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Date:      Thu, 23 May 2019 21:02:27 +0000 (UTC)
From:      Conrad Meyer <cem@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r348199 - head/sys/dev/random
Message-ID:  <201905232102.x4NL2RDC049069@repo.freebsd.org>
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Author: cem
Date: Thu May 23 21:02:27 2019
New Revision: 348199
URL: https://svnweb.freebsd.org/changeset/base/348199

Log:
  random(4): deduplicate explicit_bzero() in harvest
  
  Pull the responsibility for zeroing events, which is general to any
  conceivable implementation of a random device algorithm, out of the
  algorithm-specific Fortuna code and into the callers.  Most callers
  indirect through random_fortuna_process_event(), so add the logic there.
  Most callers already explicitly bzeroed the events they provided, so the
  logic in Fortuna was mostly redundant.
  
  Add one missing bzero in randomdev_accumulate().  Also, remove a redundant
  bzero in the same function -- randomdev_hash_finish() is obliged to bzero
  the hash state.
  
  Reviewed by:	delphij
  Approved by:	secteam(delphij)
  Sponsored by:	Dell EMC Isilon
  Differential Revision:	https://reviews.freebsd.org/D20318

Modified:
  head/sys/dev/random/fortuna.c
  head/sys/dev/random/random_harvestq.c
  head/sys/dev/random/randomdev.c

Modified: head/sys/dev/random/fortuna.c
==============================================================================
--- head/sys/dev/random/fortuna.c	Thu May 23 20:18:46 2019	(r348198)
+++ head/sys/dev/random/fortuna.c	Thu May 23 21:02:27 2019	(r348199)
@@ -254,7 +254,6 @@ random_fortuna_process_event(struct harvest_event *eve
 	fortuna_state.fs_pool[pl].fsp_length = MIN(RANDOM_FORTUNA_MAXPOOLSIZE,
 	    fortuna_state.fs_pool[pl].fsp_length +
 	    sizeof(event->he_somecounter) + event->he_size);
-	explicit_bzero(event, sizeof(*event));
 	RANDOM_RESEED_UNLOCK();
 }
 

Modified: head/sys/dev/random/random_harvestq.c
==============================================================================
--- head/sys/dev/random/random_harvestq.c	Thu May 23 20:18:46 2019	(r348198)
+++ head/sys/dev/random/random_harvestq.c	Thu May 23 21:02:27 2019	(r348199)
@@ -163,6 +163,7 @@ random_harvestq_fast_process_event(struct harvest_even
 #if defined(RANDOM_LOADABLE)
 	RANDOM_CONFIG_S_UNLOCK();
 #endif
+	explicit_bzero(event, sizeof(*event));
 }
 
 static void
@@ -437,7 +438,6 @@ random_harvestq_prime(void *unused __unused)
 				    harvest_context.hc_destination[RANDOM_CACHED]++;
 				memcpy(event.he_entropy, data + i, sizeof(event.he_entropy));
 				random_harvestq_fast_process_event(&event);
-				explicit_bzero(&event, sizeof(event));
 			}
 			explicit_bzero(data, size);
 			if (bootverbose)
@@ -540,7 +540,6 @@ random_harvest_direct_(const void *entropy, u_int size
 	event.he_destination = harvest_context.hc_destination[origin]++;
 	memcpy(event.he_entropy, entropy, size);
 	random_harvestq_fast_process_event(&event);
-	explicit_bzero(&event, sizeof(event));
 }
 
 void

Modified: head/sys/dev/random/randomdev.c
==============================================================================
--- head/sys/dev/random/randomdev.c	Thu May 23 20:18:46 2019	(r348198)
+++ head/sys/dev/random/randomdev.c	Thu May 23 21:02:27 2019	(r348199)
@@ -321,7 +321,6 @@ randomdev_accumulate(uint8_t *buf, u_int count)
 	timestamp = (uint32_t)get_cyclecount();
 	randomdev_hash_iterate(&hash, &timestamp, sizeof(timestamp));
 	randomdev_hash_finish(&hash, entropy_data);
-	explicit_bzero(&hash, sizeof(hash));
 	for (i = 0; i < RANDOM_KEYSIZE_WORDS; i += sizeof(event.he_entropy)/sizeof(event.he_entropy[0])) {
 		event.he_somecounter = (uint32_t)get_cyclecount();
 		event.he_size = sizeof(event.he_entropy);
@@ -330,6 +329,7 @@ randomdev_accumulate(uint8_t *buf, u_int count)
 		memcpy(event.he_entropy, entropy_data + i, sizeof(event.he_entropy));
 		p_random_alg_context->ra_event_processor(&event);
 	}
+	explicit_bzero(&event, sizeof(event));
 	explicit_bzero(entropy_data, sizeof(entropy_data));
 }

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