X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=site.c;h=afa85e886ebf27da76236db92405906be13ec26f;hp=1a664ce30c0d6e52d5f3259e2579e746fb11bcd7;hb=90d7e3ad26101cf3538171aec2d194e9de1aaed5;hpb=4efd681a66c15bc6f81eefc69396669e165e5e0f diff --git a/site.c b/site.c index 1a664ce..afa85e8 100644 --- a/site.c +++ b/site.c @@ -1,17 +1,46 @@ /* site.c - manage communication with a remote network site */ -#include -#include +/* The 'site' code doesn't know anything about the structure of the + packets it's transmitting. In fact, under the new netlink + configuration scheme it doesn't need to know anything at all about + IP addresses, except how to contact its peer. This means it could + potentially be used to tunnel other protocols too (IPv6, IPX, plain + old Ethernet frames) if appropriate netlink code can be written + (and that ought not to be too hard, eg. using the TUN/TAP device to + pretend to be an Ethernet interface). */ + +/* At some point in the future the netlink code will be asked for + configuration information to go in the PING/PONG packets at the end + of the key exchange. */ #include "secnet.h" +#include +#include +#include +#include +#include + +#include #include "util.h" +#include "unaligned.h" +#include "magic.h" #define SETUP_BUFFER_LEN 2048 -#define DEFAULT_KEY_LIFETIME 15000 +#define DEFAULT_KEY_LIFETIME (3600*1000) /* [ms] */ +#define DEFAULT_KEY_RENEGOTIATE_GAP (5*60*1000) /* [ms] */ #define DEFAULT_SETUP_RETRIES 5 -#define DEFAULT_SETUP_TIMEOUT 500 -#define DEFAULT_WAIT_TIME 10000 +#define DEFAULT_SETUP_RETRY_INTERVAL (2*1000) /* [ms] */ +#define DEFAULT_WAIT_TIME (20*1000) /* [ms] */ + +#define DEFAULT_MOBILE_KEY_LIFETIME (2*24*3600*1000) /* [ms] */ +#define DEFAULT_MOBILE_KEY_RENEGOTIATE_GAP (12*3600*1000) /* [ms] */ +#define DEFAULT_MOBILE_SETUP_RETRIES 30 +#define DEFAULT_MOBILE_SETUP_RETRY_INTERVAL (1*1000) /* [ms] */ +#define DEFAULT_MOBILE_WAIT_TIME (10*1000) /* [ms] */ + +#define DEFAULT_MOBILE_PEER_EXPIRY (2*60) /* [s] */ +#define DEFAULT_MOBILE_PEERS_MAX 3 /* send at most this many copies (default) */ /* Each site can be in one of several possible states. */ @@ -60,33 +89,24 @@ #define SITE_SENTMSG5 7 #define SITE_WAIT 8 -static string_t state_name(uint32_t state) +int32_t site_max_start_pad = 4*4; + +static cstring_t state_name(uint32_t state) { switch (state) { - case 0: return "SITE_STOP"; - case 1: return "SITE_RUN"; - case 2: return "SITE_RESOLVE"; - case 3: return "SITE_SENTMSG1"; - case 4: return "SITE_SENTMSG2"; - case 5: return "SITE_SENTMSG3"; - case 6: return "SITE_SENTMSG4"; - case 7: return "SITE_SENTMSG5"; - case 8: return "SITE_WAIT"; + case 0: return "STOP"; + case 1: return "RUN"; + case 2: return "RESOLVE"; + case 3: return "SENTMSG1"; + case 4: return "SENTMSG2"; + case 5: return "SENTMSG3"; + case 6: return "SENTMSG4"; + case 7: return "SENTMSG5"; + case 8: return "WAIT"; default: return "*bad state*"; } } -#define LABEL_MSG0 0x00020200 -#define LABEL_MSG1 0x01010101 -#define LABEL_MSG2 0x02020202 -#define LABEL_MSG3 0x03030303 -#define LABEL_MSG4 0x04040404 -#define LABEL_MSG5 0x05050505 -#define LABEL_MSG6 0x06060606 -#define LABEL_MSG7 0x07070707 -#define LABEL_MSG8 0x08080808 -#define LABEL_MSG9 0x09090909 - #define NONCELEN 8 #define LOG_UNEXPECTED 0x00000001 @@ -94,11 +114,118 @@ static string_t state_name(uint32_t state) #define LOG_SETUP_TIMEOUT 0x00000004 #define LOG_ACTIVATE_KEY 0x00000008 #define LOG_TIMEOUT_KEY 0x00000010 -#define LOG_SECURITY 0x00000020 +#define LOG_SEC 0x00000020 #define LOG_STATE 0x00000040 #define LOG_DROP 0x00000080 #define LOG_DUMP 0x00000100 #define LOG_ERROR 0x00000400 +#define LOG_PEER_ADDRS 0x00000800 + +static struct flagstr log_event_table[]={ + { "unexpected", LOG_UNEXPECTED }, + { "setup-init", LOG_SETUP_INIT }, + { "setup-timeout", LOG_SETUP_TIMEOUT }, + { "activate-key", LOG_ACTIVATE_KEY }, + { "timeout-key", LOG_TIMEOUT_KEY }, + { "security", LOG_SEC }, + { "state-change", LOG_STATE }, + { "packet-drop", LOG_DROP }, + { "dump-packets", LOG_DUMP }, + { "errors", LOG_ERROR }, + { "peer-addrs", LOG_PEER_ADDRS }, + { "default", LOG_SETUP_INIT|LOG_SETUP_TIMEOUT| + LOG_ACTIVATE_KEY|LOG_TIMEOUT_KEY|LOG_SEC|LOG_ERROR }, + { "all", 0xffffffff }, + { NULL, 0 } +}; + + +/***** TRANSPORT PEERS declarations *****/ + +/* Details of "mobile peer" semantics: + + - We record mobile_peers_max peer address/port numbers ("peers") + for key setup, and separately mobile_peers_max for data + transfer. If these lists fill up, we retain the newest peers. + (For non-mobile peers we only record one of each.) + + - Outgoing packets are sent to every recorded peer in the + applicable list. + + - Data transfer peers are straightforward: whenever we successfully + process a data packet, we record the peer. Also, whenever we + successfully complete a key setup, we merge the key setup + peers into the data transfer peers. + + (For "non-mobile" peers we simply copy the peer used for + successful key setup, and don't change the peer otherwise.) + + - Key setup peers are slightly more complicated. + + Whenever we receive and successfully process a key exchange + packet, we record the peer. + + Whenever we try to initiate a key setup, we copy the list of data + transfer peers and use it for key setup. But we also look to see + if the config supplies an address and port number and if so we + add that as a key setup peer (possibly evicting one of the data + transfer peers we just copied). + + (For "non-mobile" peers, if we if we have a configured peer + address and port, we always use that; otherwise if we have a + current data peer address we use that; otherwise we do not + attempt to initiate a key setup for lack of a peer address.) + + "Record the peer" means + 1. expire any peers last seen >120s ("mobile-peer-expiry") ago + 2. add the peer of the just received packet to the applicable list + (possibly evicting older entries) + NB that we do not expire peers until an incoming packet arrives. + + */ + +#define MAX_MOBILE_PEERS_MAX 5 /* send at most this many copies, compiled max */ + +typedef struct { + struct timeval last; + struct comm_addr addr; +} transport_peer; + +typedef struct { +/* configuration information */ +/* runtime information */ + int npeers; + transport_peer peers[MAX_MOBILE_PEERS_MAX]; +} transport_peers; + +static void transport_peers_clear(struct site *st, transport_peers *peers); +static int transport_peers_valid(transport_peers *peers); +static void transport_peers_copy(struct site *st, transport_peers *dst, + const transport_peers *src); + +static void transport_setup_msgok(struct site *st, const struct comm_addr *a); +static void transport_data_msgok(struct site *st, const struct comm_addr *a); +static bool_t transport_compute_setupinit_peers(struct site *st, + const struct comm_addr *configured_addr /* 0 if none