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cpython/Modules/_hashopenssl.c

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/* Module that wraps all OpenSSL hash algorithms */
/*
* Copyright (C) 2005-2010 Gregory P. Smith (greg@krypto.org)
* Licensed to PSF under a Contributor Agreement.
*
* Derived from a skeleton of shamodule.c containing work performed by:
*
* Andrew Kuchling (amk@amk.ca)
* Greg Stein (gstein@lyra.org)
*
*/
#define PY_SSIZE_T_CLEAN
#include "Python.h"
#include "structmember.h"
#ifdef WITH_THREAD
#include "pythread.h"
#define ENTER_HASHLIB(obj) \
if ((obj)->lock) { \
if (!PyThread_acquire_lock((obj)->lock, 0)) { \
Py_BEGIN_ALLOW_THREADS \
PyThread_acquire_lock((obj)->lock, 1); \
Py_END_ALLOW_THREADS \
} \
}
#define LEAVE_HASHLIB(obj) \
if ((obj)->lock) { \
PyThread_release_lock((obj)->lock); \
}
#else
#define ENTER_HASHLIB(obj)
#define LEAVE_HASHLIB(obj)
#endif
/* EVP is the preferred interface to hashing in OpenSSL */
#include <openssl/evp.h>
#define MUNCH_SIZE INT_MAX
/* TODO(gps): We should probably make this a module or EVPobject attribute
* to allow the user to optimize based on the platform they're using. */
#define HASHLIB_GIL_MINSIZE 2048
#ifndef HASH_OBJ_CONSTRUCTOR
#define HASH_OBJ_CONSTRUCTOR 0
#endif
/* Minimum OpenSSL version needed to support sha224 and higher. */
#if defined(OPENSSL_VERSION_NUMBER) && (OPENSSL_VERSION_NUMBER >= 0x00908000)
#define _OPENSSL_SUPPORTS_SHA2
#endif
typedef struct {
PyObject_HEAD
PyObject *name; /* name of this hash algorithm */
EVP_MD_CTX ctx; /* OpenSSL message digest context */
#ifdef WITH_THREAD
PyThread_type_lock lock; /* OpenSSL context lock */
#endif
} EVPobject;
static PyTypeObject EVPtype;
#define DEFINE_CONSTS_FOR_NEW(Name) \
static PyObject *CONST_ ## Name ## _name_obj = NULL; \
static EVP_MD_CTX CONST_new_ ## Name ## _ctx; \
static EVP_MD_CTX *CONST_new_ ## Name ## _ctx_p = NULL;
DEFINE_CONSTS_FOR_NEW(md5)
DEFINE_CONSTS_FOR_NEW(sha1)
#ifdef _OPENSSL_SUPPORTS_SHA2
DEFINE_CONSTS_FOR_NEW(sha224)
DEFINE_CONSTS_FOR_NEW(sha256)
DEFINE_CONSTS_FOR_NEW(sha384)
DEFINE_CONSTS_FOR_NEW(sha512)
#endif
static EVPobject *
newEVPobject(PyObject *name)
{
EVPobject *retval = (EVPobject *)PyObject_New(EVPobject, &EVPtype);
/* save the name for .name to return */
if (retval != NULL) {
Py_INCREF(name);
retval->name = name;
#ifdef WITH_THREAD
retval->lock = NULL;
#endif
}
return retval;
}
static void
EVP_hash(EVPobject *self, const void *vp, Py_ssize_t len)
{
unsigned int process;
const unsigned char *cp = (const unsigned char *)vp;
while (0 < len)
{
if (len > (Py_ssize_t)MUNCH_SIZE)
process = MUNCH_SIZE;
else
process = Py_SAFE_DOWNCAST(len, Py_ssize_t, unsigned int);
EVP_DigestUpdate(&self->ctx, (const void*)cp, process);
len -= process;
cp += process;
}
}
/* Internal methods for a hash object */
static void
EVP_dealloc(EVPobject *self)
{
#ifdef WITH_THREAD
if (self->lock != NULL)
PyThread_free_lock(self->lock);
#endif
EVP_MD_CTX_cleanup(&self->ctx);
Py_XDECREF(self->name);
PyObject_Del(self);
}
static void locked_EVP_MD_CTX_copy(EVP_MD_CTX *new_ctx_p, EVPobject *self)
{
ENTER_HASHLIB(self);
EVP_MD_CTX_copy(new_ctx_p, &self->ctx);
LEAVE_HASHLIB(self);
}
/* External methods for a hash object */
PyDoc_STRVAR(EVP_copy__doc__, "Return a copy of the hash object.");
static PyObject *
EVP_copy(EVPobject *self, PyObject *unused)
{
EVPobject *newobj;
if ( (newobj = newEVPobject(self->name))==NULL)
