#define TRACE_MACERR(pmac, tagsz) do { IF_TRACING(T_KEYSET, { \
trace(T_KEYSET, "keyset: incorrect MAC: decryption failed"); \
- trace_block(T_CRYPTO, "crypto: expected MAC", (pmac), (tagsz)); \
+ trace_block(T_CRYPTO, "crypto: provided MAC", (pmac), (tagsz)); \
}) } while (0)
/* --- @derivekey@ --- *
return (0);
}
+/*----- The AEAD transform ------------------------------------------------*
+ *
+ * This transform uses a general authenticated encryption scheme (the
+ * additional data isn't necessary). Good options include
+ * `chacha20-poly1305' or `rijndael-ocb3'.
+ *
+ * To be acceptable, the scheme must accept at least a 64-bit nonce. (All of
+ * Catacomb's current AEAD schemes are suitable.) The low 32 bits are the
+ * sequence number, and the high 32 bits are the type, both big-endian.
+ *
+ * +------+------+
+ * | seq | type |
+ * +------+------+
+ * 32 32
+ *
+ * The ciphertext is formatted as
+ *
+ * +---...---+------+------...------+
+ * | tag | seq | ciphertext |
+ * +---...---+------+------...------+
+ * tagsz 32 sz
+ *
+ */
+
+#define AEAD_NONCEMAX 64
+
+typedef struct aead_algs {
+ bulkalgs _b;
+ const gcaead *c;
+ size_t ksz, nsz, tsz;
+} aead_algs;
+
+typedef struct aead_ctx {
+ bulkctx _b;
+ struct { gaead_key *k; } d[NDIR];
+ size_t nsz, tsz;
+} aead_ctx;
+
+static bulkalgs *aead_getalgs(const algswitch *asw, dstr *e,
+ key_file *kf, key *k)
+{
+ aead_algs *a = CREATE(aead_algs);
+ const char *p;
+ char *qq;
+ gaead_key *kk = 0;
+ size_t ksz;
+ size_t csz = 0;
+ unsigned long n;
+
+ /* --- Collect the selected cipher and check that it's supported --- */
+
+ p = key_getattr(kf, k, "cipher"); if (!p) p = "rijndael-ocb3";
+ a->c = gaead_byname(p);
+ if (!a->c) { a_format(e, "unknown-cipher", "%s", p, A_END); goto fail; }
+ if (a->c->f&AEADF_NOAAD) {
+ a_format(e, "unsuitable-aead-cipher", "%s", p, "no-aad", A_END);
+ goto fail;
+ }
+ a->nsz = keysz_pad(8, a->c->noncesz);
+ if (!a->nsz) {
+ a_format(e, "unsuitable-aead-cipher", "%s", p, "nonce-too-small", A_END);
+ goto fail;
+ } else if (a->nsz > AEAD_NONCEMAX) {
+ a_format(e, "unsuitable-aead-cipher", "%s", p, "nonce-too-large", A_END);
+ goto fail;
+ }
+
+ /* --- Collect the selected MAC, and check the tag length --- *
+ *
+ * Of course, there isn't a separate MAC, so only accept `aead'.
+ */
+
+ p = key_getattr(kf, k, "tagsz");
+ if (!p) {
+ p = key_getattr(kf, k, "mac");
+ if (strncmp(p, "aead", 4) != 0 || (p[4] && p[4] != '/')) {
+ a_format(e, "unknown-mac", "%s", p, A_END);
+ goto fail;
+ }
+ if (p[4] == '/') p += 5;
+ else p = 0;
+ }
+ if (!p)
+ a->tsz = keysz(0, a->c->tagsz);
+ else {
+ n = strtoul(p, &qq, 0);
+ if (*qq) {
+ a_format(e, "bad-tag-length-string", "%s", p, A_END);
+ goto fail;
+ }
+ if (n%8 || (a->tsz = keysz(n/8, a->c->tagsz)) == 0)
+ { a_format(e, "bad-tag-length", "%lu", n, A_END); goto fail; }
+ }
+
+ /* --- Check that an empty message gives an empty ciphertext --- *
+ *
+ * This is necessary for producing challenges. If the overhead is zero
+ * then we're fine; otherwise, we have to check the hard way.
