cpython/Modules/_ssl.c

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/* SSL socket module
SSL support based on patches by Brian E Gallew and Laszlo Kovacs.
This module is imported by socket.py. It should *not* be used
directly.
*/
#include "Python.h"
enum py_ssl_error {
/* these mirror ssl.h */
PY_SSL_ERROR_NONE,
PY_SSL_ERROR_SSL,
PY_SSL_ERROR_WANT_READ,
PY_SSL_ERROR_WANT_WRITE,
PY_SSL_ERROR_WANT_X509_LOOKUP,
PY_SSL_ERROR_SYSCALL, /* look at error stack/return value/errno */
PY_SSL_ERROR_ZERO_RETURN,
PY_SSL_ERROR_WANT_CONNECT,
/* start of non ssl.h errorcodes */
PY_SSL_ERROR_EOF, /* special case of SSL_ERROR_SYSCALL */
PY_SSL_ERROR_INVALID_ERROR_CODE
};
/* Include symbols from _socket module */
#include "socketmodule.h"
/* Include OpenSSL header files */
#include "openssl/rsa.h"
#include "openssl/crypto.h"
#include "openssl/x509.h"
#include "openssl/pem.h"
#include "openssl/ssl.h"
#include "openssl/err.h"
#include "openssl/rand.h"
/* SSL error object */
static PyObject *PySSLErrorObject;
/* SSL socket object */
#define X509_NAME_MAXLEN 256
/* RAND_* APIs got added to OpenSSL in 0.9.5 */
#if OPENSSL_VERSION_NUMBER >= 0x0090500fL
# define HAVE_OPENSSL_RAND 1
#else
# undef HAVE_OPENSSL_RAND
#endif
typedef struct {
PyObject_HEAD
PySocketSockObject *Socket; /* Socket on which we're layered */
SSL_CTX* ctx;
SSL* ssl;
X509* server_cert;
BIO* sbio;
char server[X509_NAME_MAXLEN];
char issuer[X509_NAME_MAXLEN];
} PySSLObject;
static PyTypeObject PySSL_Type;
static PyObject *PySSL_SSLwrite(PySSLObject *self, PyObject *args);
static PyObject *PySSL_SSLread(PySSLObject *self, PyObject *args);
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static int wait_for_timeout(PySocketSockObject *s, int writing);
#define PySSLObject_Check(v) ((v)->ob_type == &PySSL_Type)
/* XXX It might be helpful to augment the error message generated
below with the name of the SSL function that generated the error.
I expect it's obvious most of the time.
*/
static PyObject *
PySSL_SetError(PySSLObject *obj, int ret)
{
PyObject *v, *n, *s;
char *errstr;
int err;
enum py_ssl_error p;
assert(ret <= 0);
err = SSL_get_error(obj->ssl, ret);
switch (err) {
case SSL_ERROR_ZERO_RETURN:
errstr = "TLS/SSL connection has been closed";
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p = PY_SSL_ERROR_ZERO_RETURN;
break;
case SSL_ERROR_WANT_READ:
errstr = "The operation did not complete (read)";
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p = PY_SSL_ERROR_WANT_READ;
break;
case SSL_ERROR_WANT_WRITE:
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p = PY_SSL_ERROR_WANT_WRITE;
errstr = "The operation did not complete (write)";
break;
case SSL_ERROR_WANT_X509_LOOKUP:
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p = PY_SSL_ERROR_WANT_X509_LOOKUP;
errstr = "The operation did not complete (X509 lookup)";
break;
case SSL_ERROR_WANT_CONNECT:
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p = PY_SSL_ERROR_WANT_CONNECT;
errstr = "The operation did not complete (connect)";
break;
case SSL_ERROR_SYSCALL:
{
unsigned long e = ERR_get_error();
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if (e == 0) {
if (ret == 0) {
p = PY_SSL_ERROR_EOF;
errstr = "EOF occurred in violation of protocol";
