*
* This file is part of Trivial IP Encryption (TrIPE).
*
- * TrIPE is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * TrIPE is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your
+ * option) any later version.
*
- * TrIPE is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * TrIPE is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
*
* You should have received a copy of the GNU General Public License
- * along with TrIPE; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
*/
/*----- Header files ------------------------------------------------------*/
#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 = ks->cout;
- const octet *p = BCUR(b);
+ int rc;
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 --- */
- if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz))
- return (0); /* Caution! */
- qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz;
- BSTEP(bb, tagsz + SEQSZ + ivsz + sz);
- STORE32(t, ty);
+ /* --- Initial tracing --- */
- oseq = ks->oseq++; STORE32(qseq, oseq);
IF_TRACING(T_KEYSET, {
- trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u",
- (unsigned long)oseq, ks->seq);
- trace_block(T_CRYPTO, "crypto: plaintext packet", p, sz);
+ trace(T_KEYSET,
+ "keyset: encrypting packet %lu (type 0x%02x) using keyset %u",
+ (unsigned long)ks->oseq, ty, ks->seq);
+ trace_block(T_CRYPTO, "crypto: plaintext packet", BCUR(b), sz);
})
- /* --- Encrypt the packet --- */
-
- 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: encrypted packet", qpk, sz);
- })
+ /* --- Apply the bulk-crypto transformation --- */
- /* --- 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);
- })
- }
+ rc = ks->bulk->ops->encrypt(ks->bulk, ty, b, bb, ks->oseq);
+ if (rc || !BOK(bb)) return (rc);
+ ks->oseq++;
- /* --- Deduct the packet size from the key's data life --- */
+ /* --- Do the necessary accounting for data volume --- */
osz = ks->sz_exp;
- if (osz > sz)
- nsz = osz - sz;
- else
- nsz = 0;
+ nsz = osz > sz ? osz - sz : 0;
if (osz >= ks->sz_regen && ks->sz_regen > nsz) {
T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- "
"forcing exchange", ks->seq); )
rc = KSERR_REGEN;
}
ks->sz_exp = nsz;
+
+ /* --- We're done --- */
+
return (rc);
}
static int dodecrypt(keyset *ks, unsigned ty, buf *b, buf *bb, uint32 *seq)
{
- const octet *pmac, *piv, *pseq, *ppk;
- size_t psz = BLEFT(b);
- size_t sz;
- octet *q = BCUR(bb);
- ghash *h;
- gcipher *c = ks->cin;
- 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 + SEQSZ + tagsz) {
- T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); )
- return (KSERR_MALFORMED);
- }
- sz = psz - ivsz - SEQSZ - tagsz;
- pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz;
- STORE32(t, ty);
+ const octet *q = BCUR(bb);
+ int rc;
IF_TRACING(T_KEYSET, {
- trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq);
- trace_block(T_CRYPTO, "crypto: ciphertext packet", ppk, sz);
+ trace(T_KEYSET,
+ "keyset: try decrypting packet (type 0x%02x) using keyset %u",
+ ty, ks->seq);
+ trace_block(T_CRYPTO, "crypto: ciphertext packet", BCUR(b), BLEFT(b));
})
- /* --- 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_block(T_CRYPTO, "crypto: computed MAC", mac, tagsz);
- })
- 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 (KSERR_DECRYPT);
- }
- }
-
- /* --- Decrypt the packet --- */
+ rc = ks->bulk->ops->decrypt(ks->bulk, ty, b, bb, seq);
+ if (rc) return (rc);
- 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, {
trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)",
- (unsigned long)LOAD32(pseq));
- trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz);
+ (unsigned long)*seq);
+ trace_block(T_CRYPTO, "crypto: decrypted packet", q, BCUR(bb) - q);
})
- BSTEP(bb, sz);
return (0);
}
void ks_drop(keyset *ks)
{
- if (--ks->ref)
- return;
- GC_DESTROY(ks->cin);
- GC_DESTROY(ks->cout);
- GM_DESTROY(ks->min);
- GM_DESTROY(ks->mout);
+ if (--ks->ref) return;
+ ks->bulk->ops->freectx(ks->bulk);
DESTROY(ks);
}
/* --- @ks_gen@ --- *
*
- * Arguments: @const void *k@ = pointer to key material
- * @size_t x, y, z@ = offsets into key material (see below)
+ * Arguments: @deriveargs *a@ = key derivation parameters (modified)
* @peer *p@ = pointer to peer information
*
* Returns: A pointer to the new keyset.
*
- * Use: Derives a new keyset from the given key material. The
- * offsets @x@, @y@ and @z@ separate the key material into three
- * parts. Between the @k@ and @k + x@ is `my' contribution to
- * the key material; between @k + x@ and @k + y@ is `your'
- * contribution; and between @k + y@ and @k + z@ is a shared
- * value we made together. These are used to construct two
- * pairs of symmetric keys. Each pair consists of an encryption
- * key and a message authentication key. One pair is used for
- * outgoing messages, the other for incoming messages.
+ * Use: Derives a new keyset from the given key material. This will
+ * set the @what@, @f@, and @hc@ members in @*a@; other members
+ * must be filled in by the caller.
*
* The new key is marked so that it won't be selected for output
* by @ksl_encrypt@. You can still encrypt data with it by
* calling @ks_encrypt@ directly.
*/
-keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p)
+keyset *ks_gen(deriveargs *a, peer *p)
{
- ghash *h;
- const octet *hh;
keyset *ks = CREATE(keyset);
time_t now = time(0);
- const octet *pp = k;
const algswitch *algs = &p->kx.kpriv->algs;
T( static unsigned seq = 0; )
T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); )
- /* --- Construct the various keys --- *
- *
- * This is done with macros, because it's quite tedious.
- */
-
-#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_##a, \
- hh, algs->a##ksz); \
- }) \
- ks->a##dir = INIT_##a(hh); \
- GH_DESTROY(h); \
-} while (0)
-
- SETKEY(c, in); SETKEY(c, out);
- SETKEY(m, in); SETKEY(m, out);
-
-#undef MINE
-#undef YOURS
-#undef OURS
-#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
+ a->what = "tripe-"; a->f = DF_IN | DF_OUT; a->hc = algs->h;
+ ks->bulk = algs->bulk->ops->genkeys(algs->bulk, a);
+ ks->bulk->ops = algs->bulk->ops;
T( ks->seq = seq++; )
ks->ref = 1;
ks->t_exp = now + T_EXP;
- ks->sz_exp = algs->expsz;
- ks->sz_regen = algs->expsz/2;
+ ks->sz_exp = algs->bulk->ops->expsz(algs->bulk);
+ ks->sz_regen = ks->sz_exp/2;
ks->oseq = 0;
seq_reset(&ks->iseq);
ks->next = 0;
ks->p = p;
ks->f = KSF_LISTEN;
- ks->tagsz = algs->tagsz;
return (ks);
}
* ought to be replaced' notification is only ever given once
* for each key. Also note that this call forces a keyset to be
* used even if it's marked as not for data output.
+ *
+ * The encryption transform is permitted to corrupt @buf_u@ for
+ * its own purposes. Neither the source nor destination should
+ * be within @buf_u@; and callers mustn't expect anything stored
+ * in @buf_u@ to still
*/
int ks_encrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
* Use: Attempts to decrypt a message using a given key. Note that
* requesting decryption with a key directly won't clear a
* marking that it's not for encryption.
+ *
+ * The decryption transform is permitted to corrupt @buf_u@ for
+ * its own purposes. Neither the source nor destination should
+ * be within @buf_u@; and callers mustn't expect anything stored
+ * in @buf_u@ to still
*/
int ks_decrypt(keyset *ks, unsigned ty, buf *b, buf *bb)