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bpo-32433: Optimized HMAC digest (#5023)

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The hmac module now has hmac.digest(), which provides an optimized HMAC
digest for short messages. hmac.digest() is up to three times faster
than hmac.HMAC().digest().

Signed-off-by: Christian Heimes <christian@python.org>
This commit is contained in:
Christian Heimes 2018-01-27 09:53:43 +01:00 • committed by GitHub
parent a49ac99029
commit 2f050c7e1b
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7 changed files with 204 additions and 3 deletions
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59
Modules/_hashopenssl.c
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@ -21,6 +21,7 @@
/* EVP is the preferred interface to hashing in OpenSSL */
#include <openssl/evp.h>
#include <openssl/hmac.h>
/* We use the object interface to discover what hashes OpenSSL supports. */
#include <openssl/objects.h>
#include "openssl/err.h"
@ -528,8 +529,6 @@ EVP_new(PyObject *self, PyObject *args, PyObject *kwdict)
return ret_obj;
}
#if (OPENSSL_VERSION_NUMBER >= 0x10000000 && !defined(OPENSSL_NO_HMAC) \
&& !defined(OPENSSL_NO_SHA))
@ -849,6 +848,61 @@ _hashlib_scrypt_impl(PyObject *module, Py_buffer *password, Py_buffer *salt,
}
#endif
/* Fast HMAC for hmac.digest()
*/
/*[clinic input]
_hashlib.hmac_digest
key: Py_buffer
msg: Py_buffer
digest: str
Single-shot HMAC
[clinic start generated code]*/
static PyObject *
_hashlib_hmac_digest_impl(PyObject *module, Py_buffer *key, Py_buffer *msg,
const char *digest)
/*[clinic end generated code: output=75630e684cdd8762 input=10e964917921e2f2]*/
{
unsigned char md[EVP_MAX_MD_SIZE] = {0};
unsigned int md_len = 0;
unsigned char *result;
const EVP_MD *evp;
evp = EVP_get_digestbyname(digest);
if (evp == NULL) {
PyErr_SetString(PyExc_ValueError, "unsupported hash type");
return NULL;
}
if (key->len > INT_MAX) {
PyErr_SetString(PyExc_OverflowError,
"key is too long.");
return NULL;
}
if (msg->len > INT_MAX) {
PyErr_SetString(PyExc_OverflowError,
"msg is too long.");
return NULL;
}
Py_BEGIN_ALLOW_THREADS
result = HMAC(
evp,
(const void*)key->buf, (int)key->len,
(const unsigned char*)msg->buf, (int)msg->len,
md, &md_len
);
Py_END_ALLOW_THREADS
if (result == NULL) {
_setException(PyExc_ValueError);
return NULL;
}
return PyBytes_FromStringAndSize((const char*)md, md_len);
}
/* State for our callback function so that it can accumulate a result. */
typedef struct _internal_name_mapper_state {
PyObject *set;
@ -982,6 +1036,7 @@ static struct PyMethodDef EVP_functions[] = {
pbkdf2_hmac__doc__},
#endif
_HASHLIB_SCRYPT_METHODDEF
_HASHLIB_HMAC_DIGEST_METHODDEF
CONSTRUCTOR_METH_DEF(md5),
CONSTRUCTOR_METH_DEF(sha1),
CONSTRUCTOR_METH_DEF(sha224),