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} else if (ret == -1) {
/* the underlying BIO reported an I/O error */
return obj->Socket->errorhandler();
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} else { /* possible? */
p = PY_SSL_ERROR_SYSCALL;
errstr = "Some I/O error occurred";
}
} else {
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p = PY_SSL_ERROR_SYSCALL;
/* XXX Protected by global interpreter lock */
errstr = ERR_error_string(e, NULL);
}
break;
}
case SSL_ERROR_SSL:
{
unsigned long e = ERR_get_error();
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p = PY_SSL_ERROR_SSL;
if (e != 0)
/* XXX Protected by global interpreter lock */
errstr = ERR_error_string(e, NULL);
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else { /* possible? */
errstr = "A failure in the SSL library occurred";
}
break;
}
default:
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p = PY_SSL_ERROR_INVALID_ERROR_CODE;
errstr = "Invalid error code";
}
n = PyInt_FromLong((long) p);
if (n == NULL)
return NULL;
v = PyTuple_New(2);
if (v == NULL) {
Py_DECREF(n);
return NULL;
}
s = PyString_FromString(errstr);
if (s == NULL) {
Py_DECREF(v);
Py_DECREF(n);
}
PyTuple_SET_ITEM(v, 0, n);
PyTuple_SET_ITEM(v, 1, s);
PyErr_SetObject(PySSLErrorObject, v);
return NULL;
}
static PySSLObject *
newPySSLObject(PySocketSockObject *Sock, char *key_file, char *cert_file)
{
PySSLObject *self;
char *errstr = NULL;
int ret;
int err;
int timedout;
self = PyObject_New(PySSLObject, &PySSL_Type); /* Create new object */
if (self == NULL){
errstr = "newPySSLObject error";
goto fail;
}
memset(self->server, '\0', sizeof(char) * X509_NAME_MAXLEN);
memset(self->issuer, '\0', sizeof(char) * X509_NAME_MAXLEN);
self->server_cert = NULL;
self->ssl = NULL;
self->ctx = NULL;
self->Socket = NULL;
if ((key_file && !cert_file) || (!key_file && cert_file)) {
errstr = "Both the key & certificate files must be specified";
goto fail;
}
Py_BEGIN_ALLOW_THREADS
self->ctx = SSL_CTX_new(SSLv23_method()); /* Set up context */
Py_END_ALLOW_THREADS
if (self->ctx == NULL) {
errstr = "SSL_CTX_new error";
goto fail;
}
if (key_file) {
Py_BEGIN_ALLOW_THREADS
ret = SSL_CTX_use_PrivateKey_file(self->ctx, key_file,
SSL_FILETYPE_PEM);
Py_END_ALLOW_THREADS
if (ret < 1) {
errstr = "SSL_CTX_use_PrivateKey_file error";
goto fail;
}
Py_BEGIN_ALLOW_THREADS
ret = SSL_CTX_use_certificate_chain_file(self->ctx,
cert_file);
Py_END_ALLOW_THREADS
if (ret < 1) {
errstr = "SSL_CTX_use_certificate_chain_file error";
goto fail;
}
}
Py_BEGIN_ALLOW_THREADS
SSL_CTX_set_verify(self->ctx,
SSL_VERIFY_NONE, NULL); /* set verify lvl */
self->ssl = SSL_new(self->ctx); /* New ssl struct */
Py_END_ALLOW_THREADS
SSL_set_fd(self->ssl, Sock->sock_fd); /* Set the socket for SSL */
/* If the socket is is non-blocking mode or timeout mode, set the BIO
* to non-blocking mode (blocking is the default)
*/
if (Sock->sock_timeout >= 0.0) {
/* Set both the read and write BIO's to non-blocking mode */
BIO_set_nbio(SSL_get_rbio(self->ssl), 1);
BIO_set_nbio(SSL_get_wbio(self->ssl), 1);
}
Py_BEGIN_ALLOW_THREADS
SSL_set_connect_state(self->ssl);
Py_END_ALLOW_THREADS
/* Actually negotiate SSL connection */
/* XXX If SSL_connect() returns 0, it's also a failure. */
timedout = 0;
do {
Py_BEGIN_ALLOW_THREADS
