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Make ssh_hash and ssh_mac expose a BinarySink.

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Just as I did a few commits ago with the low-level SHA_Bytes type
functions, the ssh_hash and ssh_mac abstract types now no longer have
a direct foo->bytes() update method at all. Instead, each one has a
foo->sink() function that returns a BinarySink with the same lifetime
as the hash context, and then the caller can feed data into that in
the usual way.

This lets me get rid of a couple more duplicate marshalling routines
in ssh.c: hash_string(), hash_uint32(), hash_mpint().
This commit is contained in:
Simon Tatham
2018-05-24 13:05:48 +01:00
parent 67de463cca
commit e27ddf6d28
9 changed files with 105 additions and 133 deletions
Download Patch File Download Diff File Expand all files Collapse all files

121
ssh.c
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@ -871,6 +871,7 @@ struct ssh_tag {
char *v_c, *v_s;
void *exhash;
BinarySink *exhash_bs;
Socket s;
@ -892,6 +893,7 @@ struct ssh_tag {
const struct ssh_mac *csmac, *scmac;
int csmac_etm, scmac_etm;
void *cs_mac_ctx, *sc_mac_ctx;
BinarySink *sc_mac_bs;
const struct ssh_compress *cscomp, *sccomp;
void *cs_comp_ctx, *sc_comp_ctx;
const struct ssh_kex *kex;
@ -1800,12 +1802,9 @@ static void ssh2_rdpkt(Ssh ssh)
st->pktin->data, st->maclen));
st->packetlen = 0;
{
unsigned char seq[4];
ssh->scmac->start(ssh->sc_mac_ctx);
PUT_32BIT(seq, st->incoming_sequence);
ssh->scmac->bytes(ssh->sc_mac_ctx, seq, 4);
}
ssh->scmac->start(ssh->sc_mac_ctx);
ssh->sc_mac_bs = ssh->scmac->sink(ssh->sc_mac_ctx);
put_uint32(ssh->sc_mac_bs, st->incoming_sequence);
for (;;) { /* Once around this loop per cipher block. */
/* Read another cipher-block's worth, and tack it onto the end. */
@ -1819,8 +1818,8 @@ static void ssh2_rdpkt(Ssh ssh)
st->pktin->data + st->packetlen,
st->cipherblk);
/* Feed that block to the MAC. */
ssh->scmac->bytes(ssh->sc_mac_ctx,
st->pktin->data + st->packetlen, st->cipherblk);
put_data(ssh->sc_mac_bs,
st->pktin->data + st->packetlen, st->cipherblk);
st->packetlen += st->cipherblk;
/* See if that gives us a valid packet. */
if (ssh->scmac->verresult(ssh->sc_mac_ctx,
@ -2284,25 +2283,6 @@ static int ssh_versioncmp(const char *a, const char *b)
return 0;
}
/*
* Utility routines for putting an SSH-protocol `string' and
* `uint32' into a hash state.
*/
static void hash_string(const struct ssh_hash *h, void *s, void *str, int len)
{
unsigned char lenblk[4];
PUT_32BIT(lenblk, len);
h->bytes(s, lenblk, 4);
h->bytes(s, str, len);
}
static void hash_uint32(const struct ssh_hash *h, void *s, unsigned i)
{
unsigned char intblk[4];
PUT_32BIT(intblk, i);
h->bytes(s, intblk, 4);
}
/*
* Packet construction functions. Mostly shared between SSH-1 and SSH-2.
*/
@ -2733,14 +2713,6 @@ void bndebug(char *string, Bignum b)
}
#endif
static void hash_mpint(const struct ssh_hash *h, void *s, Bignum b)
{
strbuf *tmp = strbuf_new();
put_mp_ssh2(tmp, b);
hash_string(h, s, tmp->u, tmp->len);
strbuf_free(tmp);
}
/*
* Packet decode functions for both SSH-1 and SSH-2.
*/
@ -6340,6 +6312,7 @@ static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
int keylen_padded;
unsigned char *key;
void *s, *s2;
BinarySink *bs;
if (keylen == 0)
return NULL;
@ -6351,11 +6324,12 @@ static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
/* First hlen bytes. */
s = h->init();
bs = h->sink(s);
if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
hash_mpint(h, s, K);
h->bytes(s, H, h->hlen);
h->bytes(s, &chr, 1);
h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
put_mp_ssh2(bs, K);
put_data(bs, H, h->hlen);
put_byte(bs, chr);
put_data(bs, ssh->v2_session_id, ssh->v2_session_id_len);
h->final(s, key);
/* Subsequent blocks of hlen bytes. */
@ -6363,12 +6337,13 @@ static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
int offset;
s = h->init();
bs = h->sink(s);
if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
hash_mpint(h, s, K);
h->bytes(s, H, h->hlen);
put_mp_ssh2(bs, K);
put_data(bs, H, h->hlen);
for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
h->bytes(s, key + offset - h->hlen, h->hlen);
put_data(bs, key + offset - h->hlen, h->hlen);
s2 = h->copy(s);
h->final(s2, key + offset);
}
@ -7155,14 +7130,13 @@ static void do_ssh2_transport(void *vctx)
s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
ssh->exhash = ssh->kex->hash->init();
hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c));
hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s));
hash_string(ssh->kex->hash, ssh->exhash,
s->our_kexinit, s->our_kexinitlen);
ssh->exhash_bs = ssh->kex->hash->sink(ssh->exhash);
