-----Original Message-----
From: Conrad Meyer <c...@freebsd.org>
Reply-To: <c...@freebsd.org>
Date: 2019-11-22, Friday at 13:07
To: Ravi Pokala <rpok...@freebsd.org>
Cc: src-committers <src-committ...@freebsd.org>, svn-src-all
<svn-src-...@freebsd.org>, svn-src-head <svn-src-head@freebsd.org>
Subject: Re: svn commit: r355018 - in head/sys: dev/random sys
It wasn't lost in the change. The parameters now have the names
"entropy" and "len," but it is the same functionality.
<sigh>
I really need to get new glasses... <facepalm>
-Ravi (rpokala@)
Best,
Conrad
On Fri, Nov 22, 2019 at 12:56 PM Ravi Pokala <rpok...@freebsd.org> wrote:
>
> Hi Conrad,
>
> The original code did
>
> explicit_bzero(data, size);
>
> which appears to have been lost in this change. Is that intentional? If
so, why is that okay?
>
> Thanks,
>
> Ravi (rpokala@)
>
> -----Original Message-----
> From: <owner-src-committ...@freebsd.org> on behalf of Conrad Meyer
<c...@freebsd.org>
> Date: 2019-11-22, Friday at 12:20
> To: <src-committ...@freebsd.org>, <svn-src-...@freebsd.org>,
<svn-src-head@freebsd.org>
> Subject: svn commit: r355018 - in head/sys: dev/random sys
>
> Author: cem
> Date: Fri Nov 22 20:20:37 2019
> New Revision: 355018
> URL: https://svnweb.freebsd.org/changeset/base/355018
>
> Log:
> random(4): Abstract loader entropy injection
>
> Break random_harvestq_prime up into some logical subroutines. The
goal
> is that it becomes easier to add other early entropy sources.
>
> While here, drop pre-12.0 compatibility logic. loader default
configuration
> should preload the file as expeced since 12.0.
>
> Approved by: csprng(delphij, markm)
> Differential Revision: https://reviews.freebsd.org/D22482
>
> Modified:
> head/sys/dev/random/random_harvestq.c
> head/sys/sys/random.h
>
> Modified: head/sys/dev/random/random_harvestq.c
>
==============================================================================
> --- head/sys/dev/random/random_harvestq.c Fri Nov 22 20:18:07 2019
(r355017)
> +++ head/sys/dev/random/random_harvestq.c Fri Nov 22 20:20:37 2019
(r355018)
> @@ -402,6 +402,57 @@ random_harvestq_init(void *unused __unused)
> SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND,
random_harvestq_init, NULL);
>
> /*
> + * Subroutine to slice up a contiguous chunk of 'entropy' and feed
it into the
> + * underlying algorithm. Returns number of bytes actually fed into
underlying
> + * algorithm.
> + */
> +static size_t
> +random_early_prime(char *entropy, size_t len)
> +{
> + struct harvest_event event;
> + size_t i;
> +
> + len = rounddown(len, sizeof(event.he_entropy));
> + if (len == 0)
> + return (0);
> +
> + for (i = 0; i < len; i += sizeof(event.he_entropy)) {
> + event.he_somecounter = (uint32_t)get_cyclecount();
> + event.he_size = sizeof(event.he_entropy);
> + event.he_source = RANDOM_CACHED;
> + event.he_destination =
> + harvest_context.hc_destination[RANDOM_CACHED]++;
> + memcpy(event.he_entropy, entropy + i,
sizeof(event.he_entropy));
> + random_harvestq_fast_process_event(&event);
> + }
> + explicit_bzero(entropy, len);
> + return (len);
> +}
> +
> +/*
> + * Subroutine to search for known loader-loaded files in memory and
feed them
> + * into the underlying algorithm early in boot. Returns the number
of bytes
> + * loaded (zero if none were loaded).
> + */
> +static size_t
> +random_prime_loader_file(const char *type)
> +{
> + uint8_t *keyfile, *data;
> + size_t size;
> +
> + keyfile = preload_search_by_type(type);
> + if (keyfile == NULL)
> + return (0);
> +
> + data = preload_fetch_addr(keyfile);
> + size = preload_fetch_size(keyfile);
> + if (data == NULL)
> + return (0);
> +
> + return (random_early_prime(data, size));
> +}
> +
> +/*
> * This is used to prime the RNG by grabbing any early random stuff
> * known to the kernel, and inserting it directly into the hashing
> * module, currently Fortuna.
> @@ -410,41 +461,19 @@ SYSINIT(random_device_h_init, SI_SUB_RANDOM,
SI_ORDER_
> static void
> random_harvestq_prime(void *unused __unused)
> {
> - struct harvest_event event;
> - size_t count, size, i;
> - uint8_t *keyfile, *data;
> + size_t size;
>
> /*
> * Get entropy that may have been preloaded by loader(8)
> * and use it to pre-charge the entropy harvest queue.
> */
> - keyfile =
preload_search_by_type(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
> -#ifndef NO_BACKWARD_COMPATIBILITY
> - if (keyfile == NULL)
> - keyfile =
preload_search_by_type(RANDOM_LEGACY_BOOT_ENTROPY_MODULE);
> -#endif
> - if (keyfile != NULL) {
> - data = preload_fetch_addr(keyfile);
> - size = preload_fetch_size(keyfile);
> - /* Trim the size. If the admin has a file with a funny
size, we lose some. Tough. */
> - size -= (size % sizeof(event.he_entropy));
> - if (data != NULL && size != 0) {
> - for (i = 0; i < size; i +=
sizeof(event.he_entropy)) {
> - count = sizeof(event.he_entropy);
> - event.he_somecounter =
(uint32_t)get_cyclecount();
> - event.he_size = count;
> - event.he_source = RANDOM_CACHED;
> - event.he_destination =
> -
harvest_context.hc_destination[RANDOM_CACHED]++;
> - memcpy(event.he_entropy, data + i,
sizeof(event.he_entropy));
> -
random_harvestq_fast_process_event(&event);
> - }
> - explicit_bzero(data, size);
> - if (bootverbose)
> - printf("random: read %zu bytes from
preloaded cache\n", size);
> - } else
> - if (bootverbose)
> - printf("random: no preloaded entropy
cache\n");
> + size =
random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
> + if (bootverbose) {
> + if (size > 0)
> + printf("random: read %zu bytes from preloaded
cache\n",
> + size);
> + else
> + printf("random: no preloaded entropy cache\n");
> }
> }
> SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE,
random_harvestq_prime, NULL);
>
> Modified: head/sys/sys/random.h
>
==============================================================================
> --- head/sys/sys/random.h Fri Nov 22 20:18:07 2019 (r355017)
> +++ head/sys/sys/random.h Fri Nov 22 20:20:37 2019 (r355018)
> @@ -81,7 +81,6 @@ enum random_entropy_source {
> _Static_assert(ENTROPYSOURCE <= 32,
> "hardcoded assumption that values fit in a typical word-sized
bitset");
>
> -#define RANDOM_LEGACY_BOOT_ENTROPY_MODULE "/boot/entropy"
> #define RANDOM_CACHED_BOOT_ENTROPY_MODULE "boot_entropy_cache"
>
> extern u_int hc_source_mask;
>
>
>
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