ret = SSL_connect(self->ssl);
err = SSL_get_error(self->ssl, ret);
Py_END_ALLOW_THREADS
if (err == SSL_ERROR_WANT_READ) {
timedout = wait_for_timeout(Sock, 0);
} else if (err == SSL_ERROR_WANT_WRITE) {
timedout = wait_for_timeout(Sock, 1);
}
if (timedout) {
PyErr_SetString(PySSLErrorObject, "The connect operation timed out");
return NULL;
}
} while (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE);
if (ret <= 0) {
PySSL_SetError(self, ret);
goto fail;
}
self->ssl->debug = 1;
Py_BEGIN_ALLOW_THREADS
if ((self->server_cert = SSL_get_peer_certificate(self->ssl))) {
X509_NAME_oneline(X509_get_subject_name(self->server_cert),
self->server, X509_NAME_MAXLEN);
X509_NAME_oneline(X509_get_issuer_name(self->server_cert),
self->issuer, X509_NAME_MAXLEN);
}
Py_END_ALLOW_THREADS
self->Socket = Sock;
Py_INCREF(self->Socket);
return self;
fail:
if (errstr)
PyErr_SetString(PySSLErrorObject, errstr);
Py_DECREF(self);
return NULL;
}
static PyObject *
PySocket_ssl(PyObject *self, PyObject *args)
{
PySSLObject *rv;
PySocketSockObject *Sock;
char *key_file = NULL;
char *cert_file = NULL;
if (!PyArg_ParseTuple(args, "O!|zz:ssl",
PySocketModule.Sock_Type,
(PyObject*)&Sock,
&key_file, &cert_file))
return NULL;
rv = newPySSLObject(Sock, key_file, cert_file);
if (rv == NULL)
return NULL;
return (PyObject *)rv;
}
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PyDoc_STRVAR(ssl_doc,
"ssl(socket, [keyfile, certfile]) -> sslobject");
/* SSL object methods */
static PyObject *
PySSL_server(PySSLObject *self)
{
return PyString_FromString(self->server);
}
static PyObject *
PySSL_issuer(PySSLObject *self)
{
return PyString_FromString(self->issuer);
}
static void PySSL_dealloc(PySSLObject *self)
{
if (self->server_cert) /* Possible not to have one? */
X509_free (self->server_cert);
if (self->ssl)
SSL_free(self->ssl);
if (self->ctx)
SSL_CTX_free(self->ctx);
Py_XDECREF(self->Socket);
PyObject_Del(self);
}
/* If the socket has a timeout, do a select() on the socket.
The argument writing indicates the direction.
Return non-zero if the socket timed out, zero otherwise.
*/
static int
wait_for_timeout(PySocketSockObject *s, int writing)
{
fd_set fds;
struct timeval tv;
int rc;
/* Nothing to do unless we're in timeout mode (not non-blocking) */
if (s->sock_timeout <= 0.0)
return 0;
/* Guard against closed socket */
if (s->sock_fd < 0)
return 0;
/* Construct the arguments to select */
tv.tv_sec = (int)s->sock_timeout;
tv.tv_usec = (int)((s->sock_timeout - tv.tv_sec) * 1e6);
FD_ZERO(&fds);
FD_SET(s->sock_fd, &fds);
/* See if the socket is ready */
Py_BEGIN_ALLOW_THREADS
if (writing)
rc = select(s->sock_fd+1, NULL, &fds, NULL, &tv);
else
rc = select(s->sock_fd+1, &fds, NULL, NULL, &tv);
Py_END_ALLOW_THREADS
/* Return 1 on timeout, 0 otherwise */
return rc == 0;
}
static PyObject *PySSL_SSLwrite(PySSLObject *self, PyObject *args)
{
char *data;
int len;
int timedout;
int err;
if (!PyArg_ParseTuple(args, "s#:write", &data, &len))
return NULL;
timedout = wait_for_timeout(self->Socket, 1);
if (timedout) {
PyErr_SetString(PySSLErrorObject, "The write operation timed out");
return NULL;
}
do {
err = 0;
Py_BEGIN_ALLOW_THREADS
len = SSL_write(self->ssl, data, len);
err = SSL_get_error(self->ssl, len);
Py_END_ALLOW_THREADS
if (err == SSL_ERROR_WANT_READ) {