put_stringz(ssh->exhash_bs, ssh->v_c);
put_stringz(ssh->exhash_bs, ssh->v_s);
put_string(ssh->exhash_bs, s->our_kexinit, s->our_kexinitlen);
sfree(s->our_kexinit);
/* Include the type byte in the hash of server's KEXINIT */
hash_string(ssh->kex->hash, ssh->exhash,
pktin->body - 1, pktin->length + 1);
put_string(ssh->exhash_bs, pktin->body - 1, pktin->length + 1);
if (s->warn_kex) {
ssh_set_frozen(ssh, 1);
@ -7402,18 +7376,18 @@ static void do_ssh2_transport(void *vctx)
* involve user interaction. */
set_busy_status(ssh->frontend, BUSY_NOT);
hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
put_string(ssh->exhash_bs, s->hostkeydata, s->hostkeylen);
if (dh_is_gex(ssh->kex)) {
if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
hash_uint32(ssh->kex->hash, ssh->exhash, DH_MIN_SIZE);
hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
put_uint32(ssh->exhash_bs, DH_MIN_SIZE);
put_uint32(ssh->exhash_bs, s->pbits);
if (!(ssh->remote_bugs & BUG_SSH2_OLDGEX))
hash_uint32(ssh->kex->hash, ssh->exhash, DH_MAX_SIZE);
hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
put_uint32(ssh->exhash_bs, DH_MAX_SIZE);
put_mp_ssh2(ssh->exhash_bs, s->p);
put_mp_ssh2(ssh->exhash_bs, s->g);
}
hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
put_mp_ssh2(ssh->exhash_bs, s->e);
put_mp_ssh2(ssh->exhash_bs, s->f);
dh_cleanup(ssh->kex_ctx);
freebn(s->f);
@ -7455,15 +7429,14 @@ static void do_ssh2_transport(void *vctx)
bombout(("unable to parse ECDH reply packet"));
crStopV;
}
hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
put_string(ssh->exhash_bs, s->hostkeydata, s->hostkeylen);
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
s->hostkeydata, s->hostkeylen);
{
strbuf *pubpoint = strbuf_new();
ssh_ecdhkex_getpublic(s->eckey, BinarySink_UPCAST(pubpoint));
hash_string(ssh->kex->hash, ssh->exhash,
pubpoint->u, pubpoint->len);
put_string(ssh->exhash_bs, pubpoint->u, pubpoint->len);
strbuf_free(pubpoint);
}
@ -7475,7 +7448,7 @@ static void do_ssh2_transport(void *vctx)
bombout(("unable to parse ECDH reply packet"));
crStopV;
}
hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
put_string(ssh->exhash_bs, keydata, keylen);
s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
if (!s->K) {
ssh_ecdhkex_freekey(s->eckey);
@ -7673,8 +7646,7 @@ static void do_ssh2_transport(void *vctx)
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
s->hostkeydata,
s->hostkeylen);
hash_string(ssh->kex->hash, ssh->exhash,
s->hostkeydata, s->hostkeylen);
put_string(ssh->exhash_bs, s->hostkeydata, s->hostkeylen);
}
/*
* Can't loop as we have no token to pass to
@ -7722,18 +7694,18 @@ static void do_ssh2_transport(void *vctx)
set_busy_status(ssh->frontend, BUSY_NOT);
if (!s->hkey)
hash_string(ssh->kex->hash, ssh->exhash, NULL, 0);
put_stringz(ssh->exhash_bs, "");
if (dh_is_gex(ssh->kex)) {
/* min, preferred, max */
hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits);
hash_uint32(ssh->kex->hash, ssh->exhash, s->pbits * 2);
put_uint32(ssh->exhash_bs, s->pbits);
put_uint32(ssh->exhash_bs, s->pbits);
put_uint32(ssh->exhash_bs, s->pbits * 2);
hash_mpint(ssh->kex->hash, ssh->exhash, s->p);
hash_mpint(ssh->kex->hash, ssh->exhash, s->g);
put_mp_ssh2(ssh->exhash_bs, s->p);
put_mp_ssh2(ssh->exhash_bs, s->g);
}
hash_mpint(ssh->kex->hash, ssh->exhash, s->e);
hash_mpint(ssh->kex->hash, ssh->exhash, s->f);
put_mp_ssh2(ssh->exhash_bs, s->e);
put_mp_ssh2(ssh->exhash_bs, s->f);
/*
* MIC verification is done below, after we compute the hash
@ -7767,8 +7739,7 @@ static void do_ssh2_transport(void *vctx)
bombout(("unable to parse RSA public key packet"));
crStopV;
}
hash_string(ssh->kex->hash, ssh->exhash,
s->hostkeydata, s->hostkeylen);
put_string(ssh->exhash_bs, s->hostkeydata, s->hostkeylen);
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
s->hostkeydata, s->hostkeylen);
@ -7790,7 +7761,7 @@ static void do_ssh2_transport(void *vctx)
crStopV;
}
hash_string(ssh->kex->hash, ssh->exhash, s->rsakeydata, s->rsakeylen);
put_string(ssh->exhash_bs, s->rsakeydata, s->rsakeylen);
/*
* Next, set up a shared secret K, of precisely KLEN -
@ -7836,7 +7807,7 @@ static void do_ssh2_transport(void *vctx)
put_string(s->pktout, outstr, outstrlen);
ssh2_pkt_send_noqueue(ssh, s->pktout);
hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
put_string(ssh->exhash_bs, outstr, outstrlen);
strbuf_free(buf);
sfree(outstr);
@ -7860,7 +7831,7 @@ static void do_ssh2_transport(void *vctx)
sfree(s->rsakeydata);
}
hash_mpint(ssh->kex->hash, ssh->exhash, s->K);
put_mp_ssh2(ssh->exhash_bs, s->K);
assert(ssh->kex->hash->hlen <= sizeof(s->exchange_hash));
ssh->kex->hash->final(ssh->exhash, s->exchange_hash);