+ */
+
+ if (a->c->ohd) {
+ ksz = keysz(0, a->c->keysz);
+ memset(buf_t, 0, ksz > a->nsz ? ksz : a->nsz);
+ kk = GAEAD_KEY(a->c, buf_t, ksz);
+ if (gaead_encrypt(kk, buf_t, a->nsz,
+ buf_t, ksz,
+ 0, 0,
+ buf_t, &csz,
+ buf_t, a->tsz)) {
+ a_format(e, "unsuitable-aead-cipher", "%s", a->c->name,
+ "nonempty-ciphertext-for-empty-message", A_END);
+ goto fail;
+ }
+ GAEAD_DESTROY(kk); kk = 0;
+ }
+
+ return (&a->_b);
+fail:
+ if (kk) GAEAD_DESTROY(kk);
+ DESTROY(a);
+ return (0);
+}
+
+#ifndef NTRACE
+static void aead_tracealgs(const bulkalgs *aa)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+
+ trace(T_CRYPTO, "crypto: cipher = %s", a->c->name);
+ trace(T_CRYPTO, "crypto: noncesz = %lu", (unsigned long)a->nsz);
+ trace(T_CRYPTO, "crypto: tagsz = %lu", (unsigned long)a->tsz);
+}
+#endif
+
+static int aead_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
+{
+ aead_algs *a = (aead_algs *)aa;
+
+ if ((a->ksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
+ a_format(e, "cipher", "%s", a->c->name,
+ "no-key-size", "%lu", (unsigned long)asw->hashsz,
+ A_END);
+ return (-1);
+ }
+ return (0);
+}
+
+static int aead_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
+{
+ const aead_algs *a = (const aead_algs *)aa,
+ *b = (const aead_algs *)bb;
+ return (a->c == b->c && a->tsz == b->tsz);
+}
+
+static void aead_alginfo(const bulkalgs *aa, admin *adm)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+ a_info(adm, "cipher=%s", a->c->name,
+ "cipher-keysz=%lu", (unsigned long)a->ksz,
+ A_END);
+ a_info(adm, "mac=aead", "mac-tagsz=%lu", (unsigned long)a->tsz, A_END);
+}
+
+static size_t aead_overhead(const bulkalgs *aa)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+ return (a->tsz + SEQSZ + a->c->ohd);
+}
+
+static size_t aead_expsz(const bulkalgs *aa)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+ return (a->c->blksz < 16 ? MEG(64) : MEG(2048));
+}
+
+static bulkctx *aead_genkeys(const bulkalgs *aa, const deriveargs *da)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+ aead_ctx *bc = CREATE(aead_ctx);
+ octet k[MAXHASHSZ];
+ int i;
+
+ for (i = 0; i < NDIR; i++) {
+ if (!(da->f&(1 << i))) { bc->d[i].k = 0; continue; }
+ derivekey(k, a->ksz, da, i, "encryption");
+ bc->d[i].k = GAEAD_KEY(a->c, k, a->ksz);
+ }
+ bc->nsz = a->nsz; bc->tsz = a->tsz;
+ return (&bc->_b);
+}
+
+typedef struct aead_chal {
+ bulkchal _b;
+ gaead_key *k;
+} aead_chal;
+
+static bulkchal *aead_genchal(const bulkalgs *aa)
+{
+ const aead_algs *a = (const aead_algs *)aa;
+ aead_chal *c = CREATE(aead_chal);
