extmod/modussl: improve exception error messages

tve · tve · commit 43260c6cea57 · 2020-04-23T23:44:41.000-07:00
diff --git a/extmod/modussl_axtls.c b/extmod/modussl_axtls.c
@@ -54,6 +54,46 @@ struct ssl_args {
 
 STATIC const mp_obj_type_t ussl_socket_type;
 
+// Table of errors
+struct ssl_errs {
+    int16_t errnum;
+    const char *errstr;
+};
+STATIC const struct ssl_errs ssl_error_tab[] = {
+    { SSL_NOT_OK, "NOT_OK" },
+    { SSL_ERROR_DEAD, "DEAD" },
+    { SSL_CLOSE_NOTIFY, "CLOSE_NOTIFY" },
+    { SSL_EAGAIN, "EAGAIN" },
+    { SSL_ERROR_CONN_LOST, "CONN_LOST" },
+    { SSL_ERROR_RECORD_OVERFLOW, "RECORD_OVERFLOW" },
+    { SSL_ERROR_SOCK_SETUP_FAILURE, "SOCK_SETUP_FAILURE" },
+    { SSL_ERROR_INVALID_HANDSHAKE, "INVALID_HANDSHAKE" },
+    { SSL_ERROR_INVALID_PROT_MSG, "INVALID_PROT_MSG" },
+    { SSL_ERROR_INVALID_HMAC, "INVALID_HMAC" },
+    { SSL_ERROR_INVALID_VERSION, "INVALID_VERSION" },
+    { SSL_ERROR_UNSUPPORTED_EXTENSION, "UNSUPPORTED_EXTENSION" },
+    { SSL_ERROR_INVALID_SESSION, "INVALID_SESSION" },
+    { SSL_ERROR_NO_CIPHER, "NO_CIPHER" },
+    { SSL_ERROR_INVALID_CERT_HASH_ALG, "INVALID_CERT_HASH_ALG" },
+    { SSL_ERROR_BAD_CERTIFICATE, "BAD_CERTIFICATE" },
+    { SSL_ERROR_INVALID_KEY, "INVALID_KEY" },
+    { SSL_ERROR_FINISHED_INVALID, "FINISHED_INVALID" },
+    { SSL_ERROR_NO_CERT_DEFINED, "NO_CERT_DEFINED" },
+    { SSL_ERROR_NO_CLIENT_RENOG, "NO_CLIENT_RENOG" },
+    { SSL_ERROR_NOT_SUPPORTED, "NOT_SUPPORTED" },
+    { 0, 0 },
+};
+
+STATIC NORETURN void ussl_raise_error(int err) {
+    for (int i = 0; ssl_error_tab[i].errnum != 0; i++) {
+        if (ssl_error_tab[i].errnum == err) {
+            mp_raise_msg_varg(&mp_type_OSError, "AXTLS %d: %s", err, ssl_error_tab[i].errstr);
+        }
+    }
+    mp_raise_OSError(err);
+}
+
+
 STATIC mp_obj_ssl_socket_t *ussl_socket_new(mp_obj_t sock, struct ssl_args *args) {
     #if MICROPY_PY_USSL_FINALISER
     mp_obj_ssl_socket_t *o = m_new_obj_with_finaliser(mp_obj_ssl_socket_t);
@@ -107,9 +147,8 @@ STATIC mp_obj_ssl_socket_t *ussl_socket_new(mp_obj_t sock, struct ssl_args *args
             int res = ssl_handshake_status(o->ssl_sock);
 
             if (res != SSL_OK) {
-                printf("ssl_handshake_status: %d\n", res);
                 ssl_display_error(res);
-                mp_raise_OSError(MP_EIO);
+                ussl_raise_error(res);
             }
         }
 
diff --git a/extmod/modussl_mbedtls.c b/extmod/modussl_mbedtls.c
@@ -34,6 +34,7 @@
 
 #include "py/runtime.h"
 #include "py/stream.h"
+#include "py/objstr.h"
 
 // mbedtls_time_t
 #include "mbedtls/platform.h"
@@ -43,6 +44,8 @@
 #include "mbedtls/entropy.h"
 #include "mbedtls/ctr_drbg.h"
 #include "mbedtls/debug.h"
+#include "mbedtls/error.h"
+#include MBEDTLS_CONFIG_FILE
 
 typedef struct _mp_obj_ssl_socket_t {
     mp_obj_base_t base;
@@ -74,6 +77,41 @@ STATIC void mbedtls_debug(void *ctx, int level, const char *file, int line, cons
 }
 #endif
 
