cpython/Modules/_hashopenssl.c

/* 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 "hashlib.h"
#include "pystrhex.h"


/* 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"

#include <openssl/crypto.h>       // FIPS_mode()

#if (OPENSSL_VERSION_NUMBER < 0x10100000L) || defined(LIBRESSL_VERSION_NUMBER)
/* OpenSSL < 1.1.0 */
#define EVP_MD_CTX_new EVP_MD_CTX_create
#define EVP_MD_CTX_free EVP_MD_CTX_destroy
#endif

#define MUNCH_SIZE INT_MAX

#ifdef NID_sha3_224
#define PY_OPENSSL_HAS_SHA3 1
#endif

#if defined(EVP_MD_FLAG_XOF) && defined(NID_shake128)
#define PY_OPENSSL_HAS_SHAKE 1
#endif

#if defined(NID_blake2b512) && !defined(OPENSSL_NO_BLAKE2)
#define PY_OPENSSL_HAS_BLAKE2 1
#endif

static PyModuleDef _hashlibmodule;

typedef struct {
    PyTypeObject *EVPtype;
} _hashlibstate;

static inline _hashlibstate*
get_hashlib_state(PyObject *module)
{
    void *state = PyModule_GetState(module);
    assert(state != NULL);
    return (_hashlibstate *)state;
}

#define _hashlibstate_global ((_hashlibstate *)PyModule_GetState(PyState_FindModule(&_hashlibmodule)))


typedef struct {
    PyObject_HEAD
    EVP_MD_CTX          *ctx;   /* OpenSSL message digest context */
    PyThread_type_lock   lock;  /* OpenSSL context lock */
} EVPobject;


#include "clinic/_hashopenssl.c.h"
/*[clinic input]
module _hashlib
class _hashlib.HASH "EVPobject *" "((_hashlibstate *)PyModule_GetState(module))->EVPtype"
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=1adf85e8eb2ab979]*/


/* LCOV_EXCL_START */
static PyObject *
_setException(PyObject *exc)
{
    unsigned long errcode;
    const char *lib, *func, *reason;

    errcode = ERR_peek_last_error();
    if (!errcode) {
        PyErr_SetString(exc, "unknown reasons");
        return NULL;
    }
    ERR_clear_error();

    lib = ERR_lib_error_string(errcode);
    func = ERR_func_error_string(errcode);
    reason = ERR_reason_error_string(errcode);

    if (lib && func) {
        PyErr_Format(exc, "[%s: %s] %s", lib, func, reason);
    }
    else if (lib) {
        PyErr_Format(exc, "[%s] %s", lib, reason);
    }
    else {
        PyErr_SetString(exc, reason);
    }
    return NULL;
}
/* LCOV_EXCL_STOP */

static PyObject*
py_digest_name(const EVP_MD *md)
{
    int nid = EVP_MD_nid(md);
    const char *name = NULL;

    /* Hard-coded names for well-known hashing algorithms.
     * OpenSSL uses slightly different names algorithms like SHA3.
     */
    switch (nid) {
    case NID_md5:
        name = "md5";
        break;
    case NID_sha1:
        name = "sha1";
        break;
    case NID_sha224:
        name ="sha224";
        break;
    case NID_sha256:
        name ="sha256";
        break;
    case NID_sha384:
        name ="sha384";
        break;
    case NID_sha512:
        name ="sha512";
        break;
#ifdef NID_sha512_224
    case NID_sha512_224:
        name ="sha512_224";
        break;
    case NID_sha512_256:
        name ="sha512_256";
        break;
#endif
#ifdef PY_OPENSSL_HAS_SHA3
    case NID_sha3_224:
        name ="sha3_224";
        break;
    case NID_sha3_256:
        name ="sha3_256";
        break;
    case NID_sha3_384:
        name ="sha3_384";
        break;
    case NID_sha3_512:
        name ="sha3_512";
        break;
#endif
#ifdef PY_OPENSSL_HAS_SHAKE
    case NID_shake128:
        name ="shake_128";
        break;
    case NID_shake256:
        name ="shake_256";
        break;
#endif
#ifdef PY_OPENSSL_HAS_BLAKE2
    case NID_blake2s256:
        name ="blake2s";
        break;
    case NID_blake2b512:
        name ="blake2b";
        break;
#endif
    default:
        /* Ignore aliased names and only use long, lowercase name. The aliases
         * pollute the list and OpenSSL appears to have its own definition of
         * alias as the resulting list still contains duplicate and alternate
         * names for several algorithms.
         */
        name = OBJ_nid2ln(nid);
        if (name == NULL)
            name = OBJ_nid2sn(nid);
        break;
    }