+ rand_get(RAND_GLOBAL, buf_t, a->ksz);
+ c->k = GAEAD_KEY(a->c, buf_t, a->ksz);
+ IF_TRACING(T_CHAL, {
+ trace(T_CHAL, "chal: generated new challenge key");
+ trace_block(T_CRYPTO, "chal: new key", buf_t, a->ksz);
+ })
+ c->_b.tagsz = a->tsz;
+ return (&c->_b);
+}
+
+static int aead_chaltag(bulkchal *bc, const void *m, size_t msz,
+ uint32 seq, void *t)
+{
+ aead_chal *c = (aead_chal *)bc;
+ octet b[AEAD_NONCEMAX];
+ size_t nsz = keysz_pad(4, c->k->ops->c->noncesz);
+ size_t csz = 0;
+ int rc;
+
+ assert(nsz); assert(nsz <= sizeof(b));
+ memset(b, 0, nsz - 4); STORE32(b + nsz - 4, seq);
+ rc = gaead_encrypt(c->k, b, nsz, m, msz, 0, 0,
+ buf_t, &csz, t, c->_b.tagsz);
+ assert(!rc);
+ return (0);
+}
+
+static int aead_chalvrf(bulkchal *bc, const void *m, size_t msz,
+ uint32 seq, const void *t)
+{
+ aead_chal *c = (aead_chal *)bc;
+ octet b[AEAD_NONCEMAX];
+ size_t nsz = keysz(4, c->k->ops->c->noncesz);
+ size_t psz = 0;
+ int rc;
+
+ assert(nsz); assert(nsz <= sizeof(b));
+ memset(b, 0, nsz - 4); STORE32(b + nsz - 4, seq);
+ rc = gaead_decrypt(c->k, b, nsz, m, msz, 0, 0,
+ buf_t, &psz, t, c->_b.tagsz);
+ assert(rc >= 0);
+ return (rc == 1 ? 0 : -1);
+}
+
+static void aead_freechal(bulkchal *bc)
+ { aead_chal *c = (aead_chal *)bc; GAEAD_DESTROY(c->k); DESTROY(c); }
+
+static void aead_freealgs(bulkalgs *aa)
+ { aead_algs *a = (aead_algs *)aa; DESTROY(a); }
+
+static void aead_freectx(bulkctx *bbc)
+{
+ aead_ctx *bc = (aead_ctx *)bbc;
+ int i;
+
+ for (i = 0; i < NDIR; i++) { if (bc->d[i].k) GAEAD_DESTROY(bc->d[i].k); }
+ DESTROY(bc);
+}
+
+static int aead_encrypt(bulkctx *bbc, unsigned ty,
+ buf *b, buf *bb, uint32 seq)
+{
+ aead_ctx *bc = (aead_ctx *)bbc;
+ const octet *p = BCUR(b);
+ gaead_key *k = bc->d[DIR_OUT].k;
+ size_t sz = BLEFT(b);
+ size_t csz = sz + k->ops->c->ohd;
+ octet *qmac, *qseq, *qpk;
+ octet n[AEAD_NONCEMAX];
+ int rc;
+
+ assert(k);
+
+ if (buf_ensure(bb, bc->tsz + SEQSZ + csz)) return (0);
+ qmac = BCUR(bb); qseq = qmac + bc->tsz; qpk = qseq + SEQSZ;
+ STORE32(qseq, seq);
+
+ assert(bc->nsz <= sizeof(n));
+ memcpy(n, qseq, SEQSZ); STORE32(n + SEQSZ, ty);
+ if (bc->nsz > 8) memset(n + 8, 0, bc->nsz - 8);
+ TRACE_IV(n, bc->nsz);
+
+ rc = gaead_encrypt(k, n, bc->nsz, 0, 0, p, sz, qpk, &csz, qmac, bc->tsz);
+ assert(!rc);
+ BSTEP(bb, bc->tsz + SEQSZ + csz);
+ TRACE_CT(qpk, csz);
+ TRACE_MAC(qmac, bc->tsz);
+
+ return (0);
+}
+
+static int aead_decrypt(bulkctx *bbc, unsigned ty,
+ buf *b, buf *bb, uint32 *seq)
+{
+ aead_ctx *bc = (aead_ctx *)bbc;
+ gaead_key *k = bc->d[DIR_IN].k;
