Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: 74f4bd53e03ded8408bcc2de67cf0f5a4ac5b1a1 authored by Barry Warsaw on 23 February 2012, 15:59:38 UTC
Bump some more copyright years (as per PEP 101), since this is the first
Bump some more copyright years (as per PEP 101), since this is the first
Tip revision: 74f4bd5
random.c
#include "Python.h"
#ifdef MS_WINDOWS
#include <windows.h>
#else
#include <fcntl.h>
#endif
#ifdef Py_DEBUG
int _Py_HashSecret_Initialized = 0;
#else
static int _Py_HashSecret_Initialized = 0;
#endif
#ifdef MS_WINDOWS
typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTA)(HCRYPTPROV *phProv,\
LPCSTR pszContainer, LPCSTR pszProvider, DWORD dwProvType,\
DWORD dwFlags );
typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV hProv, DWORD dwLen,\
BYTE *pbBuffer );
static CRYPTGENRANDOM pCryptGenRandom = NULL;
/* This handle is never explicitly released. Instead, the operating
system will release it when the process terminates. */
static HCRYPTPROV hCryptProv = 0;
static int
win32_urandom_init(int raise)
{
HINSTANCE hAdvAPI32 = NULL;
CRYPTACQUIRECONTEXTA pCryptAcquireContext = NULL;
/* Obtain handle to the DLL containing CryptoAPI. This should not fail. */
hAdvAPI32 = GetModuleHandle("advapi32.dll");
if(hAdvAPI32 == NULL)
goto error;
/* Obtain pointers to the CryptoAPI functions. This will fail on some early
versions of Win95. */
pCryptAcquireContext = (CRYPTACQUIRECONTEXTA)GetProcAddress(
hAdvAPI32, "CryptAcquireContextA");
if (pCryptAcquireContext == NULL)
goto error;
pCryptGenRandom = (CRYPTGENRANDOM)GetProcAddress(hAdvAPI32,
"CryptGenRandom");
if (pCryptGenRandom == NULL)
goto error;
/* Acquire context */
if (! pCryptAcquireContext(&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 -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 (!pCryptGenRandom(hCryptProv, 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;
}
#endif /* MS_WINDOWS */
#ifdef __VMS
/* Use openssl random routine */
#include <openssl/rand.h>
static int
vms_urandom(unsigned char *buffer, Py_ssize_t size, int raise)
{
if (RAND_pseudo_bytes(buffer, size) < 0) {
if (raise) {
PyErr_Format(PyExc_ValueError,
"RAND_pseudo_bytes");
} else {
Py_FatalError("Failed to initialize the randomized hash "
"secret using RAND_pseudo_bytes");
}
return -1;
}
return 0;
}
#endif /* __VMS */
#if !defined(MS_WINDOWS) && !defined(__VMS)
/* Read size bytes from /dev/urandom into buffer.
Call Py_FatalError() on error. */
static void
dev_urandom_noraise(char *buffer, Py_ssize_t size)
{
int fd;
Py_ssize_t n;
assert (0 < size);
fd = 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;
if (size <= 0)
return 0;
Py_BEGIN_ALLOW_THREADS
fd = open("/dev/urandom", O_RDONLY);
Py_END_ALLOW_THREADS
if (fd < 0)
{
PyErr_SetFromErrnoWithFilename(PyExc_OSError, "/dev/urandom");
return -1;
}
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);
close(fd);
return -1;
}
close(fd);
return 0;
}
#endif /* !defined(MS_WINDOWS) && !defined(__VMS) */
/* 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, not suitable for cryptographic
use, from the operating random number generator (RNG).
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);
#else
# ifdef __VMS
return vms_urandom((unsigned char *)buffer, size, 1);
# else
return dev_urandom_python((char*)buffer, size);
# endif
#endif
}
void
_PyRandom_Init(void)
{
char *env;
void *secret = &_Py_HashSecret;
Py_ssize_t secret_size = sizeof(_Py_HashSecret_t);
if (_Py_HashSecret_Initialized)
return;
_Py_HashSecret_Initialized = 1;
/*
By default, hash randomization is disabled, and only
enabled if PYTHONHASHSEED is set to non-empty or if
"-R" is provided at the command line:
*/
if (!Py_HashRandomizationFlag) {
/* Disable the randomized hash: */
memset(secret, 0, secret_size);
return;
}
/*
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, (unsigned char*)secret, secret_size);
}
}
else {
#ifdef MS_WINDOWS
(void)win32_urandom((unsigned char *)secret, secret_size, 0);
#else /* #ifdef MS_WINDOWS */
# ifdef __VMS
vms_urandom((unsigned char *)secret, secret_size, 0);
# else
dev_urandom_noraise((char*)secret, secret_size);
# endif
#endif
}
}