    return PyUnicode_FromString(name);
}

static const EVP_MD*
py_digest_by_name(const char *name)
{
    const EVP_MD *digest = EVP_get_digestbyname(name);

    /* OpenSSL uses dash instead of underscore in names of some algorithms
     * like SHA3 and SHAKE. Detect different spellings. */
    if (digest == NULL) {
        if (0) {}
#ifdef NID_sha512_224
        else if (!strcmp(name, "sha512_224") || !strcmp(name, "SHA512_224")) {
            digest = EVP_sha512_224();
        }
        else if (!strcmp(name, "sha512_256") || !strcmp(name, "SHA512_256")) {
            digest = EVP_sha512_256();
        }
#endif
#ifdef PY_OPENSSL_HAS_SHA3
        /* could be sha3_ or shake_, Python never defined upper case */
        else if (!strcmp(name, "sha3_224")) {
            digest = EVP_sha3_224();
        }
        else if (!strcmp(name, "sha3_256")) {
            digest = EVP_sha3_256();
        }
        else if (!strcmp(name, "sha3_384")) {
            digest = EVP_sha3_384();
        }
        else if (!strcmp(name, "sha3_512")) {
            digest = EVP_sha3_512();
        }
#endif
#ifdef PY_OPENSSL_HAS_SHAKE
        else if (!strcmp(name, "shake_128")) {
            digest = EVP_shake128();
        }
        else if (!strcmp(name, "shake_256")) {
            digest = EVP_shake256();
        }
#endif
#ifdef PY_OPENSSL_HAS_BLAKE2
        else if (!strcmp(name, "blake2s256")) {
            digest = EVP_blake2s256();
        }
        else if (!strcmp(name, "blake2b512")) {
            digest = EVP_blake2b512();
        }
#endif
    }

    return digest;
}

static EVPobject *
newEVPobject(void)
{
    EVPobject *retval = (EVPobject *)PyObject_New(
        EVPobject, _hashlibstate_global->EVPtype
    );
    if (retval == NULL) {
        return NULL;
    }

    retval->lock = NULL;

    retval->ctx = EVP_MD_CTX_new();
    if (retval->ctx == NULL) {
        Py_DECREF(retval);
        PyErr_NoMemory();
        return NULL;
    }

    return retval;
}

static int
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);
        if (!EVP_DigestUpdate(self->ctx, (const void*)cp, process)) {
            _setException(PyExc_ValueError);
            return -1;
        }
        len -= process;
        cp += process;
    }
    return 0;
}

/* Internal methods for a hash object */

static void
EVP_dealloc(EVPobject *self)
{
    PyTypeObject *tp = Py_TYPE(self);
    if (self->lock != NULL)
        PyThread_free_lock(self->lock);
    EVP_MD_CTX_free(self->ctx);
    PyObject_Del(self);
    Py_DECREF(tp);
}

static int
locked_EVP_MD_CTX_copy(EVP_MD_CTX *new_ctx_p, EVPobject *self)
{
    int result;
    ENTER_HASHLIB(self);
    result = EVP_MD_CTX_copy(new_ctx_p, self->ctx);
    LEAVE_HASHLIB(self);
    return result;
}

/* External methods for a hash object */

/*[clinic input]
_hashlib.HASH.copy as EVP_copy

Return a copy of the hash object.
[clinic start generated code]*/

static PyObject *
EVP_copy_impl(EVPobject *self)
/*[clinic end generated code: output=b370c21cdb8ca0b4 input=31455b6a3e638069]*/
{
    EVPobject *newobj;

    if ( (newobj = newEVPobject())==NULL)
        return NULL;

    if (!locked_EVP_MD_CTX_copy(newobj->ctx, self)) {
        Py_DECREF(newobj);
        return _setException(PyExc_ValueError);
    }
    return (PyObject *)newobj;
}

/*[clinic input]
_hashlib.HASH.digest as EVP_digest

Return the digest value as a bytes object.
[clinic start generated code]*/

static PyObject *
EVP_digest_impl(EVPobject *self)
/*[clinic end generated code: output=0f6a3a0da46dc12d input=03561809a419bf00]*/
{
    unsigned char digest[EVP_MAX_MD_SIZE];
    EVP_MD_CTX *temp_ctx;
    PyObject *retval;
    unsigned int digest_size;

    temp_ctx = EVP_MD_CTX_new();
    if (temp_ctx == NULL) {
        PyErr_NoMemory();
        return NULL;
    }

    if (!locked_EVP_MD_CTX_copy(temp_ctx, self)) {
        return _setException(PyExc_ValueError);
    }
    digest_size = EVP_MD_CTX_size(temp_ctx);
    if (!EVP_DigestFinal(temp_ctx, digest, NULL)) {
        _setException(PyExc_ValueError);
        return NULL;
    }

    retval = PyBytes_FromStringAndSize((const char *)digest, digest_size);
    EVP_MD_CTX_free(temp_ctx);
    return retval;
}

/*[clinic input]
_hashlib.HASH.hexdigest as EVP_hexdigest

Return the digest value as a string of hexadecimal digits.
[clinic start generated code]*/

static PyObject *
EVP_hexdigest_impl(EVPobject *self)
/*[clinic end generated code: output=18e6decbaf197296 input=aff9cf0e4c741a9a]*/
{
    unsigned char digest[EVP_MAX_MD_SIZE];
    EVP_MD_CTX *temp_ctx;
    unsigned int digest_size;

    temp_ctx = EVP_MD_CTX_new();
    if (temp_ctx == NULL) {
        PyErr_NoMemory();
        return NULL;
    }

    /* Get the raw (binary) digest value */
    if (!locked_EVP_MD_CTX_copy(temp_ctx, self)) {
        return _setException(PyExc_ValueError);
    }
    digest_size = EVP_MD_CTX_size(temp_ctx);
    if (!EVP_DigestFinal(temp_ctx, digest, NULL)) {
        _setException(PyExc_ValueError);
        return NULL;
    }

    EVP_MD_CTX_free(temp_ctx);

    return _Py_strhex((const char *)digest, (Py_ssize_t)digest_size);
}

/*[clinic input]
_hashlib.HASH.update as EVP_update

    obj: object
    /

Update this hash object's state with the provided string.
[clinic start generated code]*/

static PyObject *
EVP_update(EVPobject *self, PyObject *obj)
/*[clinic end generated code: output=ec1d55ed2432e966 input=9b30ec848f015501]*/
{
    int result;
    Py_buffer view;

    GET_BUFFER_VIEW_OR_ERROUT(obj, &view);

    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);
        result = EVP_hash(self, view.buf, view.len);
        PyThread_release_lock(self->lock);
        Py_END_ALLOW_THREADS
    } else {
        result = EVP_hash(self, view.buf, view.len);
    }

    PyBuffer_Release(&view);

    if (result == -1)
        return NULL;
    Py_RETURN_NONE;
}

static PyMethodDef EVP_methods[] = {
    EVP_UPDATE_METHODDEF
    EVP_DIGEST_METHODDEF
    EVP_HEXDIGEST_METHODDEF
    EVP_COPY_METHODDEF
    {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 PyObject *
EVP_get_name(EVPobject *self, void *closure)
{
    return py_digest_name(EVP_MD_CTX_md(self->ctx));
}

static PyGetSetDef EVP_getseters[] = {
    {"digest_size",
     (getter)EVP_get_digest_size, NULL,
     NULL,
     NULL},
    {"block_size",
     (getter)EVP_get_block_size, NULL,
     NULL,
     NULL},
    {"name",
     (getter)EVP_get_name, NULL,
     NULL,
     PyDoc_STR("algorithm name.")},
    {NULL}  /* Sentinel */
};


static PyObject *
EVP_repr(EVPobject *self)
{
    PyObject *name_obj, *repr;
    name_obj = py_digest_name(EVP_MD_CTX_md(self->ctx));
    if (!name_obj) {
        return NULL;
    }
    repr = PyUnicode_FromFormat("<%U HASH object @ %p>", name_obj, self);
    Py_DECREF(name_obj);
    return repr;
}

PyDoc_STRVAR(hashtype_doc,
"HASH(name, string=b\'\')\n"
"--\n"
"\n"
"A hash is an object used to calculate a checksum of a 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");

static PyType_Slot EVPtype_slots[] = {
    {Py_tp_dealloc, EVP_dealloc},
    {Py_tp_repr, EVP_repr},
    {Py_tp_doc, (char *)hashtype_doc},
    {Py_tp_methods, EVP_methods},
    {Py_tp_getset, EVP_getseters},
    {0, 0},
};

static PyType_Spec EVPtype_spec = {
    "_hashlib.HASH",    /*tp_name*/
    sizeof(EVPobject),  /*tp_basicsize*/
    0,                  /*tp_itemsize*/
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
    EVPtype_slots
};

static PyObject *
EVPnew(const EVP_MD *digest,
       const unsigned char *cp, Py_ssize_t len, int usedforsecurity)
{
    int result = 0;
    EVPobject *self;

    if (!digest) {
        PyErr_SetString(PyExc_ValueError, "unsupported hash type");
        return NULL;
    }

    if ((self = newEVPobject()) == NULL)
        return NULL;

    if (!usedforsecurity) {
#ifdef EVP_MD_CTX_FLAG_NON_FIPS_ALLOW
        EVP_MD_CTX_set_flags(self->ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
#endif
    }


    if (!EVP_DigestInit_ex(self->ctx, digest, NULL)) {
        _setException(PyExc_ValueError);
        Py_DECREF(self);
        return NULL;
    }

    if (cp && len) {
        if (len >= HASHLIB_GIL_MINSIZE) {
            Py_BEGIN_ALLOW_THREADS
            result = EVP_hash(self, cp, len);
            Py_END_ALLOW_THREADS
        } else {
            result = EVP_hash(self, cp, len);
        }
        if (result == -1) {
            Py_DECREF(self);
            return NULL;
        }
    }

    return (PyObject *)self;
}


/* The module-level function: new() */

/*[clinic input]
_hashlib.new as EVP_new

    name as name_obj: object
    string as data_obj: object(c_default="NULL") = b''
    *
    usedforsecurity: bool = True

Return a new hash object using the named algorithm.

An optional string argument may be provided and will be
automatically hashed.

The MD5 and SHA1 algorithms are always supported.
[clinic start generated code]*/

static PyObject *
EVP_new_impl(PyObject *module, PyObject *name_obj, PyObject *data_obj,
             int usedforsecurity)
/*[clinic end generated code: output=ddd5053f92dffe90 input=c24554d0337be1b0]*/
{
    Py_buffer view = { 0 };
    PyObject *ret_obj;
    char *name;
    const EVP_MD *digest;

    if (!PyArg_Parse(name_obj, "s", &name)) {
        PyErr_SetString(PyExc_TypeError, "name must be a string");
        return NULL;
    }

    if (data_obj)
        GET_BUFFER_VIEW_OR_ERROUT(data_obj, &view);

    digest = py_digest_by_name(name);

    ret_obj = EVPnew(digest,
                     (unsigned char*)view.buf, view.len,
                     usedforsecurity);

    if (data_obj)
        PyBuffer_Release(&view);
    return ret_obj;
}

static PyObject*
EVP_fast_new(PyObject *module, PyObject *data_obj, const EVP_MD *digest,
             int usedforsecurity)
{
    Py_buffer view = { 0 };
    PyObject *ret_obj;

    if (data_obj)
        GET_BUFFER_VIEW_OR_ERROUT(data_obj, &view);

    ret_obj = EVPnew(digest,
                     (unsigned char*)view.buf, view.len,
                     usedforsecurity);

    if (data_obj)
        PyBuffer_Release(&view);

    return ret_obj;
}

/*[clinic input]
_hashlib.openssl_md5

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a md5 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_md5_impl(PyObject *module, PyObject *data_obj,
                          int usedforsecurity)
/*[clinic end generated code: output=87b0186440a44f8c input=990e36d5e689b16e]*/
{
    return EVP_fast_new(module, data_obj, EVP_md5(), usedforsecurity);
}


/*[clinic input]
_hashlib.openssl_sha1

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a sha1 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_sha1_impl(PyObject *module, PyObject *data_obj,
                           int usedforsecurity)
/*[clinic end generated code: output=6813024cf690670d input=948f2f4b6deabc10]*/
{
    return EVP_fast_new(module, data_obj, EVP_sha1(), usedforsecurity);
}


/*[clinic input]
_hashlib.openssl_sha224

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a sha224 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_sha224_impl(PyObject *module, PyObject *data_obj,
                             int usedforsecurity)
/*[clinic end generated code: output=a2dfe7cc4eb14ebb input=f9272821fadca505]*/
{
    return EVP_fast_new(module, data_obj, EVP_sha224(), usedforsecurity);
}


/*[clinic input]
_hashlib.openssl_sha256

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a sha256 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_sha256_impl(PyObject *module, PyObject *data_obj,
                             int usedforsecurity)
/*[clinic end generated code: output=1f874a34870f0a68 input=549fad9d2930d4c5]*/
{
    return EVP_fast_new(module, data_obj, EVP_sha256(), usedforsecurity);
}


/*[clinic input]
_hashlib.openssl_sha384

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a sha384 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_sha384_impl(PyObject *module, PyObject *data_obj,
                             int usedforsecurity)
/*[clinic end generated code: output=58529eff9ca457b2 input=48601a6e3bf14ad7]*/
{
    return EVP_fast_new(module, data_obj, EVP_sha384(), usedforsecurity);
}


/*[clinic input]
_hashlib.openssl_sha512

    string as data_obj: object(py_default="b''") = NULL
    *
    usedforsecurity: bool = True

Returns a sha512 hash object; optionally initialized with a string

[clinic start generated code]*/

static PyObject *
_hashlib_openssl_sha512_impl(PyObject *module, PyObject *data_obj,
                             int usedforsecurity)
/*[clinic end generated code: output=2c744c9e4a40d5f6 input=c5c46a2a817aa98f]*/
{
    return EVP_fast_new(module, data_obj, EVP_sha512(), usedforsecurity);
}


/*[clinic input]
_hashlib.pbkdf2_hmac as pbkdf2_hmac

    hash_name: str
    password: Py_buffer
    salt: Py_buffer
    iterations: long
    dklen as dklen_obj: object = None

Password based key derivation function 2 (PKCS #5 v2.0) with HMAC as pseudorandom function.
[clinic start generated code]*/

static PyObject *
pbkdf2_hmac_impl(PyObject *module, const char *hash_name,
                 Py_buffer *password, Py_buffer *salt, long iterations,
                 PyObject *dklen_obj)
/*[clinic end generated code: output=144b76005416599b input=ed3ab0d2d28b5d5c]*/
{
    PyObject *key_obj = NULL;
    char *key;
    long dklen;
    int retval;
    const EVP_MD *digest;

    digest = EVP_get_digestbyname(hash_name);
    if (digest == NULL) {
        PyErr_SetString(PyExc_ValueError, "unsupported hash type");
        goto end;
    }

    if (password->len > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "password is too long.");
        goto end;
    }

    if (salt->len > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "salt is too long.");
        goto end;
    }

    if (iterations < 1) {
        PyErr_SetString(PyExc_ValueError,
                        "iteration value must be greater than 0.");
        goto end;
    }
    if (iterations > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "iteration value is too great.");
        goto end;
    }

    if (dklen_obj == Py_None) {
        dklen = EVP_MD_size(digest);
    } else {
        dklen = PyLong_AsLong(dklen_obj);
        if ((dklen == -1) && PyErr_Occurred()) {
            goto end;
        }
    }
    if (dklen < 1) {
        PyErr_SetString(PyExc_ValueError,
                        "key length must be greater than 0.");
        goto end;
    }
    if (dklen > INT_MAX) {
        /* INT_MAX is always smaller than dkLen max (2^32 - 1) * hLen */
        PyErr_SetString(PyExc_OverflowError,
                        "key length is too great.");
        goto end;
    }

    key_obj = PyBytes_FromStringAndSize(NULL, dklen);
    if (key_obj == NULL) {
        goto end;
    }
    key = PyBytes_AS_STRING(key_obj);

    Py_BEGIN_ALLOW_THREADS
    retval = PKCS5_PBKDF2_HMAC((char*)password->buf, (int)password->len,
                               (unsigned char *)salt->buf, (int)salt->len,
                               iterations, digest, dklen,
                               (unsigned char *)key);
    Py_END_ALLOW_THREADS

    if (!retval) {
        Py_CLEAR(key_obj);
        _setException(PyExc_ValueError);
        goto end;
    }

  end:
    return key_obj;
}

#if OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_SCRYPT) && !defined(LIBRESSL_VERSION_NUMBER)
#define PY_SCRYPT 1

/* XXX: Parameters salt, n, r and p should be required keyword-only parameters.
   They are optional in the Argument Clinic declaration only due to a
   limitation of PyArg_ParseTupleAndKeywords. */

/*[clinic input]
_hashlib.scrypt

    password: Py_buffer
    *
    salt: Py_buffer = None
    n as n_obj: object(subclass_of='&PyLong_Type') = None
    r as r_obj: object(subclass_of='&PyLong_Type') = None
    p as p_obj: object(subclass_of='&PyLong_Type') = None
    maxmem: long = 0
    dklen: long = 64


scrypt password-based key derivation function.
[clinic start generated code]*/

static PyObject *
_hashlib_scrypt_impl(PyObject *module, Py_buffer *password, Py_buffer *salt,
                     PyObject *n_obj, PyObject *r_obj, PyObject *p_obj,
                     long maxmem, long dklen)
/*[clinic end generated code: output=14849e2aa2b7b46c input=48a7d63bf3f75c42]*/
{
    PyObject *key_obj = NULL;
    char *key;
    int retval;
    unsigned long n, r, p;

    if (password->len > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "password is too long.");
        return NULL;
    }

    if (salt->buf == NULL) {
        PyErr_SetString(PyExc_TypeError,
                        "salt is required");
        return NULL;
    }
    if (salt->len > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "salt is too long.");
        return NULL;
    }

    n = PyLong_AsUnsignedLong(n_obj);
    if (n == (unsigned long) -1 && PyErr_Occurred()) {
        PyErr_SetString(PyExc_TypeError,
                        "n is required and must be an unsigned int");
        return NULL;
    }
    if (n < 2 || n & (n - 1)) {
        PyErr_SetString(PyExc_ValueError,
                        "n must be a power of 2.");
        return NULL;
    }

    r = PyLong_AsUnsignedLong(r_obj);
    if (r == (unsigned long) -1 && PyErr_Occurred()) {
        PyErr_SetString(PyExc_TypeError,
                         "r is required and must be an unsigned int");
        return NULL;
    }