+ const octet *pmac, *pseq, *ppk;
+ size_t psz = BLEFT(b);
+ size_t sz;
+ octet *q = BCUR(bb);
+ octet n[AEAD_NONCEMAX];
+ int rc;
+
+ assert(k);
+
+ if (psz < bc->tsz + SEQSZ) {
+ T( trace(T_KEYSET, "keyset: block too small for keyset"); )
+ return (KSERR_MALFORMED);
+ }
+ sz = psz - bc->tsz - SEQSZ;
+ pmac = BCUR(b); pseq = pmac + bc->tsz; ppk = pseq + SEQSZ;
+
+ assert(bc->nsz <= sizeof(n));
+ memcpy(n, pseq, SEQSZ); STORE32(n + SEQSZ, ty);
+ if (bc->nsz > 8) memset(n + 8, 0, bc->nsz - 8);
+ TRACE_IV(n, bc->nsz);
+
+ rc = gaead_decrypt(k, n, bc->nsz, 0, 0, ppk, sz, q, &sz, pmac, bc->tsz);
+ assert(rc >= 0);
+ if (!rc) { TRACE_MACERR(pmac, bc->tsz); return (KSERR_DECRYPT); }
+
+ *seq = LOAD32(pseq);
+ BSTEP(bb, sz);
+ return (0);
+}
+
/*----- The NaCl box transform --------------------------------------------*
*
* This transform is very similar to the NaCl `crypto_secretbox' transform
*/
typedef struct naclbox_algs {
- bulkalgs _b;
- const gccipher *c; size_t cksz;
+ aead_algs _b;
+ const gccipher *c;
} naclbox_algs;
-typedef struct naclbox_ctx {
- bulkctx _b;
- struct { gcipher *c; } d[NDIR];
-} naclbox_ctx;
-
-
static bulkalgs *naclbox_getalgs(const algswitch *asw, dstr *e,
key_file *kf, key *k)
{
/* --- Collect the selected cipher and check that it's supported --- */
p = key_getattr(kf, k, "cipher");
- if (!p || strcmp(p, "salsa20") == 0) a->c = &salsa20;
- else if (strcmp(p, "salsa20/12") == 0) a->c = &salsa2012;
- else if (strcmp(p, "salsa20/8") == 0) a->c = &salsa208;
- else if (strcmp(p, "chacha20") == 0) a->c = &chacha20;
- else if (strcmp(p, "chacha12") == 0) a->c = &chacha12;
- else if (strcmp(p, "chacha8") == 0) a->c = &chacha8;
+ if (!p || strcmp(p, "salsa20") == 0)
+ { a->_b.c = &salsa20_naclbox; a->c = &salsa20; }
+ else if (strcmp(p, "salsa20/12") == 0)
+ { a->_b.c = &salsa2012_naclbox; a->c = &salsa2012; }
+ else if (strcmp(p, "salsa20/8") == 0)
+ { a->_b.c = &salsa208_naclbox; a->c = &salsa208; }
+ else if (strcmp(p, "chacha20") == 0)
+ { a->_b.c = &chacha20_naclbox; a->c = &chacha20; }
+ else if (strcmp(p, "chacha12") == 0)
+ { a->_b.c = &chacha12_naclbox; a->c = &chacha12; }
+ else if (strcmp(p, "chacha8") == 0)
+ { a->_b.c = &chacha8_naclbox; a->c = &chacha8; }
else {
a_format(e, "unknown-cipher", "%s", p, A_END);
goto fail;
}
+ a->_b.nsz = 8;
/* --- Collect the selected MAC, and check the tag length --- */
goto fail;
}
}
+ a->_b.tsz = 16;
- return (&a->_b);
+ return (&a->_b._b);
fail:
DESTROY(a);
return (0);
}
#endif
-static int naclbox_checkalgs(bulkalgs *aa, const algswitch *asw, dstr *e)