or not found */, + const struct comm_addr *prod_hint_addr /* 0 if none */); +static void transport_resolve_complete(struct site *st, + const struct comm_addr *a); +static void transport_resolve_complete_tardy(struct site *st, + const struct comm_addr *ca_use); +static void transport_record_peer(struct site *st, transport_peers *peers, + const struct comm_addr *addr, const char *m); + +static void transport_xmit(struct site *st, transport_peers *peers, + struct buffer_if *buf, bool_t candebug); + + /***** END of transport peers declarations *****/ + + +struct data_key { + struct transform_inst_if *transform; + uint64_t key_timeout; /* End of life of current key */ + uint32_t remote_session_id; +}; struct site { closure_t cl; @@ -106,30 +233,36 @@ struct site { /* configuration information */ string_t localname; string_t remotename; - string_t tunname; /* localname<->remotename by default */ + bool_t local_mobile, peer_mobile; /* Mobile client support */ + int32_t transport_peers_max; + string_t tunname; /* localname<->remotename by default, used in logs */ string_t address; /* DNS name for bootstrapping, optional */ - int remoteport; + int remoteport; /* Port for bootstrapping, optional */ + uint32_t mtu_target; struct netlink_if *netlink; - struct comm_if *comm; + struct comm_if **comms; + int ncomms; struct resolver_if *resolver; struct log_if *log; struct random_if *random; struct rsaprivkey_if *privkey; - struct subnet_list remotenets; struct rsapubkey_if *pubkey; - struct transform_if *transform; + struct transform_if **transforms; + int ntransforms; struct dh_if *dh; struct hash_if *hash; - void *netlink_cid; - uint32_t setup_retries; /* How many times to send setup packets */ - uint32_t setup_timeout; /* Initial timeout for setup packets */ - uint32_t wait_timeout; /* How long to wait if setup unsuccessful */ - uint32_t key_lifetime; /* How long a key lasts once set up */ + 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 */ + 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) + after this time, initiate a new + key exchange */ - uint8_t *setupsig; /* Expected signature of incoming MSG1 packets */ - uint32_t setupsiglen; /* Allows us to discard packets quickly if - they are not for us */ bool_t setup_priority; /* Do we have precedence if both sites emit message 1 simultaneously? */ uint32_t log_events; @@ -137,125 +270,351 @@ struct site { /* runtime information */ uint32_t state; uint64_t now; /* Most recently seen time */ - - uint32_t remote_session_id; - struct transform_inst_if *current_transform; - bool_t current_valid; - uint64_t current_key_timeout; /* End of life of current key */ - struct sockaddr_in peer; /* Current address of peer */ - bool_t peer_valid; /* Peer address becomes invalid when key times out, - but only if we have a DNS name for our peer */ - + bool_t allow_send_prod; + bool_t resolving; + + /* The currently established session */ + struct data_key current; + struct data_key auxiliary_key; + bool_t auxiliary_is_new; + uint64_t renegotiate_key_time; /* When we can negotiate a new key */ + uint64_t auxiliary_renegotiate_key_time; + transport_peers peers; /* Current address(es) of peer for data traffic */ + + /* The current key setup protocol exchange. We can only be + involved in one of these at a time. There's a potential for + denial of service here (the attacker keeps sending a setup + 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; + uint16_t remote_adv_mtu; + struct transform_if *chosen_transform; uint32_t setup_session_id; - struct sockaddr_in setup_peer; + transport_peers setup_peers; uint8_t localN[NONCELEN]; /* Nonces for key exchange */ uint8_t remoteN[NONCELEN]; struct buffer_if buffer; /* Current outgoing key exchange packet */ - uint32_t retries; /* Number of retries remaining */ + struct buffer_if scratch; + int32_t retries; /* Number of retries remaining */ uint64_t timeout; /* Timeout for current state */ uint8_t *dhsecret; uint8_t *sharedsecret; - + uint32_t sharedsecretlen, sharedsecretallocd; struct transform_inst_if *new_transform; /* For key setup/verify */ }; -static void slog(struct site *st, uint32_t event, string_t msg, ...) +static uint32_t event_log_priority(struct site *st, uint32_t event) { - va_list ap; - uint8_t buf[240]; + if (!(event&st->log_events)) + return 0; + switch(event) { + case LOG_UNEXPECTED: return M_INFO; + case LOG_SETUP_INIT: return M_INFO; + case LOG_SETUP_TIMEOUT: return M_NOTICE; + case LOG_ACTIVATE_KEY: return M_INFO; + case LOG_TIMEOUT_KEY: return M_INFO; + case LOG_SEC: return M_SECURITY; + case LOG_STATE: return M_DEBUG; + case LOG_DROP: return M_DEBUG; + case LOG_DUMP: return M_DEBUG; + case LOG_ERROR: return M_ERR; + case LOG_PEER_ADDRS: return M_DEBUG; + default: return M_ERR; + } +} + +static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap) +FORMAT(printf,3,0); +static void vslog(struct site *st, uint32_t event, cstring_t msg, va_list ap) +{ + uint32_t class; + + class=event_log_priority(st, event); + if (class) { + slilog_part(st->log,class,"%s: ",st->tunname); + vslilog_part(st->log,class,msg,ap); + slilog_part(st->log,class,"\n"); + } +} +static void slog(struct site *st, uint32_t event, cstring_t msg, ...) +FORMAT(printf,3,4); +static void slog(struct site *st, uint32_t event, cstring_t msg, ...) +{ + va_list ap; va_start(ap,msg); + vslog(st,event,msg,ap); + va_end(ap); +} + +static void logtimeout(struct site *st, const char *fmt, ...) +FORMAT(printf,2,3); +static void logtimeout(struct site *st, const char *fmt, ...) +{ + uint32_t class=event_log_priority(st,LOG_SETUP_TIMEOUT); + if (!class) + return; - if (event&st->log_events) { - vsnprintf(buf,240,msg,ap); - st->log->log(st->log->st,0,"%s: %s",st->tunname,buf); + va_list ap; + va_start(ap,fmt); + + slilog_part(st->log,class,"%s: ",st->tunname); + vslilog_part(st->log,class,fmt,ap); + + const char *delim; + int i; + for (i=0, delim=" (tried "; + isetup_peers.npeers; + i++, delim=", ") { + transport_peer *peer=&st->setup_peers.peers[i]; + const char *s=comm_addr_to_string(&peer->addr); + slilog_part(st->log,class,"%s%s",delim,s); } + + slilog_part(st->log,class,")\n"); va_end(ap); } +static void set_link_quality(struct site *st); +static void delete_keys(struct site *st, cstring_t reason, uint32_t loglevel); +static void delete_one_key(struct site *st, struct data_key *key, + const char *reason /* may be 0 meaning don't log*/, + const char *which /* ignored if !reasonn */, + uint32_t loglevel /* ignored if !reasonn */); +static bool_t initiate_key_setup(struct site *st, cstring_t reason, + const struct comm_addr *prod_hint); static void enter_state_run(struct site *st); static bool_t enter_state_resolve(struct site *st); -static bool_t enter_state_sentmsg1(struct site *st); -static bool_t enter_state_sentmsg2(struct site *st); -static bool_t enter_state_sentmsg3(struct site *st); -static bool_t enter_state_sentmsg4(struct site *st); -static bool_t enter_state_sentmsg5(struct site *st); +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 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; \ CHECK_AVAIL((b),4); \ - type=*(uint32_t *)buf_unprepend((b),4); \ + type=buf_unprepend_uint32((b)); \ if (type!