339 lines
8.4 KiB
C
339 lines
8.4 KiB
C
#include "Python.h"
|
|
#ifdef MS_WINDOWS
|
|
#include <windows.h>
|
|
#else
|
|
#include <fcntl.h>
|
|
#ifdef HAVE_SYS_STAT_H
|
|
#include <sys/stat.h>
|
|
#endif
|
|
#endif
|
|
|
|
#ifdef Py_DEBUG
|
|
int _Py_HashSecret_Initialized = 0;
|
|
#else
|
|
static int _Py_HashSecret_Initialized = 0;
|
|
#endif
|
|
|
|
#ifdef MS_WINDOWS
|
|
static HCRYPTPROV hCryptProv = 0;
|
|
|
|
static int
|
|
win32_urandom_init(int raise)
|
|
{
|
|
/* Acquire context */
|
|
if (!CryptAcquireContext(&hCryptProv, NULL, NULL,
|
|
PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
|
|
goto error;
|
|
|
|
return 0;
|
|
|
|
error:
|
|
if (raise)
|
|
PyErr_SetFromWindowsErr(0);
|
|
else
|
|
Py_FatalError("Failed to initialize Windows random API (CryptoGen)");
|
|
return -1;
|
|
}
|
|
|
|
/* Fill buffer with size pseudo-random bytes generated by the Windows CryptoGen
|
|
API. Return 0 on success, or raise an exception and return -1 on error. */
|
|
static int
|
|
win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise)
|
|
{
|
|
Py_ssize_t chunk;
|
|
|
|
if (hCryptProv == 0)
|
|
{
|
|
if (win32_urandom_init(raise) == -1)
|
|
return -1;
|
|
}
|
|
|
|
while (size > 0)
|
|
{
|
|
chunk = size > INT_MAX ? INT_MAX : size;
|
|
if (!CryptGenRandom(hCryptProv, (DWORD)chunk, buffer))
|
|
{
|
|
/* CryptGenRandom() failed */
|
|
if (raise)
|
|
PyErr_SetFromWindowsErr(0);
|
|
else
|
|
Py_FatalError("Failed to initialized the randomized hash "
|
|
"secret using CryptoGen)");
|
|
return -1;
|
|
}
|
|
buffer += chunk;
|
|
size -= chunk;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#elif HAVE_GETENTROPY
|
|
/* Fill buffer with size pseudo-random bytes generated by getentropy().
|
|
Return 0 on success, or raise an exception and return -1 on error.
|
|
|
|
If fatal is nonzero, call Py_FatalError() instead of raising an exception
|
|
on error. */
|
|
static int
|
|
py_getentropy(unsigned char *buffer, Py_ssize_t size, int fatal)
|
|
{
|
|
while (size > 0) {
|
|
Py_ssize_t len = Py_MIN(size, 256);
|
|
int res = getentropy(buffer, len);
|
|
if (res < 0) {
|
|
if (fatal) {
|
|
Py_FatalError("getentropy() failed");
|
|
}
|
|
else {
|
|
PyErr_SetFromErrno(PyExc_OSError);
|
|
return -1;
|
|
}
|
|
}
|
|
buffer += len;
|
|
size -= len;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#else
|
|
static struct {
|
|
int fd;
|
|
dev_t st_dev;
|
|
ino_t st_ino;
|
|
} urandom_cache = { -1 };
|
|
|
|
/* Read size bytes from /dev/urandom into buffer.
