pythongh-127257: ssl: Raise OSError for ERR_LIB_SYS (pythonGH-127361) (pythonGH-127905) (pythonGH-131971)

pythongh-127257: ssl: Raise OSError for ERR_LIB_SYS (pythonGH-127361)

From the ERR_raise manpage:

    ERR_LIB_SYS

        This "library code" indicates that a system error is
        being reported.  In this case, the reason code given
        to `ERR_raise()` and `ERR_raise_data()` *must* be
        `errno(3)`.

This PR only handles ERR_LIB_SYS for the high-lever error types
SSL_ERROR_SYSCALL and SSL_ERROR_SSL, i.e., not the ones where
OpenSSL indicates it has some more information about the issue.

(cherry picked from commit f4b31ed)
(cherry picked from commit 7f707fa)

Co-authored-by: Petr Viktorin <[email protected]>

Author: 2 people

Modules/_ssl.c

@@ -638,6 +638,11 @@ PySSL_SetError(PySSLSocket *obj, int ret, const char *filename, int lineno)
                     errstr = "Some I/O error occurred";
                 }
             } else {
+                if (ERR_GET_LIB(e) == ERR_LIB_SYS) {
+                    // A system error is being reported; reason is set to errno
+                    errno = ERR_GET_REASON(e);
+                    return PyErr_SetFromErrno(PyExc_OSError);
+                }
                 p = PY_SSL_ERROR_SYSCALL;
             }
             break;
@@ -648,6 +653,11 @@ PySSL_SetError(PySSLSocket *obj, int ret, const char *filename, int lineno)
             if (e == 0)
                 /* possible? */
                 errstr = "A failure in the SSL library occurred";
+            if (ERR_GET_LIB(e) == ERR_LIB_SYS) {
+                // A system error is being reported; reason is set to errno
+                errno = ERR_GET_REASON(e);
+                return PyErr_SetFromErrno(PyExc_OSError);
+            }
             break;
         }
         default: