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Issue #22585: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(),

Browse source 
instead of reading /dev/urandom, to get pseudo-random bytes.
This commit is contained in:
Victor Stinner 2014-12-21 01:16:38 +01:00
parent 3c6fe4da88
commit 4d6a3d6c01
6 changed files with 50 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

39
Python/random.c
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@ -36,7 +36,7 @@ error:
}
/* Fill buffer with size pseudo-random bytes generated by the Windows CryptoGen
API. Return 0 on success, or -1 on error. */
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)
{
@ -66,10 +66,35 @@ win32_urandom(unsigned char *buffer, Py_ssize_t size, int raise)
}
return 0;
}
#endif /* MS_WINDOWS */
#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.
#ifndef MS_WINDOWS
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;
@ -201,7 +226,7 @@ dev_urandom_close(void)
}
}
#endif /* MS_WINDOWS */
#endif /* HAVE_GETENTROPY */
/* Fill buffer with pseudo-random bytes generated by a linear congruent
generator (LCG):
@ -242,6 +267,8 @@ _PyOS_URandom(void *buffer, Py_ssize_t size)
#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
@ -287,6 +314,8 @@ _PyRandom_Init(void)
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
@ -301,6 +330,8 @@ _PyRandom_Fini(void)
CryptReleaseContext(hCryptProv, 0);
hCryptProv = 0;
}
#elif HAVE_GETENTROPY
/* nothing to clean */
#else
dev_urandom_close();
#endif