return NULL;
locked_EVP_MD_CTX_copy(&newobj->ctx, self);
return (PyObject *)newobj;
}
PyDoc_STRVAR(EVP_digest__doc__,
"Return the digest value as a string of binary data.");
static PyObject *
EVP_digest(EVPobject *self, PyObject *unused)
{
unsigned char digest[EVP_MAX_MD_SIZE];
EVP_MD_CTX temp_ctx;
PyObject *retval;
unsigned int digest_size;
locked_EVP_MD_CTX_copy(&temp_ctx, self);
digest_size = EVP_MD_CTX_size(&temp_ctx);
EVP_DigestFinal(&temp_ctx, digest, NULL);
retval = PyString_FromStringAndSize((const char *)digest, digest_size);
EVP_MD_CTX_cleanup(&temp_ctx);
return retval;
}
PyDoc_STRVAR(EVP_hexdigest__doc__,
"Return the digest value as a string of hexadecimal digits.");
static PyObject *
EVP_hexdigest(EVPobject *self, PyObject *unused)
{
unsigned char digest[EVP_MAX_MD_SIZE];
EVP_MD_CTX temp_ctx;
PyObject *retval;
char *hex_digest;
unsigned int i, j, digest_size;
/* Get the raw (binary) digest value */
locked_EVP_MD_CTX_copy(&temp_ctx, self);
digest_size = EVP_MD_CTX_size(&temp_ctx);
EVP_DigestFinal(&temp_ctx, digest, NULL);
EVP_MD_CTX_cleanup(&temp_ctx);
/* Create a new string */
/* NOTE: not thread safe! modifying an already created string object */
/* (not a problem because we hold the GIL by default) */
retval = PyString_FromStringAndSize(NULL, digest_size * 2);
if (!retval)
return NULL;
hex_digest = PyString_AsString(retval);
if (!hex_digest) {
Py_DECREF(retval);
return NULL;
}
/* Make hex version of the digest */
for(i=j=0; i<digest_size; i++) {
char c;
c = (digest[i] >> 4) & 0xf;
c = (c>9) ? c+'a'-10 : c + '0';
hex_digest[j++] = c;
c = (digest[i] & 0xf);
c = (c>9) ? c+'a'-10 : c + '0';
hex_digest[j++] = c;
}
return retval;
}
PyDoc_STRVAR(EVP_update__doc__,
"Update this hash object's state with the provided string.");
static PyObject *
EVP_update(EVPobject *self, PyObject *args)
{
Py_buffer view;
if (!PyArg_ParseTuple(args, "s*:update", &view))
return NULL;
#ifdef WITH_THREAD
if (self->lock == NULL && view.len >= HASHLIB_GIL_MINSIZE) {
self->lock = PyThread_allocate_lock();
/* fail? lock = NULL and we fail over to non-threaded code. */
}
if (self->lock != NULL) {
Py_BEGIN_ALLOW_THREADS
PyThread_acquire_lock(self->lock, 1);
EVP_hash(self, view.buf, view.len);
PyThread_release_lock(self->lock);
Py_END_ALLOW_THREADS
}
else
#endif
{
EVP_hash(self, view.buf, view.len);
}
PyBuffer_Release(&view);
Py_RETURN_NONE;
}
static PyMethodDef EVP_methods[] = {
{"update", (PyCFunction)EVP_update, METH_VARARGS, EVP_update__doc__},
{"digest", (PyCFunction)EVP_digest, METH_NOARGS, EVP_digest__doc__},
{"hexdigest", (PyCFunction)EVP_hexdigest, METH_NOARGS, EVP_hexdigest__doc__},
{"copy", (PyCFunction)EVP_copy, METH_NOARGS, EVP_copy__doc__},
{NULL, NULL} /* sentinel */
};
static PyObject *
EVP_get_block_size(EVPobject *self, void *closure)
{
long block_size;
block_size = EVP_MD_CTX_block_size(&self->ctx);
return PyLong_FromLong(block_size);
}
static PyObject *
EVP_get_digest_size(EVPobject *self, void *closure)
{
long size;
size = EVP_MD_CTX_size(&self->ctx);
return PyLong_FromLong(size);
}
static PyMemberDef EVP_members[] = {
{"name", T_OBJECT, offsetof(EVPobject, name), READONLY, PyDoc_STR("algorithm name.")},
{NULL} /* Sentinel */
};
static PyGetSetDef EVP_getseters[] = {
{"digest_size",
(getter)EVP_get_digest_size, NULL,
NULL,
NULL},
{"block_size",
(getter)EVP_get_block_size, NULL,
NULL,
NULL},
/* the old md5 and sha modules support 'digest_size' as in PEP 247.