+STATIC NORETURN void mbedtls_raise_error(int err) {
+    // "small" negative integer error codes come from underlying stream/sockets, not mbedtls
+    if (err < 0 && err > -256) {
+        mp_raise_OSError(-err);
+    }
+    #if defined(MBEDTLS_ERROR_C)
+    // Including mbedtls_strerror takes about 16KB on the esp32 due to all the strings.
+    // MBEDTLS_ERROR_C is the define used by mbedtls to conditionally include mbedtls_strerror.
+    // It is set/unset in the MBEDTLS_CONFIG_FILE which is defined in the Makefile.
+    #define ERR_STR_LEN 100  // mbedtls_strerror truncates if it doesn't fit
+
+    // Try to allocate memory for the message
+    mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
+    byte *o_str_buf = m_new_maybe(byte, ERR_STR_LEN);
+    if (o_str == NULL || o_str_buf == NULL) {
+        mp_raise_OSError(err);
+    }
+
+    // print the error message into the allocated buffer
+    mbedtls_strerror(err, (char *)o_str_buf, ERR_STR_LEN);
+    size_t len = strnlen((char *)o_str_buf, ERR_STR_LEN);
+
+    // Put the exception object together
+    o_str->base.type = &mp_type_str;
+    o_str->data = o_str_buf;
+    o_str->len = len;
+    o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
+    // raise
+    mp_obj_t args[2] = { MP_OBJ_NEW_SMALL_INT(err), MP_OBJ_FROM_PTR(o_str)};
+    nlr_raise(mp_obj_exception_make_new(&mp_type_OSError, 2, 0, args));
+    #else
+    mp_raise_OSError(err); // typ. err is negative
+    #endif
+}
+
 STATIC int _mbedtls_ssl_send(void *ctx, const byte *buf, size_t len) {
     mp_obj_t sock = *(mp_obj_t *)ctx;
 
@@ -85,7 +123,7 @@ STATIC int _mbedtls_ssl_send(void *ctx, const byte *buf, size_t len) {
         if (mp_is_nonblocking_error(err)) {
             return MBEDTLS_ERR_SSL_WANT_WRITE;
         }
-        return -err;
+        return -err; // convert an MP_ERRNO to something mbedtls passes through as error
     } else {
         return out_sz;
     }
@@ -197,7 +235,6 @@ STATIC mp_obj_ssl_socket_t *socket_new(mp_obj_t sock, struct ssl_args *args) {
     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) {
-                printf("mbedtls_ssl_handshake error: -%x\n", -ret);
                 goto cleanup;
             }
         }
@@ -221,7 +258,7 @@ STATIC mp_obj_ssl_socket_t *socket_new(mp_obj_t sock, struct ssl_args *args) {
     } else if (ret == MBEDTLS_ERR_X509_BAD_INPUT_DATA) {
         mp_raise_ValueError(MP_ERROR_TEXT("invalid cert"));
     } else {
-        mp_raise_OSError(MP_EIO);
+        mbedtls_raise_error(ret);
     }
 }
 
diff --git a/ports/esp32/Makefile b/ports/esp32/Makefile
@@ -354,6 +354,7 @@ SRC_C = \
 	mpthreadport.c \
 	machine_rtc.c \
 	machine_sdcard.c \
+	lwip_err.c \
 	$(wildcard $(BOARD_DIR)/*.c) \
 	$(SRC_MOD)
 
@@ -493,7 +494,7 @@ ESPIDF_SPI_FLASH_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/spi_flash/*.c))
 ESPIDF_ULP_O = $(patsubst %.c,%.o,$(wildcard $(ESPCOMP)/ulp/*.c))
 
