/* -*-c-*-
*
- * $Id: keyset.c,v 1.10 2004/04/08 01:36:17 mdw Exp $
+ * $Id: keyset.c,v 1.11 2004/04/18 18:08:11 mdw Exp $
*
* Handling of symmetric keysets
*
*
* For a 64-bit block cipher (e.g., Blowfish), the probability of a collision
* occurring after 32 MB is less than %$2^{-21}$%, and the probability of a
- * collision occurring after 64 MB is less than %$2^{-19}$%.
+ * collision occurring after 64 MB is less than %$2^{-19}$%. These could be
+ * adjusted dependent on the encryption scheme, but it's too much pain.
*/
#define T_EXP MIN(60) /* Expiry time for a key */
#define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now)
+#define SEQSZ 4 /* Size of sequence number packet */
+
/*----- Low-level packet encryption and decryption ------------------------*/
/* --- Encrypted data format --- *
static int doencrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
{
ghash *h;
- gcipher *c;
+ gcipher *c = ks->cout;
const octet *p = BCUR(b);
size_t sz = BLEFT(b);
octet *qmac, *qseq, *qiv, *qpk;
uint32 oseq;
+ size_t ivsz = GC_CLASS(c)->blksz;
+ size_t tagsz = ks->tagsz;
size_t osz, nsz;
octet t[4];
int rc = 0;
/* --- Allocate the required buffer space --- */
- c = ks->cout;
- if (buf_ensure(bb, MACSZ + SEQSZ + IVSZ + sz))
+ if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz))
return (0); /* Caution! */
- qmac = BCUR(bb); qseq = qmac + MACSZ; qiv = qseq + SEQSZ; qpk = qiv + IVSZ;
- BSTEP(bb, MACSZ + SEQSZ + IVSZ + sz);
+ qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz;
+ BSTEP(bb, tagsz + SEQSZ + ivsz + sz);
STORE32(t, ty);
- /* --- Encrypt the packet --- */
-
oseq = ks->oseq++; STORE32(qseq, oseq);
- rand_get(RAND_GLOBAL, qiv, IVSZ);
- c->ops->setiv(c, qiv);
- c->ops->encrypt(c, p, qpk, sz);
IF_TRACING(T_KEYSET, {
trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u",
(unsigned long)oseq, ks->seq);
- trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz);
+ trace_block(T_CRYPTO, "crypto: plaintext packet", p, sz);
})
- /* --- Now compute the MAC --- */
+ /* --- Encrypt the packet --- */
- h = ks->mout->ops->init(ks->mout);
- h->ops->hash(h, t, sizeof(t));
- h->ops->hash(h, qseq, SEQSZ + IVSZ + sz);
- memcpy(qmac, h->ops->done(h, 0), MACSZ);
- h->ops->destroy(h);
+ if (ivsz) {
+ rand_get(RAND_GLOBAL, qiv, ivsz);
+ GC_SETIV(c, qiv);
+ IF_TRACING(T_KEYSET, {
+ trace_block(T_CRYPTO, "crypto: initialization vector", qiv, ivsz);
+ })
+ }
+ GC_ENCRYPT(c, p, qpk, sz);
IF_TRACING(T_KEYSET, {
- trace_block(T_CRYPTO, "crypto: computed MAC", qmac, MACSZ);
+ trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz);
})
+ /* --- Now compute the MAC --- */
+
+ if (tagsz) {
+ h = GM_INIT(ks->mout);
+ GH_HASH(h, t, sizeof(t));
+ GH_HASH(h, qseq, SEQSZ + ivsz + sz);
+ memcpy(qmac, GH_DONE(h, 0), tagsz);
+ GH_DESTROY(h);
+ IF_TRACING(T_KEYSET, {
+ trace_block(T_CRYPTO, "crypto: computed MAC", qmac, tagsz);
+ })
+ }
+
/* --- Deduct the packet size from the key's data life --- */
osz = ks->sz_exp;
octet *q = BCUR(bb);
ghash *h;
gcipher *c = ks->cin;
- size_t ivsz = c->ops->c->blksz;
+ size_t ivsz = GC_CLASS(c)->blksz;
+ size_t tagsz = ks->tagsz;
octet *mac;
int eq;
octet t[4];
/* --- Break up the packet into its components --- */
- if (psz < ivsz + 4) {
+ if (psz < ivsz + SEQSZ + tagsz) {
T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); )
return (-1);
}
- sz = psz - IVSZ - SEQSZ - MACSZ;
- pmac = BCUR(b); pseq = pmac + MACSZ; piv = pseq + SEQSZ; ppk = piv + IVSZ;
+ sz = psz - ivsz - SEQSZ - tagsz;
+ pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz;
STORE32(t, ty);
- /* --- Verify the MAC on the packet --- */
-
- h = ks->min->ops->init(ks->min);
- h->ops->hash(h, t, sizeof(t));
- h->ops->hash(h, pseq, SEQSZ + IVSZ + sz);
