bpo-339827: Do not swallow exceptions in the _ssl module. (GH-12756)

Modules/_ssl.c

@@ -590,19 +590,18 @@ fill_and_set_sslerror(PySSLSocket *sslsock, PyObject *type, int ssl_errno,
         key = Py_BuildValue("ii", lib, reason);
         if (key == NULL)
             goto fail;
-        reason_obj = PyDict_GetItem(err_codes_to_names, key);
+        reason_obj = PyDict_GetItemWithError(err_codes_to_names, key);
         Py_DECREF(key);
-        if (reason_obj == NULL) {
-            /* XXX if reason < 100, it might reflect a library number (!!) */
-            PyErr_Clear();
+        if (reason_obj == NULL && PyErr_Occurred()) {
+            goto fail;
         }
         key = PyLong_FromLong(lib);
         if (key == NULL)
             goto fail;
-        lib_obj = PyDict_GetItem(lib_codes_to_names, key);
+        lib_obj = PyDict_GetItemWithError(lib_codes_to_names, key);
         Py_DECREF(key);
-        if (lib_obj == NULL) {
-            PyErr_Clear();
+        if (lib_obj == NULL && PyErr_Occurred()) {
+            goto fail;
         }
         if (errstr == NULL)
             errstr = ERR_reason_error_string(errcode);
@@ -3682,7 +3681,7 @@ _pwinfo_set(_PySSLPasswordInfo *pw_info, PyObject* password,
     Py_ssize_t size;
 
     if (PyUnicode_Check(password)) {
-        password_bytes = PyUnicode_AsEncodedString(password, NULL, NULL);
+        password_bytes = PyUnicode_AsUTF8String(password);
         if (!password_bytes) {
             goto error;
         }
@@ -3787,13 +3786,17 @@ _ssl__SSLContext_load_cert_chain_impl(PySSLContext *self, PyObject *certfile,
     if (keyfile == Py_None)
         keyfile = NULL;
     if (!PyUnicode_FSConverter(certfile, &certfile_bytes)) {
-        PyErr_SetString(PyExc_TypeError,
-                        "certfile should be a valid filesystem path");
+        if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "certfile should be a valid filesystem path");
+        }
         return NULL;
     }
     if (keyfile && !PyUnicode_FSConverter(keyfile, &keyfile_bytes)) {
-        PyErr_SetString(PyExc_TypeError,
-                        "keyfile should be a valid filesystem path");
+        if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "keyfile should be a valid filesystem path");
+        }
         goto error;
     }
     if (password && password != Py_None) {
@@ -3985,22 +3988,44 @@ _ssl__SSLContext_load_verify_locations_impl(PySSLContext *self,
         goto error;
     }
     if (cafile && !PyUnicode_FSConverter(cafile, &cafile_bytes)) {
-        PyErr_SetString(PyExc_TypeError,
-                        "cafile should be a valid filesystem path");
+        if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "cafile should be a valid filesystem path");
+        }
         goto error;
     }
     if (capath && !PyUnicode_FSConverter(capath, &capath_bytes)) {
-        PyErr_SetString(PyExc_TypeError,
-                        "capath should be a valid filesystem path");
+        if (PyErr_ExceptionMatches(PyExc_TypeError)) {
+            PyErr_SetString(PyExc_TypeError,
+                            "capath should be a valid filesystem path");
+        }
         goto error;
     }
 
     /* validata cadata type and load cadata */
     if (cadata) {
-        Py_buffer buf;
-        PyObject *cadata_ascii = NULL;
-
-        if (PyObject_GetBuffer(cadata, &buf, PyBUF_SIMPLE) == 0) {
+        if (PyUnicode_Check(cadata)) {
+            PyObject *cadata_ascii = PyUnicode_AsASCIIString(cadata);
+            if (cadata_ascii == NULL) {
+                if (PyErr_ExceptionMatches(PyExc_UnicodeEncodeError)) {
+                    goto invalid_cadata;
+                }
+                goto error;
+            }
+            r = _add_ca_certs(self,
+                              PyBytes_AS_STRING(cadata_ascii),
+                              PyBytes_GET_SIZE(cadata_ascii),
+                              SSL_FILETYPE_PEM);
+            Py_DECREF(cadata_ascii);
+            if (r == -1) {
+                goto error;
+            }
+        }
+        else if (PyObject_CheckBuffer(cadata)) {
+            Py_buffer buf;
+            if (PyObject_GetBuffer(cadata, &buf, PyBUF_SIMPLE)) {
+                goto error;
+            }
             if (!PyBuffer_IsContiguous(&buf, 'C') || buf.ndim > 1) {
                 PyBuffer_Release(&buf);
                 PyErr_SetString(PyExc_TypeError,
@@ -4013,23 +4038,13 @@ _ssl__SSLContext_load_verify_locations_impl(PySSLContext *self,
             if (r == -1) {
                 goto error;
             }
-        } else {
-            PyErr_Clear();
-            cadata_ascii = PyUnicode_AsASCIIString(cadata);
-            if (cadata_ascii == NULL) {
-                PyErr_SetString(PyExc_TypeError,
-                                "cadata should be an ASCII string or a "
-                                "bytes-like object");
-                goto error;
-            }
-            r = _add_ca_certs(self,
-                              PyBytes_AS_STRING(cadata_ascii),
-                              PyBytes_GET_SIZE(cadata_ascii),
-                              SSL_FILETYPE_PEM);
-            Py_DECREF(cadata_ascii);
-            if (r == -1) {
-                goto error;
-            }
+        }
+        else {
+  invalid_cadata:
+            PyErr_SetString(PyExc_TypeError,
+                            "cadata should be an ASCII string or a "
+                            "bytes-like object");
+            goto error;
         }
     }