    p = PyLong_AsUnsignedLong(p_obj);
    if (p == (unsigned long) -1 && PyErr_Occurred()) {
        PyErr_SetString(PyExc_TypeError,
                         "p is required and must be an unsigned int");
        return NULL;
    }

    if (maxmem < 0 || maxmem > INT_MAX) {
        /* OpenSSL 1.1.0 restricts maxmem to 32 MiB. It may change in the
           future. The maxmem constant is private to OpenSSL. */
        PyErr_Format(PyExc_ValueError,
                     "maxmem must be positive and smaller than %d",
                      INT_MAX);
        return NULL;
    }

    if (dklen < 1 || dklen > INT_MAX) {
        PyErr_Format(PyExc_ValueError,
                    "dklen must be greater than 0 and smaller than %d",
                    INT_MAX);
        return NULL;
    }

    /* let OpenSSL validate the rest */
    retval = EVP_PBE_scrypt(NULL, 0, NULL, 0, n, r, p, maxmem, NULL, 0);
    if (!retval) {
        /* sorry, can't do much better */
        PyErr_SetString(PyExc_ValueError,
                        "Invalid parameter combination for n, r, p, maxmem.");
        return NULL;
   }

    key_obj = PyBytes_FromStringAndSize(NULL, dklen);
    if (key_obj == NULL) {
        return NULL;
    }
    key = PyBytes_AS_STRING(key_obj);

    Py_BEGIN_ALLOW_THREADS
    retval = EVP_PBE_scrypt(
        (const char*)password->buf, (size_t)password->len,
        (const unsigned char *)salt->buf, (size_t)salt->len,
        n, r, p, maxmem,
        (unsigned char *)key, (size_t)dklen
    );
    Py_END_ALLOW_THREADS

    if (!retval) {
        Py_CLEAR(key_obj);
        _setException(PyExc_ValueError);
        return NULL;
    }
    return key_obj;
}
#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=562d2f4249511bd3]*/
{
    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;
    int error;
} _InternalNameMapperState;


/* A callback function to pass to OpenSSL's OBJ_NAME_do_all(...) */
static void
_openssl_hash_name_mapper(const EVP_MD *md, const char *from,
                          const char *to, void *arg)
{
    _InternalNameMapperState *state = (_InternalNameMapperState *)arg;
    PyObject *py_name;

    assert(state != NULL);
    if (md == NULL)
        return;

    py_name = py_digest_name(md);
    if (py_name == NULL) {
        state->error = 1;
    } else {
        if (PySet_Add(state->set, py_name) != 0) {
            state->error = 1;
        }
        Py_DECREF(py_name);
    }
}


/* Ask OpenSSL for a list of supported ciphers, filling in a Python set. */
static PyObject*
generate_hash_name_list(void)
{
    _InternalNameMapperState state;
    state.set = PyFrozenSet_New(NULL);
    if (state.set == NULL)
        return NULL;
    state.error = 0;

    EVP_MD_do_all(&_openssl_hash_name_mapper, &state);

    if (state.error) {
        Py_DECREF(state.set);
        return NULL;
    }
    return state.set;
}

/* LibreSSL doesn't support FIPS:
   https://marc.info/?l=openbsd-misc&m=139819485423701&w=2

   Ted Unangst wrote: "I figured I should mention our current libressl policy
   wrt FIPS mode.  It's gone and it's not coming back." */
#ifndef LIBRESSL_VERSION_NUMBER
/*[clinic input]
_hashlib.get_fips_mode -> int

Determine the OpenSSL FIPS mode of operation.

For OpenSSL 3.0.0 and newer it returns the state of the default provider
in the default OSSL context. It's not quite the same as FIPS_mode() but good
enough for unittests.

