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cpython/Modules/_hashopenssl.c

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/* Module that wraps all OpenSSL hash algorithms */
/*
* Copyright (C) 2005 Gregory P. Smith (greg@electricrain.com)
* 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)
*
*/
#include "Python.h"
#include "structmember.h"
/* EVP is the preferred interface to hashing in OpenSSL */
#include <openssl/evp.h>
typedef struct {
PyObject_HEAD
PyObject *name; /* name of this hash algorithm */
EVP_MD_CTX ctx; /* OpenSSL message digest context */
} EVPobject;
static PyTypeObject EVPtype;
#define DEFINE_CONSTS_FOR_NEW(Name) \
static PyObject *CONST_ ## Name ## _name_obj; \
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);
DEFINE_CONSTS_FOR_NEW(sha224);
DEFINE_CONSTS_FOR_NEW(sha256);
DEFINE_CONSTS_FOR_NEW(sha384);
DEFINE_CONSTS_FOR_NEW(sha512);
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;
}
return retval;
}
/* Internal methods for a hash object */
static void
EVP_dealloc(PyObject *ptr)
{
EVP_MD_CTX_cleanup(&((EVPobject *)ptr)->ctx);
Py_XDECREF(((EVPobject *)ptr)->name);
PyObject_Del(ptr);
}
/* 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 *args)
{
EVPobject *newobj;
if (!PyArg_ParseTuple(args, ":copy"))
return NULL;
if ( (newobj = newEVPobject(self->name))==NULL)
return NULL;
EVP_MD_CTX_copy(&newobj->ctx, &self->ctx);
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 *args)
{
unsigned char digest[EVP_MAX_MD_SIZE];
EVP_MD_CTX temp_ctx;
PyObject *retval;
unsigned int digest_size;
if (!PyArg_ParseTuple(args, ":digest"))
return NULL;
EVP_MD_CTX_copy(&temp_ctx, &self->ctx);
digest_size = EVP_MD_CTX_size(&temp_ctx);
EVP_DigestFinal(&temp_ctx, (char *)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 *args)
{
unsigned char digest[EVP_MAX_MD_SIZE];
EVP_MD_CTX temp_ctx;
PyObject *retval;
char *hex_digest;
unsigned int i, j, digest_size;
if (!PyArg_ParseTuple(args, ":hexdigest"))
return NULL;
/* Get the raw (binary) digest value */
EVP_MD_CTX_copy(&temp_ctx, &self->ctx);
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)
{
unsigned char *cp;
int len;
if (!PyArg_ParseTuple(args, "s#:update", &cp, &len))
return NULL;
EVP_DigestUpdate(&self->ctx, cp, len);
Py_INCREF(Py_None);
return Py_None;
}
static PyMethodDef EVP_methods[] = {
{"update", (PyCFunction)EVP_update, METH_VARARGS, EVP_update__doc__},
{"digest", (PyCFunction)EVP_digest, METH_VARARGS, EVP_digest__doc__},
{"hexdigest", (PyCFunction)EVP_hexdigest, METH_VARARGS, EVP_hexdigest__doc__},
{"copy", (PyCFunction)EVP_copy, METH_VARARGS, EVP_copy__doc__},
{NULL, NULL} /* sentinel */
};
static PyObject *
EVP_get_block_size(EVPobject *self, void *closure)
{
return PyInt_FromLong(EVP_MD_CTX_block_size(&((EVPobject *)self)->ctx));
}
static PyObject *
EVP_get_digest_size(EVPobject *self, void *closure)
{
return PyInt_FromLong(EVP_MD_CTX_size(&((EVPobject *)self)->ctx));
}
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 const char *kwlist[] = {"name", "string", NULL};
PyObject *name_obj = NULL;
char *nameStr;
unsigned char *cp = NULL;
unsigned int len;
const EVP_MD *digest;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|s#:HASH", kwlist,
&name_obj, &cp, &len)) {
return -1;
}
if (!PyArg_Parse(name_obj, "s", &nameStr)) {
PyErr_SetString(PyExc_TypeError, "name must be a string");
return -1;
}
digest = EVP_get_digestbyname(nameStr);
if (!digest) {
PyErr_SetString(PyExc_ValueError, "unknown hash function");
return -1;
}
EVP_DigestInit(&self->ctx, digest);
self->name = name_obj;
Py_INCREF(self->name);
if (cp && len)
EVP_DigestUpdate(&self->ctx, cp, len);
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 = {
PyObject_HEAD_INIT(NULL)
0, /*ob_size*/
"_hashlib.HASH", /*tp_name*/
sizeof(EVPobject), /*tp_basicsize*/
0, /*tp_itemsize*/
/* methods */
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 char *cp, unsigned int 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)
EVP_DigestUpdate(&self->ctx, 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 const char *kwlist[] = {"name", "string", NULL};
PyObject *name_obj = NULL;
char *name;
const EVP_MD *digest;
unsigned char *cp = NULL;
unsigned int len;
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "O|s#:new", kwlist,
&name_obj, &cp, &len)) {
return NULL;
}
if (!PyArg_Parse(name_obj, "s", &name)) {
PyErr_SetString(PyExc_TypeError, "name must be a string");
return NULL;
}
digest = EVP_get_digestbyname(name);
return EVPnew(name_obj, digest, NULL, cp, len);
}
/*
* 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) \
{ \
unsigned char *cp = NULL; \
unsigned int len; \
\
if (!PyArg_ParseTuple(args, "|s#:" #NAME , &cp, &len)) { \
return NULL; \
} \
\
return EVPnew( \
CONST_ ## NAME ## _name_obj, \
NULL, \
CONST_new_ ## NAME ## _ctx_p, \
cp, len); \
}
/* 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 */
#define INIT_CONSTRUCTOR_CONSTANTS(NAME) do { \
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)
GEN_CONSTRUCTOR(sha224)
GEN_CONSTRUCTOR(sha256)
GEN_CONSTRUCTOR(sha384)
GEN_CONSTRUCTOR(sha512)
/* 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),
CONSTRUCTOR_METH_DEF(sha224),
CONSTRUCTOR_METH_DEF(sha256),
CONSTRUCTOR_METH_DEF(sha384),
CONSTRUCTOR_METH_DEF(sha512),
{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. */
EVPtype.ob_type = &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);
INIT_CONSTRUCTOR_CONSTANTS(sha224);
INIT_CONSTRUCTOR_CONSTANTS(sha256);
INIT_CONSTRUCTOR_CONSTANTS(sha384);
INIT_CONSTRUCTOR_CONSTANTS(sha512);
}
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