TeaSpeak/tomcrypt
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ensure that fortuna has been seeded properly

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(cherry picked from commit 04ce8cf613f635a8445b5de09cdd58847f0fcd64)
This commit is contained in:
Steffen Jaeckel 2017-12-07 10:43:07 +01:00
parent 243898972c
commit 67d8ca19f5
1 changed files with 11 additions and 3 deletions
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14
src/prngs/fortuna.c
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@ -66,9 +66,9 @@ static int _fortuna_reseed(prng_state *prng)
{ {
unsigned char tmp[MAXBLOCKSIZE]; unsigned char tmp[MAXBLOCKSIZE];
hash_state md; hash_state md;
ulong64 reset_cnt;
int err, x; int err, x;
++prng->fortuna.reset_cnt;
/* new K == LTC_SHA256(K || s) where s == LTC_SHA256(P0) || LTC_SHA256(P1) ... */ /* new K == LTC_SHA256(K || s) where s == LTC_SHA256(P0) || LTC_SHA256(P1) ... */
sha256_init(&md); sha256_init(&md);
@ -77,8 +77,10 @@ static int _fortuna_reseed(prng_state *prng)
return err; return err;
} }
reset_cnt = prng->fortuna.reset_cnt + 1;
for (x = 0; x < LTC_FORTUNA_POOLS; x++) { for (x = 0; x < LTC_FORTUNA_POOLS; x++) {
if (x == 0 || ((prng->fortuna.reset_cnt >> (x-1)) & 1) == 0) { if (x == 0 || ((reset_cnt >> (x-1)) & 1) == 0) {
/* terminate this hash */ /* terminate this hash */
if ((err = sha256_done(&prng->fortuna.pool[x], tmp)) != CRYPT_OK) { if ((err = sha256_done(&prng->fortuna.pool[x], tmp)) != CRYPT_OK) {
sha256_done(&md, tmp); sha256_done(&md, tmp);
@ -108,9 +110,10 @@ static int _fortuna_reseed(prng_state *prng)
} }
_fortuna_update_iv(prng); _fortuna_update_iv(prng);
/* reset pool len */ /* reset/update internals */
prng->fortuna.pool0_len = 0; prng->fortuna.pool0_len = 0;
prng->fortuna.wd = 0; prng->fortuna.wd = 0;
prng->fortuna.reset_cnt = reset_cnt;
#ifdef LTC_CLEAN_STACK #ifdef LTC_CLEAN_STACK
@ -251,6 +254,11 @@ unsigned long fortuna_read(unsigned char *out, unsigned long outlen, prng_state
} }
} }
/* ensure that one reseed happened before allowing to read */
if (prng->fortuna.reset_cnt == 0) {
goto LBL_UNLOCK;
}
/* now generate the blocks required */ /* now generate the blocks required */
tlen = outlen; tlen = outlen;