Hi.
Any news on that?
On Friday, September 21, 2012, Alexey Suslikov wrote:
> On Fri, Sep 21, 2012 at 10:36 AM, Alexey Suslikov
> <alexey.susli...@gmail.com <javascript:;>> wrote:
> > On Wed, Sep 19, 2012 at 10:24 PM, Ted Unangst
> > <t...@tedunangst.com<javascript:;>>
> wrote:
> >> On Wed, Sep 19, 2012 at 18:50, Alexey Suslikov wrote:
> >>> On Wednesday, September 19, 2012, Theo de Raadt wrote:
> >>>
> >>>> > arc4random() is also thread-safe (it has interal locking) and very
> >>>> > desirable for other reasons. But no way to save state.
> >>>>
> >>>> The last part of this is intentional. Saving the state of pseudo
> >>>> random number generators is a stupid concept from the 80's.
> >>>>
> >>>
> >>> I see many rng functions behaving very differently. Is it a good idea
> >>> to create a common locking layer on top of need-to-be-safe rng
> >>> functions? Or we should deal only with original problem (and only
> >>> port random.c code from netbsd)?
> >>
> >> just slap a mutex around it.
> >
> > With the diff below Kannel no longer crashes. Only protecting random()
> > for now.
> >
> > Make random() thread-safe by surrounding real call with a mutex locking.
> > Found by and diff from Roman Kravchuk. Mainly from NetBSD.
>
> Sorry. Here is correct diff.
>
> We kinda unsure about the approach. For now, we follow arc4random pattern.
> Should we use generic _thread_mutex_lock/_thread_mutex_unlock instead?
>
> Index: lib/libc/include/thread_private.h
> ===================================================================
> RCS file: /cvs/src/lib/libc/include/thread_private.h,v
> retrieving revision 1.25
> diff -u -p -r1.25 thread_private.h
> --- lib/libc/include/thread_private.h 16 Oct 2011 06:29:56 -0000
> 1.25
> +++ lib/libc/include/thread_private.h 21 Sep 2012 07:59:34 -0000
> @@ -172,4 +172,16 @@ void _thread_arc4_unlock(void);
> _thread_arc4_unlock();\
> } while (0)
>
> +void _thread_random_lock(void);
> +void _thread_random_unlock(void);
> +
> +#define _RANDOM_LOCK() do { \
> + if (__isthreaded) \
> + _thread_random_lock(); \
> + } while (0)
> +#define _RANDOM_UNLOCK() do { \
> + if (__isthreaded) \
> + _thread_random_unlock();\
> + } while (0)
> +
> #endif /* _THREAD_PRIVATE_H_ */
> Index: lib/libc/stdlib/random.c
> ===================================================================
> RCS file: /cvs/src/lib/libc/stdlib/random.c,v
> retrieving revision 1.17
> diff -u -p -r1.17 random.c
> --- lib/libc/stdlib/random.c 1 Jun 2012 01:01:57 -0000 1.17
> +++ lib/libc/stdlib/random.c 21 Sep 2012 07:59:35 -0000
> @@ -35,6 +35,7 @@
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> +#include "thread_private.h"
>
> /*
> * random.c:
> @@ -376,21 +377,38 @@ setstate(char *arg_state)
> *
> * Returns a 31-bit random number.
> */
> -long
> -random(void)
> +static long
> +random_unlocked(void)
> {
> int32_t i;
> + int32_t *f, *r;
>
> if (rand_type == TYPE_0)
> i = state[0] = (state[0] * 1103515245 + 12345) &
> 0x7fffffff;
> else {
> - *fptr += *rptr;
> - i = (*fptr >> 1) & 0x7fffffff; /* chucking least random
> bit */
> - if (++fptr >= end_ptr) {
> - fptr = state;
> - ++rptr;
> - } else if (++rptr >= end_ptr)
> - rptr = state;
> + /*
> + * Use local variables rather than static variables for
> speed.
