X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=site.c;h=6e5c5a67d56ed0d8b2bf8a06662298c9039a6c27;hb=403cdd364693a05c700f04085fc05dbf575d97ef;hp=2bab3f769238af33fa4fd1d48e8baf07de361513;hpb=04c5c5d72fc4f8fad0bfeec693ccdf040e0a4a55;p=secnet.git diff --git a/site.c b/site.c index 2bab3f7..6e5c5a6 100644 --- a/site.c +++ b/site.c @@ -107,6 +107,8 @@ #define SITE_SENTMSG5 7 #define SITE_WAIT 8 +#define CASES_MSG3_KNOWN LABEL_MSG3: case LABEL_MSG3BIS + int32_t site_max_start_pad = 4*4; static cstring_t state_name(uint32_t state) @@ -310,18 +312,19 @@ struct site { struct resolver_if *resolver; struct log_if *log; struct random_if *random; - struct rsaprivkey_if *privkey; - struct rsapubkey_if *pubkey; + struct sigprivkey_if *privkey; + struct sigpubkey_if *pubkey; struct transform_if **transforms; int ntransforms; struct dh_if *dh; struct hash_if *hash; uint32_t index; /* Index of this site */ + uint32_t early_capabilities; uint32_t local_capabilities; int32_t setup_retries; /* How many times to send setup packets */ int32_t setup_retry_interval; /* Initial timeout for setup packets */ - int32_t wait_timeout; /* How long to wait if setup unsuccessful */ + int32_t wait_timeout_mean; /* How long to wait if setup unsuccessful */ int32_t mobile_peer_expiry; /* How long to remember 2ary addresses */ int32_t key_lifetime; /* How long a key lasts once set up */ int32_t key_renegotiate_time; /* If we see traffic (or a keepalive) @@ -505,10 +508,10 @@ static void dispose_transform(struct transform_inst_if **transform_var) static _Bool type_is_msg34(uint32_t type) { - return - type == LABEL_MSG3 || - type == LABEL_MSG3BIS || - type == LABEL_MSG4; + switch (type) { + case CASES_MSG3_KNOWN: case LABEL_MSG4: return True; + default: return False; + } } struct parsedname { @@ -535,6 +538,16 @@ struct msg { char *sig; }; +static int32_t wait_timeout(struct site *st) { + int32_t t = st->wait_timeout_mean; + int8_t factor; + if (t < INT_MAX/2) { + st->random->generate(st->random->st,sizeof(factor),&factor); + t += (t / 256) * factor; + } + return t; +} + static _Bool set_new_transform(struct site *st, char *pk) { _Bool ok; @@ -565,7 +578,7 @@ static _Bool set_new_transform(struct site *st, char *pk) slog(st,LOG_SETUP_INIT,"key exchange negotiated transform" " %d (capabilities ours=%#"PRIx32" theirs=%#"PRIx32")", - st->chosen_transform->capab_transformnum, + st->chosen_transform->capab_bit, st->local_capabilities, st->remote_capabilities); return True; } @@ -604,7 +617,8 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) { void *hst; uint8_t *hash; - string_t dhpub, sig; + string_t dhpub; + unsigned minor; st->retries=st->setup_retries; BUF_ALLOC(&st->buffer,what); @@ -616,7 +630,8 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) struct xinfoadd xia; append_string_xinfo_start(&st->buffer,&xia,st->localname); - if ((st->local_capabilities & CAPAB_EARLY) || (type != LABEL_MSG1)) { + if ((st->local_capabilities & st->early_capabilities) || + (type != LABEL_MSG1)) { buf_append_uint32(&st->buffer,st->local_capabilities); } if (type_is_msg34(type)) { @@ -632,8 +647,11 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) if (hacky_par_mid_failnow()) return False; - if (type==LABEL_MSG3BIS) - buf_append_uint8(&st->buffer,st->chosen_transform->capab_transformnum); + if (MSGMAJOR(type) == 3) do { + minor = MSGMINOR(type); + if (minor < 1) break; + buf_append_uint8(&st->buffer,st->chosen_transform->capab_bit); + } while (0); dhpub=st->dh->makepublic(st->dh->st,st->dhsecret,st->dh->len); buf_append_string(&st->buffer,dhpub); @@ -642,11 +660,15 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) hst=st->hash->init(); st->hash->update(hst,st->buffer.start,st->buffer.size); st->hash->final(hst,hash); - sig=st->privkey->sign(st->privkey->st,hash,st->hash->len); - buf_append_string(&st->buffer,sig); - free(sig); + bool_t ok=st->privkey->sign(st->privkey->st,hash,st->hash->len, + &st->buffer); + if (!ok) goto fail; free(hash); return True; + + fail: + free(hash); + return False; } static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm) @@ -668,6 +690,8 @@ static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm) static bool_t unpick_msg(struct site *st, uint32_t type, struct buffer_if *msg, struct msg *m) { + unsigned minor; + m->capab_transformnum=-1; m->hashstart=msg->start; CHECK_AVAIL(msg,4); @@ -703,12 +727,19 @@ static bool_t unpick_msg(struct site *st, uint32_t type, CHECK_EMPTY(msg); return True; } - if (type==LABEL_MSG3BIS) { - CHECK_AVAIL(msg,1); - m->capab_transformnum = buf_unprepend_uint8(msg); - } else { - m->capab_transformnum = CAPAB_TRANSFORMNUM_ANCIENT; - } + if (MSGMAJOR(type) == 3) do { + minor = MSGMINOR(type); +#define MAYBE_READ_CAP(minminor, kind, dflt) do { \ + if (minor < (minminor)) \ + m->capab_##kind##num = (dflt); \ + else { \ + CHECK_AVAIL(msg, 1); \ + m->capab_##kind##num = buf_unprepend_uint8(msg); \ + } \ +} while (0) + MAYBE_READ_CAP(1, transform, CAPAB_BIT_ANCIENTTRANSFORM); +#undef MAYBE_READ_CAP + } while (0); CHECK_AVAIL(msg,2); m->pklen=buf_unprepend_uint16(msg); CHECK_AVAIL(msg,m->pklen); @@ -757,13 +788,13 @@ static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, return False; } if (type==LABEL_MSG2) return True; - if (!consttime_memeq(m->nR,st->remoteN,NONCELEN)!=0) { + if (!consttime_memeq(m->nR,st->remoteN,NONCELEN)) { *error="wrong remotely-generated nonce"; return False; } /* MSG3 has complicated rules about capabilities, which are * handled in process_msg3. */ - if (type==LABEL_MSG3 || type==LABEL_MSG3BIS) return True; + if (MSGMAJOR(type) == 3) return True; if (m->remote_capabilities!=st->remote_capabilities) { *error="remote capabilities changed"; return False; @@ -814,25 +845,32 @@ static bool_t process_msg2(struct site *st, struct buffer_if *msg2, /* Select the transform to use */ - uint32_t remote_transforms = st->remote_capabilities & CAPAB_TRANSFORM_MASK; - if (!remote_transforms) + uint32_t remote_crypto_caps = st->remote_capabilities & CAPAB_TRANSFORM_MASK; + if (!remote_crypto_caps) /* old secnets only had this one transform */ - remote_transforms = 1UL << CAPAB_TRANSFORMNUM_ANCIENT; + remote_crypto_caps = 1UL << CAPAB_BIT_ANCIENTTRANSFORM; + +#define CHOOSE_CRYPTO(kind, whats) do { \ + struct kind##_if *iface; \ + uint32_t bit, ours = 0; \ + int i; \ + for (i= 0; i < st->n##kind##s; i++) { \ + iface=st->kind##s[i]; \ + bit = 1UL << iface->capab_bit; \ + if (bit & remote_crypto_caps) goto kind##_found; \ + ours |= bit; \ + } \ + slog(st,LOG_ERROR,"no " whats " in common" \ + " (us %#"PRIx32"; them: %#"PRIx32")", \ + st->local_capabilities & ours, remote_crypto_caps); \ + return False; \ +kind##_found: \ + st->chosen_##kind = iface; \ +} while (0) - struct transform_if *ti; - int i; - for (i=0; intransforms; i++) { - ti=st->transforms[i]; - if ((1UL << ti->capab_transformnum) & remote_transforms) - goto transform_found; - } - slog(st,LOG_ERROR,"no transforms in common" - " (us %#"PRIx32"; them: %#"PRIx32")", - st->local_capabilities & CAPAB_TRANSFORM_MASK, - remote_transforms); - return False; - transform_found: - st->chosen_transform=ti; + CHOOSE_CRYPTO(transform, "transforms"); + +#undef CHOOSE_CRYPTO memcpy(st->remoteN,m.nR,NONCELEN); return True; @@ -844,8 +882,9 @@ static bool_t generate_msg3(struct site *st) and create message number 3. */ st->random->generate(st->random->st,st->dh->len,st->dhsecret); return generate_msg(st, - (st->remote_capabilities & CAPAB_TRANSFORM_MASK - ? LABEL_MSG3BIS : LABEL_MSG3), + (st->remote_capabilities & CAPAB_TRANSFORM_MASK) + ? LABEL_MSG3BIS + : LABEL_MSG3, "site:MSG3"); } @@ -879,7 +918,10 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, struct msg m; cstring_t err; - assert(msgtype==LABEL_MSG3 || msgtype==LABEL_MSG3BIS); + switch (msgtype) { + case CASES_MSG3_KNOWN: break; + default: assert(0); + } if (!unpick_msg(st,msgtype,msg3,&m)) return False; if (!check_msg(st,msgtype,&m,&err)) { @@ -887,31 +929,46 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, return