-{
- naclbox_algs *a = (naclbox_algs *)aa;
-
- if ((a->cksz = keysz(asw->hashsz, a->c->keysz)) == 0) {
- a_format(e, "cipher", "%s", a->c->name,
- "no-key-size", "%lu", (unsigned long)asw->hashsz,
- A_END);
- return (-1);
- }
- return (0);
-}
-
-static int naclbox_samealgsp(const bulkalgs *aa, const bulkalgs *bb)
-{
- const naclbox_algs *a = (const naclbox_algs *)aa,
- *b = (const naclbox_algs *)bb;
- return (a->c == b->c);
-}
+#define naclbox_checkalgs aead_checkalgs
+#define naclbox_samealgsp aead_samealgsp
static void naclbox_alginfo(const bulkalgs *aa, admin *adm)
{
a_info(adm, "mac=poly1305", "mac-tagsz=16", A_END);
}
-static size_t naclbox_overhead(const bulkalgs *aa)
- { return (POLY1305_TAGSZ + SEQSZ); }
-
-static size_t naclbox_expsz(const bulkalgs *aa)
- { return (MEG(2048)); }
-
-static bulkctx *naclbox_genkeys(const bulkalgs *aa, const deriveargs *da)
-{
- const naclbox_algs *a = (const naclbox_algs *)aa;
- naclbox_ctx *bc = CREATE(naclbox_ctx);
- octet k[MAXHASHSZ];
- int i;
-
- for (i = 0; i < NDIR; i++) {
- if (!(da->f&(1 << i))) { bc->d[i].c = 0; continue; }
- derivekey(k, a->cksz, da, i, "encryption");
- bc->d[i].c = GC_INIT(a->c, k, a->cksz);
- }
- return (&bc->_b);
-}
+#define naclbox_overhead aead_overhead
+#define naclbox_expsz aead_expsz
+#define naclbox_genkeys aead_genkeys
typedef struct naclbox_chal {
bulkchal _b;
{
const naclbox_algs *a = (const naclbox_algs *)aa;
naclbox_chal *c = CREATE(naclbox_chal);
- rand_get(RAND_GLOBAL, buf_t, a->cksz);
- c->c = GC_INIT(a->c, buf_t, a->cksz);
+ rand_get(RAND_GLOBAL, buf_t, a->_b.ksz);
+ c->c = GC_INIT(a->c, buf_t, a->_b.ksz);
IF_TRACING(T_CHAL, {
trace(T_CHAL, "chal: generated new challenge key");
- trace_block(T_CRYPTO, "chal: new key", buf_t, a->cksz);
+ trace_block(T_CRYPTO, "chal: new key", buf_t, a->_b.ksz);
})
c->_b.tagsz = POLY1305_TAGSZ;
return (&c->_b);
static void naclbox_freealgs(bulkalgs *aa)
{ naclbox_algs *a = (naclbox_algs *)aa; DESTROY(a); }
-static void naclbox_freectx(bulkctx *bbc)
-{
- naclbox_ctx *bc = (naclbox_ctx *)bbc;
- int i;
-
- for (i = 0; i < NDIR; i++) { if (bc->d[i].c) GC_DESTROY(bc->d[i].c); }
- DESTROY(bc);
-}
-
-static int naclbox_encrypt(bulkctx *bbc, unsigned ty,
- buf *b, buf *bb, uint32 seq)
-{
- naclbox_ctx *bc = (naclbox_ctx *)bbc;
- gcipher *c = bc->d[DIR_OUT].c;
- poly1305_key polyk;
- poly1305_ctx poly;
- const octet *p = BCUR(b);
- size_t sz = BLEFT(b);
- octet *qmac, *qseq, *qpk;
-
- assert(c);
-
- /* --- Determine the ciphertext layout --- */
-
- if (buf_ensure(bb, POLY1305_TAGSZ + SEQSZ + sz)) return (0);
