it on, so until now every
+# SOCK_STREAM socket on these boards failed inside net_context_get() with
+# EPROTOTYPE -- surfaced by socketpool as "Out of sockets" -- which also means
+# the web workflow's listener never opened. HTTP(S) clients and servers need it.
+CONFIG_NET_TCP=y
+
 CONFIG_WIFI=y
 CONFIG_WIFI_NM_WPA_SUPPLICANT_LEGACY_CRYPTO=n
 CONFIG_NET_L2_WIFI_MGMT=y
@@ -19,6 +25,21 @@ CONFIG_MBEDTLS_CIPHERSUITE_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256=y
 CONFIG_MBEDTLS_ENTROPY_C=y
 CONFIG_MBEDTLS_CTR_DRBG_C=y
 
+# The collector's captive portal serves HTTPS from a PEM certificate chain
+# (fullchain.pem / key.pem via ssl.SSLContext.load_cert_chain); mbedTLS only
+# parses DER unless PEM decoding is compiled in.
+CONFIG_MBEDTLS_PEM_PARSE_C=y
+
+# TLS 1.2 ECDHE. Zephyr's mbedTLS 4 default serves secp256r1 through the p256-m
+# PSA driver and leaves the builtin ECP module out. mbedTLS then defines a dummy
+# MBEDTLS_ECP_MAX_BITS of 1, and ssl.h sizes the TLS 1.2 premaster buffer
+# (union mbedtls_ssl_premaster_secret._pms_ecdh[MBEDTLS_ECP_MAX_BYTES]) from
+# it, so every ECDHE key agreement fails with PSA_ERROR_BUFFER_TOO_SMALL -- a
+# 1-byte buffer for a 32-byte shared secret -- and surfaces as OSError 138 on
+# the first read of any TLS connection, client or server. Keep the builtin
+# ECP module (p256-m off) until the header sizes that buffer from PSA.
+CONFIG_MBEDTLS_PSA_P256M_DRIVER_ENABLED=n
+
 # Bluetooth over the shared gSPI bus (CONFIG_BT itself comes from the
 # zephyr,bt-hci chosen node in the overlay).
 #
@@ -46,8 +67,16 @@ CONFIG_BT_EXT_ADV=n
 CONFIG_NET_MAX_CONTEXTS=12
 CONFIG_NET_MAX_CONN=16
 
+# File descriptors. Zephyr sizes the fd table from the subsystems' declared
+# needs (ZVFS_OPEN_ADD_SIZE_*), which came to 4 here; the DHCPv4 server takes
+# one socket plus the socket-service eventfd, leaving a program two, and
+# socketpool.socket() then fails with "Out of sockets" at the first TLS
+# listener. Give sockets a real ceiling (each fd entry is ~12 bytes).
+CONFIG_ZVFS_OPEN_MAX=16
+
 # Zephyr defaults BT_MAX_CONN to 1, which would limit the hub to a single
 # peer and force a connectionless (advertisement-only) node protocol. The
 # CYW43439 controller is not the constraint; raise it so nodes can connect
 # and sync data. Costs RAM per connection.
 CONFIG_BT_MAX_CONN=4
+

ports/zephyr-cp/boards/raspberrypi/rpi_pico_w_zephyr/board.conf

@@ -3,6 +3,12 @@ CONFIG_NET_IPV4=y
 CONFIG_NET_DHCPV4=y
 CONFIG_NET_SOCKETS=y
 
+# TCP. Nothing in the port or the SoC defaults turns it on, so until now every
+# SOCK_STREAM socket on these boards failed inside net_context_get() with
+# EPROTOTYPE -- surfaced by socketpool as "Out of sockets" -- which also means
+# the web workflow's listener never opened. HTTP(S) clients and servers need it.
+CONFIG_NET_TCP=y
+
 CONFIG_WIFI=y
 CONFIG_WIFI_NM_WPA_SUPPLICANT_LEGACY_CRYPTO=n
 CONFIG_NET_L2_WIFI_MGMT=y
@@ -19,6 +25,28 @@ CONFIG_MBEDTLS_CIPHERSUITE_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256=y
 CONFIG_MBEDTLS_ENTROPY_C=y
 CONFIG_MBEDTLS_CTR_DRBG_C=y
 
+# The collector's captive portal serves HTTPS from a PEM certificate chain
+# (fullchain.pem / key.pem via ssl.SSLContext.load_cert_chain); mbedTLS only
+# parses DER unless PEM decoding is compiled in.
+CONFIG_MBEDTLS_PEM_PARSE_C=y
+
+# TLS 1.2 ECDHE. Zephyr's mbedTLS 4 default serves secp256r1 through the p256-m
+# PSA driver and leaves the builtin ECP module out. mbedTLS then defines a dummy
+# MBEDTLS_ECP_MAX_BITS of 1, and ssl.h sizes the TLS 1.2 premaster buffer
+# (union mbedtls_ssl_premaster_secret._pms_ecdh[MBEDTLS_ECP_MAX_BYTES]) from
+# it, so every ECDHE key agreement fails with PSA_ERROR_BUFFER_TOO_SMALL -- a
+# 1-byte buffer for a 32-byte shared secret -- and surfaces as OSError 138 on
+# the first read of any TLS connection, client or server. Keep the builtin
+# ECP module (p256-m off) until the header sizes that buffer from PSA.
+CONFIG_MBEDTLS_PSA_P256M_DRIVER_ENABLED=n
+
+# File descriptors. Zephyr sizes the fd table from the subsystems' declared
+# needs (ZVFS_OPEN_ADD_SIZE_*), which came to 4 here; the DHCPv4 server takes
+# one socket plus the socket-service eventfd, leaving a program two, and
+# socketpool.socket() then fails with "Out of sockets" at the first TLS
+# listener. Give sockets a real ceiling (each fd entry is ~12 bytes).
+CONFIG_ZVFS_OPEN_MAX=16
+
 CONFIG_TEST_RANDOM_GENERATOR=y
 
 # Bluetooth over the shared gSPI bus (CONFIG_BT itself comes from the

ports/zephyr-cp/common-hal/socketpool/Socket.c

@@ -9,6 +9,7 @@
 #include "shared/runtime/interrupt_char.h"
 #include "py/mperrno.h"
 #include "py/runtime.h"
+#include "bindings/zephyr_kernel/__init__.h"
 #include "shared-bindings/socketpool/SocketPool.h"
 #include "common-hal/socketpool/__init__.h"
 #include "common-hal/wifi/__init__.h"
@@ -156,6 +157,13 @@ static bool _socketpool_socket(socketpool_socketpool_obj_t *self,
     sock->ipproto = ipproto;
     sock->pool = self;
     sock->timeout_ms = (uint)-1;
+    // The object was allocated with a finaliser and zeroed, so until a socket
+    // exists it must read as closed (num < 0). Left at 0 after a failed
+    // zsock_socket(), the finaliser later called zsock_shutdown(0) -- fd 0
+    // belongs to the socket service's eventfd, whose shorter vtable has no
+    // shutdown slot -- and the CPU branched into cdc_acm_1's data (usage
+    // fault, halt).
+    sock->num = -1;
 
     int socknum = zsock_socket(sock->family, sock->type, sock->ipproto);
     if (socknum < 0) {
@@ -205,6 +213,11 @@ socketpool_socket_obj_t *common_hal_socketpool_socket(socketpool_socketpool_obj_
     socketpool_socket_obj_t *sock = mp_obj_malloc_with_finaliser(socketpool_socket_obj_t, &socketpool_socket_type);
 
     if (!_socketpool_socket(self, family, type, proto, sock)) {
+        // Say which limit was hit (ENOMEM: net_contexts, ENFILE/EMFILE: the
+        // fd table) rather than a generic message.
+        if (errno != 0) {
+            raise_zephyr_error(-errno);
+        }
         mp_raise_RuntimeError(MP_ERROR_TEXT("Out of sockets"));
     }
     return sock;
@@ -255,6 +268,13 @@ int socketpool_socket_accept(socketpool_socket_obj_t *self, mp_obj_t *peer_out,
         accepted->pool = self->pool;
         accepted->connected = true;
         accepted->type = self->type;
+        accepted->family = self->family;
+        accepted->ipproto = self->ipproto;
+        // Inherit the listener's timeout, as the other ports do. A freshly
+        // allocated socket object reads as timeout 0 (non-blocking), which made
+        // the first ssl recv on an accepted connection raise EAGAIN before the
+        // TLS handshake had a chance to complete.
+        accepted->timeout_ms = self->timeout_ms;
     }
 
     if (peer_out) {
@@ -277,6 +297,14 @@ socketpool_socket_obj_t *common_hal_socketpool_socket_accept(socketpool_socket_o
         sock->pool = self->pool;
         sock->connected = true;
         sock->type = self->type;
+        sock->family = self->family;
+        sock->ipproto = self->ipproto;
+        // Inherit the listener's timeout, as the other ports do. A freshly
+        // allocated object reads as timeout 0 (non-blocking), and ssl's
+        // recv_into relies on the plain socket's recv blocking for it: the
+        // first read on an accepted TLS connection raised EAGAIN before the
+        // handshake could complete.
+        sock->timeout_ms = self->timeout_ms;
 
         return sock;
     } else {

shared-module/ssl/SSLSocket.c

@@ -280,7 +280,16 @@ ssl_sslsocket_obj_t *common_hal_ssl_sslcontext_wrap_socket(ssl_sslcontext_obj_t
         goto cleanup;
     }
 
-    if (self->crt_bundle_attach != NULL) {
+    if (server_side && !(self->cacert_buf && self->cacert_bytes)) {
+        // On a server the CA store is about authenticating *clients*. A
+        // context that only had load_cert_chain() called on it -- the normal
+        // HTTPS-server setup -- must not demand a client certificate, which is
+        // what the default root bundle turned into: every handshake failed
+        // with MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE. Match CPython, where a
+        // server-side context defaults to CERT_NONE; a program that loads its
+        // own CA with load_verify_locations() still gets client verification.
+        mbedtls_ssl_conf_authmode(&o->conf, MBEDTLS_SSL_VERIFY_NONE);
+    } else if (self->crt_bundle_attach != NULL) {
         mbedtls_ssl_conf_authmode(&o->conf, MBEDTLS_SSL_VERIFY_REQUIRED);
         self->crt_bundle_attach(&o->conf);
     } else if (self->cacert_buf && self->cacert_bytes) {