False; } uint32_t capab_adv_late = m.remote_capabilities - & ~st->remote_capabilities & CAPAB_EARLY; + & ~st->remote_capabilities & st->early_capabilities; if (capab_adv_late) { slog(st,LOG_SEC,"msg3 impermissibly adds early capability flag(s)" " %#"PRIx32" (was %#"PRIx32", now %#"PRIx32")", capab_adv_late, st->remote_capabilities, m.remote_capabilities); return False; } - st->remote_capabilities|=m.remote_capabilities; - struct transform_if *ti; - int i; - for (i=0; intransforms; i++) { - ti=st->transforms[i]; - if (ti->capab_transformnum == m.capab_transformnum) - goto transform_found; - } - slog(st,LOG_SEC,"peer chose unknown-to-us transform %d!", - m.capab_transformnum); - return False; - transform_found: - st->chosen_transform=ti; +#define CHOSE_CRYPTO(kind, what) do { \ + struct kind##_if *iface; \ + int i; \ + for (i=0; in##kind##s; i++) { \ + iface=st->kind##s[i]; \ + if (iface->capab_bit == m.capab_##kind##num) \ + goto kind##_found; \ + } \ + slog(st,LOG_SEC,"peer chose unknown-to-us " what " %d!", \ + m.capab_##kind##num); \ + return False; \ +kind##_found: \ + st->chosen_##kind=iface; \ +} while (0) + + CHOSE_CRYPTO(transform, "transform"); + +#undef CHOSE_CRYPTO if (!process_msg3_msg4(st,&m)) return False; + /* Update our idea of the remote site's capabilities, now that we've + * verified that its message was authentic. + * + * Our previous idea of the remote site's capabilities came from the + * unauthenticated MSG1. We've already checked that this new message + * doesn't change any of the bits we relied upon in the past, but it may + * also have set additional capability bits. We simply throw those away + * now, and use the authentic capabilities from this MSG3. */ + st->remote_capabilities=m.remote_capabilities; + /* Terminate their DH public key with a '0' */ m.pk[m.pklen]=0; /* Invent our DH secret key */ @@ -1353,7 +1410,7 @@ static void decrement_resolving_count(struct site *st, int by) } else if (st->local_mobile) { /* Not very good. We should queue (another) renegotiation * so that we can update the peer address. */ - st->key_renegotiate_time=st->now+st->wait_timeout; + st->key_renegotiate_time=st->now+wait_timeout(st); } else { slog(st,LOG_SETUP_INIT,"resolution failed: " " continuing to use source address of peer's packets"); @@ -1466,7 +1523,8 @@ static void set_link_quality(struct site *st) static void enter_state_run(struct site *st) { - slog(st,LOG_STATE,"entering state RUN"); + slog(st,LOG_STATE,"entering state RUN%s", + current_valid(st) ? " (keyed)" : " (unkeyed)"); st->state=SITE_RUN; st->timeout=0; @@ -1628,7 +1686,7 @@ static bool_t send_msg7(struct site *st, cstring_t reason) static void enter_state_wait(struct site *st) { slog(st,LOG_STATE,"entering state WAIT"); - st->timeout=st->now+st->wait_timeout; + st->timeout=st->now+wait_timeout(st); st->state=SITE_WAIT; set_link_quality(st); BUF_FREE(&st->buffer); /* will have had an outgoing packet in it */ @@ -1770,14 +1828,34 @@ static bool_t named_for_us(struct site *st, const struct buffer_if *buf_in, } static bool_t we_have_priority(struct site *st, const struct msg *m) { - if ((st->local_capabilities & m->remote_capabilities) - && CAPAB_PRIORITY_MOBILE) { + if (st->local_capabilities & m->remote_capabilities & + CAPAB_PRIORITY_MOBILE) { if (st->local_mobile) return True; if (st-> peer_mobile) return False; } return st->our_name_later; } +static bool_t setup_late_msg_ok(struct site *st, + const struct buffer_if *buf_in, + uint32_t msgtype, + const struct comm_addr *source) { + /* For setup packets which seem from their type like they are + * late. Maybe they came via a different path. All we do is make + * a note of the sending address, iff they look like they are part + * of the current key setup attempt. */ + struct msg m; + if (!named_for_us(st,buf_in,msgtype,&m)) + /* named_for_us calls unpick_msg which gets the nonces */ + return False; + if (!consttime_memeq(m.nR,st->remoteN,NONCELEN) || + !consttime_memeq(m.nL,st->localN, NONCELEN)) + /* spoof ? from stale run ? who knows */ + return False; + transport_setup_msgok(st,source); + return True; +} + /* This function is called by the communication device to deliver packets from our peers. It should return True if the packet is recognised as being for @@ -1898,6 +1976,10 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, case LABEL_MSG2: /* Setup packet: expected only in state SENTMSG1 */ if (st->state!