Effectively any non-zero return value indicates FIPS mode;
values other than 1 may have additional significance.
[clinic start generated code]*/

static int
_hashlib_get_fips_mode_impl(PyObject *module)
/*[clinic end generated code: output=87eece1bab4d3fa9 input=2db61538c41c6fef]*/

{
    int result;
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
    result = EVP_default_properties_is_fips_enabled(NULL);
#else
    ERR_clear_error();
    result = FIPS_mode();
    if (result == 0) {
        // "If the library was built without support of the FIPS Object Module,
        // then the function will return 0 with an error code of
        // CRYPTO_R_FIPS_MODE_NOT_SUPPORTED (0x0f06d065)."
        // But 0 is also a valid result value.
        unsigned long errcode = ERR_peek_last_error();
        if (errcode) {
            _setException(PyExc_ValueError);
            return -1;
        }
    }
    return result;
#endif
}
#endif  // !LIBRESSL_VERSION_NUMBER


/* List of functions exported by this module */

static struct PyMethodDef EVP_functions[] = {
    EVP_NEW_METHODDEF
    PBKDF2_HMAC_METHODDEF
    _HASHLIB_SCRYPT_METHODDEF
    _HASHLIB_GET_FIPS_MODE_METHODDEF
    _HASHLIB_HMAC_DIGEST_METHODDEF
    _HASHLIB_OPENSSL_MD5_METHODDEF
    _HASHLIB_OPENSSL_SHA1_METHODDEF
    _HASHLIB_OPENSSL_SHA224_METHODDEF
    _HASHLIB_OPENSSL_SHA256_METHODDEF
    _HASHLIB_OPENSSL_SHA384_METHODDEF
    _HASHLIB_OPENSSL_SHA512_METHODDEF
    {NULL,      NULL}            /* Sentinel */
};


/* Initialize this module. */

static int
hashlib_traverse(PyObject *m, visitproc visit, void *arg)
{
    _hashlibstate *state = get_hashlib_state(m);
    Py_VISIT(state->EVPtype);
    return 0;
}

static int
hashlib_clear(PyObject *m)
{
    _hashlibstate *state = get_hashlib_state(m);
    Py_CLEAR(state->EVPtype);
    return 0;
}

static void
hashlib_free(void *m)
{
    hashlib_clear((PyObject *)m);
}


static struct PyModuleDef _hashlibmodule = {
    PyModuleDef_HEAD_INIT,
    "_hashlib",
    NULL,
    sizeof(_hashlibstate),
    EVP_functions,
    NULL,
    hashlib_traverse,
    hashlib_clear,
    hashlib_free
};

PyMODINIT_FUNC
PyInit__hashlib(void)
{
    PyObject *m, *openssl_md_meth_names;

#if (OPENSSL_VERSION_NUMBER < 0x10100000L) || defined(LIBRESSL_VERSION_NUMBER)
    /* Load all digest algorithms and initialize cpuid */
    OPENSSL_add_all_algorithms_noconf();
    ERR_load_crypto_strings();
#endif

    m = PyState_FindModule(&_hashlibmodule);
    if (m != NULL) {
        Py_INCREF(m);
        return m;
    }

    m = PyModule_Create(&_hashlibmodule);
    if (m == NULL)
        return NULL;

    PyTypeObject *EVPtype = (PyTypeObject *)PyType_FromSpec(&EVPtype_spec);
    if (EVPtype == NULL)
        return NULL;
    get_hashlib_state(m)->EVPtype = EVPtype;

    openssl_md_meth_names = generate_hash_name_list();
    if (openssl_md_meth_names == NULL) {
        Py_DECREF(m);
        return NULL;
    }
    if (PyModule_AddObject(m, "openssl_md_meth_names", openssl_md_meth_names)) {
        Py_DECREF(m);
        return NULL;
    }

    Py_INCREF((PyObject *)get_hashlib_state(m)->EVPtype);
    PyModule_AddObject(m, "HASH", (PyObject *)get_hashlib_state(m)->EVPtype);

    PyState_AddModule(m, &_hashlibmodule);
    return m;
}