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static const char *Cryptography_osrandom_engine_id = "osrandom";
static const char *Cryptography_osrandom_engine_name = "osrandom_engine";
#if defined(_WIN32)
static HCRYPTPROV hCryptProv = 0;
static int osrandom_init(ENGINE *e) {
if (hCryptProv > 0) {
return 1;
}
if (CryptAcquireContext(&hCryptProv, NULL, NULL,
PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
return 1;
} else {
return 0;
}
}
static int osrandom_rand_bytes(unsigned char *buffer, int size) {
if (hCryptProv == 0) {
return 0;
}
if (!CryptGenRandom(hCryptProv, (DWORD)size, buffer)) {
ERR_put_error(
ERR_LIB_RAND, 0, ERR_R_RAND_LIB, "osrandom_engine.py", 0
);
return 0;
}
return 1;
}
static int osrandom_finish(ENGINE *e) {
if (CryptReleaseContext(hCryptProv, 0)) {
hCryptProv = 0;
return 1;
} else {
return 0;
}
}
static int osrandom_rand_status(void) {
if (hCryptProv == 0) {
return 0;
} else {
return 1;
}
}
#else
static int urandom_fd = -1;
static int osrandom_finish(ENGINE *e);
static int osrandom_init(ENGINE *e) {
if (urandom_fd > -1) {
return 1;
}
urandom_fd = open("/dev/urandom", O_RDONLY);
if (urandom_fd > -1) {
int flags = fcntl(urandom_fd, F_GETFD);
if (flags == -1) {
osrandom_finish(e);
return 0;
} else if (fcntl(urandom_fd, F_SETFD, flags | FD_CLOEXEC) == -1) {
osrandom_finish(e);
return 0;
}
return 1;
} else {
return 0;
}
}
static int osrandom_rand_bytes(unsigned char *buffer, int size) {
ssize_t n;
while (size > 0) {
do {
n = read(urandom_fd, buffer, (size_t)size);
} while (n < 0 && errno == EINTR);
if (n <= 0) {
ERR_put_error(
ERR_LIB_RAND, 0, ERR_R_RAND_LIB, "osrandom_engine.py", 0
);
return 0;
}
buffer += n;
size -= n;
}
return 1;
}
static int osrandom_finish(ENGINE *e) {
int n;
do {
n = close(urandom_fd);
} while (n < 0 && errno == EINTR);
urandom_fd = -1;
if (n < 0) {
return 0;
} else {
return 1;
}
}
static int osrandom_rand_status(void) {
if (urandom_fd == -1) {
return 0;
} else {
return 1;
}
}
#endif
/* This replicates the behavior of the OpenSSL FIPS RNG, which returns a
-1 in the event that there is an error when calling RAND_pseudo_bytes. */
static int osrandom_pseudo_rand_bytes(unsigned char *buffer, int size) {
int res = osrandom_rand_bytes(buffer, size);
if (res == 0) {
return -1;
} else {
return res;
}
}
static RAND_METHOD osrandom_rand = {
NULL,
osrandom_rand_bytes,
NULL,
NULL,
osrandom_pseudo_rand_bytes,
osrandom_rand_status,
};
/* Returns 1 if successfully added, 2 if engine has previously been added,
and 0 for error. */
int Cryptography_add_osrandom_engine(void) {
ENGINE *e;
e = ENGINE_by_id(Cryptography_osrandom_engine_id);
if (e != NULL) {
ENGINE_free(e);
return 2;
} else {
ERR_clear_error();
}
e = ENGINE_new();
if (e == NULL) {
return 0;
}
if(!ENGINE_set_id(e, Cryptography_osrandom_engine_id) ||
!ENGINE_set_name(e, Cryptography_osrandom_engine_name) ||
!ENGINE_set_RAND(e, &osrandom_rand) ||
!ENGINE_set_init_function(e, osrandom_init) ||
!ENGINE_set_finish_function(e, osrandom_finish)) {
ENGINE_free(e);
return 0;
}
if (!ENGINE_add(e)) {
ENGINE_free(e);
return 0;
}
if (!ENGINE_free(e)) {
return 0;
}
return 1;
}
|