=(t)) return False; } while(0) +static _Bool type_is_msg34(uint32_t type) +{ + return + type == LABEL_MSG3 || + type == LABEL_MSG3BIS || + type == LABEL_MSG4; +} + +struct parsedname { + int32_t len; + uint8_t *name; + struct buffer_if extrainfo; +}; + struct msg { uint8_t *hashstart; uint32_t dest; uint32_t source; - uint32_t remlen; - uint8_t *remote; - uint32_t loclen; - uint8_t *local; + struct parsedname remote; + struct parsedname local; + uint32_t remote_capabilities; + uint16_t remote_mtu; + int capab_transformnum; uint8_t *nR; uint8_t *nL; - uint32_t pklen; - uint8_t *pk; - uint32_t hashlen; - uint32_t siglen; - uint8_t *sig; + int32_t pklen; + char *pk; + int32_t hashlen; + int32_t siglen; + char *sig; +}; + +static void set_new_transform(struct site *st, char *pk) +{ + /* Make room for the shared key */ + st->sharedsecretlen=st->chosen_transform->keylen?:st->dh->ceil_len; + assert(st->sharedsecretlen); + if (st->sharedsecretlen > st->sharedsecretallocd) { + st->sharedsecretallocd=st->sharedsecretlen; + st->sharedsecret=realloc(st->sharedsecret,st->sharedsecretallocd); + } + if (!st->sharedsecret) fatal_perror("site:sharedsecret"); + + /* Generate the shared key */ + st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,pk, + st->sharedsecret,st->sharedsecretlen); + + /* Set up the transform */ + struct transform_if *generator=st->chosen_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; + + slog(st,LOG_SETUP_INIT,"key exchange negotiated transform" + " %d (capabilities ours=%#"PRIx32" theirs=%#"PRIx32")", + st->chosen_transform->capab_transformnum, + st->local_capabilities, st->remote_capabilities); +} + +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. */ -static bool_t generate_msg(struct site *st, uint32_t type, string_t what) +/* 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) { void *hst; - uint8_t *hash=alloca(st->hash->len); + uint8_t *hash; string_t dhpub, sig; st->retries=st->setup_retries; BUF_ALLOC(&st->buffer,what); buffer_init(&st->buffer,0); - *(uint32_t *)buf_append(&st->buffer,4)= - (type==LABEL_MSG1?0:st->setup_session_id); - *(uint32_t *)buf_append(&st->buffer,4)=(uint32_t)st; - *(uint32_t *)buf_append(&st->buffer,4)=type; - buf_append_string(&st->buffer,st->localname); + buf_append_uint32(&st->buffer, + (type==LABEL_MSG1?0:st->setup_session_id)); + buf_append_uint32(&st->buffer,st->index); + buf_append_uint32(&st->buffer,type); + + 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); + } + if (type_is_msg34(type)) { + buf_append_uint16(&st->buffer,st->mtu_target); + } + 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; memcpy(buf_append(&st->buffer,NONCELEN),st->remoteN,NONCELEN); if (type==LABEL_MSG2) return True; + + if (hacky_par_mid_failnow()) return False; + + if (type==LABEL_MSG3BIS) + buf_append_uint8(&st->buffer,st->chosen_transform->capab_transformnum); + dhpub=st->dh->makepublic(st->dh->st,st->dhsecret,st->dh->len); buf_append_string(&st->buffer,dhpub); free(dhpub); + hash=safe_malloc(st->hash->len, "generate_msg"); 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); + free(hash); + return True; +} + +static bool_t unpick_name(struct buffer_if *msg, struct parsedname *nm) +{ + CHECK_AVAIL(msg,2); + nm->len=buf_unprepend_uint16(msg); + CHECK_AVAIL(msg,nm->len); + nm->name=buf_unprepend(msg,nm->len); + uint8_t *nul=memchr(nm->name,0,nm->len); + if (!nul) { + buffer_readonly_view(&nm->extrainfo,0,0); + } else { + buffer_readonly_view(&nm->extrainfo, nul+1, msg->start-(nul+1)); + nm->len=nul-nm->name; + } return True; } static bool_t unpick_msg(struct site *st, uint32_t type, struct buffer_if *msg, struct msg *m) { + m->capab_transformnum=-1; m->hashstart=msg->start; CHECK_AVAIL(msg,4); - m->dest=*(uint32_t *)buf_unprepend(msg,4); + m->dest=buf_unprepend_uint32(msg); CHECK_AVAIL(msg,4); - m->source=*(uint32_t *)buf_unprepend(msg,4); + m->source=buf_unprepend_uint32(msg); CHECK_TYPE(msg,type); - CHECK_AVAIL(msg,2); - m->remlen=ntohs(*(uint16_t *)buf_unprepend(msg,2)); - CHECK_AVAIL(msg,m->remlen); - m->remote=buf_unprepend(msg,m->remlen); - CHECK_AVAIL(msg,2); - m->loclen=ntohs(*(uint16_t *)buf_unprepend(msg,2)); - CHECK_AVAIL(msg,m->loclen); - m->local=buf_unprepend(msg,m->loclen); + if (!unpick_name(msg,&m->remote)) return False; + m->remote_capabilities=0; + m->remote_mtu=0; + if (m->remote.extrainfo.size) { + CHECK_AVAIL(&m->remote.extrainfo,4); + m->remote_capabilities=buf_unprepend_uint32(&m->remote.extrainfo); + } + if (type_is_msg34(type) && m->remote.extrainfo.size) { + CHECK_AVAIL(&m->remote.extrainfo,2); + m->remote_mtu=buf_unprepend_uint16(&m->remote.extrainfo); + } + if (!unpick_name(msg,&m->local)) return False; + if (type==LABEL_PROD) { + CHECK_EMPTY(msg); + return True; + } CHECK_AVAIL(msg,NONCELEN); m->nR=buf_unprepend(msg,NONCELEN); if (type==LABEL_MSG1) { @@ -268,19 +627,69 @@ 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; + } CHECK_AVAIL(msg,2); - m->pklen=ntohs(*(uint16_t *)buf_unprepend(msg,2)); + m->pklen=buf_unprepend_uint16(msg); CHECK_AVAIL(msg,m->pklen); m->pk=buf_unprepend(msg,m->pklen); m->hashlen=msg->start-m->hashstart; CHECK_AVAIL(msg,2); - m->siglen=ntohs(*(uint16_t *)buf_unprepend(msg,2)); + m->siglen=buf_unprepend_uint16(msg); CHECK_AVAIL(msg,m->siglen); m->sig=buf_unprepend(msg,m->siglen); CHECK_EMPTY(msg); return True; } +static bool_t name_matches(const struct parsedname *nm, const char *expected) +{ + int expected_len=strlen(expected); + return + nm->len == expected_len && + !memcmp(nm->name, expected, expected_len); +} + +static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, + cstring_t *error) +{ + if (type==LABEL_MSG1) return True; + + /* Check that the site names and our nonce have been sent + back correctly, and then store our peer's nonce. */ + if (!name_matches(&m->remote,st->remotename)) { + *error="wrong remote site name"; + return False; + } + if (!name_matches(&m->local,st->localname)) { + *error="wrong local site name"; + return False; + } + if (memcmp(m->nL,st->localN,NONCELEN)!=0) { + *error="wrong locally-generated nonce"; + return False; + } + if (type==LABEL_MSG2) return True; + if (!consttime_memeq(m->nR,st->remoteN,NONCELEN)!=0) { + *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 (m->remote_capabilities!=st->remote_capabilities) { + *error="remote capabilities changed"; + return False; + } + if (type==LABEL_MSG4) return True; + *error="unknown message type"; + return False; +} + static bool_t generate_msg1(struct site *st) { st->random->generate(st->random->st,NONCELEN,st->localN); @@ -288,21 +697,15 @@ static bool_t generate_msg1(struct site *st) } static bool_t process_msg1(struct site *st, struct buffer_if *msg1, - struct sockaddr_in *src) + const struct comm_addr *src, struct msg *m) { - struct msg m; - /* We've already determined we're in an appropriate state to process an incoming MSG1, and that the MSG1 has correct values of A and B. */ - if (!unpick_msg(st,LABEL_MSG1,msg1,&m)) return False; - - /* XXX save src as our peer address here? */ - st->setup_peer=*src; - - st->setup_session_id=m.source; - memcpy(st->remoteN,m.nR,NONCELEN); + st->setup_session_id=m->source; + st->remote_capabilities=m->remote_capabilities; + memcpy(st->remoteN,m->nR,NONCELEN); return True; } @@ -313,27 +716,41 @@ static bool_t generate_msg2(struct site *st) } static bool_t process_msg2(struct site *st, struct buffer_if *msg2, - struct sockaddr_in *src) + const struct comm_addr *src) { struct msg m; + cstring_t err; if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False; - - /* Check that the site names and our nonce have been sent - back correctly, and then store our peer's nonce. */ - if (memcmp(m.remote,st->remotename,strlen(st->remotename)!=0)) { - slog(st,LOG_SECURITY,"msg2: bad B (remote site name)"); - return False; - } - if (memcmp(m.local,st->localname,strlen(st->localname)!=0)) { - slog(st,LOG_SECURITY,"msg2: bad A (local site name)"); - return False; - } - if (memcmp(m.nL,st->localN,NONCELEN)!=0) { - slog(st,LOG_SECURITY,"msg2: bad nA (locally generated nonce)"); + if (!check_msg(st,LABEL_MSG2,&m,&err)) { + slog(st,LOG_SEC,"msg2: %s",err); return False; } st->setup_session_id=m.source; + st->remote_capabilities=m.remote_capabilities; + + /* Select the transform to use */ + + uint32_t remote_transforms = st->remote_capabilities & CAPAB_TRANSFORM_MASK; + if (!remote_transforms) + /* old secnets only had this one transform */ + remote_transforms = 1UL << CAPAB_TRANSFORMNUM_ANCIENT; + + 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; + memcpy(st->remoteN,m.nR,NONCELEN); return True; } @@ -343,60 +760,82 @@ static bool_t generate_msg3(struct site *st) /* Now we have our nonce and their nonce. Think of a secret key, and create message number 3. */ st->random->generate(st->random->st,st->dh->len,st->dhsecret); - return generate_msg(st,LABEL_MSG3,"site:MSG3"); + return generate_msg(st, + (st->remote_capabilities & CAPAB_TRANSFORM_MASK + ? LABEL_MSG3BIS : LABEL_MSG3), + "site:MSG3"); } -static bool_t process_msg3(struct site *st, struct buffer_if *msg3, - struct sockaddr_in *src) +static bool_t process_msg3_msg4(struct site *st, struct msg *m) { - struct msg m; - uint8_t *hash=alloca(st->hash->len); + uint8_t *hash; void *hst; - if (!unpick_msg(st,LABEL_MSG3,msg3,&m)) return False; - - /* Check that the site names and nonces have been sent back - correctly */ - if (memcmp(m.remote,st->remotename,strlen(st->remotename)!=0)) { - slog(st,LOG_SECURITY,"msg3: bad A (remote site name)"); + /* Check signature and store g^x mod m */ + hash=safe_malloc(st->hash->len, "process_msg3_msg4"); + hst=st->hash->init(); + st->hash->update(hst,m->hashstart,m->hashlen); + st->hash->final(hst,hash); + /* Terminate signature with a '0' - cheating, but should be ok */ + m->sig[m->siglen]=0; + if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m->sig)) { + slog(st,LOG_SEC,"msg3/msg4 signature failed check!"); + free(hash); return False; } - if (memcmp(m.local,st->localname,strlen(st->localname)!=0)) { - slog(st,LOG_SECURITY,"msg3: bad B (local site name)"); + free(hash); + + st->remote_adv_mtu=m->remote_mtu; + + return True; +} + +static bool_t process_msg3(struct site *st, struct buffer_if *msg3, + const struct comm_addr *src, uint32_t msgtype) +{ + struct msg m; + cstring_t err; + + assert(msgtype==LABEL_MSG3 || msgtype==LABEL_MSG3BIS); + + if (!unpick_msg(st,msgtype,msg3,&m)) return False; + if (!check_msg(st,msgtype,&m,&err)) { + slog(st,LOG_SEC,"msg3: %s",err); return False; } - if (memcmp(m.nR,st->remoteN,NONCELEN)!=0) { - slog(st,LOG_SECURITY,"msg3: bad nA (remotely generated nonce)"); + 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; } - if (memcmp(m.nL,st->localN,NONCELEN)!=0) { - slog(st,LOG_SECURITY,"msg3: bad nB (locally generated nonce)"); - 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; } - - /* Check signature and store g^x mod m */ - hst=st->hash->init(); - st->hash->update(hst,m.hashstart,m.hashlen); - st->hash->final(hst,hash); - /* Terminate signature with a '0' - cheating, but should be ok */ - m.sig[m.siglen]=0; - if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { - slog(st,LOG_SECURITY,"msg3 signature failed check!"); + slog(st,LOG_SEC,"peer chose unknown-to-us transform %d!", + m.capab_transformnum); + return False; + transform_found: + st->chosen_transform=ti; + + if (!process_msg3_msg4(st,&m)) return False; - } /* Terminate their DH public key with a '0' */ m.pk[m.pklen]=0; /* Invent our DH secret key */ st->random->generate(st->random->st,st->dh->len,st->dhsecret); - /* Generate the shared key */ - st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk, - st->sharedsecret,st->transform->keylen); - - /* Set up the transform */ - st->new_transform->setkey(st->new_transform->st,st->sharedsecret, - st->transform->keylen); + /* Generate the shared key and set up the transform */ + set_new_transform(st,m.pk); return True; } @@ -409,71 +848,26 @@ static bool_t generate_msg4(struct site *st) } static bool_t process_msg4(struct site *st, struct buffer_if *msg4, - struct sockaddr_in *src) + const struct comm_addr *src) { struct msg m; - uint8_t *hash=alloca(st->hash->len); - void *hst; + cstring_t err; if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False; - - /* Check that the site names and nonces have been sent back - correctly */ - if (memcmp(m.remote,st->remotename,strlen(st->remotename)!=0)) { - slog(st,LOG_SECURITY,"msg4: bad B (remote site name)"); - return False; - } - if (memcmp(m.local,st->localname,strlen(st->localname)!=0)) { - slog(st,LOG_SECURITY,"msg4: bad A (local site name)"); - return False; - } - if (memcmp(m.nR,st->remoteN,NONCELEN)!=0) { - slog(st,LOG_SECURITY,"msg4: bad nB (remotely generated nonce)"); - return False; - } - if (memcmp(m.nL,st->localN,NONCELEN)!=0) { - slog(st,LOG_SECURITY,"msg4: bad nA (locally generated nonce)"); + if (!check_msg(st,LABEL_MSG4,&m,&err)) { + slog(st,LOG_SEC,"msg4: %s",err); return False; } - /* Check signature and store g^x mod m */ - hst=st->hash->init(); - st->hash->update(hst,m.hashstart,m.hashlen); - st->hash->final(hst,hash); - /* Terminate signature with a '0' - cheating, but should be ok */ - m.sig[m.siglen]=0; - if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { - slog(st,LOG_SECURITY,"msg4 signature failed check!"); + if (!process_msg3_msg4(st,&m)) return False; - } /* Terminate their DH public key with a '0' */ m.pk[m.pklen]=0; - /* Generate the shared key */ - st->dh->makeshared(st->dh->st,st->dhsecret,st->dh->len,m.pk, - st->sharedsecret,st->transform->keylen); - /* Set up the transform */ - st->new_transform->setkey(st->new_transform->st,st->sharedsecret, - st->transform->keylen); - return True; -} - -static bool_t generate_msg5(struct site *st) -{ - string_t transform_err; - - BUF_ALLOC(&st->buffer,"site:MSG5"); - /* We are going to add three words to the transformed message */ - buffer_init(&st->buffer,st->transform->max_start_pad+(4*3)); - *(uint32_t *)buf_append(&st->buffer,4)=LABEL_MSG5; - st->new_transform->forwards(st->new_transform->st,&st->buffer, - &transform_err); - *(uint32_t *)buf_prepend(&st->buffer,4)=LABEL_MSG5; - *(uint32_t *)buf_prepend(&st->buffer,4)=(uint32_t)st; - *(uint32_t *)buf_prepend(&st->buffer,4)=st->setup_session_id; + /* Generate the shared key and set up the transform */ + set_new_transform(st,m.pk); - st->retries=st->setup_retries; return True; } @@ -487,132 +881,231 @@ static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0, struct msg0 *m) { CHECK_AVAIL(msg0,4); - m->dest=*(uint32_t *)buf_unprepend(msg0,4); + m->dest=buf_unprepend_uint32(msg0); CHECK_AVAIL(msg0,4); - m->source=*(uint32_t *)buf_unprepend(msg0,4); + m->source=buf_unprepend_uint32(msg0); CHECK_AVAIL(msg0,4); - m->type=*(uint32_t *)buf_unprepend(msg0,4); + m->type=buf_unprepend_uint32(msg0); return True; /* Leaves transformed part of buffer untouched */ } +static bool_t generate_msg5(struct site *st) +{ + cstring_t transform_err; + + BUF_ALLOC(&st->buffer,"site:MSG5"); + /* We are going to add four words to the message */ + buffer_init(&st->buffer,calculate_max_start_pad()); + /* Give the netlink code an opportunity to put its own stuff in the + message (configuration information, etc.) */ + buf_prepend_uint32(&st->buffer,LABEL_MSG5); + 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); + + st->retries=st->setup_retries; + return True; +} + static bool_t process_msg5(struct site *st, struct buffer_if *msg5, - struct sockaddr_in *src) + const struct comm_addr *src, + struct transform_inst_if *transform) { struct msg0 m; - string_t transform_err; + cstring_t transform_err; if (!unpick_msg0(st,msg5,&m)) return False; - if (st->new_transform->reverse(st->new_transform->st, - msg5,&transform_err)) { + if (call_transform_reverse(st,transform,msg5,&transform_err)) { /* There's a problem */ - slog(st,LOG_SECURITY,"process_msg5: transform: %s",transform_err); + slog(st,LOG_SEC,"process_msg5: transform: %s",transform_err); return False; } /* Buffer should now contain untransformed PING packet data */ CHECK_AVAIL(msg5,4); - if ((*(uint32_t *)buf_unprepend(msg5,4))!=LABEL_MSG5) { - slog(st,LOG_SECURITY,"MSG5/PING packet contained invalid data"); + if (buf_unprepend_uint32(msg5)!=LABEL_MSG5) { + slog(st,LOG_SEC,"MSG5/PING packet contained wrong label"); return False; } - CHECK_EMPTY(msg5); + /* Older versions of secnet used to write some config data here + * which we ignore. So we don't CHECK_EMPTY */ return True; } -static bool_t generate_msg6(struct site *st) +static void create_msg6(struct site *st, struct transform_inst_if *transform, + uint32_t session_id) { - string_t transform_err; + cstring_t transform_err; BUF_ALLOC(&st->buffer,"site:MSG6"); - /* We are going to add three words to the transformed message */ - buffer_init(&st->buffer,st->transform->max_start_pad+(4*3)); - *(uint32_t *)buf_append(&st->buffer,4)=LABEL_MSG6; - st->new_transform->forwards(st->new_transform->st,&st->buffer, - &transform_err); - *(uint32_t *)buf_prepend(&st->buffer,4)=LABEL_MSG6; - *(uint32_t *)buf_prepend(&st->buffer,4)=(uint32_t)st; - *(uint32_t *)buf_prepend(&st->buffer,4)=st->setup_session_id; - - st->retries=1; /* Peer will retransmit MSG5 if necessary */ + /* We are going to add four words to the message */ + buffer_init(&st->buffer,calculate_max_start_pad()); + /* Give the netlink code an opportunity to put its own stuff in the + message (configuration information, etc.) */ + buf_prepend_uint32(&st->buffer,LABEL_MSG6); + 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); +} + +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; } static bool_t process_msg6(struct site *st, struct buffer_if *msg6, - struct sockaddr_in *src) + const struct comm_addr *src) { struct msg0 m; - string_t transform_err; + cstring_t transform_err; 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_SECURITY,"process_msg6: transform: %s",transform_err); + slog(st,LOG_SEC,"process_msg6: transform: %s",transform_err); return False; } /* Buffer should now contain untransformed PING packet data */ CHECK_AVAIL(msg6,4); - if ((*(uint32_t *)buf_unprepend(msg6,4))!=LABEL_MSG6) { - slog(st,LOG_SECURITY,"MSG6/PONG packet contained invalid data"); + if (buf_unprepend_uint32(msg6)!=LABEL_MSG6) { + slog(st,LOG_SEC,"MSG6/PONG packet contained invalid data"); return False; } - CHECK_EMPTY(msg6); + /* Older versions of secnet used to write some config data here + * which we ignore. So we don't CHECK_EMPTY */ return True; } -static bool_t process_msg0(struct site *st, struct buffer_if *msg0, - struct sockaddr_in *src) +static bool_t decrypt_msg0(struct site *st, struct buffer_if *msg0, + const struct comm_addr *src) { + cstring_t transform_err, auxkey_err, newkey_err="n/a"; struct msg0 m; - string_t transform_err; - uint32_t type; + uint32_t problem; + + if (!unpick_msg0(st,msg0,&m)) return False; - if (!st->current_valid) { - slog(st,LOG_DROP,"incoming message but no current key -> dropping"); - if (st->state==SITE_RUN) { - slog(st,LOG_SETUP_INIT|LOG_STATE, - "now initiating setup of new key"); - return enter_state_resolve(st); + /* Keep a copy so we can try decrypting it with multiple keys */ + buffer_copy(&st->scratch, msg0); + + 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, + "peer has used new key","auxiliary key",LOG_SEC); + return True; + } + if (problem==2) + goto skew; + + buffer_copy(msg0, &st->scratch); + 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) { + /* We previously timed out in state SENTMSG5 but it turns + * out that our peer did in fact get our MSG5 and is + * using the new key. So we should switch to it too. */ + /* This is a bit like activate_new_key. */ + struct data_key t; + t=st->current; + st->current=st->auxiliary_key; + st->auxiliary_key=t; + + delete_one_key(st,&st->auxiliary_key,"peer has used new key", + "previous key",LOG_SEC); + st->auxiliary_is_new=0; + st->renegotiate_key_time=st->auxiliary_renegotiate_key_time; } - return False; + return True; + } + if (problem==2) + goto skew; + + if (st->state==SITE_SENTMSG5) { + buffer_copy(msg0, &st->scratch); + 