[Python-checkins] cpython: Issue #22585: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(),

Sun Dec 21 01:18:34 CET 2014

https://hg.python.org/cpython/rev/75ede5bec8db
changeset: 93943:75ede5bec8db
parent: 93941:4d3066d4a5df
user: Victor Stinner <victor.stinner at gmail.com>
date: Sun Dec 21 01:16:38 2014 +0100
summary:
 Issue #22585: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(),
instead of reading /dev/urandom, to get pseudo-random bytes.
files:
 Lib/test/test_os.py | 7 +++++
 Misc/NEWS | 3 ++
 Python/random.c | 39 +++++++++++++++++++++++++++++---
 configure | 2 +-
 configure.ac | 2 +-
 pyconfig.h.in | 3 ++
 6 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -27,6 +27,7 @@
 import decimal
 import fractions
 import pickle
+import sysconfig
 try:
 import threading
 except ImportError:
@@ -1103,6 +1104,12 @@
 data2 = self.get_urandom_subprocess(16)
 self.assertNotEqual(data1, data2)
 
+
+HAVE_GETENTROPY = (sysconfig.get_config_var('HAVE_GETENTROPY') == 1)
+
+ at unittest.skipIf(HAVE_GETENTROPY,
+ "getentropy() does not use a file descriptor")
+class URandomFDTests(unittest.TestCase):
 @unittest.skipUnless(resource, "test requires the resource module")
 def test_urandom_failure(self):
 # Check urandom() failing when it is not able to open /dev/random.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -196,6 +196,9 @@
 Library
 -------
 
+- Issue #22585: On OpenBSD 5.6 and newer, os.urandom() now calls getentropy(),
+ instead of reading /dev/urandom, to get pseudo-random bytes.
+
 - Issue #19104: pprint now produces evaluable output for wrapped strings.
 
 - Issue #23071: Added missing names to codecs.__all__. Patch by Martin Panter.
diff --git a/Python/random.c b/Python/random.c
--- a/Python/random.c
+++ b/Python/random.c
@@ -36,7 +36,7 @@
 }
 
 /* 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 @@
 }
 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 @@
 }
 }
 
-#endif /* MS_WINDOWS */
+#endif /* HAVE_GETENTROPY */
 
 /* Fill buffer with pseudo-random bytes generated by a linear congruent
 generator (LCG):
@@ -242,6 +267,8 @@
 
 #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 @@
 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 @@
 CryptReleaseContext(hCryptProv, 0);
 hCryptProv = 0;
 }
+#elif HAVE_GETENTROPY
+ /* nothing to clean */
 #else
 dev_urandom_close();
 #endif
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -10697,7 +10697,7 @@
 for ac_func in alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
 clock confstr ctermid dup3 execv faccessat fchmod fchmodat fchown fchownat \
 fexecve fdopendir fork fpathconf fstatat ftime ftruncate futimesat \
- futimens futimes gai_strerror \
+ futimens futimes gai_strerror getentropy \
 getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
 getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
 if_nameindex \
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -3004,7 +3004,7 @@
 AC_CHECK_FUNCS(alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
 clock confstr ctermid dup3 execv faccessat fchmod fchmodat fchown fchownat \
 fexecve fdopendir fork fpathconf fstatat ftime ftruncate futimesat \
- futimens futimes gai_strerror \
+ futimens futimes gai_strerror getentropy \
 getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
 getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
 if_nameindex \
diff --git a/pyconfig.h.in b/pyconfig.h.in
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -332,6 +332,9 @@
 /* Define this if you have flockfile(), getc_unlocked(), and funlockfile() */
 #undef HAVE_GETC_UNLOCKED
 
+/* Define to 1 if you have the `getentropy' function. */
+#undef HAVE_GETENTROPY
+
 /* Define to 1 if you have the `getgrouplist' function. */
 #undef HAVE_GETGROUPLIST
 
-- 
Repository URL: https://hg.python.org/cpython
