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There is an issue (not seen in our testing) where "yarrow" and

Browse source 
"dummy" switch priorities, and the users are left with no usable
/dev/random. The fix assigns priories to these and gives the users
what they want. The override tuneable has a stupid name (blame me!)
and this fixes it to be something that 'sysctl kern.random' emits
and is the right thing to set.

Approved by:	re (gjb)
Approved by:	secteam (cperciva)
This commit is contained in:
Mark Murray 2013-10-13 00:10:48 +00:00
parent 9acbeddc57 4024528a27
commit 3d659cc19b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=256412
4 changed files with 19 additions and 7 deletions
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1
sys/dev/random/dummy_rng.c
View file

@ -102,6 +102,7 @@ struct random_adaptor dummy_random = {
.read = (random_read_func_t *)random_null_func,
.reseed = (random_reseed_func_t *)random_null_func,
.seeded = 0, /* This device can never be seeded */
.priority = 1, /* Bottom priority, so goes to last position */
};
static int

22
sys/dev/random/random_adaptors.c
View file

@ -104,12 +104,13 @@ void
random_adaptor_choose(struct random_adaptor **adaptor)
{
char rngs[128], *token, *cp;
struct random_adaptors *rpp;
struct random_adaptors *rppi, *ramax;
unsigned primax;
KASSERT(adaptor != NULL, ("pre-conditions failed"));
*adaptor = NULL;
if (TUNABLE_STR_FETCH("rngs_want", rngs, sizeof(rngs))) {
if (TUNABLE_STR_FETCH("kern.random.active_adaptor", rngs, sizeof(rngs))) {
cp = rngs;
while ((token = strsep(&cp, ",")) != NULL)
@ -120,16 +121,23 @@ random_adaptor_choose(struct random_adaptor **adaptor)
" skipping\n", token);
}
primax = 0U;
if (*adaptor == NULL) {
/*
* Fallback to the first thing that's on the list of
* available RNGs.
* Fall back to the highest priority item on the available
* RNG list.
*/
sx_slock(&adaptors_lock);
rpp = LIST_FIRST(&adaptors);
if (rpp != NULL)
*adaptor = rpp->rsp;
ramax = NULL;
LIST_FOREACH(rppi, &adaptors, entries) {
if (rppi->rsp->priority >= primax) {
ramax = rppi;
primax = rppi->rsp->priority;
}
}
if (ramax != NULL)
*adaptor = ramax->rsp;
sx_sunlock(&adaptors_lock);

1
sys/dev/random/randomdev.h
View file

@ -44,6 +44,7 @@ struct random_adaptor {
struct selinfo rsel;
const char *ident;
int seeded;
unsigned priority;
random_init_func_t *init;
random_deinit_func_t *deinit;
random_block_func_t *block;

2
sys/dev/random/randomdev_soft.c
View file

@ -84,6 +84,7 @@ static struct random_adaptor random_context = {
.poll = randomdev_poll,
.reseed = randomdev_flush_reseed,
.seeded = 0, /* This will be seeded during entropy processing */
.priority = 90, /* High priority, so top of the list. Fortuna may still win. */
};
#define RANDOM_MODULE_NAME yarrow
#define RANDOM_CSPRNG_NAME "yarrow"
@ -99,6 +100,7 @@ static struct random_adaptor random_context = {
.poll = randomdev_poll,
.reseed = randomdev_flush_reseed,
.seeded = 0, /* This will be excplicitly seeded at startup when secured */
.priority = 100, /* High priority, so top of the list. Beat Yarrow. */
};
#define RANDOM_MODULE_NAME fortuna
#define RANDOM_CSPRNG_NAME "fortuna"