- mac = h->ops->done(h, 0);
- eq = !memcmp(mac, pmac, MACSZ);
IF_TRACING(T_KEYSET, {
trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq);
- trace_block(T_CRYPTO, "crypto: computed MAC", mac, MACSZ);
+ trace_block(T_CRYPTO, "crypto: ciphertext packet", ppk, sz);
})
- h->ops->destroy(h);
- if (!eq) {
+
+ /* --- Verify the MAC on the packet --- */
+
+ if (tagsz) {
+ h = GM_INIT(ks->min);
+ GH_HASH(h, t, sizeof(t));
+ GH_HASH(h, pseq, SEQSZ + ivsz + sz);
+ mac = GH_DONE(h, 0);
+ eq = !memcmp(mac, pmac, tagsz);
IF_TRACING(T_KEYSET, {
- trace(T_KEYSET, "keyset: incorrect MAC: decryption failed");
- trace_block(T_CRYPTO, "crypto: expected MAC", pmac, MACSZ);
+ trace_block(T_CRYPTO, "crypto: computed MAC", mac, tagsz);
})
- return (-1);
+ GH_DESTROY(h);
+ if (!eq) {
+ IF_TRACING(T_KEYSET, {
+ trace(T_KEYSET, "keyset: incorrect MAC: decryption failed");
+ trace_block(T_CRYPTO, "crypto: expected MAC", pmac, tagsz);
+ })
+ return (-1);
+ }
}
/* --- Decrypt the packet --- */
- c->ops->setiv(c, piv);
- c->ops->decrypt(c, ppk, q, sz);
+ if (ivsz) {
+ GC_SETIV(c, piv);
+ IF_TRACING(T_KEYSET, {
+ trace_block(T_CRYPTO, "crypto: initialization vector", piv, ivsz);
+ })
+ }
+ GC_DECRYPT(c, ppk, q, sz);
if (seq)
*seq = LOAD32(pseq);
IF_TRACING(T_KEYSET, {
{
if (--ks->ref)
return;
- ks->cin->ops->destroy(ks->cin);
- ks->cout->ops->destroy(ks->cout);
- ks->min->ops->destroy(ks->min);
- ks->mout->ops->destroy(ks->mout);
+ GC_DESTROY(ks->cin);
+ GC_DESTROY(ks->cout);
+ GM_DESTROY(ks->min);
+ GM_DESTROY(ks->mout);
DESTROY(ks);
}
keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p)
{
- HASH_CTX h;
- octet buf[HASHSZ];
+ ghash *h;
+ const octet *hh;
keyset *ks = CREATE(keyset);
time_t now = time(0);
const octet *pp = k;
* This is done with macros, because it's quite tedious.
*/
-#define MINE HASH(&h, pp, x)
-#define YOURS HASH(&h, pp + x, y - x)
-#define OURS HASH(&h, pp + y, z - y)
-
-#define IN MINE; YOURS; OURS
-#define OUT YOURS; MINE; OURS
-#define STR_IN "incoming"
-#define STR_OUT "outgoing"
-
-#define GETHASH(str, dir) do { \
- HASH_INIT(&h); \
- HASH_STRING(&h, "tripe-" str); \
- dir; \
- HASH_DONE(&h, buf); \
+#define MINE GH_HASH(h, pp, x)
+#define YOURS GH_HASH(h, pp + x, y - x)
+#define OURS GH_HASH(h, pp + y, z - y)
+
+#define HASH_in MINE; YOURS; OURS
+#define HASH_out YOURS; MINE; OURS
+#define INIT_c(k) GC_INIT(algs.c, (k), algs.cksz)
+#define INIT_m(k) GM_KEY(algs.m, (k), algs.mksz)
+#define STR_c "encryption"
+#define STR_m "integrity"
+#define STR_in "incoming"
+#define STR_out "outgoing"
+
+#define SETKEY(a, dir) do { \
+ h = GH_INIT(algs.h); \
+ HASH_STRING(h, "tripe-" STR_##a); \
+ HASH_##dir; \
+ hh = GH_DONE(h, 0); \
IF_TRACING(T_KEYSET, { \
- trace_block(T_CRYPTO, "crypto: " STR_##dir " key " str, \
- buf, sizeof(buf)); \
+ trace_block(T_CRYPTO, "crypto: " STR_##dir " key " STR_##a, \
+ hh, algs.a##ksz); \
}) \
+ ks->a##dir = INIT_##a(hh); \
+ GH_DESTROY(h); \
} while (0)
- GETHASH("encryption", IN); ks->cin = CIPHER->init(buf, sizeof(buf));
- GETHASH("integrity", IN); ks->min = MAC->key(buf, sizeof(buf));
- GETHASH("encryption", OUT); ks->cout = CIPHER->init(buf, sizeof(buf));
- GETHASH("integrity", OUT); ks->mout = MAC->key(buf, sizeof(buf));
+ SETKEY(c, in); SETKEY(c, out);
+ SETKEY(m, in); SETKEY(m, out);
#undef MINE
#undef YOURS
#undef OURS
-#undef IN
-#undef OUT
-#undef STR_IN
-#undef STR_OUT
-#undef GETHASH
+#undef STR_c
+#undef STR_m
+#undef STR_in
+#undef STR_out
+#undef INIT_c
+#undef INIT_m
+#undef HASH_in
+#undef HASH_out
+#undef SETKEY
T( ks->seq = seq++; )
ks->ref = 1;
ks->next = 0;
ks->p = p;
ks->f = KSF_LISTEN;
- BURN(buf);
+ ks->tagsz = algs.tagsz;
return (ks);
}
~mdw / tripe / blobdiff