X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=site.c;h=2cb53f6038a8fc8775eabdc7e88b33e9298d42e9;hp=98bd6b678a7bc73f0d2b903e2931e560cc4933f8;hb=45a1170652384baf744a5e61d576af534c7b8b14;hpb=7e29719ec13da8db08c7aa4753d958141967bf0a diff --git a/site.c b/site.c index 98bd6b6..2cb53f6 100644 --- a/site.c +++ b/site.c @@ -244,6 +244,7 @@ struct site { struct hash_if *hash; uint32_t index; /* Index of this site */ + 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 */ @@ -275,6 +276,7 @@ struct site { packet; we keep trying to continue the exchange, and have to timeout before we can listen for another setup packet); perhaps we should keep a list of 'bad' sources for setup packets. */ + uint32_t remote_capabilities; uint32_t setup_session_id; transport_peers setup_peers; uint8_t localN[NONCELEN]; /* Nonces for key exchange */ @@ -332,11 +334,42 @@ static bool_t enter_new_state(struct site *st,uint32_t next); static void enter_state_wait(struct site *st); static void activate_new_key(struct site *st); +static bool_t is_transform_valid(struct transform_inst_if *transform) +{ + return transform && transform->valid(transform->st); +} + static bool_t current_valid(struct site *st) { - return st->current.transform->valid(st->current.transform->st); + return is_transform_valid(st->current.transform); +} + +#define DEFINE_CALL_TRANSFORM(fwdrev) \ +static int call_transform_##fwdrev(struct site *st, \ + struct transform_inst_if *transform, \ + struct buffer_if *buf, \ + const char **errmsg) \ +{ \ + if (!is_transform_valid(transform)) { \ + *errmsg="transform not set up"; \ + return 1; \ + } \ + return transform->fwdrev(transform->st,buf,errmsg); \ } +DEFINE_CALL_TRANSFORM(forwards) +DEFINE_CALL_TRANSFORM(reverse) + +static void dispose_transform(struct transform_inst_if **transform_var) +{ + struct transform_inst_if *transform=*transform_var; + if (transform) { + transform->delkey(transform->st); + transform->destroy(transform->st); + } + *transform_var = 0; +} + #define CHECK_AVAIL(b,l) do { if ((b)->size<(l)) return False; } while(0) #define CHECK_EMPTY(b) do { if ((b)->size!=0) return False; } while(0) #define CHECK_TYPE(b,t) do { uint32_t type; \ @@ -347,8 +380,7 @@ static bool_t current_valid(struct site *st) struct parsedname { int32_t len; uint8_t *name; - int32_t extrainfo_len; - uint8_t *extrainfo; + struct buffer_if extrainfo; }; struct msg { @@ -357,6 +389,7 @@ struct msg { uint32_t source; struct parsedname remote; struct parsedname local; + uint32_t remote_capabilities; uint8_t *nR; uint8_t *nL; int32_t pklen; @@ -366,6 +399,44 @@ struct msg { char *sig; }; +static void set_new_transform(struct site *st) +{ + struct transform_if *generator=st->transform; + struct transform_inst_if *generated=generator->create(generator->st); + generated->setkey(generated->st,st->sharedsecret, + st->sharedsecretlen,st->setup_priority); + dispose_transform(&st->new_transform); + st->new_transform=generated; +} + +struct xinfoadd { + int32_t lenpos, afternul; +}; +static void append_string_xinfo_start(struct buffer_if *buf, + struct xinfoadd *xia, + const char *str) + /* Helps construct one of the names with additional info as found + * in MSG1..4. Call this function first, then append all the + * desired extra info (not including the nul byte) to the buffer, + * then call append_string_xinfo_done. */ +{ + xia->lenpos = buf->size; + buf_append_string(buf,str); + buf_append_uint8(buf,0); + xia->afternul = buf->size; +} +static void append_string_xinfo_done(struct buffer_if *buf, + struct xinfoadd *xia) +{ + /* we just need to adjust the string length */ + if (buf->size == xia->afternul) { + /* no extra info, strip the nul too */ + buf_unappend_uint8(buf); + } else { + put_uint16(buf->start+xia->lenpos, buf->size-(xia->lenpos+2)); + } +} + /* Build any of msg1 to msg4. msg5 and msg6 are built from the inside out using a transform of config data supplied by netlink */ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) @@ -381,7 +452,14 @@ static bool_t generate_msg(struct site *st, uint32_t type, cstring_t