From: Jonathan Wakely <jwakely@redhat.com>
To: Alexandre Oliva <oliva@adacore.com>
Cc: "libstdc++" <libstdc++@gcc.gnu.org>,
gcc Patches <gcc-patches@gcc.gnu.org>
Subject: Re: require et random_device for cons token test
Date: Tue, 9 Nov 2021 15:02:28 +0000 [thread overview]
Message-ID: <CACb0b4nwf3EBQct4GfnvGcbweS4iguSqFht8fugUBQZpsrHwUA@mail.gmail.com> (raw)
In-Reply-To: <20210325113827.GK3008@redhat.com>
[-- Attachment #1: Type: text/plain, Size: 820 bytes --]
On Thu, 25 Mar 2021 at 11:38, Jonathan Wakely wrote:
> On 25/03/21 08:00 -0300, Alexandre Oliva wrote:
> >On Mar 24, 2021, Jonathan Wakely <jwakely@redhat.com> wrote:
> >
> >> Does vxworks provide any platform-specific source of randomness, like
> >> Linux getrandom(2) or BSD arc4random(3) or Windows rand_s? If yes, we
> >> should add support for that (in the next stage 1).
> >
> >There appears to be a randNumGenCtl syscall that appears to be relevant
> >to that end, and randAdd to seed and randBytes to obtain random bytes in
> >vxRandLib. I couldn't find documentation on how to use it, but there
> >seems to be some code using it in openssl. Sorry, I don't know a lot
> >about vxworks.
>
> Thanks! We could look into that in stage 1.
>
Maybe something like this, completely untested and not ready to commit.
[-- Attachment #2: patch.txt --]
[-- Type: text/plain, Size: 2431 bytes --]
diff --git a/libstdc++-v3/src/c++11/random.cc b/libstdc++-v3/src/c++11/random.cc
index 70fd520077a..eb092cd0950 100644
--- a/libstdc++-v3/src/c++11/random.cc
+++ b/libstdc++-v3/src/c++11/random.cc
@@ -75,6 +75,14 @@
# include <unistd.h>
#endif
+#if __has_include(<_vxworks-versions.h>)
+# include <_vxworks-versions.h>
+# if _VXWORKS_MAJOR_GE(7) && __has_include(<randomNumGen.h>)
+# include <randomNumGen.h>
+# define USE_RANDBYTES 1
+# endif
+#endif
+
#if defined _GLIBCXX_USE_CRT_RAND_S || defined _GLIBCXX_USE_DEV_RANDOM \
|| _GLIBCXX_HAVE_GETENTROPY
// The OS provides a source of randomness we can use.
@@ -221,6 +229,29 @@ namespace std _GLIBCXX_VISIBILITY(default)
}
#endif
+#if USE_RANDBYTES
+ unsigned int
+ __vx_randBytes(void*)
+ {
+ int retries = 10;
+ unsigned int val;
+ auto bytes = reinterpret_cast<unsigned char*>(&val);
+ while (retries-- > 0)
+ {
+ RANDOM_NUM_GEN_STATUS status = randStatus();
+ if (status == RANDOM_NUM_GEN_ENOUGH_ENTROPY
+ || status == RANDOM_NUM_GEN_MAX_ENTROPY)
+ {
+ if (randBytes(bytes, sizeof(val)) == OK)
+ return val;
+ }
+ else
+ taskDelay(5);
+ }
+ std::__throw_runtime_error(__N("random_device: randBytes failed"));
+ }
+#endif
+
#ifdef USE_LCG
// TODO: use this to seed std::mt19937 engine too.
unsigned
@@ -271,6 +302,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
enum Which : unsigned {
device_file = 1, prng = 2, rand_s = 4, getentropy = 8, arc4random = 16,
rdseed = 64, rdrand = 128, darn = 256, rndr = 512,
+ randBytes = 1024,
any = 0xffff
};
@@ -326,6 +358,11 @@ namespace std _GLIBCXX_VISIBILITY(default)
return getentropy;
#endif
+#if USE_RANDBYTES
+ if (func == __vx_randBytes)
+ return randBytes;
+#endif
+
#ifdef USE_LCG
if (func == &__lcg)
return prng;
@@ -506,6 +543,14 @@ namespace std _GLIBCXX_VISIBILITY(default)
}
#endif // _GLIBCXX_HAVE_GETENTROPY
+#if USE_RANDBYTES
+ if (which & randBytes)
+ {
+ _M_func = __vx_randBytes;
+ return;
+ }
+#endif
+
#ifdef _GLIBCXX_USE_DEV_RANDOM
if (which & device_file)
{
@@ -666,6 +711,8 @@ namespace std _GLIBCXX_VISIBILITY(default)
case rand_s:
case prng:
return 0.0;
+ case randBytes: // XXX is this a real source of entropy or PRNG?
+ return 0.0;
case device_file:
// handled below
break;
next prev parent reply other threads:[~2021-11-09 15:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 6:53 Alexandre Oliva
2021-03-24 8:59 ` Jonathan Wakely
2021-03-24 10:33 ` Alexandre Oliva
2021-03-24 11:27 ` Jonathan Wakely
2021-03-24 14:01 ` Jonathan Wakely
2021-03-25 10:17 ` Alexandre Oliva
2021-03-25 11:57 ` Jonathan Wakely
2021-03-26 19:17 ` Jonathan Wakely
2021-03-25 11:03 ` Alexandre Oliva
2021-03-25 11:39 ` Jonathan Wakely
2021-03-25 11:00 ` Alexandre Oliva
2021-03-25 11:38 ` Jonathan Wakely
2021-11-09 15:02 ` Jonathan Wakely [this message]
2021-03-24 10:55 ` Jonathan Wakely
2021-03-24 13:22 ` Koning, Paul
2021-03-24 13:38 ` Jonathan Wakely
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CACb0b4nwf3EBQct4GfnvGcbweS4iguSqFht8fugUBQZpsrHwUA@mail.gmail.com \
--to=jwakely@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=libstdc++@gcc.gnu.org \
--cc=oliva@adacore.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).