timedout = wait_for_timeout(self->Socket, 0);
} else if (err == SSL_ERROR_WANT_WRITE) {
timedout = wait_for_timeout(self->Socket, 1);
}
if (timedout) {
PyErr_SetString(PySSLErrorObject, "The write operation timed out");
return NULL;
}
} while (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE);
if (len > 0)
return PyInt_FromLong(len);
else
return PySSL_SetError(self, len);
}
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PyDoc_STRVAR(PySSL_SSLwrite_doc,
"write(s) -> len\n\
\n\
Writes the string s into the SSL object. Returns the number\n\
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of bytes written.");
static PyObject *PySSL_SSLread(PySSLObject *self, PyObject *args)
{
PyObject *buf;
int count = 0;
int len = 1024;
int timedout;
int err;
if (!PyArg_ParseTuple(args, "|i:read", &len))
return NULL;
if (!(buf = PyString_FromStringAndSize((char *) 0, len)))
return NULL;
timedout = wait_for_timeout(self->Socket, 0);
if (timedout) {
PyErr_SetString(PySSLErrorObject, "The read operation timed out");
return NULL;
}
do {
err = 0;
Py_BEGIN_ALLOW_THREADS
count = SSL_read(self->ssl, PyString_AsString(buf), len);
err = SSL_get_error(self->ssl, count);
Py_END_ALLOW_THREADS
if (err == SSL_ERROR_WANT_READ) {
timedout = wait_for_timeout(self->Socket, 0);
} else if (err == SSL_ERROR_WANT_WRITE) {
timedout = wait_for_timeout(self->Socket, 1);
}
if (timedout) {
PyErr_SetString(PySSLErrorObject, "The read operation timed out");
return NULL;
}
} while (err == SSL_ERROR_WANT_READ || err == SSL_ERROR_WANT_WRITE);
if (count <= 0) {
Py_DECREF(buf);
return PySSL_SetError(self, count);
}
if (count != len)
_PyString_Resize(&buf, count);
return buf;
}
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PyDoc_STRVAR(PySSL_SSLread_doc,
"read([len]) -> string\n\
\n\
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Read up to len bytes from the SSL socket.");
static PyMethodDef PySSLMethods[] = {
{"write", (PyCFunction)PySSL_SSLwrite, METH_VARARGS,
PySSL_SSLwrite_doc},
{"read", (PyCFunction)PySSL_SSLread, METH_VARARGS,
PySSL_SSLread_doc},
{"server", (PyCFunction)PySSL_server, METH_NOARGS},
{"issuer", (PyCFunction)PySSL_issuer, METH_NOARGS},
{NULL, NULL}
};
static PyObject *PySSL_getattr(PySSLObject *self, char *name)
{
return Py_FindMethod(PySSLMethods, (PyObject *)self, name);
}
static PyTypeObject PySSL_Type = {
PyObject_HEAD_INIT(NULL)
0, /*ob_size*/
"socket.SSL", /*tp_name*/
sizeof(PySSLObject), /*tp_basicsize*/
0, /*tp_itemsize*/
/* methods */
(destructor)PySSL_dealloc, /*tp_dealloc*/
0, /*tp_print*/
(getattrfunc)PySSL_getattr, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
0, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash*/
};
#ifdef HAVE_OPENSSL_RAND
/* helper routines for seeding the SSL PRNG */
static PyObject *
PySSL_RAND_add(PyObject *self, PyObject *args)
{
char *buf;
int len;
double entropy;
if (!PyArg_ParseTuple(args, "s#d:RAND_add", &buf, &len, &entropy))
return NULL;
RAND_add(buf, len, entropy);
Py_INCREF(Py_None);
return Py_None;
}
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PyDoc_STRVAR(PySSL_RAND_add_doc,
"RAND_add(string, entropy)\n\
\n\
Mix string into the OpenSSL PRNG state. entropy (a float) is a lower\n\