 $(BUILD)/$(ESPCOMP)/lwip/%.o: CFLAGS += -Wno-address -Wno-unused-variable -Wno-unused-but-set-variable
-ESPIDF_LWIP_O = $(patsubst %.c,%.o,\
+ESPIDF_LWIP_O = $(patsubst %.c,%.o, $(filter-out %lwip/src/api/err.c, \
 	$(wildcard $(ESPCOMP)/lwip/apps/dhcpserver/*.c) \
 	$(wildcard $(ESPCOMP)/lwip/lwip/src/api/*.c) \
 	$(wildcard $(ESPCOMP)/lwip/lwip/src/apps/sntp/*.c) \
@@ -504,7 +505,7 @@ ESPIDF_LWIP_O = $(patsubst %.c,%.o,\
 	$(wildcard $(ESPCOMP)/lwip/lwip/src/netif/*/*/*.c) \
 	$(wildcard $(ESPCOMP)/lwip/port/esp32/*.c) \
 	$(wildcard $(ESPCOMP)/lwip/port/esp32/*/*.c) \
-	)
+	))
 
 ESPIDF_MBEDTLS_O = $(patsubst %.c,%.o,\
 	$(wildcard $(ESPCOMP)/mbedtls/mbedtls/library/*.c) \
diff --git a/ports/esp32/lwip_err.c b/ports/esp32/lwip_err.c
@@ -0,0 +1,72 @@
+//
+// Micropython note: this is a copy of ESP-IDFv4.0's components/lwip/lwip/src/api/err.c with
+// the error EXXX constants replaced by MicroPython's to avoid getting the wrong values because
+// ESP-IDFv4.0 uses ones from newlib (in components/newlib) that have a bunch of different values.
+// It is assumed that ESP-IDFv4.1 fixes this discrepancy.
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ */
+
+#include "lwip/def.h"
+#include "lwip/sys.h"
+#include "py/mperrno.h"
+
+/** Table to quickly map an lwIP error (err_t) to a socket error
+  * by using -err as an index */
+static const int err_to_errno_table[] = {
+    0,              /* ERR_OK          0      No error, everything OK. */
+    MP_ENOMEM,      /* ERR_MEM        -1      Out of memory error.     */
+    MP_ENOBUFS,     /* ERR_BUF        -2      Buffer error.            */
+    MP_EWOULDBLOCK, /* ERR_TIMEOUT    -3      Timeout                  */
+    MP_EHOSTUNREACH, /* ERR_RTE        -4      Routing problem.         */
+    MP_EINPROGRESS, /* ERR_INPROGRESS -5      Operation in progress    */
+    MP_EINVAL,      /* ERR_VAL        -6      Illegal value.           */
+    MP_EWOULDBLOCK, /* ERR_WOULDBLOCK -7      Operation would block.   */
+    MP_EADDRINUSE,  /* ERR_USE        -8      Address in use.          */
+    MP_EALREADY,    /* ERR_ALREADY    -9      Already connecting.      */
+    MP_EISCONN,     /* ERR_ISCONN     -10     Conn already established.*/
+    MP_ENOTCONN,    /* ERR_CONN       -11     Not connected.           */
+    -1,             /* ERR_IF         -12     Low-level netif error    */
+    MP_ECONNABORTED, /* ERR_ABRT       -13     Connection aborted.      */
+    MP_ECONNRESET,  /* ERR_RST        -14     Connection reset.        */
+    MP_ENOTCONN,    /* ERR_CLSD       -15     Connection closed.       */
+    MP_EIO          /* ERR_ARG        -16     Illegal argument.        */
+};
+
+int
+err_to_errno(err_t err) {
+    if ((err > 0) || (-err >= (err_t)LWIP_ARRAYSIZE(err_to_errno_table))) {
+        return EIO;
+    }
+    //printf("lwip err_to_errno %d->%d\n", err, err_to_errno_table[-err]);
+    return err_to_errno_table[-err];
+}
diff --git a/ports/esp32/modsocket.c b/ports/esp32/modsocket.c
@@ -153,6 +153,13 @@ void usocket_events_handler(void) {
 
