diff options
author | Bodo Möller <bodo@openssl.org> | 2001-04-18 15:07:35 +0000 |
---|---|---|
committer | Bodo Möller <bodo@openssl.org> | 2001-04-18 15:07:35 +0000 |
commit | 6e6d04e29a9ea25d3ebc77a314c00dc62fdb6047 (patch) | |
tree | 7d204e62b865d36deb625fe79d4743799d3ba444 /crypto/rand | |
parent | 48ff22530016104e2a5416247874e4dc2994a5cc (diff) |
fix md_rand.c locking bugs
Diffstat (limited to 'crypto/rand')
-rw-r--r-- | crypto/rand/md_rand.c | 71 | ||||
-rw-r--r-- | crypto/rand/rand_unix.c | 3 |
2 files changed, 54 insertions, 20 deletions
diff --git a/crypto/rand/md_rand.c b/crypto/rand/md_rand.c index 98c6a39f5d..c8728a07bf 100644 --- a/crypto/rand/md_rand.c +++ b/crypto/rand/md_rand.c @@ -141,10 +141,11 @@ static long md_count[2]={0,0}; static double entropy=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; +static unsigned int crypto_lock_rand = 0; /* may be set only when a thread + * holds CRYPTO_LOCK_RAND + * (to prevent double locking) */ +static unsigned long locking_thread = 0; /* valid iff crypto_lock_rand is set */ + #ifdef PREDICT int rand_predictable=0; @@ -191,6 +192,7 @@ static void ssleay_rand_add(const void *buf, int num, double add) long md_c[2]; unsigned char local_md[MD_DIGEST_LENGTH]; MD_CTX m; + int do_not_lock; /* * (Based on the rand(3) manpage) @@ -207,7 +209,10 @@ static void ssleay_rand_add(const void *buf, int num, double add) * hash function. */ - if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); + /* check if we already have the lock */ + do_not_lock = crypto_lock_rand && (locking_thread == CRYPTO_thread_id()); + + if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); st_idx=state_index; /* use our own copies of the counters so that even @@ -239,7 +244,7 @@ static void ssleay_rand_add(const void *buf, int num, double add) md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0); - if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); + if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); for (i=0; i<num; i+=MD_DIGEST_LENGTH) { @@ -281,7 +286,7 @@ static void ssleay_rand_add(const void *buf, int num, double add) } memset((char *)&m,0,sizeof(m)); - if (!add_do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); + if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); /* Don't just copy back local_md into md -- this could mean that * other thread's seeding remains without effect (except for * the incremented counter). By XORing it we keep at least as @@ -292,7 +297,7 @@ static void ssleay_rand_add(const void *buf, int num, double add) } if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */ entropy += add; - if (!add_do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); + if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32) assert(md_c[1] == md_count[1]); @@ -347,14 +352,18 @@ static int ssleay_rand_bytes(unsigned char *buf, int num) * global 'md'. */ - if (!initialized) - RAND_poll(); - CRYPTO_w_lock(CRYPTO_LOCK_RAND); - add_do_not_lock = 1; /* Since we call ssleay_rand_add while in - this locked state. */ - initialized = 1; + /* prevent ssleay_rand_bytes() from trying to obtain the lock again */ + crypto_lock_rand = 1; + locking_thread = CRYPTO_thread_id(); + + if (!initialized) + { + RAND_poll(); + initialized = 1; + } + if (!stirred_pool) do_stir_pool = 1; @@ -418,8 +427,9 @@ static int ssleay_rand_bytes(unsigned char *buf, int num) 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. */ + /* before unlocking, we must clear 'crypto_lock_rand' */ + crypto_lock_rand = 0; + locking_thread = 0; CRYPTO_w_unlock(CRYPTO_LOCK_RAND); while (num > 0) @@ -498,14 +508,37 @@ static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num) static int ssleay_rand_status(void) { int ret; + int do_not_lock; + /* check if we already have the lock + * (could happen if a RAND_poll() implementation calls RAND_status()) */ + do_not_lock = crypto_lock_rand && (locking_thread == CRYPTO_thread_id()); + + if (!do_not_lock) + { + CRYPTO_w_lock(CRYPTO_LOCK_RAND); + + /* prevent ssleay_rand_bytes() from trying to obtain the lock again */ + crypto_lock_rand = 1; + locking_thread = CRYPTO_thread_id(); + } + if (!initialized) + { RAND_poll(); + initialized = 1; + } - CRYPTO_w_lock(CRYPTO_LOCK_RAND); - initialized = 1; ret = entropy >= ENTROPY_NEEDED; - CRYPTO_w_unlock(CRYPTO_LOCK_RAND); + if (!do_not_lock) + { + /* before unlocking, we must clear 'crypto_lock_rand' */ + crypto_lock_rand = 0; + locking_thread = 0; + + CRYPTO_w_unlock(CRYPTO_LOCK_RAND); + } + return ret; } diff --git a/crypto/rand/rand_unix.c b/crypto/rand/rand_unix.c index 63b5efc32c..c491280b1f 100644 --- a/crypto/rand/rand_unix.c +++ b/crypto/rand/rand_unix.c @@ -228,8 +228,9 @@ int RAND_poll(void) #if defined(DEVRANDOM) || defined(DEVRANDOM_EGD) return 1; -#endif +#else return 0; +#endif } #endif |