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bound on the entropy contained in string.");
static PyObject *
PySSL_RAND_status(PyObject *self)
{
return PyInt_FromLong(RAND_status());
}
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PyDoc_STRVAR(PySSL_RAND_status_doc,
"RAND_status() -> 0 or 1\n\
\n\
Returns 1 if the OpenSSL PRNG has been seeded with enough data and 0 if not.\n\
It is necessary to seed the PRNG with RAND_add() on some platforms before\n\
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using the ssl() function.");
static PyObject *
PySSL_RAND_egd(PyObject *self, PyObject *arg)
{
int bytes;
if (!PyString_Check(arg))
return PyErr_Format(PyExc_TypeError,
"RAND_egd() expected string, found %s",
arg->ob_type->tp_name);
bytes = RAND_egd(PyString_AS_STRING(arg));
if (bytes == -1) {
PyErr_SetString(PySSLErrorObject,
"EGD connection failed or EGD did not return "
"enough data to seed the PRNG");
return NULL;
}
return PyInt_FromLong(bytes);
}
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PyDoc_STRVAR(PySSL_RAND_egd_doc,
"RAND_egd(path) -> bytes\n\
\n\
Queries the entropy gather daemon (EGD) on socket path. Returns number\n\
of bytes read. Raises socket.sslerror if connection to EGD fails or\n\
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if it does provide enough data to seed PRNG.");
#endif
/* List of functions exported by this module. */
static PyMethodDef PySSL_methods[] = {
{"ssl", PySocket_ssl,
METH_VARARGS, ssl_doc},
#ifdef HAVE_OPENSSL_RAND
{"RAND_add", PySSL_RAND_add, METH_VARARGS,
PySSL_RAND_add_doc},
{"RAND_egd", PySSL_RAND_egd, METH_O,
PySSL_RAND_egd_doc},
{"RAND_status", (PyCFunction)PySSL_RAND_status, METH_NOARGS,
PySSL_RAND_status_doc},
#endif
{NULL, NULL} /* Sentinel */
};
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PyDoc_STRVAR(module_doc,
"Implementation module for SSL socket operations. See the socket module\n\
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for documentation.");
PyMODINIT_FUNC
init_ssl(void)
{
PyObject *m, *d;
PySSL_Type.ob_type = &PyType_Type;
m = Py_InitModule3("_ssl", PySSL_methods, module_doc);
d = PyModule_GetDict(m);
/* Load _socket module and its C API */
if (PySocketModule_ImportModuleAndAPI())
return;
/* Init OpenSSL */
SSL_load_error_strings();
SSLeay_add_ssl_algorithms();
/* Add symbols to module dict */
PySSLErrorObject = PyErr_NewException("socket.sslerror", NULL, NULL);
if (PySSLErrorObject == NULL)
return;
PyDict_SetItemString(d, "sslerror", PySSLErrorObject);
if (PyDict_SetItemString(d, "SSLType",
(PyObject *)&PySSL_Type) != 0)
return;
PyModule_AddIntConstant(m, "SSL_ERROR_ZERO_RETURN",
PY_SSL_ERROR_ZERO_RETURN);
PyModule_AddIntConstant(m, "SSL_ERROR_WANT_READ",
PY_SSL_ERROR_WANT_READ);
PyModule_AddIntConstant(m, "SSL_ERROR_WANT_WRITE",
PY_SSL_ERROR_WANT_WRITE);
PyModule_AddIntConstant(m, "SSL_ERROR_WANT_X509_LOOKUP",
PY_SSL_ERROR_WANT_X509_LOOKUP);
PyModule_AddIntConstant(m, "SSL_ERROR_SYSCALL",
PY_SSL_ERROR_SYSCALL);
PyModule_AddIntConstant(m, "SSL_ERROR_SSL",
PY_SSL_ERROR_SSL);
PyModule_AddIntConstant(m, "SSL_ERROR_WANT_CONNECT",
PY_SSL_ERROR_WANT_CONNECT);
/* non ssl.h errorcodes */
PyModule_AddIntConstant(m, "SSL_ERROR_EOF",
PY_SSL_ERROR_EOF);
PyModule_AddIntConstant(m, "SSL_ERROR_INVALID_ERROR_CODE",
PY_SSL_ERROR_INVALID_ERROR_CODE);
}