|
|
Call Py_FatalError() on error. */
|
|
static void
|
|
dev_urandom_noraise(unsigned char *buffer, Py_ssize_t size)
|
|
{
|
|
int fd;
|
|
Py_ssize_t n;
|
|
|
|
assert (0 < size);
|
|
|
|
fd = _Py_open("/dev/urandom", O_RDONLY);
|
|
if (fd < 0)
|
|
Py_FatalError("Failed to open /dev/urandom");
|
|
|
|
while (0 < size)
|
|
{
|
|
do {
|
|
n = read(fd, buffer, (size_t)size);
|
|
} while (n < 0 && errno == EINTR);
|
|
if (n <= 0)
|
|
{
|
|
/* stop on error or if read(size) returned 0 */
|
|
Py_FatalError("Failed to read bytes from /dev/urandom");
|
|
break;
|
|
}
|
|
buffer += n;
|
|
size -= (Py_ssize_t)n;
|
|
}
|
|
close(fd);
|
|
}
|
|
|
|
/* Read size bytes from /dev/urandom into buffer.
|
|
Return 0 on success, raise an exception and return -1 on error. */
|
|
static int
|
|
dev_urandom_python(char *buffer, Py_ssize_t size)
|
|
{
|
|
int fd;
|
|
Py_ssize_t n;
|
|
struct stat st;
|
|
|
|
if (size <= 0)
|
|
return 0;
|
|
|
|
if (urandom_cache.fd >= 0) {
|
|
/* Does the fd point to the same thing as before? (issue #21207) */
|
|
if (fstat(urandom_cache.fd, &st)
|
|
|| st.st_dev != urandom_cache.st_dev
|
|
|| st.st_ino != urandom_cache.st_ino) {
|
|
/* Something changed: forget the cached fd (but don't close it,
|
|
since it probably points to something important for some
|
|
third-party code). */
|
|
urandom_cache.fd = -1;
|
|
}
|
|
}
|
|
if (urandom_cache.fd >= 0)
|
|
fd = urandom_cache.fd;
|
|
else {
|
|
Py_BEGIN_ALLOW_THREADS
|
|
fd = _Py_open("/dev/urandom", O_RDONLY);
|
|
Py_END_ALLOW_THREADS
|
|
if (fd < 0)
|
|
{
|
|
if (errno == ENOENT || errno == ENXIO ||
|
|
errno == ENODEV || errno == EACCES)
|
|
PyErr_SetString(PyExc_NotImplementedError,
|
|
"/dev/urandom (or equivalent) not found");
|
|
else
|
|
PyErr_SetFromErrno(PyExc_OSError);
|
|
return -1;
|
|
}
|
|
if (urandom_cache.fd >= 0) {
|
|
/* urandom_fd was initialized by another thread while we were
|
|
not holding the GIL, keep it. */
|
|
close(fd);
|
|
fd = urandom_cache.fd;
|
|
}
|
|
else {
|
|
if (fstat(fd, &st)) {
|
|
PyErr_SetFromErrno(PyExc_OSError);
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
else {
|
|
urandom_cache.fd = fd;
|
|
urandom_cache.st_dev = st.st_dev;
|
|
urandom_cache.st_ino = st.st_ino;
|
|
}
|
|
}
|
|
}
|
|
|
|
Py_BEGIN_ALLOW_THREADS
|
|
do {
|
|
do {
|
|
n = read(fd, buffer, (size_t)size);
|
|
} while (n < 0 && errno == EINTR);
|
|
if (n <= 0)
|
|
break;
|
|
buffer += n;
|
|
size -= (Py_ssize_t)n;
|
|
} while (0 < size);
|
|
Py_END_ALLOW_THREADS
|
|
|
|
if (n <= 0)
|
|
{
|
|
/* stop on error or if read(size) returned 0 */
|
|
if (n < 0)
|
|
PyErr_SetFromErrno(PyExc_OSError);
|
|
else
|
|
PyErr_Format(PyExc_RuntimeError,
|
|
"Failed to read %zi bytes from /dev/urandom",
|
|
size);
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
dev_urandom_close(void)
|
|
{
|
|
if (urandom_cache.fd >= 0) {
|
|
close(urandom_cache.fd);
|
|
urandom_cache.fd = -1;
|
|
}
|
|
}
|
|
|
|
#endif /* HAVE_GETENTROPY */
|
|
|
|
/* Fill buffer with pseudo-random bytes generated by a linear congruent
|
|
generator (LCG):
|
|
|
|
x(n+1) = (x(n) * 214013 + 2531011) % 2^32
|
|
|
|
Use bits 23..16 of x(n) to generate a byte. */
|
|
static void
|
|
lcg_urandom(unsigned int x0, unsigned char *buffer, size_t size)
|
|
{
|
|
size_t index;
|
|
unsigned int x;
|
|
|
|
x = x0;
|
|
for (index=0; index < size; index++) {
|
|
x *= 214013;
|
|
x += 2531011;
|
|
/* modulo 2 ^ (8 * sizeof(int)) */
|
|
buffer[index] = (x >> 16) & 0xff;
|
|
}
|
|
}
|
|
|
|
/* Fill buffer with size pseudo-random bytes from the operating system random
|
|
number generator (RNG). It is suitable for most cryptographic purposes
|
|
except long living private keys for asymmetric encryption.