what) (type==LABEL_MSG1?0:st->setup_session_id)); buf_append_uint32(&st->buffer,st->index); buf_append_uint32(&st->buffer,type); - buf_append_string(&st->buffer,st->localname); + + struct xinfoadd xia; + append_string_xinfo_start(&st->buffer,&xia,st->localname); + if ((st->local_capabilities & CAPAB_EARLY) || (type != LABEL_MSG1)) { + buf_append_uint32(&st->buffer,st->local_capabilities); + } + append_string_xinfo_done(&st->buffer,&xia); + buf_append_string(&st->buffer,st->remotename); memcpy(buf_append(&st->buffer,NONCELEN),st->localN,NONCELEN); if (type==LABEL_MSG1) return True; @@ -412,11 +490,9 @@ static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm) nm->name=buf_unprepend(msg,nm->len); uint8_t *nul=memchr(nm->name,0,nm->len); if (!nul) { - nm->extrainfo_len=0; - nm->extrainfo=0; + buffer_readonly_view(&nm->extrainfo,0,0); } else { - nm->extrainfo=nul+1; - nm->extrainfo_len=msg->start-nm->extrainfo; + buffer_readonly_view(&nm->extrainfo, nul+1, msg->start-(nul+1)); nm->len=nul-nm->name; } return True; @@ -432,6 +508,11 @@ static bool_t unpick_msg(struct site *st, uint32_t type, m->source=buf_unprepend_uint32(msg); CHECK_TYPE(msg,type); if (!unpick_name(msg,&m->remote)) return False; + m->remote_capabilities=0; + if (m->remote.extrainfo.size) { + CHECK_AVAIL(&m->remote.extrainfo,4); + m->remote_capabilities=buf_unprepend_uint32(&m->remote.extrainfo); + } if (!unpick_name(msg,&m->local)) return False; CHECK_AVAIL(msg,NONCELEN); m->nR=buf_unprepend(msg,NONCELEN); @@ -490,7 +571,13 @@ static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, *error="wrong remotely-generated nonce"; return False; } + /* MSG3 has complicated rules about capabilities, which are + * handled in process_msg3. */ if (type==LABEL_MSG3) return True; + if (m->remote_capabilities!=st->remote_capabilities) { + *error="remote capabilities changed"; + return False; + } if (type==LABEL_MSG4) return True; *error="unknown message type"; return False; @@ -511,6 +598,7 @@ static bool_t process_msg1(struct site *st, struct buffer_if *msg1, transport_record_peer(st,&st->setup_peers,src,"msg1"); st->setup_session_id=m->source; + st->remote_capabilities=m->remote_capabilities; memcpy(st->remoteN,m->nR,NONCELEN); return True; } @@ -533,6 +621,7 @@ static bool_t process_msg2(struct site *st, struct buffer_if *msg2, return False; } st->setup_session_id=m.source; + st->remote_capabilities=m.remote_capabilities; memcpy(st->remoteN,m.nR,NONCELEN); return True; } @@ -558,6 +647,15 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, slog(st,LOG_SEC,"msg3: %s",err); return False; } + uint32_t capab_adv_late = m.remote_capabilities + & ~st->remote_capabilities & CAPAB_EARLY; + 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; /* Check signature and store g^x mod m */ hash=safe_malloc(st->hash->len, "process_msg3"); @@ -583,8 +681,7 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, st->sharedsecret,st->sharedsecretlen); /* Set up the transform */ - st->new_transform->setkey(st->new_transform->st,st->sharedsecret, - st->sharedsecretlen,st->setup_priority); + set_new_transform(st); return True; } @@ -630,8 +727,7 @@ static bool_t process_msg4(struct site *st, struct buffer_if *msg4, st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk, st->sharedsecret,st->sharedsecretlen); /* Set up the transform */ - st->new_transform->setkey(st->new_transform->st,st->sharedsecret, - st->sharedsecretlen,st->setup_priority); + set_new_transform(st); return True; } @@ -665,8 +761,9 @@ static bool_t generate_msg5(struct site *st) /* Give the netlink code an opportunity to put its own stuff in the message (configuration information, etc.) */ buf_prepend_uint32(&st->buffer,LABEL_MSG5); - st->new_transform->forwards(st->new_transform->st,&st->buffer, - &transform_err); + if (call_transform_forwards(st,st->new_transform, + &st->buffer,&transform_err)) + return False; buf_prepend_uint32(&st->buffer,LABEL_MSG5); buf_prepend_uint32(&st->buffer,st->index); buf_prepend_uint32(&st->buffer,st->setup_session_id); @@ -684,7 +781,7 @@ static bool_t process_msg5(struct site *st, struct buffer_if *msg5, if (!unpick_msg0(st,msg5,&m)) return False; - if (transform->reverse(transform->st,msg5,&transform_err)) { + if (call_transform_reverse(st,transform,msg5,&transform_err)) { /* There's a problem */ slog(st,LOG_SEC,"process_msg5: transform: %s",transform_err); return False; @@ -711,7 +808,9 @@ static void create_msg6(struct site *st, struct transform_inst_if *transform, /* Give the netlink code an opportunity to put its own stuff in the message (configuration information, etc.) */ buf_prepend_uint32(&st->buffer,LABEL_MSG6); - transform->forwards(transform->st,&st->buffer,&transform_err); + int problem = call_transform_forwards(st,transform, + &st->buffer,&transform_err); + assert(!problem); buf_prepend_uint32(&st->buffer,LABEL_MSG6); buf_prepend_uint32(&st->buffer,st->index); buf_prepend_uint32(&st->buffer,session_id); @@ -719,6 +818,8 @@ static void create_msg6(struct site *st, struct transform_inst_if *transform, static bool_t generate_msg6(struct site *st) { + if (!is_transform_valid(st->new_transform)) + return False; create_msg6(st,st->new_transform,st->setup_session_id); st->retries=1; /* Peer will retransmit MSG5 if this packet gets lost */ return True; @@ -732,8 +833,7 @@ static bool_t process_msg6(struct site *st, struct buffer_if *msg6, if (!unpick_msg0(st,msg6,&m)) return False; - if (st->new_transform->reverse(st->new_transform->st, - msg6,&transform_err)) { + if (call_transform_reverse(st,st->new_transform,msg6,&transform_err)) { /* There's a problem */ slog(st,LOG_SEC,"process_msg6: transform: %s",transform_err); return False; @@ -761,8 +861,8 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0, /* Keep a copy so we can try decrypting it with multiple keys */ buffer_copy(&st->scratch, msg0); - problem = st->current.transform->reverse(st->current.transform->st, - msg0,&transform_err); + problem = call_transform_reverse(st,st->current.transform, + msg0,&transform_err); if (!problem) { if (!st->auxiliary_is_new) delete_one_key(st,&st->auxiliary_key, @@ -773,8 +873,8 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0, goto skew; buffer_copy(msg0, &st->scratch); - problem = st->auxiliary_key.transform->reverse - (st->auxiliary_key.transform->st,msg0,&auxkey_err); + problem = call_transform_reverse(st,st->auxiliary_key.transform, + msg0,&auxkey_err); if (problem==0) { slog(st,LOG_DROP,"processing packet which uses auxiliary key"); if (st->auxiliary_is_new) { @@ -799,8 +899,8 @@ static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0, if (st->state==SITE_SENTMSG5) { buffer_copy(msg0, &st->scratch); - problem = st->new_transform->reverse(st->new_transform->st, - msg0,&newkey_err); + problem = call_transform_reverse(st,st->new_transform, + msg0,&newkey_err); if (!problem) { /* It looks like we didn't get the peer's MSG6 */ /* This is like a cut-down enter_new_state(SITE_RUN) */ @@ -859,9 +959,9 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0, static void dump_packet(struct site *st, struct buffer_if *buf, const struct comm_addr *addr, bool_t incoming) { - uint32_t dest=ntohl(*(uint32_t *)buf->start); - uint32_t source=ntohl(*(uint32_t *)(buf->start+4)); - uint32_t msgtype=ntohl(*(uint32_t *)(buf->start+8)); + uint32_t dest=get_uint32(buf->start); + uint32_t source=get_uint32(buf->start+4); + uint32_t msgtype=get_uint32(buf->start+8); if (st->log_events & LOG_DUMP) slilog(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x:", @@ -890,8 +990,8 @@ static bool_t send_msg(struct site *st) t=st->auxiliary_key.transform; st->auxiliary_key.transform=st->new_transform; st->new_transform=t; + dispose_transform(&st->new_transform); - t->delkey(t->st); st->auxiliary_is_new=1; st->auxiliary_key.key_timeout=st->now+st->key_lifetime; st->auxiliary_renegotiate_key_time=st->now+st->key_renegotiate_time; @@ -960,8 +1060,8 @@ static void activate_new_key(struct site *st) st->auxiliary_key.transform=st->current.transform; st->current.transform=st->new_transform; st->new_transform=t; + dispose_transform(&st->new_transform); - t->delkey(t->st); st->timeout=0; st->auxiliary_is_new=0; st->auxiliary_key.key_timeout=st->current.key_timeout; @@ -977,9 +1077,9 @@ static void activate_new_key(struct site *st) static void delete_one_key(struct site *st, struct data_key *key, cstring_t reason, cstring_t which, uint32_t loglevel) { - if (!key->transform->valid(key->transform->st)) return; + if (!is_transform_valid(key->transform)) return; if (reason) slog(st,loglevel,"%s deleted (%s)",which,reason); - key->transform->delkey(key->transform->st); + dispose_transform(&key->transform); key->key_timeout=0; } @@ -1004,7 +1104,7 @@ static void enter_state_stop(struct site *st) st->state=SITE_STOP; st->timeout=0; delete_keys(st,"entering state STOP",LOG_TIMEOUT_KEY); - st->new_transform->delkey(st->new_transform->st); + dispose_transform(&st->new_transform); } static void set_link_quality(struct site *st) @@ -1034,7 +1134,7 @@ static void enter_state_run(struct site *st) transport_peers_clear(st,&st->setup_peers); memset(st->localN,0,NONCELEN); memset(st->remoteN,0,NONCELEN); - st->new_transform->delkey(st->new_transform->st); + dispose_transform(&st->new_transform); memset(st->dhsecret,0,st->dh->len); memset(st->sharedsecret,0,st->sharedsecretlen); set_link_quality(st); @@ -1128,13 +1228,15 @@ static bool_t send_msg7(struct site *st, cstring_t reason) buffer_init(&st->buffer,st->transform->max_start_pad+(4*3)); buf_append_uint32(&st->buffer,LABEL_MSG7); buf_append_string(&st->buffer,reason); - st->current.transform->forwards(st->current.transform->st, - &st->buffer, &transform_err); + if (call_transform_forwards(st, st->current.transform, + &st->buffer, &transform_err)) + goto free_out; buf_prepend_uint32(&st->buffer,LABEL_MSG0); buf_prepend_uint32(&st->buffer,st->index); buf_prepend_uint32(&st->buffer,st->current.remote_session_id); transport_xmit(st,&st->peers,&st->buffer,True); BUF_FREE(&st->buffer); + free_out: return True; } return False; @@ -1231,13 +1333,15 @@ static void site_outgoing(void *sst, struct buffer_if *buf) /* Transform it and send it */ if (buf->size>0) { buf_prepend_uint32(buf,LABEL_MSG9); - st->current.transform->forwards(st->current.transform->st, - buf, &transform_err); + if (call_transform_forwards(st, st->current.transform, + buf, &transform_err)) + goto free_out; buf_prepend_uint32(buf,LABEL_MSG0); buf_prepend_uint32(buf,st->index); buf_prepend_uint32(buf,st->current.remote_session_id); transport_xmit(st,&st->peers,buf,False); } + free_out: BUF_FREE(buf); return; } @@ -1268,8 +1372,8 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, if (buf->size < 12) return False; - uint32_t msgtype=ntohl(get_uint32(buf->start+8)); - uint32_t dest=ntohl(*(uint32_t *)buf->start); + uint32_t dest=get_uint32(buf->start); + uint32_t msgtype=get_uint32(buf->start+8); struct msg named_msg; if (msgtype==LABEL_MSG1) { @@ -1493,6 +1597,7 @@ 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->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc); list_t *comms_cfg=dict_lookup(dict,"comm"); @@ -1579,6 +1684,7 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, register_for_poll(st, site_beforepoll, site_afterpoll, 0, "site"); st->timeout=0; + st->remote_capabilities=0; st->current.key_timeout=0; st->auxiliary_key.key_timeout=0; transport_peers_clear(st,&st->peers); @@ -1597,20 +1703,18 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, worst_##pad=thispad; \ } COMPUTE_WORST(min_start_pad) - COMPUTE_WORST(min_end_pad) /* We need to register the remote networks with the netlink device */ st->netlink->reg(st->netlink->st, site_outgoing, st, st->transform->max_start_pad+(4*4)+ - worst_min_start_pad, - st->transform->max_end_pad+worst_min_end_pad); + worst_min_start_pad); for (i=0; incomms; i++) st->comms[i]->request_notify(st->comms[i]->st, st, site_incoming); - st->current.transform=st->transform->create(st->transform->st); - st->auxiliary_key.transform=st->transform->create(st->transform->st); - st->new_transform=st->transform->create(st->transform->st); + st->current.transform=0; + st->auxiliary_key.transform=0; + st->new_transform=0; st->auxiliary_is_new=0; enter_state_stop(st);