/* -*-c-*-
*
- * $Id: keyset.c,v 1.6 2003/04/06 10:26:35 mdw Exp $
+ * $Id: keyset.c,v 1.9 2003/10/15 09:29:38 mdw Exp $
*
* Handling of symmetric keysets
*
/*----- Revision history --------------------------------------------------*
*
* $Log: keyset.c,v $
+ * Revision 1.9 2003/10/15 09:29:38 mdw
+ * Cosmetic fix to changelog comment.
+ *
+ * Revision 1.8 2003/07/13 11:19:49 mdw
+ * Incompatible protocol fix! Include message type code under MAC tag to
+ * prevent cut-and-paste from key-exchange messages to general packet
+ * transport.
+ *
+ * Revision 1.7 2003/05/17 11:00:47 mdw
+ * Don't make scary messages just because one key didn't work on a message:
+ * only be frightened if they all fail. Set initial keyset refcount
+ * correctly.
+ *
* Revision 1.6 2003/04/06 10:26:35 mdw
* Report peer name on decrypt errors.
*
/* --- Encrypted data format --- *
*
- * Let %$p_i$% be the %$i$%-th plaintext message. We first compute
+ * Let %$p_i$% be the %$i$%-th plaintext message, with type %$t$%. We first
+ * compute
*
* %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$%
*
* as the CBC-ciphertext of %$p_i$%, and then
*
- * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(i, c_i)$%
+ * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(t, i, c_i)$%
*
* as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair
* %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA
/* --- @doencrypt@ --- *
*
* Arguments: @keyset *ks@ = pointer to keyset to use
+ * @unsigned ty@ = type of message this is
* @buf *b@ = pointer to an input buffer
* @buf *bb@ = pointer to an output buffer
*
* keyset is OK to use.
*/
-static int doencrypt(keyset *ks, buf *b, buf *bb)
+static int doencrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
{
ghash *h;
gcipher *c;
octet *qmac, *qseq, *qiv, *qpk;
uint32 oseq;
size_t osz, nsz;
+ octet t[4];
int rc = 0;
/* --- Allocate the required buffer space --- */
return (0); /* Caution! */
qmac = BCUR(bb); qseq = qmac + MACSZ; qiv = qseq + SEQSZ; qpk = qiv + IVSZ;
BSTEP(bb, MACSZ + SEQSZ + IVSZ + sz);
+ STORE32(t, ty);
/* --- Encrypt the packet --- */
/* --- Now compute the MAC --- */
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);
/* --- @dodecrypt@ --- *
*
* Arguments: @keyset *ks@ = pointer to keyset to use
+ * @unsigned ty@ = expected type code
* @buf *b@ = pointer to an input buffer
* @buf *bb@ = pointer to an output buffer
* @uint32 *seq@ = where to store the sequence number
* packet, and the packet's sequence number is stored in @*seq@.
*/
-static int dodecrypt(keyset *ks, buf *b, buf *bb, uint32 *seq)
+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 ivsz = c->ops->c->blksz;
octet *mac;
int eq;
+ octet t[4];
/* --- Break up the packet into its components --- */
}
sz = psz - IVSZ - SEQSZ - MACSZ;
pmac = BCUR(b); pseq = pmac + MACSZ; 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);
})
h->ops->destroy(h);
if (!eq) {
- a_warn("incorrect MAC on packet from `%s'", p_name(ks->p));
IF_TRACING(T_KEYSET, {
- trace(T_KEYSET, "keyset: decryption failed");
+ trace(T_KEYSET, "keyset: incorrect MAC: decryption failed");
trace_block(T_CRYPTO, "crypto: expected MAC", pmac, MACSZ);
})
return (-1);
#undef GETHASH
T( ks->seq = seq++; )
+ ks->ref = 1;
ks->t_exp = now + T_EXP;
ks->sz_exp = SZ_EXP;
ks->oseq = ks->iseq = 0;
/* --- @ks_encrypt@ --- *
*
* Arguments: @keyset *ks@ = pointer to a keyset
+ * @unsigned ty@ = message type
* @buf *b@ = pointer to input buffer
* @buf *bb@ = pointer to output buffer
*
* used even if it's marked as not for data output.
*/
-int ks_encrypt(keyset *ks, buf *b, buf *bb)
+int ks_encrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
{
time_t now = time(0);
buf_break(bb);
return (0);
}
- return (doencrypt(ks, b, bb));
+ return (doencrypt(ks, ty, b, bb));
}
/* --- @ks_decrypt@ --- *
*
* Arguments: @keyset *ks@ = pointer to a keyset
+ * @unsigned ty@ = expected type code
* @buf *b@ = pointer to an input buffer
* @buf *bb@ = pointer to an output buffer
*
* marking that it's not for encryption.
*/
-int ks_decrypt(keyset *ks, buf *b, buf *bb)
+int ks_decrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
{
time_t now = time(0);
uint32 seq;
if (!KEYOK(ks, now) ||
buf_ensure(bb, BLEN(b)) ||
- dodecrypt(ks, b, bb, &seq) ||
+ dodecrypt(ks, ty, b, bb, &seq) ||
dosequence(ks, seq))
return (-1);
return (0);
/* --- @ksl_encrypt@ --- *
*
* Arguments: @keyset **ksroot@ = pointer to keyset list head
+ * @unsigned ty@ = message type
* @buf *b@ = pointer to input buffer
* @buf *bb@ = pointer to output buffer
*
* Use: Encrypts a packet.
*/
-int ksl_encrypt(keyset **ksroot, buf *b, buf *bb)
+int ksl_encrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb)
{
time_t now = time(0);
keyset *ks = *ksroot;
ks = ks->next;
}
- return (doencrypt(ks, b, bb));
+ return (doencrypt(ks, ty, b, bb));
}
/* --- @ksl_decrypt@ --- *
*
* Arguments: @keyset **ksroot@ = pointer to keyset list head
+ * @unsigned ty@ = expected type code
* @buf *b@ = pointer to input buffer
* @buf *bb@ = pointer to output buffer
*
* Use: Decrypts a packet.
*/
-int ksl_decrypt(keyset **ksroot, buf *b, buf *bb)
+int ksl_decrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb)
{
time_t now = time(0);
keyset *ks;
for (ks = *ksroot; ks; ks = ks->next) {
if (!KEYOK(ks, now))
continue;
- if (!dodecrypt(ks, b, bb, &seq)) {
+ if (!dodecrypt(ks, ty, b, bb, &seq)) {
if (ks->f & KSF_LISTEN) {
T( trace(T_KEYSET, "keyset: implicitly activating keyset %u",
ks->seq); )
return (dosequence(ks, seq));
}
}
- T( trace(T_KEYSET, "keyset: no matching keys"); )
+ T( trace(T_KEYSET, "keyset: no matching keys, or incorrect MAC"); )
return (-1);
}
~mdw / tripe / blobdiff