* the old sha module also supported 'digestsize'. ugh. */
{"digestsize",
(getter)EVP_get_digest_size, NULL,
NULL,
NULL},
{NULL} /* Sentinel */
};
static PyObject *
EVP_repr(PyObject *self)
{
char buf[100];
PyOS_snprintf(buf, sizeof(buf), "<%s HASH object @ %p>",
PyString_AsString(((EVPobject *)self)->name), self);
return PyString_FromString(buf);
}
#if HASH_OBJ_CONSTRUCTOR
static int
EVP_tp_init(EVPobject *self, PyObject *args, PyObject *kwds)
{
static char *kwlist[] = {"name", "string", NULL};
PyObject *name_obj = NULL;
Py_buffer view = { 0 };
char *nameStr;
const EVP_MD *digest;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|s*:HASH", kwlist,
&name_obj, &view)) {
return -1;
}
if (!PyArg_Parse(name_obj, "s", &nameStr)) {
PyErr_SetString(PyExc_TypeError, "name must be a string");
PyBuffer_Release(&view);
return -1;
}
digest = EVP_get_digestbyname(nameStr);
if (!digest) {
PyErr_SetString(PyExc_ValueError, "unknown hash function");
PyBuffer_Release(&view);
return -1;
}
EVP_DigestInit(&self->ctx, digest);
self->name = name_obj;
Py_INCREF(self->name);
if (view.obj) {
if (view.len >= HASHLIB_GIL_MINSIZE) {
Py_BEGIN_ALLOW_THREADS
EVP_hash(self, view.buf, view.len);
Py_END_ALLOW_THREADS
} else {
EVP_hash(self, view.buf, view.len);
}
PyBuffer_Release(&view);
}
return 0;
}
#endif
PyDoc_STRVAR(hashtype_doc,
"A hash represents the object used to calculate a checksum of a\n\
string of information.\n\
\n\
Methods:\n\
\n\
update() -- updates the current digest with an additional string\n\
digest() -- return the current digest value\n\
hexdigest() -- return the current digest as a string of hexadecimal digits\n\
copy() -- return a copy of the current hash object\n\
\n\
Attributes:\n\
\n\
name -- the hash algorithm being used by this object\n\
digest_size -- number of bytes in this hashes output\n");
static PyTypeObject EVPtype = {
PyVarObject_HEAD_INIT(NULL, 0)
"_hashlib.HASH", /*tp_name*/
sizeof(EVPobject), /*tp_basicsize*/
0, /*tp_itemsize*/
/* methods */
(destructor)EVP_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
EVP_repr, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash*/
0, /*tp_call*/
0, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro*/
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
hashtype_doc, /*tp_doc*/
0, /*tp_traverse*/
0, /*tp_clear*/
0, /*tp_richcompare*/
0, /*tp_weaklistoffset*/
0, /*tp_iter*/
0, /*tp_iternext*/
EVP_methods, /* tp_methods */
EVP_members, /* tp_members */
EVP_getseters, /* tp_getset */
#if 1
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
#endif
#if HASH_OBJ_CONSTRUCTOR
(initproc)EVP_tp_init, /* tp_init */
#endif
};
static PyObject *
EVPnew(PyObject *name_obj,
const EVP_MD *digest, const EVP_MD_CTX *initial_ctx,
const unsigned char *cp, Py_ssize_t len)
{
EVPobject *self;
if (!digest && !initial_ctx) {
PyErr_SetString(PyExc_ValueError, "unsupported hash type");
return NULL;
}
if ((self = newEVPobject(name_obj)) == NULL)
return NULL;
if (initial_ctx) {
EVP_MD_CTX_copy(&self->ctx, initial_ctx);
} else {
EVP_DigestInit(&self->ctx, digest);
}
if (cp && len) {
if (len >= HASHLIB_GIL_MINSIZE) {
Py_BEGIN_ALLOW_THREADS
EVP_hash(self, cp, len);
Py_END_ALLOW_THREADS
} else {
EVP_hash(self, cp, len);
}
}
return (PyObject *)self;
}
/* The module-level function: new() */
PyDoc_STRVAR(EVP_new__doc__,
"Return a new hash object using the named algorithm.\n\
An optional string argument may be provided and will be\n\
automatically hashed.\n\
\n\
The MD5 and SHA1 algorithms are always supported.\n");
static PyObject *
EVP_new(PyObject *self, PyObject *args, PyObject *kwdict)
{
static char *kwlist[] = {"name", "string", NULL};
PyObject *name_obj = NULL;
Py_buffer view = { 0 };
PyObject *ret_obj;
char *name;
const EVP_MD *digest;
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "O|s*:new", kwlist,
&name_obj, &view)) {
return NULL;
}
if (!PyArg_Parse(name_obj, "s", &name)) {
PyBuffer_Release(&view);
PyErr_SetString(PyExc_TypeError, "name must be a string");
return NULL;
}
digest = EVP_get_digestbyname(name);
ret_obj = EVPnew(name_obj, digest, NULL, (unsigned char*)view.buf,
view.len);
PyBuffer_Release(&view);
return ret_obj;
}
/*
* This macro generates constructor function definitions for specific
* hash algorithms. These constructors are much faster than calling
* the generic one passing it a python string and are noticably
* faster than calling a python new() wrapper. Thats important for
* code that wants to make hashes of a bunch of small strings.
