/* -*-c-*-
*
- * $Id: keymgmt.c,v 1.4 2004/04/03 12:35:13 mdw Exp $
+ * $Id$
*
* Key loading and storing
*
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: keymgmt.c,v $
- * Revision 1.4 2004/04/03 12:35:13 mdw
- * Support elliptic curve key exchange.
- *
- * Revision 1.3 2001/06/22 19:40:36 mdw
- * Support expiry of other peers' public keys.
- *
- * Revision 1.2 2001/06/19 22:07:09 mdw
- * Cosmetic fixes.
- *
- * Revision 1.1 2001/02/03 20:26:37 mdw
- * Initial checkin.
- *
- */
-
/*----- Header files ------------------------------------------------------*/
#include "tripe.h"
group *gg;
mp *kpriv;
+algswitch algs;
/*----- Static variables --------------------------------------------------*/
static const kgops *kgtab[] = { &kgdh_ops, &kgec_ops, 0 };
+/*----- Algswitch stuff ---------------------------------------------------*/
+
+/* --- @algs_get@ --- *
+ *
+ * Arguments: @algswitch *a@ = where to put the algorithms
+ * @key_file *kf@ = key file (for some stupid reason)
+ * @key *k@ = key to inspect
+ *
+ * Returns: Null if OK, or an error message.
+ *
+ * Use: Extracts an algorithm choice from a key.
+ */
+
+static const char *algs_get(algswitch *a, key_file *kf, key *k)
+{
+ const char *p;
+ char *q;
+ dstr d = DSTR_INIT;
+ const char *e;
+
+#define FAIL(msg) do { e = msg; goto done; } while (0)
+
+ if ((p = key_getattr(kf, k, "cipher")) == 0)
+ p = "blowfish-cbc";
+ if ((a->c = gcipher_byname(p)) == 0)
+ FAIL("unknown-cipher");
+
+ if ((p = key_getattr(kf, k, "hash")) == 0)
+ p = "rmd160";
+ if ((a->h = ghash_byname(p)) == 0)
+ FAIL("unknown-hash");
+
+ if ((p = key_getattr(kf, k, "mgf")) == 0) {
+ dstr_reset(&d);
+ dstr_putf(&d, "%s-mgf", a->h->name);
+ p = d.buf;
+ }
+ if ((a->mgf = gcipher_byname(p)) == 0)
+ FAIL("unknown-mgf-cipher");
+
+ if ((p = key_getattr(kf, k, "mac")) != 0) {
+ dstr_reset(&d);
+ dstr_puts(&d, p);
+ if ((q = strchr(d.buf, '/')) != 0)
+ *q++ = 0;
+ if ((a->m = gmac_byname(d.buf)) == 0)
+ FAIL("unknown-mac");
+ if (!q)
+ a->tagsz = a->m->hashsz;
+ else {
+ unsigned long n = strtoul(q, &q, 0);
+ if (*q) FAIL("bad-tag-length-string");
+ if (n%8 || n > ~(size_t)0) FAIL("bad-tag-length");
+ a->tagsz = n/8;
+ }
+ } else {
+ dstr_reset(&d);
+ dstr_putf(&d, "%s-hmac", a->h->name);
+ if ((a->m = gmac_byname(d.buf)) == 0)
+ FAIL("no-hmac-for-hash");
+ a->tagsz = a->h->hashsz/2;
+ }
+
+ e = 0;
+done:
+ dstr_destroy(&d);
+ return (e);
+}
+
+/* --- @algs_check@ --- *
+ *
+ * Arguments: @algswitch *a@ = a choice of algorithms
+ * @const group *g@ = the group we're working in
+ *
+ * Returns: Null if OK, or an error message.
+ *
+ * Use: Checks an algorithm choice for sensibleness. This also
+ * derives some useful information from the choices, and you
+ * must call this before committing the algorithm selection
+ * for use by @keyset@ functions.