> + */
> + f = fptr; r = rptr;
> + *f += *r;
> + i = (*f >> 1) & 0x7fffffff; /* chucking least random
> bit */
> + if (++f >= end_ptr) {
> + f = state;
> + ++r;
> + } else if (++r >= end_ptr)
> + r = state;
> + fptr = f; rptr = r;
> }
> return((long)i);
> +}
> +
> +long
> +random(void)
> +{
> + long r;
> +
> + _RANDOM_LOCK();
> + r = random_unlocked();
> + _RANDOM_UNLOCK();
> + return (r);
> }
> Index: lib/libc/thread/unithread_malloc_lock.c
> ===================================================================
> RCS file: /cvs/src/lib/libc/thread/unithread_malloc_lock.c,v
> retrieving revision 1.8
> diff -u -p -r1.8 unithread_malloc_lock.c
> --- lib/libc/thread/unithread_malloc_lock.c 13 Jun 2008 21:18:43 -0000
> 1.8
> +++ lib/libc/thread/unithread_malloc_lock.c 21 Sep 2012 07:59:35 -0000
> @@ -21,6 +21,12 @@ WEAK_PROTOTYPE(_thread_arc4_unlock);
> WEAK_ALIAS(_thread_arc4_lock);
> WEAK_ALIAS(_thread_arc4_unlock);
>
> +WEAK_PROTOTYPE(_thread_random_lock);
> +WEAK_PROTOTYPE(_thread_random_unlock);
> +
> +WEAK_ALIAS(_thread_random_lock);
> +WEAK_ALIAS(_thread_random_unlock);
> +
> void
> WEAK_NAME(_thread_malloc_lock)(void)
> {
> @@ -53,6 +59,18 @@ WEAK_NAME(_thread_arc4_lock)(void)
>
> void
> WEAK_NAME(_thread_arc4_unlock)(void)
> +{
> + return;
> +}
> +
> +void
> +WEAK_NAME(_thread_random_lock)(void)
> +{
> + return;
> +}
> +
> +void
> +WEAK_NAME(_thread_random_unlock)(void)
> {
> return;
> }
> Index: lib/librthread/rthread.c
> ===================================================================
> RCS file: /cvs/src/lib/librthread/rthread.c,v
> retrieving revision 1.66
> diff -u -p -r1.66 rthread.c
> --- lib/librthread/rthread.c 22 Aug 2012 23:43:32 -0000 1.66
> +++ lib/librthread/rthread.c 21 Sep 2012 07:59:36 -0000
> @@ -674,6 +674,8 @@ static void *__libc_overrides[] __used =
> &__errno,
> &_thread_arc4_lock,
> &_thread_arc4_unlock,
> + &_thread_random_lock,
> + &_thread_random_unlock,
> &_thread_atexit_lock,
> &_thread_atexit_unlock,
> &_thread_malloc_lock,
> Index: lib/librthread/rthread_fork.c
> ===================================================================
> RCS file: /cvs/src/lib/librthread/rthread_fork.c,v
> retrieving revision 1.6
> diff -u -p -r1.6 rthread_fork.c
> --- lib/librthread/rthread_fork.c 22 Aug 2012 23:43:32 -0000 1.6
> +++ lib/librthread/rthread_fork.c 21 Sep 2012 07:59:36 -0000
> @@ -91,6 +91,7 @@ _dofork(int is_vfork)
> _thread_atexit_lock();
> _thread_malloc_lock();
> _thread_arc4_lock();
> + _thread_random_lock();
>
> #if defined(__ELF__)
> if (_DYNAMIC)
> @@ -107,6 +108,7 @@ _dofork(int is_vfork)
> _thread_arc4_unlock();
> _thread_malloc_unlock();
> _thread_atexit_unlock();
> + _thread_random_unlock();
>
> #if defined(__ELF__)
> if (_DYNAMIC)
> Index: lib/librthread/rthread_libc.c
> ===================================================================
> RCS file: /cvs/src/lib/librthread/rthread_libc.c,v
> retrieving revision 1.10
> diff -u -p -r1.10 rthread_libc.c
> --- lib/librthread/rthread_libc.c 17 Apr 2012 15:10:11 -0000
> 1.10
> +++ lib/librthread/rthread_libc.c 21 Sep 2012 07:59:36 -0000
> @@ -200,3 +200,19 @@ _thread_arc4_unlock(void)
> _spinunlock(&arc4_lock);
> }
>
> +/*
> + * random lock
> + */
> +static _spinlock_lock_t random_lock = _SPINLOCK_UNLOCKED;
> +
> +void
> +_thread_random_lock(void)
> +{
> + _spinlock(&random_lock);
> +}
> +
> +void
> +_thread_random_unlock(void)
> +{
> + _spinunlock(&random_lock);
> +}