*/
#define GEN_CONSTRUCTOR(NAME) \
static PyObject * \
EVP_new_ ## NAME (PyObject *self, PyObject *args) \
{ \
Py_buffer view = { 0 }; \
PyObject *ret_obj; \
\
if (!PyArg_ParseTuple(args, "|s*:" #NAME , &view)) { \
return NULL; \
} \
\
ret_obj = EVPnew( \
CONST_ ## NAME ## _name_obj, \
NULL, \
CONST_new_ ## NAME ## _ctx_p, \
(unsigned char*)view.buf, view.len); \
PyBuffer_Release(&view); \
return ret_obj; \
}
/* a PyMethodDef structure for the constructor */
#define CONSTRUCTOR_METH_DEF(NAME) \
{"openssl_" #NAME, (PyCFunction)EVP_new_ ## NAME, METH_VARARGS, \
PyDoc_STR("Returns a " #NAME \
" hash object; optionally initialized with a string") \
}
/* used in the init function to setup a constructor: initialize OpenSSL
constructor constants if they haven't been initialized already. */
#define INIT_CONSTRUCTOR_CONSTANTS(NAME) do { \
if (CONST_ ## NAME ## _name_obj == NULL) { \
CONST_ ## NAME ## _name_obj = PyString_FromString(#NAME); \
if (EVP_get_digestbyname(#NAME)) { \
CONST_new_ ## NAME ## _ctx_p = &CONST_new_ ## NAME ## _ctx; \
EVP_DigestInit(CONST_new_ ## NAME ## _ctx_p, EVP_get_digestbyname(#NAME)); \
} \
} \
} while (0);
GEN_CONSTRUCTOR(md5)
GEN_CONSTRUCTOR(sha1)
#ifdef _OPENSSL_SUPPORTS_SHA2
GEN_CONSTRUCTOR(sha224)
GEN_CONSTRUCTOR(sha256)
GEN_CONSTRUCTOR(sha384)
GEN_CONSTRUCTOR(sha512)
#endif
/* List of functions exported by this module */
static struct PyMethodDef EVP_functions[] = {
{"new", (PyCFunction)EVP_new, METH_VARARGS|METH_KEYWORDS, EVP_new__doc__},
CONSTRUCTOR_METH_DEF(md5),
CONSTRUCTOR_METH_DEF(sha1),
#ifdef _OPENSSL_SUPPORTS_SHA2
CONSTRUCTOR_METH_DEF(sha224),
CONSTRUCTOR_METH_DEF(sha256),
CONSTRUCTOR_METH_DEF(sha384),
CONSTRUCTOR_METH_DEF(sha512),
#endif
{NULL, NULL} /* Sentinel */
};
/* Initialize this module. */
PyMODINIT_FUNC
init_hashlib(void)
{
PyObject *m;
OpenSSL_add_all_digests();
/* TODO build EVP_functions openssl_* entries dynamically based
* on what hashes are supported rather than listing many
* but having some be unsupported. Only init appropriate
* constants. */
Py_TYPE(&EVPtype) = &PyType_Type;
if (PyType_Ready(&EVPtype) < 0)
return;
m = Py_InitModule("_hashlib", EVP_functions);
if (m == NULL)
return;
#if HASH_OBJ_CONSTRUCTOR
Py_INCREF(&EVPtype);
PyModule_AddObject(m, "HASH", (PyObject *)&EVPtype);
#endif
/* these constants are used by the convenience constructors */
INIT_CONSTRUCTOR_CONSTANTS(md5);
INIT_CONSTRUCTOR_CONSTANTS(sha1);
#ifdef _OPENSSL_SUPPORTS_SHA2
INIT_CONSTRUCTOR_CONSTANTS(sha224);
INIT_CONSTRUCTOR_CONSTANTS(sha256);
INIT_CONSTRUCTOR_CONSTANTS(sha384);
INIT_CONSTRUCTOR_CONSTANTS(sha512);
#endif
}
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