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) */ + slog(st,LOG_STATE,"will enter state RUN (MSG0 with new key)"); + BUF_FREE(&st->buffer); + st->timeout=0; + activate_new_key(st); + return True; /* do process the data in this packet */ + } + if (problem==2) + goto skew; } - if (!unpick_msg0(st,msg0,&m)) return False; + slog(st,LOG_SEC,"transform: %s (aux: %s, new: %s)", + transform_err,auxkey_err,newkey_err); + initiate_key_setup(st,"incoming message would not decrypt",0); + send_nak(src,m.dest,m.source,m.type,msg0,"message would not decrypt"); + return False; - if (st->current_transform->reverse(st->current_transform->st, - msg0,&transform_err)) { - /* There's a problem */ - slog(st,LOG_SECURITY,"transform: %s",transform_err); + skew: + slog(st,LOG_DROP,"transform: %s (merely skew)",transform_err); + return False; +} + +static bool_t process_msg0(struct site *st, struct buffer_if *msg0, + const struct comm_addr *src) +{ + uint32_t type; + + if (!decrypt_msg0(st,msg0,src)) return False; - } + CHECK_AVAIL(msg0,4); - type=*(uint32_t *)buf_unprepend(msg0,4); + type=buf_unprepend_uint32(msg0); switch(type) { + case LABEL_MSG7: + /* We must forget about the current session. */ + delete_keys(st,"request from peer",LOG_SEC); + return True; case LABEL_MSG9: /* Deliver to netlink layer */ - st->netlink->deliver(st->netlink->st,st->netlink_cid,msg0); + st->netlink->deliver(st->netlink->st,msg0); + transport_data_msgok(st,src); + /* See whether we should start negotiating a new key */ + if (st->now > st->renegotiate_key_time) + initiate_key_setup(st,"incoming packet in renegotiation window",0); return True; - break; default: - slog(st,LOG_SECURITY,"incoming message of type %08x (unknown)",type); + slog(st,LOG_SEC,"incoming encrypted message of type %08x " + "(unknown)",type); break; } return False; } static void dump_packet(struct site *st, struct buffer_if *buf, - struct sockaddr_in *addr, bool_t incoming) + const struct comm_addr *addr, bool_t incoming) { - uint32_t dest=*(uint32_t *)buf->start; - uint32_t source=*(uint32_t *)(buf->start+4); - uint32_t msgtype=*(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) - log(st->log,0,"(%s,%s): %s: %08x<-%08x: %08x:", - st->localname,st->remotename,incoming?"incoming":"outgoing", - dest,source,msgtype); + slilog(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x:", + st->tunname,incoming?"incoming":"outgoing", + dest,source,msgtype); } static uint32_t site_status(void *st) @@ -623,13 +1116,31 @@ static uint32_t site_status(void *st) static bool_t send_msg(struct site *st) { if (st->retries>0) { - dump_packet(st,&st->buffer,&st->setup_peer,False); - st->comm->sendmsg(st->comm->st,&st->buffer,&st->setup_peer); - st->timeout=st->now+st->setup_timeout; + transport_xmit(st, &st->setup_peers, &st->buffer, True); + st->timeout=st->now+st->setup_retry_interval; st->retries--; return True; + } else if (st->state==SITE_SENTMSG5) { + logtimeout(st,"timed out sending MSG5, stashing new key"); + /* We stash the key we have produced, in case it turns out that + * our peer did see our MSG5 after all and starts using it. */ + /* This is a bit like some of activate_new_key */ + struct transform_inst_if *t; + t=st->auxiliary_key.transform; + st->auxiliary_key.transform=st->new_transform; + st->new_transform=t; + dispose_transform(&st->new_transform); + + 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; + st->auxiliary_key.remote_session_id=st->setup_session_id; + + enter_state_wait(st); + return False; } else { - slog(st,LOG_SETUP_TIMEOUT,"timed out sending key setup packet"); + logtimeout(st,"timed out sending key setup packet " + "(in state %s)",state_name(st->state)); enter_state_wait(st); return False; } @@ -638,60 +1149,175 @@ static bool_t send_msg(struct site *st) static void site_resolve_callback(void *sst, struct in_addr *address) { struct site *st=sst; + struct comm_addr ca_buf, *ca_use; + + st->resolving=False; - if (st->state!=SITE_RESOLVE) { - slog(st,LOG_UNEXPECTED,"site_resolve_callback called unexpectedly"); - return; - } if (address) { - memset(&st->setup_peer,0,sizeof(st->setup_peer)); - st->setup_peer.sin_family=AF_INET; - st->setup_peer.sin_port=htons(st->remoteport); - st->setup_peer.sin_addr=*address; - enter_state_sentmsg1(st); + FILLZERO(ca_buf); + ca_buf.comm=st->comms[0]; + ca_buf.sin.sin_family=AF_INET; + ca_buf.sin.sin_port=htons(st->remoteport); + ca_buf.sin.sin_addr=*address; + ca_use=&ca_buf; + slog(st,LOG_STATE,"resolution of %s completed: %s", + st->address, comm_addr_to_string(ca_use));; } else { - /* Resolution failed */ slog(st,LOG_ERROR,"resolution of %s failed",st->address); - enter_state_run(st); + ca_use=0; + } + + switch (st->state) { + case SITE_RESOLVE: + if (transport_compute_setupinit_peers(st,ca_use,0)) { + enter_new_state(st,SITE_SENTMSG1); + } else { + /* Can't figure out who to try to to talk to */ + slog(st,LOG_SETUP_INIT, + "key exchange failed: cannot find peer address"); + enter_state_run(st); + } + break; + case SITE_SENTMSG1: case SITE_SENTMSG2: + case SITE_SENTMSG3: case SITE_SENTMSG4: + case SITE_SENTMSG5: + if (ca_use) { + /* We start using the address immediately for data too. + * It's best to store it in st->peers now because we might + * go via SENTMSG5, WAIT, and a MSG0, straight into using + * the new key (without updating the data peer addrs). */ + transport_resolve_complete(st,ca_use); + } else if (st->local_mobile) { + /* We can't let this rest because we may have a peer + * address which will break in the future. */ + slog(st,LOG_SETUP_INIT,"resolution of %s failed: " + "abandoning key exchange",st->address); + enter_state_wait(st); + } else { + slog(st,LOG_SETUP_INIT,"resolution of %s failed: " + " continuing to use source address of peer's packets" + " for key exchange and ultimately data", + st->address); + } + break; + case SITE_RUN: + if (ca_use) { + slog(st,LOG_SETUP_INIT,"resolution of %s completed tardily," + " updating peer address(es)",st->address); + transport_resolve_complete_tardy(st,ca_use); + } 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; + } else { + slog(st,LOG_SETUP_INIT,"resolution of %s failed: " + " continuing to use source address of peer's packets", + st->address); + } + break; + case SITE_WAIT: + case SITE_STOP: + /* oh well */ + break; + } +} + +static bool_t initiate_key_setup(struct site *st, cstring_t reason, + const struct comm_addr *prod_hint) +{ + /* Reentrancy hazard: can call enter_new_state/enter_state_* */ + if (st->state!