=SITE_SENTMSG1) { + if ((st->state==SITE_SENTMSG3 || + st->state==SITE_SENTMSG5) && + setup_late_msg_ok(st,buf,msgtype,source)) + break; slog(st,LOG_UNEXPECTED,"unexpected MSG2"); } else if (process_msg2(st,buf,source)) { transport_setup_msgok(st,source); @@ -1906,10 +1988,12 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, slog(st,LOG_SEC,"invalid MSG2"); } break; - case LABEL_MSG3: - case LABEL_MSG3BIS: + case CASES_MSG3_KNOWN: /* Setup packet: expected only in state SENTMSG2 */ if (st->state!=SITE_SENTMSG2) { + if ((st->state==SITE_SENTMSG4) && + setup_late_msg_ok(st,buf,msgtype,source)) + break; slog(st,LOG_UNEXPECTED,"unexpected MSG3"); } else if (process_msg3(st,buf,source,msgtype)) { transport_setup_msgok(st,source); @@ -1921,6 +2005,9 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, case LABEL_MSG4: /* Setup packet: expected only in state SENTMSG3 */ if (st->state!=SITE_SENTMSG3) { + if ((st->state==SITE_SENTMSG5) && + setup_late_msg_ok(st,buf,msgtype,source)) + break; slog(st,LOG_UNEXPECTED,"unexpected MSG4"); } else if (process_msg4(st,buf,source)) { transport_setup_msgok(st,source); @@ -2071,6 +2158,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, assert(index_sequence < 0xffffffffUL); st->index = ++index_sequence; st->local_capabilities = 0; + st->early_capabilities = CAPAB_PRIORITY_MOBILE; st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc); #define GET_CLOSURE_LIST(dictkey,things,nthings,CL_TYPE) do{ \ @@ -2105,12 +2193,12 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, st->log=find_cl_if(dict,"log",CL_LOG,True,"site",loc); st->random=find_cl_if(dict,"random",CL_RANDOMSRC,True,"site",loc); - st->privkey=find_cl_if(dict,"local-key",CL_RSAPRIVKEY,True,"site",loc); + st->privkey=find_cl_if(dict,"local-key",CL_SIGPRIVKEY,True,"site",loc); st->addresses=dict_read_string_array(dict,"address",False,"site",loc,0); if (st->addresses) st->remoteport=dict_read_number(dict,"port",True,"site",loc,0); else st->remoteport=0; - st->pubkey=find_cl_if(dict,"key",CL_RSAPUBKEY,True,"site",loc); + st->pubkey=find_cl_if(dict,"key",CL_SIGPUBKEY,True,"site",loc); GET_CLOSURE_LIST("transform",transforms,ntransforms,CL_TRANSFORM); @@ -2124,7 +2212,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, st->key_lifetime= CFG_NUMBER("key-lifetime", KEY_LIFETIME); st->setup_retries= CFG_NUMBER("setup-retries", SETUP_RETRIES); st->setup_retry_interval= CFG_NUMBER("setup-timeout", SETUP_RETRY_INTERVAL); - st->wait_timeout= CFG_NUMBER("wait-time", WAIT_TIME); + st->wait_timeout_mean= CFG_NUMBER("wait-time", WAIT_TIME); st->mtu_target= dict_read_number(dict,"mtu-target",False,"site",loc,0); st->mobile_peer_expiry= dict_read_number( @@ -2187,14 +2275,18 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, st->sharedsecretlen=st->sharedsecretallocd=0; st->sharedsecret=0; - for (i=0; intransforms; i++) { - struct transform_if *ti=st->transforms[i]; - uint32_t capbit = 1UL << ti->capab_transformnum; - if (st->local_capabilities & capbit) - slog(st,LOG_ERROR,"transformnum capability bit" - " %d (%#"PRIx32") reused", ti->capab_transformnum, capbit); - st->local_capabilities |= capbit; - } +#define SET_CAPBIT(bit) do { \ + uint32_t capflag = 1UL << (bit); \ + if (st->local_capabilities & capflag) \ + slog(st,LOG_ERROR,"capability bit" \ + " %d (%#"PRIx32") reused", (bit), capflag); \ + st->local_capabilities |= capflag; \ +} while (0) + + for (i=0; intransforms; i++) + SET_CAPBIT(st->transforms[i]->capab_bit); + +#undef SET_CAPBIT if (st->local_mobile || st->peer_mobile) st->local_capabilities |= CAPAB_PRIORITY_MOBILE;