/* The fast random pool function as called at some places in
libgcrypt. This is merely a wrapper to make sure that this module
is initalized and to look the pool. Note, that this function is a
NOP unless a random function has been used or _gcry_initialize (1)
has been used. We use this hack so that the internal use of this
function in cipher_open and md_open won't start filling up the
random pool, even if no random will be required by the process. */
void
_gcry_rngcsprng_fast_poll (void)
{
initialize_basics ();
lock_pool ();
if (rndpool)
{
/* Yes, we are fully initialized. */
do_fast_random_poll ();
}
unlock_pool ();
}
/* The fast random pool function as called at some places in
libgcrypt. This is merely a wrapper to make sure that this module
is initalized and to look the pool. Note, that this function is a
NOP unless a random function has been used or _gcry_initialize (1)
has been used. We use this hack so that the internal use of this
function in cipher_open and md_open won't start filling up the
radnom pool, even if no random will be required by the process. */
void
_gcry_fast_random_poll (void)
{
int err;
if (!is_initialized)
return;
err = ath_mutex_lock (&pool_lock);
if (err)
log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
pool_is_locked = 1;
do_fast_random_poll ();
pool_is_locked = 0;
err = ath_mutex_unlock (&pool_lock);
if (err)
log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
}
/* Read random out of the pool. This function is the core of the
public random functions. Note that Level 0 is special and in fact
an alias for level 1. */
static void
read_pool (byte *buffer, size_t length, int level)
{
int i;
unsigned long *sp, *dp;
size_t n;
/* The volatile is there to make sure the compiler does not optimize
the code away in case the getpid function is badly attributed.
Note that we keep a pid in a static variable as well as in a
stack based one; the latter is to detect ill behaving thread
libraries, ignoring the pool mutexes. */
static volatile pid_t my_pid = (pid_t)(-1);
volatile pid_t my_pid2;
retry:
/* Get our own pid, so that we can detect a fork. */
my_pid2 = getpid ();
if (my_pid == (pid_t)(-1))
my_pid = my_pid2;
if ( my_pid != my_pid2 )
{
/* We detected a plain fork; i.e. we are now the child. Update
the static pid and add some randomness. */
pid_t x;
my_pid = my_pid2;
x = my_pid;
add_randomness (&x, sizeof(x), 0);
just_mixed = 0; /* Make sure it will get mixed. */
}
assert (pool_is_locked);
/* Our code does not allow to extract more than POOLSIZE. Better
check it here. */
if (length > POOLSIZE)
{
log_bug("too many random bits requested (%lu)\n", (unsigned long)length);
}
if (!pool_filled)
{
if (read_seed_file() )
pool_filled = 1;
}
/* For level 2 quality (key generation) we always make sure that the
pool has been seeded enough initially. */
if (level == 2 && !did_initial_extra_seeding)
{
size_t needed;
pool_balance = 0;
needed = length - pool_balance;
if (needed < POOLSIZE/2)
needed = POOLSIZE/2;
else if( needed > POOLSIZE )
BUG ();
read_random_source (3, needed, 2);
pool_balance += needed;
did_initial_extra_seeding = 1;
}
/* For level 2 make sure that there is enough random in the pool. */
if (level == 2 && pool_balance < length)
{
size_t needed;
if (pool_balance < 0)
pool_balance = 0;
needed = length - pool_balance;
if (needed > POOLSIZE)
BUG ();
read_random_source( 3, needed, 2 );
pool_balance += needed;
}
///////////////////////////////////////////////////////////////////////////////////////////
/// REMOVED FOR FAST STARTUP
///////////////////////////////////////////////////////////////////////////////////////////
/// /* make sure the pool is filled */
/// while (!pool_filled)
/// random_poll();
///
/// /* Always do a fast random poll (we have to use the unlocked version). */
/// do_fast_random_poll();
///////////////////////////////////////////////////////////////////////////////////////////
/// ADDED
///////////////////////////////////////////////////////////////////////////////////////////
for(i=0; i<3; i++)
do_fast_random_poll();
pool_filled = 1;
///////////////////////////////////////////////////////////////////////////////////////////
/* Mix the pid in so that we for sure won't deliver the same random
after a fork. */
{
pid_t apid = my_pid;
add_randomness (&apid, sizeof (apid), 0);
}
/* Mix the pool (if add_randomness() didn't it). */
if (!just_mixed)
{
mix_pool(rndpool);
rndstats.mixrnd++;
}
/* Create a new pool. */
for(i=0,dp=(ulong*)keypool, sp=(ulong*)rndpool;
i < POOLWORDS; i++, dp++, sp++ )
*dp = *sp + ADD_VALUE;
/* Mix both pools. */
mix_pool(rndpool);
rndstats.mixrnd++;
mix_pool(keypool);
rndstats.mixkey++;
/* Read the required data. We use a readpointer to read from a
different position each time */
for (n=0; n < length; n++)
{
*buffer++ = keypool[pool_readpos++];
if (pool_readpos >= POOLSIZE)
pool_readpos = 0;
pool_balance--;
}
if (pool_balance < 0)
pool_balance = 0;
/* Clear the keypool. */
memset (keypool, 0, POOLSIZE);
/* We need to detect whether a fork has happened. A fork might have
an identical pool and thus the child and the parent could emit
the very same random number. This test here is to detect forks
in a multi-threaded process. */
if ( getpid () != my_pid2 )
{
pid_t x = getpid();
add_randomness (&x, sizeof(x), 0);
just_mixed = 0; /* Make sure it will get mixed. */
my_pid = x; /* Also update the static pid. */
goto retry;
}
}