- qmac = BCUR(bb); qseq = qmac + POLY1305_TAGSZ; qpk = qseq + SEQSZ;
- BSTEP(bb, POLY1305_TAGSZ + SEQSZ + sz);
-
- /* --- Construct and set the nonce --- */
-
- STORE32(qseq, seq);
- memcpy(buf_u, qseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
- GC_SETIV(c, buf_u);
- TRACE_IV(buf_u, SALSA20_NONCESZ);
-
- /* --- Determine the MAC key --- */
-
- GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
- poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
- poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
-
- /* --- Encrypt the message --- */
-
- GC_ENCRYPT(c, p, qpk, sz);
- TRACE_CT(qpk, sz);
-
- /* --- Compute the MAC --- */
-
- poly1305_hash(&poly, qpk, sz);
- poly1305_done(&poly, qmac);
- TRACE_MAC(qmac, POLY1305_TAGSZ);
-
- /* --- We're done --- */
-
- return (0);
-}
-
-static int naclbox_decrypt(bulkctx *bbc, unsigned ty,
- buf *b, buf *bb, uint32 *seq)
-{
- naclbox_ctx *bc = (naclbox_ctx *)bbc;
- gcipher *c = bc->d[DIR_IN].c;
- poly1305_key polyk;
- poly1305_ctx poly;
- const octet *pmac, *pseq, *ppk;
- size_t psz = BLEFT(b);
- size_t sz;
- octet *q = BCUR(bb);
-
- assert(c);
-
- /* --- Break up the packet into its components --- */
-
- if (psz < SEQSZ + POLY1305_TAGSZ) {
- T( trace(T_KEYSET, "keyset: block too small for keyset"); )
- return (KSERR_MALFORMED);
- }
- sz = psz - SEQSZ - POLY1305_TAGSZ;
- pmac = BCUR(b); pseq = pmac + POLY1305_TAGSZ; ppk = pseq + SEQSZ;
-
- /* --- Construct and set the nonce --- */
-
- memcpy(buf_u, pseq, SEQSZ); STORE32(buf_u + SEQSZ, ty);
- GC_SETIV(c, buf_u);
- TRACE_IV(buf_u, SALSA20_NONCESZ);
-
- /* --- Determine the MAC key --- */
-
- GC_ENCRYPT(c, 0, buf_u, POLY1305_KEYSZ + POLY1305_MASKSZ);
- poly1305_keyinit(&polyk, buf_u, POLY1305_KEYSZ);
- poly1305_macinit(&poly, &polyk, buf_u + POLY1305_KEYSZ);
-
- /* --- Verify the MAC on the packet --- */
-
- poly1305_hash(&poly, ppk, sz);
- poly1305_done(&poly, buf_u);
- TRACE_MAC(buf_u, POLY1305_TAGSZ);
- if (!ct_memeq(buf_u, pmac, POLY1305_TAGSZ)) {
- TRACE_MACERR(pmac, POLY1305_TAGSZ);
- return (KSERR_DECRYPT);
- }
-
- /* --- Decrypt the packet --- */
-
- GC_DECRYPT(c, ppk, q, sz);
-
- /* --- Finished --- */
-
- *seq = LOAD32(pseq);
- BSTEP(bb, sz);
- return (0);
-}
+#define naclbox_freectx aead_freectx
+#define naclbox_encrypt aead_encrypt
+#define naclbox_decrypt aead_decrypt
/*----- Bulk crypto transform table ---------------------------------------*/
BULK("v0", v0),
BULK("iiv", iiv),
+ BULK("aead", aead),
BULK("naclbox", naclbox),
#undef BULK
~mdw / tripe / commitdiff