Merge 3.5 (os.urandom)

This commit is contained in:
Victor Stinner 2016-06-07 11:25:43 +02:00
commit 9ff9cbd600
7 changed files with 48 additions and 12 deletions

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@ -3768,14 +3768,21 @@ Miscellaneous Functions
This function returns random bytes from an OS-specific randomness source. The
returned data should be unpredictable enough for cryptographic applications,
though its exact quality depends on the OS implementation. On a Unix-like
system this will query ``/dev/urandom``, and on Windows it will use
``CryptGenRandom()``. If a randomness source is not found,
though its exact quality depends on the OS implementation.
On Linux, ``getrandom()`` syscall is used if available and the urandom
entropy pool is initialized (``getrandom()`` does not block).
On a Unix-like system this will query ``/dev/urandom``. On Windows, it
will use ``CryptGenRandom()``. If a randomness source is not found,
:exc:`NotImplementedError` will be raised.
For an easy-to-use interface to the random number generator
provided by your platform, please see :class:`random.SystemRandom`.
.. versionchanged:: 3.5.2
On Linux, if ``getrandom()`` blocks (the urandom entropy pool is not
initialized yet), fall back on reading ``/dev/urandom``.
.. versionchanged:: 3.5
On Linux 3.17 and newer, the ``getrandom()`` syscall is now used
when available. On OpenBSD 5.6 and newer, the C ``getentropy()``

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@ -201,6 +201,7 @@ Ian Bruntlett
Floris Bruynooghe
Matt Bryant
Stan Bubrouski
Colm Buckley
Erik de Bueger
Jan-Hein Bührman
Lars Buitinck

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@ -27,6 +27,10 @@ Core and Builtins
Library
-------
- Issue #26839: On Linux, :func:`os.urandom` now calls ``getrandom()`` with
``GRND_NONBLOCK`` to fall back on reading ``/dev/urandom`` if the urandom
entropy pool is not initialized yet. Patch written by Colm Buckley.
- Issue #23883: Added missing APIs to __all__ to match the documented APIs
for the following modules: cgi, mailbox, mimetypes, plistlib and smtpd.
Patches by Jacek Kołodziej.

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@ -6,6 +6,9 @@
# ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
# endif
# ifdef HAVE_LINUX_RANDOM_H
# include <linux/random.h>
# endif
# ifdef HAVE_GETRANDOM
# include <sys/random.h>
# elif defined(HAVE_GETRANDOM_SYSCALL)
@ -122,9 +125,13 @@ py_getrandom(void *buffer, Py_ssize_t size, int raise)
/* Is getrandom() supported by the running kernel?
* Need Linux kernel 3.17 or newer, or Solaris 11.3 or newer */
static int getrandom_works = 1;
/* Use non-blocking /dev/urandom device. On Linux at boot, the getrandom()
* syscall blocks until /dev/urandom is initialized with enough entropy. */
const int flags = 0;
/* getrandom() on Linux will block if called before the kernel has
* initialized the urandom entropy pool. This will cause Python
* to hang on startup if called very early in the boot process -
* see https://bugs.python.org/issue26839. To avoid this, use the
* GRND_NONBLOCK flag. */
const int flags = GRND_NONBLOCK;
int n;
if (!getrandom_works)
@ -168,6 +175,17 @@ py_getrandom(void *buffer, Py_ssize_t size, int raise)
getrandom_works = 0;
return 0;
}
if (errno == EAGAIN) {
/* If we failed with EAGAIN, the entropy pool was
* uninitialized. In this case, we return failure to fall
* back to reading from /dev/urandom.
*
* Note: In this case the data read will not be random so
* should not be used for cryptographic purposes. Retaining
* the existing semantics for practical purposes. */
getrandom_works = 0;
return 0;
}
if (errno == EINTR) {
if (PyErr_CheckSignals()) {

8
configure vendored
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@ -2876,6 +2876,7 @@ fi
ac_config_headers="$ac_config_headers pyconfig.h"
ac_aux_dir=
for ac_dir in "$srcdir" "$srcdir/.." "$srcdir/../.."; do
if test -f "$ac_dir/install-sh"; then
@ -7568,7 +7569,7 @@ sys/param.h sys/select.h sys/sendfile.h sys/socket.h sys/statvfs.h \
sys/stat.h sys/syscall.h sys/sys_domain.h sys/termio.h sys/time.h \
sys/times.h sys/types.h sys/uio.h sys/un.h sys/utsname.h sys/wait.h pty.h \
libutil.h sys/resource.h netpacket/packet.h sysexits.h bluetooth.h \
bluetooth/bluetooth.h linux/tipc.h spawn.h util.h alloca.h endian.h \
bluetooth/bluetooth.h linux/tipc.h linux/random.h spawn.h util.h alloca.h endian.h \
sys/endian.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
@ -16431,12 +16432,13 @@ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
#include <unistd.h>
#include <sys/syscall.h>
#include <linux/random.h>
int main() {
char buffer[1];
const size_t buflen = sizeof(buffer);
const int flags = 0;
/* ignore the result, Python checks for ENOSYS at runtime */
const int flags = GRND_NONBLOCK;
/* ignore the result, Python checks for ENOSYS and EAGAIN at runtime */
(void)syscall(SYS_getrandom, buffer, buflen, flags);
return 0;
}

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@ -1881,7 +1881,7 @@ sys/param.h sys/select.h sys/sendfile.h sys/socket.h sys/statvfs.h \
sys/stat.h sys/syscall.h sys/sys_domain.h sys/termio.h sys/time.h \
sys/times.h sys/types.h sys/uio.h sys/un.h sys/utsname.h sys/wait.h pty.h \
libutil.h sys/resource.h netpacket/packet.h sysexits.h bluetooth.h \
bluetooth/bluetooth.h linux/tipc.h spawn.h util.h alloca.h endian.h \
bluetooth/bluetooth.h linux/tipc.h linux/random.h spawn.h util.h alloca.h endian.h \
sys/endian.h)
AC_HEADER_DIRENT
AC_HEADER_MAJOR
@ -5246,12 +5246,13 @@ AC_LINK_IFELSE(
AC_LANG_SOURCE([[
#include <unistd.h>
#include <sys/syscall.h>
#include <linux/random.h>
int main() {
char buffer[1];
const size_t buflen = sizeof(buffer);
const int flags = 0;
/* ignore the result, Python checks for ENOSYS at runtime */
const int flags = GRND_NONBLOCK;
/* ignore the result, Python checks for ENOSYS and EAGAIN at runtime */
(void)syscall(SYS_getrandom, buffer, buflen, flags);
return 0;
}

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@ -574,6 +574,9 @@
/* Define to 1 if you have the <linux/tipc.h> header file. */
#undef HAVE_LINUX_TIPC_H
/* Define to 1 if you have the <linux/random.h> header file. */
#undef HAVE_LINUX_RANDOM_H
/* Define to 1 if you have the `lockf' function. */
#undef HAVE_LOCKF