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#include "mod_auth_singleid.h"
#include <assert.h>
#include <string.h>
#include <apr_sha1.h>
/* Yes, this looks backwards. */
typedef char sid_nonce_t[40];
struct sid_storage {
/* The association with our server */
char server[256];
char handle[256];
unsigned char secret[256];
char type[64];
size_t n_secret;
time_t expires;
/* Book keeping for the records */
sid_nonce_t *records;
size_t first;
size_t total;
size_t count;
int wrapped;
};
int
sid_storage_store_assoc (sid_storage_t *store, const sid_assoc_t *assoc)
{
assert (store);
assert (assoc);
/* Check that we have enough space to store this information */
if ((assoc->server && strlen (assoc->server) > sizeof (store->server)) ||
(assoc->handle && strlen (assoc->handle) > sizeof (store->handle)) ||
(assoc->n_secret && assoc->n_secret > sizeof (store->secret)) ||
(assoc->type && strlen (assoc->type) > sizeof (store->type)))
return 0;
strcpy (store->server, assoc->server ? assoc->server : "");
strcpy (store->handle, assoc->handle ? assoc->handle : "");
memcpy (store->secret, assoc->secret, assoc->n_secret);
strcpy (store->type, assoc->type ? assoc->type : "");
store->expires = assoc->expires;
return 1;
}
int
sid_storage_find_assoc (sid_storage_t *store, const char *server,
const char *handle, sid_assoc_t *assoc)
{
assert (store);
assert (assoc);
if (server && (strlen (server) > sizeof (store->server) ||
strcmp (server, store->server) != 0))
return 0;
if (handle && (strlen (handle) > sizeof (store->handle) ||
strcmp (handle, store->handle) != 0))
return 0;
assoc->server = store->server;
assoc->handle = store->handle;
assoc->type = store->type;
assoc->secret = store->secret;
assoc->n_secret = store->n_secret;
assoc->expires = store->expires;
return 1;
}
void
sid_storage_invalidate_assoc (sid_storage_t *store, const char *server,
const char *handle)
{
sid_assoc_t dummy;
assert (store);
if (sid_storage_find_assoc (store, server, handle, &dummy)) {
store->server[0] = 0;
store->handle[0] = 0;
store->type[0] = 0;
memset (store->secret, 0, sizeof (store->secret));
store->n_secret = 0;
store->expires = 0;
store->secret[0] = 0;
}
}
#define nonce_compare(a, b) \
memcmp (a, b, sizeof (sid_nonce_t))
static void
nonce_put (sid_nonce_t rec, const char *nonce)
{
size_t len = strlen (nonce);
char *dst = (char*)rec;
/* If it's short enough, then just store. Fast */
if (len < sizeof (rec)) {
memcpy (dst, nonce, len);
memset (dst + len, 0, sizeof (rec) - len);
/* Too long, need to compress into the record */
} else {
apr_sha1_ctx_t ctx;
assert (sizeof (sid_nonce_t) == APR_SHA1_DIGESTSIZE + 20);
assert (len > 20);
/* The date prefix we just copy in */
memcpy (dst, nonce, 20);
/* Hash the rest into the buffer */
apr_sha1_init (&ctx);
apr_sha1_update (&ctx, nonce + 20, len - 20);
apr_sha1_final ((unsigned char*)dst + 20, &ctx);
}
}
static void
insert_nonce_record (sid_storage_t *store, sid_nonce_t rec, size_t at)
{
sid_nonce_t *records = store->records;
assert (store->total > 2);
assert (at < store->total);
assert (at != store->first);
/* Insertion right after latest, either ancient, more likely top */
if (at == store->first + 1 % store->total) {
/* We can just copy in at this point */
/* Our ring has empty space in it, so always push forwards, but only until first */
} else if (!store->wrapped) {
memmove (records + at + 1, records + at, sizeof (rec) * (store->first - at));
store->first += 1;
/* Move data backwards to make space */
} else if (store->first < at) {
memmove (records + store->first + 2, records + store->first + 1,
sizeof (rec) * (at - store->first));
/* Move data forwards to make space simply */
} else {
memmove (records + at + 1, records + at, sizeof (rec) * (store->first - at - 1));
}
memcpy (records[at], rec, sizeof (rec));
++store->count;
/* Track whether we have a full ring or not. */
if (!store->wrapped && store->count > store->total)
store->wrapped = 1;
}
int
sid_storage_check_nonce (sid_storage_t *store, const char *server, const char *nonce)
{
sid_nonce_t *records;
sid_nonce_t rec;
size_t at, lower, upper, mid;
int res;
assert (store);
assert (nonce);
assert (store->records);
assert (store->first < store->total);
nonce_put (rec, nonce);
records = store->records;
/* Best case scenario, new nonce is higher than our latest one */
res = nonce_compare (rec, records[store->first]);
/* Was the last nonce */
if (res == 0) {
return 1;
/* Newer than anything, push on top */
} else if (res < 0) {
at = (store->first + 1) % store->total;
insert_nonce_record (store, rec, at);
store->first = at;
return 0;
}
/* Do a binary search for the item */
for (lower = 0, upper = store->total; lower < upper; ) {
mid = lower + ((upper - lower) / 2); // Note: not (low + high) / 2 !!
at = at + store->first % store->total;
res = nonce_compare (rec, records[at]);
if (res == 0)
return 1; /* Have the nonce */
else if (res > 0)
lower = mid + 1;
else
upper = mid;
}
insert_nonce_record (store, rec, at);
return 0; /* Didn't find nonce */
}
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