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This commit is contained in:
Michael Graff
2000-06-09 17:48:08 +00:00
parent b48abf6b85
commit 630a955711
2 changed files with 36 additions and 13 deletions
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2
bin/tests/entropy_test.c
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@@ -87,6 +87,8 @@ main(int argc, char **argv) {
} }
hex_dump("good data only:", buffer, returned); hex_dump("good data only:", buffer, returned);
isc_entropy_stats(ent, stderr);
CHECK("isc_entropy_getdata()", CHECK("isc_entropy_getdata()",
isc_entropy_getdata(ent, buffer, 128, NULL, 0)); isc_entropy_getdata(ent, buffer, 128, NULL, 0));

47
lib/isc/unix/entropy.c
View File

@@ -221,7 +221,7 @@ entropypool_adddata(isc_entropypool_t *rp, void *p, unsigned int len,
entropypool_add_word(rp, val); entropypool_add_word(rp, val);
} }
rp->entropy = ISC_MAX(rp->entropy + entropy, RND_POOLBITS); rp->entropy = ISC_MIN(rp->entropy + entropy, RND_POOLBITS);
} }
static isc_uint32_t static isc_uint32_t
@@ -230,13 +230,14 @@ get_from_filesource(isc_entropysource_t *source, isc_uint32_t desired) {
unsigned char buf[128]; unsigned char buf[128];
int fd = source->sources.file.fd; int fd = source->sources.file.fd;
ssize_t n, ndesired; ssize_t n, ndesired;
u_int32_t added = 0; isc_uint32_t added;
if (fd == -1) if (fd == -1)
return (0); return (0);
desired = desired / 8 + (((desired & 0x07) > 0) ? 1 : 0); desired = desired / 8 + (((desired & 0x07) > 0) ? 1 : 0);
added = 0;
while (desired > 0) { while (desired > 0) {
ndesired = ISC_MIN(desired, sizeof(buf)); ndesired = ISC_MIN(desired, sizeof(buf));
n = read(fd, buf, ndesired); n = read(fd, buf, ndesired);
@@ -270,17 +271,40 @@ fillpool(isc_entropy_t *ent, unsigned int needed, isc_boolean_t blocking) {
REQUIRE(VALID_ENTROPY(ent)); REQUIRE(VALID_ENTROPY(ent));
/* /*
* The best we can do is fill the pool. Clamp to that. * This logic is a little strange, so an explanation is in order.
*
* If needed is 0, it means we are being asked to "fill to whatever
* we think is best." This means that if we have at least a
* partially full pool (say, > 1/4th of the pool) we probably don't
* need to add anything.
*
* Also, we will check to see if the "pseudo" count is too high.
* If it is, try to mix in better data. Too high is currently
* defined as 1/4th of the pool.
*
* Next, if we are asked to add a specific bit of entropy, make
* certain that we will do so. Clamp how much we try to add to
* (DIGEST_SIZE * 8 < needed < POOLBITS - entropy).
*/ */
if (needed == 0 || (needed <= ent->pool.entropy)) { if (needed == 0) {
isc_uint32_t needed_ent, needed_ps;
REQUIRE(!blocking);
if ((ent->pool.entropy >= RND_POOLBITS / 4) if ((ent->pool.entropy >= RND_POOLBITS / 4)
&& (ent->pool.pseudo <= RND_POOLBITS / 4)) && (ent->pool.pseudo <= RND_POOLBITS / 4))
return; return;
needed_ent = 0;
needed_ps = 0;
if (ent->pool.entropy < RND_POOLBITS / 4)
needed_ent = RND_POOLBITS / 4 - ent->pool.entropy;
if (ent->pool.pseudo > RND_POOLBITS / 4)
needed_ps = RND_ENTROPY_THRESHOLD * 8;
needed = ISC_MAX(needed_ent, needed_ps);
} else {
needed = ISC_MAX(needed, RND_ENTROPY_THRESHOLD * 8);
needed = ISC_MIN(needed, RND_POOLBITS);
} }
needed = ISC_MAX(needed, RND_ENTROPY_THRESHOLD * 8);
needed = ISC_MIN(needed, RND_POOLBITS);
if (!blocking)
needed = ISC_MAX(needed, RND_POOLBITS / 4);
/* /*
* Poll each file source to see if we can read anything useful from * Poll each file source to see if we can read anything useful from
@@ -303,19 +327,17 @@ fillpool(isc_entropy_t *ent, unsigned int needed, isc_boolean_t blocking) {
source = ISC_LIST_NEXT(source, link); source = ISC_LIST_NEXT(source, link);
} }
isc_entropy_stats(ent, stderr);
fprintf(stderr, "fillpool: needed %u, added %u\n", fprintf(stderr, "fillpool: needed %u, added %u\n",
needed, added); needed, added);
isc_entropy_stats(ent, stderr);
/* /*
* If we added any data, decrement the pseudo variable by * If we added any data, decrement the pseudo variable by
* how much we added. * how much we added.
*/ */
if (ent->pool.pseudo <= added) if (ent->pool.pseudo <= added)
ent->pool.pseudo -= added;
else
ent->pool.pseudo = 0; ent->pool.pseudo = 0;
else
ent->pool.pseudo -= added;
/* /*
* Increment the amount of entropy we have in the pool. * Increment the amount of entropy we have in the pool.
@@ -435,7 +457,6 @@ isc_entropy_getdata(isc_entropy_t *ent, void *data, unsigned int length,
*returned = (length - remain); *returned = (length - remain);
UNLOCK(&ent->lock); UNLOCK(&ent->lock);
isc_entropy_stats(ent, stderr);
return (ISC_R_SUCCESS); return (ISC_R_SUCCESS);