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fortuna: Drop global lock to zero stack variables

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Also drop explicit zeroing of hash context -- hash finish() operation is
expected to do this.

PR:		230877
Suggested by:	delphij@
Reviewed by:	delphij, markm
Approved by:	secteam (delphij)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D16986
This commit is contained in:
Conrad Meyer 2018-10-26 21:00:26 +00:00
parent 9a88479843
commit 7be4093a84
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=339789
1 changed files with 35 additions and 32 deletions
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67
sys/dev/random/fortuna.c
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@ -374,47 +374,50 @@ random_fortuna_pre_read(void)
now = getsbinuptime();
#endif
if (fortuna_state.fs_pool[0].fsp_length >= fortuna_state.fs_minpoolsize
if (fortuna_state.fs_pool[0].fsp_length < fortuna_state.fs_minpoolsize
#ifdef _KERNEL
/* FS&K - Use 'getsbinuptime()' to prevent reseed-spamming. */
&& (now - fortuna_state.fs_lasttime > SBT_1S/10)
|| (now - fortuna_state.fs_lasttime <= SBT_1S/10)
#endif
) {
RANDOM_RESEED_UNLOCK();
return;
}
#ifdef _KERNEL
fortuna_state.fs_lasttime = now;
fortuna_state.fs_lasttime = now;
#endif
/* FS&K - ReseedCNT = ReseedCNT + 1 */
fortuna_state.fs_reseedcount++;
/* s = \epsilon at start */
for (i = 0; i < RANDOM_FORTUNA_NPOOLS; i++) {
/* FS&K - if Divides(ReseedCnt, 2^i) ... */
if ((fortuna_state.fs_reseedcount % (1 << i)) == 0) {
/*-
* FS&K - temp = (P_i)
* - P_i = \epsilon
* - s = s|H(temp)
*/
randomdev_hash_finish(&fortuna_state.fs_pool[i].fsp_hash, temp);
randomdev_hash_init(&fortuna_state.fs_pool[i].fsp_hash);
fortuna_state.fs_pool[i].fsp_length = 0;
randomdev_hash_init(&context);
randomdev_hash_iterate(&context, temp, RANDOM_KEYSIZE);
randomdev_hash_finish(&context, s + i*RANDOM_KEYSIZE_WORDS);
} else
break;
}
#ifdef _KERNEL
SDT_PROBE2(random, fortuna, event_processor, debug, fortuna_state.fs_reseedcount, fortuna_state.fs_pool);
#endif
/* FS&K */
random_fortuna_reseed_internal(s, i);
/* Clean up and secure */
explicit_bzero(s, sizeof(s));
explicit_bzero(temp, sizeof(temp));
explicit_bzero(&context, sizeof(context));
/* FS&K - ReseedCNT = ReseedCNT + 1 */
fortuna_state.fs_reseedcount++;
/* s = \epsilon at start */
for (i = 0; i < RANDOM_FORTUNA_NPOOLS; i++) {
/* FS&K - if Divides(ReseedCnt, 2^i) ... */
if ((fortuna_state.fs_reseedcount % (1 << i)) == 0) {
/*-
* FS&K - temp = (P_i)
* - P_i = \epsilon
* - s = s|H(temp)
*/
randomdev_hash_finish(&fortuna_state.fs_pool[i].fsp_hash, temp);
randomdev_hash_init(&fortuna_state.fs_pool[i].fsp_hash);
fortuna_state.fs_pool[i].fsp_length = 0;
randomdev_hash_init(&context);
randomdev_hash_iterate(&context, temp, RANDOM_KEYSIZE);
randomdev_hash_finish(&context, s + i*RANDOM_KEYSIZE_WORDS);
} else
break;
}
#ifdef _KERNEL
SDT_PROBE2(random, fortuna, event_processor, debug, fortuna_state.fs_reseedcount, fortuna_state.fs_pool);
#endif
/* FS&K */
random_fortuna_reseed_internal(s, i);
RANDOM_RESEED_UNLOCK();
/* Clean up and secure */
explicit_bzero(s, sizeof(s));
explicit_bzero(temp, sizeof(temp));
}
/*-