 #endif // MICROPY_PY_USOCKET_EVENTS
 
+// EXXX error constants in ESP-IDF v4.0 and prior come from a newlib errno.h which has some
+// non-posix values, i.e., different from mperrno.h. This used to get fixed incompletely in
+// exception_from_errno, but it turns out to be easier to fix in lwip's err.c which maps lwip's
+// netif error codes into EXXX. The old code is left in here until the whole problem really
+// goes away with ESP-IDF v4.1 (we hope).
+#define exception_from_errno(errno) mp_raise_OSError(errno)
+#if 0
 NORETURN static void exception_from_errno(int _errno) {
     // Here we need to convert from lwip errno values to MicroPython's standard ones
     if (_errno == EADDRINUSE) {
@@ -162,6 +169,7 @@ NORETURN static void exception_from_errno(int _errno) {
     }
     mp_raise_OSError(_errno);
 }
+#endif
 
 static inline void check_for_exceptions(void) {
     mp_handle_pending(true);
diff --git a/tests/extmod/ussl_basic.py b/tests/extmod/ussl_basic.py
@@ -9,7 +9,7 @@
 
 # create in client mode
 try:
-    ss = ssl.wrap_socket(io.BytesIO())
+    ss = ssl.wrap_socket(io.BytesIO(), server_hostname="test.example.com")
 except OSError as er:
     print("wrap_socket:", repr(er))
 
diff --git a/tests/extmod/ussl_basic.py.exp b/tests/extmod/ussl_basic.py.exp
@@ -1,5 +1,4 @@
-ssl_handshake_status: -256
-wrap_socket: OSError(5,)
+wrap_socket: OSError('AXTLS -256: CONN_LOST',)
 <_SSLSocket 
 4
 b''
diff --git a/tests/net_inet/tls_num_errors.py b/tests/net_inet/tls_num_errors.py
@@ -0,0 +1,39 @@
+# test that modtls produces a text error message
+
+try:
+    import usocket as socket, ussl as ssl, sys, micropython
+except:
+    import socket, ssl, sys
+
+
+# test with heap locked to see it switch to number-only error message
+def test(addr):
+    micropython.alloc_emergency_exception_buf(256)
+    s = socket.socket()
+    s.connect(addr)
+    try:
+        s.setblocking(False)
+        s = ssl.wrap_socket(s, do_handshake=False)
+        micropython.heap_lock()
+        print("heap is locked")
+        while True:
+            ret = s.write('foo')
+            if ret:
+                break
+        micropython.heap_unlock()
+        print("wrap: no exception")
+    except OSError as e:
+        micropython.heap_unlock()
+        # mbedtls produces "-29184"
+        # axtls produces "RECORD_OVERFLOW"
+        ok = "-29184" in str(e) or "RECORD_OVERFLOW" in str(e)
+        print("wrap:", ok)
+        if not ok:
+            print("got exception:", e)
+    s.close()
+
+
+if __name__ == "__main__":
+    # connect to plain HTTP port, oops!
+    addr = socket.getaddrinfo("micropython.org", 80)[0][-1]
+    test(addr)
diff --git a/tests/net_inet/tls_num_errors.py.exp b/tests/net_inet/tls_num_errors.py.exp
@@ -0,0 +1,2 @@
+heap is locked
+wrap: True
diff --git a/tests/net_inet/tls_text_errors.py b/tests/net_inet/tls_text_errors.py
@@ -0,0 +1,29 @@
+# test that modtls produces a text error message
+
+try:
+    import usocket as socket, ussl as ssl, sys
+except:
+    import socket, ssl, sys
+
+
+def test(addr):
+    s = socket.socket()
+    s.connect(addr)
+    try:
+        s = ssl.wrap_socket(s)
+        print("wrap: no exception")
+    except OSError as e:
+        # mbedtls produces "mbedtls -0x7200: SSL - An invalid SSL record was received"
+        # axtls produces "RECORD_OVERFLOW"
+        # CPython produces "[SSL: WRONG_VERSION_NUMBER] wrong version number (_ssl.c:1108)"
+        ok = "invalid SSL record" in str(e) or "RECORD_OVERFLOW" in str(e) or \
+                "wrong version" in str(e)
+        print("wrap:", ok)
+        if not ok:
+            print("got exception:", e)
+    s.close()
+
+if __name__ == "__main__":
+    # connect to plain HTTP port, oops!
+    addr = socket.getaddrinfo("micropython.org", 80)[0][-1]
+    test(addr)

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,4 @@`
`1`		`-ssl_handshake_status: -256`
`2`		`-wrap_socket: OSError(5,)`
	`1`	`+wrap_socket: OSError('AXTLS -256: CONN_LOST',)`
`3`	`2`	`<_SSLSocket`
`4`	`3`	`4`
`5`	`4`	`b''`