+ */
+
+static const char *algs_check(algswitch *a, const group *g)
+{
+ /* --- Derive the key sizes --- *
+ *
+ * Must ensure that we have non-empty keys. This isn't ideal, but it
+ * provides a handy sanity check.
+ */
+
+ a->hashsz = a->h->hashsz;
+ if ((a->cksz = keysz(a->hashsz, a->c->keysz)) == 0)
+ return ("no key size found for cipher");
+ if ((a->mksz = keysz(a->hashsz, a->m->keysz)) == 0)
+ return ("no key size found for MAC");
+
+ /* --- Ensure that the tag size is sane --- */
+
+ if (a->tagsz > a->m->hashsz) return ("tag length too large");
+
+ /* --- Ensure the MGF accepts hashes as keys --- */
+
+ if (keysz(a->hashsz, a->mgf->keysz) != a->hashsz)
+ return ("MGF not suitable -- restrictive key schedule");
+
+ /* --- All ship-shape and Bristol-fashion --- */
+
+ return (0);
+}
+
+/* --- @algs_samep@ --- *
+ *
+ * Arguments: @const algswitch *a, *aa@ = two algorithm selections
+ *
+ * Returns: Nonzero if the two selections are the same.
+ *
+ * Use: Checks sameness of algorithm selections: used to ensure that
+ * peers are using sensible algorithms.
+ */
+
+static int algs_samep(const algswitch *a, const algswitch *aa)
+{
+ return (a->c == aa->c && a->mgf == aa->mgf && a->h == aa->h &&
+ a->m == aa->m && a->tagsz == aa->tagsz);
+}
+
/*----- Main code ---------------------------------------------------------*/
/* --- @keymoan@ --- *
*/
static void keymoan(const char *file, int line, const char *msg, void *p)
- { a_warn("%s:%i: error: %s", file, line, msg); }
+{
+ a_warn("KEYMGMT",
+ "key-file-error",
+ "%s:%i", file, line,
+ "%s", msg,
+ A_END);
+}
/* --- @loadpriv@ --- *
*
{
key_file kf;
key *k;
- key_data *kd;
+ key_data **kd;
dstr t = DSTR_INIT;
group *g = 0;
mp *x = 0;
int rc = -1;
const kgops **ko;
const char *e;
+ algswitch a;
/* --- Open the private key file --- */
/* --- Load the key --- */
- if ((e = (*ko)->loadpriv(kd, &g, &x, &t)) != 0) {
+ if ((e = (*ko)->loadpriv(*kd, &g, &x, &t)) != 0) {
dstr_putf(d, "error reading private key `%s': %s", t.buf, e);
goto done_1;
}
goto done_1;
}
+ /* --- Collect the algorithms --- */
+
+ if ((e = algs_get(&a, &kf, k)) != 0 ||
+ (e = algs_check(&a, g)) != 0) {
+ dstr_putf(d, "bad symmetric algorithm selection in private key `%s': %s",
+ t.buf, e);
+ goto done_1;
+ }
+
/* --- Good, we're happy --- *
*
* Dodginess! We change the group over here, but don't free any old group
trace(T_CRYPTO, "crypto: r = %s", mpstr(g->r));
trace(T_CRYPTO, "crypto: h = %s", mpstr(g->h));
trace(T_CRYPTO, "crypto: x = %s", mpstr(x));
+ trace(T_CRYPTO, "crypto: cipher = %s", a.c->name);
+ trace(T_CRYPTO, "crypto: mgf = %s", a.mgf->name);
+ trace(T_CRYPTO, "crypto: hash = %s", a.h->name);
+ trace(T_CRYPTO, "crypto: mac = %s/%lu",
+ a.m->name, (unsigned long)a.tagsz * 8);
})
})
/* --- Success! --- */
gg = g; g = 0;
+ algs = a;
kpriv = x; x = 0;
rc = 0;
return (0);
}
-/* --- @km_interval@ --- *
+/* --- @km_reload@ --- *
*
* Arguments: ---
*
* Returns: Zero if OK, nonzero to force reloading of keys.