|
|
|
|
Return 0 on success, raise an exception and return -1 on error. */
|
|
int
|
|
_PyOS_URandom(void *buffer, Py_ssize_t size)
|
|
{
|
|
if (size < 0) {
|
|
PyErr_Format(PyExc_ValueError,
|
|
"negative argument not allowed");
|
|
return -1;
|
|
}
|
|
if (size == 0)
|
|
return 0;
|
|
|
|
#ifdef MS_WINDOWS
|
|
return win32_urandom((unsigned char *)buffer, size, 1);
|
|
#elif HAVE_GETENTROPY
|
|
return py_getentropy(buffer, size, 0);
|
|
#else
|
|
return dev_urandom_python((char*)buffer, size);
|
|
#endif
|
|
}
|
|
|
|
void
|
|
_PyRandom_Init(void)
|
|
{
|
|
char *env;
|
|
unsigned char *secret = (unsigned char *)&_Py_HashSecret.uc;
|
|
Py_ssize_t secret_size = sizeof(_Py_HashSecret_t);
|
|
assert(secret_size == sizeof(_Py_HashSecret.uc));
|
|
|
|
if (_Py_HashSecret_Initialized)
|
|
return;
|
|
_Py_HashSecret_Initialized = 1;
|
|
|
|
/*
|
|
Hash randomization is enabled. Generate a per-process secret,
|
|
using PYTHONHASHSEED if provided.
|
|
*/
|
|
|
|
env = Py_GETENV("PYTHONHASHSEED");
|
|
if (env && *env != '\0' && strcmp(env, "random") != 0) {
|
|
char *endptr = env;
|
|
unsigned long seed;
|
|
seed = strtoul(env, &endptr, 10);
|
|
if (*endptr != '\0'
|
|
|| seed > 4294967295UL
|
|
|| (errno == ERANGE && seed == ULONG_MAX))
|
|
{
|
|
Py_FatalError("PYTHONHASHSEED must be \"random\" or an integer "
|
|
"in range [0; 4294967295]");
|
|
}
|
|
if (seed == 0) {
|
|
/* disable the randomized hash */
|
|
memset(secret, 0, secret_size);
|
|
}
|
|
else {
|
|
lcg_urandom(seed, secret, secret_size);
|
|
}
|
|
}
|
|
else {
|
|
#ifdef MS_WINDOWS
|
|
(void)win32_urandom(secret, secret_size, 0);
|
|
#elif HAVE_GETENTROPY
|
|
(void)py_getentropy(secret, secret_size, 1);
|
|
#else
|
|
dev_urandom_noraise(secret, secret_size);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
void
|
|
_PyRandom_Fini(void)
|
|
{
|
|
#ifdef MS_WINDOWS
|
|
if (hCryptProv) {
|
|
CryptReleaseContext(hCryptProv, 0);
|
|
hCryptProv = 0;
|
|
}
|
|
#elif HAVE_GETENTROPY
|
|
/* nothing to clean */
|
|
#else
|
|
dev_urandom_close();
|
|
#endif
|
|
}
|