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There's a deadlock when ssleay_rand_bytes is called the first time, since

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it wants to stir the pool using ssleay_rand_add.  This fix provides the
possibility to call ssleay_rand_add inside a locked state by simply telling
it not to do any locking through a static variable.  This isn't the most
elegant way one could do this, but it does retain thread safety during the
stirring process.
This commit is contained in:
Richard Levitte 2000-07-26 08:32:00 +00:00
parent 033d001e90
commit a4125514f5
1 changed files with 14 additions and 4 deletions
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18
crypto/rand/md_rand.c
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@ -141,6 +141,11 @@ static long md_count[2]={0,0};
static double entropy=0; static double entropy=0;
static int initialized=0; static int initialized=0;
/* This should be set to 1 only when ssleay_rand_add() is called inside
an already locked state, so it doesn't try to lock and thereby cause
a hang. And it should always be reset back to 0 before unlocking. */
static int add_do_not_lock=0;
#ifdef PREDICT #ifdef PREDICT
int rand_predictable=0; int rand_predictable=0;
#endif #endif
@ -201,7 +206,7 @@ static void ssleay_rand_add(const void *buf, int num, double add)
* hash function. * hash function.
*/ */
CRYPTO_w_lock(CRYPTO_LOCK_RAND); if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
st_idx=state_index; st_idx=state_index;
/* use our own copies of the counters so that even /* use our own copies of the counters so that even
@ -233,7 +238,7 @@ static void ssleay_rand_add(const void *buf, int num, double add)
md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0); md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
CRYPTO_w_unlock(CRYPTO_LOCK_RAND); if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
for (i=0; i<num; i+=MD_DIGEST_LENGTH) for (i=0; i<num; i+=MD_DIGEST_LENGTH)
{ {
@ -275,7 +280,7 @@ static void ssleay_rand_add(const void *buf, int num, double add)
} }
memset((char *)&m,0,sizeof(m)); memset((char *)&m,0,sizeof(m));
CRYPTO_w_lock(CRYPTO_LOCK_RAND); if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
/* Don't just copy back local_md into md -- this could mean that /* Don't just copy back local_md into md -- this could mean that
* other thread's seeding remains without effect (except for * other thread's seeding remains without effect (except for
* the incremented counter). By XORing it we keep at least as * the incremented counter). By XORing it we keep at least as
@ -286,7 +291,7 @@ static void ssleay_rand_add(const void *buf, int num, double add)
} }
if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */ if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
entropy += add; entropy += add;
CRYPTO_w_unlock(CRYPTO_LOCK_RAND); if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
#ifndef THREADS #ifndef THREADS
assert(md_c[1] == md_count[1]); assert(md_c[1] == md_count[1]);
@ -345,6 +350,8 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
RAND_poll(); RAND_poll();
CRYPTO_w_lock(CRYPTO_LOCK_RAND); CRYPTO_w_lock(CRYPTO_LOCK_RAND);
add_do_not_lock = 1; /* Since we call ssleay_rand_add while in
this locked state. */
initialized = 1; initialized = 1;
if (!stirred_pool) if (!stirred_pool)
@ -409,6 +416,9 @@ static int ssleay_rand_bytes(unsigned char *buf, int num)
* are now ours (but other threads may use them too) */ * are now ours (but other threads may use them too) */
md_count[0] += 1; md_count[0] += 1;
add_do_not_lock = 0; /* If this would ever be forgotten, we can
expect any evil god to eat our souls. */
CRYPTO_w_unlock(CRYPTO_LOCK_RAND); CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
while (num > 0) while (num > 0)