*
- * Use: Called on the interval timer to perform various useful jobs.
+ * Use: Checks the keyrings to see if they need reloading.
*/
-int km_interval(void)
+int km_reload(void)
{
dstr d = DSTR_INIT;
key_file *kf;
T( trace(T_KEYMGMT, "keymgmt: private keyring updated: reloading..."); )
DRESET(&d);
if (loadpriv(&d))
- a_warn("%s -- ignoring changes", d.buf);
+ a_warn("KEYMGMT", "bad-private-key", "%s", d.buf, A_END);
else
reload = 1;
}
kf = kf_pub;
DRESET(&d);
if (loadpub(&d))
- a_warn("%s -- ignoring changes", d.buf);
+ a_warn("KEYMGMT", "bad-public-keyring", "%s", d.buf, A_END);
else {
reload = 1;
key_close(kf);
void km_init(const char *priv, const char *pub, const char *tag)
{
dstr d = DSTR_INIT;
+ const gchash *const *hh;
kr_priv = priv;
kr_pub = pub;
fwatch_init(&w_priv, kr_priv);
fwatch_init(&w_pub, kr_pub);
+ for (hh = ghashtab; *hh; hh++) {
+ if ((*hh)->hashsz > MAXHASHSZ) {
+ die(EXIT_FAILURE, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
+ (*hh)->name, (unsigned long)(*hh)->hashsz, MAXHASHSZ);
+ }
+ }
+
DRESET(&d);
if (loadpriv(&d))
die(EXIT_FAILURE, "%s", d.buf);
int km_getpubkey(const char *tag, ge *kpub, time_t *t_exp)
{
key *k;
- key_data *kd;
+ key_data **kd;
dstr t = DSTR_INIT;
const kgops **ko;
const char *e;
group *g = 0;
ge *p = 0;
+ algswitch a;
int rc = -1;
/* --- Find the key --- */
if (key_qtag(kf_pub, tag, &t, &k, &kd)) {
- a_warn("private key `%s' not found in keyring `%s'", tag_priv, kr_priv);
+ a_warn("KEYMGMT", "public-key", "%s", tag, "not-found", A_END);
goto done;
}
if (strcmp((*ko)->ty, k->type) == 0)
goto tymatch;
}
- a_warn("public key `%s' has unknown type `%s'", t.buf, k->type);
+ a_warn("KEYMGMT",
+ "public-key", "%s", t.buf,
+ "unknown-type", "%s", k->type,
+ A_END);
goto done;
tymatch:;
/* --- Load the key --- */
- if ((e = (*ko)->loadpub(kd, &g, &p, &t)) != 0) {
- a_warn("error reading public key `%s': %s", t.buf, e);
+ if ((e = (*ko)->loadpub(*kd, &g, &p, &t)) != 0) {
+ a_warn("KEYMGMT", "public-key", "%s", t.buf, "bad", "%s", e, A_END);
goto done;
}
*/
if (!group_samep(gg, g)) {
- a_warn("public key `%s' has incorrect group", t.buf);
+ a_warn("KEYMGMT", "public-key", "%s", t.buf, "incorrect-group", A_END);
goto done;
}
/* --- Check the public group element --- */
if (group_check(gg, p)) {
- a_warn("public key `%s' has bad public group element", t.buf);
+ a_warn("KEYMGMT",
+ "public-key", "%s", t.buf,
+ "bad-public-group-element",
+ A_END);
+ goto done;
+ }
+
+ /* --- Check the algorithms --- */
+
+ if ((e = algs_get(&a, kf_pub, k)) != 0) {
+ a_warn("KEYMGMT",
+ "public-key", "%s", t.buf,
+ "bad-algorithm-selection", e,
+ A_END);
+ goto done;
+ }
+ if (!algs_samep(&a, &algs)) {
+ a_warn("KEYMGMT",
+ "public-key", "%s", t.buf,
+ "algorithm-mismatch",
+ A_END);
goto done;
}
~mdw / tripe / blobdiff