=SITE_RUN) return False; + slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason); + if (st->address) { + slog(st,LOG_SETUP_INIT,"resolving peer address"); + return enter_state_resolve(st); + } else if (transport_compute_setupinit_peers(st,0,prod_hint)) { + return enter_new_state(st,SITE_SENTMSG1); } + slog(st,LOG_SETUP_INIT,"key exchange failed: no address for peer"); + return False; } static void activate_new_key(struct site *st) { struct transform_inst_if *t; - t=st->current_transform; - st->current_transform=st->new_transform; + /* We have three transform instances, which we swap between old, + active and setup */ + t=st->auxiliary_key.transform; + 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->state=SITE_RUN; st->timeout=0; - st->current_valid=True; - st->current_key_timeout=st->now+st->key_lifetime; - st->peer=st->setup_peer; - st->peer_valid=True; - st->remote_session_id=st->setup_session_id; + st->auxiliary_is_new=0; + st->auxiliary_key.key_timeout=st->current.key_timeout; + st->current.key_timeout=st->now+st->key_lifetime; + st->renegotiate_key_time=st->now+st->key_renegotiate_time; + transport_peers_copy(st,&st->peers,&st->setup_peers); + st->current.remote_session_id=st->setup_session_id; + + /* Compute the inter-site MTU. This is min( our_mtu, their_mtu ). + * But their mtu be unspecified, in which case we just use ours. */ + uint32_t intersite_mtu= + MIN(st->mtu_target, st->remote_adv_mtu ?: ~(uint32_t)0); + st->netlink->set_mtu(st->netlink->st,intersite_mtu); + + slog(st,LOG_ACTIVATE_KEY,"new key activated" + " (mtu ours=%"PRId32" theirs=%"PRId32" intersite=%"PRId32")", + st->mtu_target, st->remote_adv_mtu, intersite_mtu); + enter_state_run(st); +} + +static void delete_one_key(struct site *st, struct data_key *key, + cstring_t reason, cstring_t which, uint32_t loglevel) +{ + if (!is_transform_valid(key->transform)) return; + if (reason) slog(st,loglevel,"%s deleted (%s)",which,reason); + dispose_transform(&key->transform); + key->key_timeout=0; +} + +static void delete_keys(struct site *st, cstring_t reason, uint32_t loglevel) +{ + if (current_valid(st)) { + slog(st,loglevel,"session closed (%s)",reason); - slog(st,LOG_ACTIVATE_KEY,"new key activated"); + delete_one_key(st,&st->current,0,0,0); + set_link_quality(st); + } + delete_one_key(st,&st->auxiliary_key,0,0,0); } static void state_assert(struct site *st, bool_t ok) { - if (!ok) fatal("state_assert\n"); + if (!ok) fatal("site:state_assert"); } static void enter_state_stop(struct site *st) { st->state=SITE_STOP; st->timeout=0; - st->current_transform->delkey(st->current_transform->st); - st->current_valid=False; - st->current_key_timeout=0; - - st->peer_valid=False; - - st->new_transform->delkey(st->new_transform->st); + delete_keys(st,"entering state STOP",LOG_TIMEOUT_KEY); + dispose_transform(&st->new_transform); +} + +static void set_link_quality(struct site *st) +{ + uint32_t quality; + if (current_valid(st)) + quality=LINK_QUALITY_UP; + else if (st->state==SITE_WAIT || st->state==SITE_STOP) + quality=LINK_QUALITY_DOWN; + else if (st->address) + quality=LINK_QUALITY_DOWN_CURRENT_ADDRESS; + else if (transport_peers_valid(&st->peers)) + quality=LINK_QUALITY_DOWN_STALE_ADDRESS; + else + quality=LINK_QUALITY_DOWN; + + st->netlink->set_quality(st->netlink->st,quality); } static void enter_state_run(struct site *st) @@ -699,111 +1325,137 @@ static void enter_state_run(struct site *st) slog(st,LOG_STATE,"entering state RUN"); st->state=SITE_RUN; st->timeout=0; - st->netlink->set_delivery(st->netlink->st,st->netlink_cid,True); - /* XXX get rid of key setup data */ -} -static bool_t enter_state_resolve(struct site *st) -{ - state_assert(st,st->state==SITE_RUN); - slog(st,LOG_STATE,"entering state RESOLVE"); - st->state=SITE_RESOLVE; - st->resolver->request(st->resolver->st,st->address, - site_resolve_callback,st); - return True; + st->setup_session_id=0; + transport_peers_clear(st,&st->setup_peers); + memset(st->localN,0,NONCELEN); + memset(st->remoteN,0,NONCELEN); + dispose_transform(&st->new_transform); + memset(st->dhsecret,0,st->dh->len); + memset(st->sharedsecret,0,st->sharedsecretlen); + set_link_quality(st); } -static bool_t enter_state_sentmsg1(struct site *st) +static bool_t ensure_resolving(struct site *st) { - state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE); - slog(st,LOG_STATE,"entering state SENTMSG1"); - if (generate_msg1(st) && send_msg(st)) { - st->state=SITE_SENTMSG1; - return True; - } - slog(st,LOG_ERROR,"error entering state SENTMSG1"); - st->buffer.free=False; /* Can't tell which it was, but enter_state_wait() - will do a BUF_FREE() */ - enter_state_wait(st); - return False; + /* Reentrancy hazard: may call site_resolve_callback and hence + * enter_new_state, enter_state_* and generate_msg*. */ + if (st->resolving) + return True; + + assert(st->address); + + /* resolver->request might reentrantly call site_resolve_callback + * which will clear st->resolving, so we need to set it beforehand + * rather than afterwards; also, it might return False, in which + * case we have to clear ->resolving again. */ + st->resolving=True; + bool_t ok = st->resolver->request(st->resolver->st,st->address, + site_resolve_callback,st); + if (!ok) + st->resolving=False; + + return ok; } -static bool_t enter_state_sentmsg2(struct site *st) +static bool_t enter_state_resolve(struct site *st) { - state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE || - st->state==SITE_SENTMSG1 || st->state==SITE_WAIT); - slog(st,LOG_STATE,"entering state SENTMSG2"); - if (generate_msg2(st) && send_msg(st)) { - st->state=SITE_SENTMSG2; - return True; - } - slog(st,LOG_ERROR,"error entering state SENTMSG2"); - st->buffer.free=False; - enter_state_wait(st); - return False; + /* Reentrancy hazard! See ensure_resolving. */ + state_assert(st,st->state==SITE_RUN); + slog(st,LOG_STATE,"entering state RESOLVE"); + st->state=SITE_RESOLVE; + return ensure_resolving(st); } -static bool_t enter_state_sentmsg3(struct site *st) +static bool_t enter_new_state(struct site *st, uint32_t next) { - state_assert(st,st->state==SITE_SENTMSG1); - slog(st,LOG_STATE,"entering state SENTMSG3"); - BUF_FREE(&st->buffer); /* Free message 1 */ - if (generate_msg3(st) && send_msg(st)) { - st->state=SITE_SENTMSG3; - return True; + bool_t (*gen)(struct site *st); + int r; + + slog(st,LOG_STATE,"entering state %s",state_name(next)); + switch(next) { + case SITE_SENTMSG1: + state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE); + gen=generate_msg1; + break; + case SITE_SENTMSG2: + state_assert(st,st->state==SITE_RUN || st->state==SITE_RESOLVE || + st->state==SITE_SENTMSG1 || st->state==SITE_WAIT); + gen=generate_msg2; + break; + case SITE_SENTMSG3: + state_assert(st,st->state==SITE_SENTMSG1); + BUF_FREE(&st->buffer); + gen=generate_msg3; + break; + case SITE_SENTMSG4: + state_assert(st,st->state==SITE_SENTMSG2); + BUF_FREE(&st->buffer); + gen=generate_msg4; + break; + case SITE_SENTMSG5: + state_assert(st,st->state==SITE_SENTMSG3); + BUF_FREE(&st->buffer); + gen=generate_msg5; + break; + case SITE_RUN: + state_assert(st,st->state==SITE_SENTMSG4); + BUF_FREE(&st->buffer); + gen=generate_msg6; + break; + default: + gen=NULL; + fatal("enter_new_state(%s): invalid new state",state_name(next)); + break; } - slog(st,LOG_ERROR,"error entering state SENTMSG3"); - st->buffer.free=False; - enter_state_wait(st); - return False; -} -static bool_t enter_state_sentmsg4(struct site *st) -{ - state_assert(st,st->state==SITE_SENTMSG2); - slog(st,LOG_STATE,"entering state SENTMSG4"); - BUF_FREE(&st->buffer); /* Free message 2 */ - if (generate_msg4(st) && send_msg(st)) { - st->state=SITE_SENTMSG4; - return True; - } - slog(st,LOG_ERROR,"error entering state SENTMSG4"); - st->buffer.free=False; - enter_state_wait(st); - return False; -} + if (hacky_par_start_failnow()) return False; -static bool_t enter_state_sentmsg5(struct site *st) -{ - state_assert(st,st->state==SITE_SENTMSG3); - slog(st,LOG_STATE,"entering state SENTMSG5"); - BUF_FREE(&st->buffer); /* Free message 3 */ + r= gen(st) && send_msg(st); - if (generate_msg5(st) && send_msg(st)) { - st->state=SITE_SENTMSG5; + hacky_par_end(&r, + st->setup_retries, st->setup_retry_interval, + send_msg, st); + + if (r) { + st->state=next; + if (next==SITE_RUN) { + BUF_FREE(&st->buffer); /* Never reused */ + st->timeout=0; /* Never retransmit */ + activate_new_key(st); + } return True; } - slog(st,LOG_ERROR,"error entering state SENTMSG5"); - st->buffer.free=False; + slog(st,LOG_ERROR,"error entering state %s",state_name(next)); + st->buffer.free=False; /* Unconditionally use the buffer; it may be + in either state, and enter_state_wait() will + do a BUF_FREE() */ enter_state_wait(st); - return False; } -static bool_t send_msg6(struct site *st) +/* msg7 tells our peer that we're about to forget our key */ +static bool_t send_msg7(struct site *st, cstring_t reason) { - state_assert(st,st->state==SITE_SENTMSG4); - slog(st,LOG_STATE,"entering state RUN after sending msg6"); - BUF_FREE(&st->buffer); /* Free message 4 */ - if (generate_msg6(st) && send_msg(st)) { - BUF_FREE(&st->buffer); /* Never reused */ - st->timeout=0; /* Never retransmit */ - activate_new_key(st); + cstring_t transform_err; + + if (current_valid(st) && st->buffer.free + && transport_peers_valid(&st->peers)) { + BUF_ALLOC(&st->buffer,"site:MSG7"); + buffer_init(&st->buffer,calculate_max_start_pad()); + buf_append_uint32(&st->buffer,LABEL_MSG7); + buf_append_string(&st->buffer,reason); + 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; } - slog(st,LOG_ERROR,"error entering state RUN after sending msg6"); - st->buffer.free=False; - enter_state_wait(st); return False; } @@ -815,15 +1467,48 @@ static void enter_state_wait(struct site *st) slog(st,LOG_STATE,"entering state WAIT"); st->timeout=st->now+st->wait_timeout; st->state=SITE_WAIT; - st->peer_valid=False; - st->netlink->set_delivery(st->netlink->st,st->netlink_cid,False); + set_link_quality(st); BUF_FREE(&st->buffer); /* will have had an outgoing packet in it */ /* XXX Erase keys etc. */ } +static void generate_prod(struct site *st, struct buffer_if *buf) +{ + buffer_init(buf,0); + buf_append_uint32(buf,0); + buf_append_uint32(buf,0); + buf_append_uint32(buf,LABEL_PROD); + buf_append_string(buf,st->localname); + buf_append_string(buf,st->remotename); +} + +static void generate_send_prod(struct site *st, + const struct comm_addr *source) +{ + if (!st->allow_send_prod) return; /* too soon */ + if (!(st->state==SITE_RUN || st->state==SITE_RESOLVE || + st->state==SITE_WAIT)) return; /* we'd ignore peer's MSG1 */ + + slog(st,LOG_SETUP_INIT,"prodding peer for key exchange"); + st->allow_send_prod=0; + generate_prod(st,&st->scratch); + dump_packet(st,&st->scratch,source,False); + source->comm->sendmsg(source->comm->st, &st->scratch, source); +} + +static inline void site_settimeout(uint64_t timeout, int *timeout_io) +{ + if (timeout) { + int64_t offset=timeout-*now; + if (offset<0) offset=0; + if (offset>INT_MAX) offset=INT_MAX; + if (*timeout_io<0 || offset<*timeout_io) + *timeout_io=offset; + } +} + static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, - int *timeout_io, const struct timeval *tv_now, - uint64_t *now) + int *timeout_io) { struct site *st=sst; @@ -831,201 +1516,261 @@ static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, st->now=*now; /* Work out when our next timeout is. The earlier of 'timeout' or - 'current_key_timeout'. A stored value of '0' indicates no timeout + 'current.key_timeout'. A stored value of '0' indicates no timeout active. */ - if (st->timeout && st->timeout-*now < *timeout_io) { - *timeout_io=st->timeout-*now; - } - - if (st->current_key_timeout && st->current_key_timeout-*now < *timeout_io) - *timeout_io=st->current_key_timeout-*now; + site_settimeout(st->timeout, timeout_io); + site_settimeout(st->current.key_timeout, timeout_io); + site_settimeout(st->auxiliary_key.key_timeout, timeout_io); return 0; /* success */ } +static void check_expiry(struct site *st, struct data_key *key, + const char *which) +{ + if (key->key_timeout && *now>key->key_timeout) { + delete_one_key(st,key,"maximum life exceeded",which,LOG_TIMEOUT_KEY); + } +} + /* NB site_afterpoll will be called before site_beforepoll is ever called */ -static void site_afterpoll(void *sst, struct pollfd *fds, int nfds, - const struct timeval *tv_now, uint64_t *now) +static void site_afterpoll(void *sst, struct pollfd *fds, int nfds) { struct site *st=sst; st->now=*now; if (st->timeout && *now>st->timeout) { - /* Do stuff */ st->timeout=0; - if (st->state>=SITE_SENTMSG1 && st->state<=SITE_SENTMSG5) - send_msg(st); - else if (st->state==SITE_WAIT) { + if (st->state>=SITE_SENTMSG1 && st->state<=SITE_SENTMSG5) { + if (!hacky_par_start_failnow()) + send_msg(st); + } else if (st->state==SITE_WAIT) { enter_state_run(st); } else { slog(st,LOG_ERROR,"site_afterpoll: unexpected timeout, state=%d", st->state); } } - if (st->current_key_timeout && *now>st->current_key_timeout) { - slog(st,LOG_TIMEOUT_KEY,"maximum key life exceeded; session closed"); - st->current_valid=False; - st->current_transform->delkey(st->current_transform->st); - st->current_key_timeout=0; - } + check_expiry(st,&st->current,"current key"); + check_expiry(st,&st->auxiliary_key,"auxiliary key"); } /* This function is called by the netlink device to deliver packets intended for the remote network. The packet is in "raw" wire format, but is guaranteed to be word-aligned. */ -static void site_outgoing(void *sst, void *cid, struct buffer_if *buf) +static void site_outgoing(void *sst, struct buffer_if *buf) { struct site *st=sst; - string_t transform_err; + cstring_t transform_err; if (st->state==SITE_STOP) { BUF_FREE(buf); return; } + st->allow_send_prod=1; + /* In all other states we consider delivering the packet if we have a valid key and a valid address to send it to. */ - if (st->current_valid && st->peer_valid) { + if (current_valid(st) && transport_peers_valid(&st->peers)) { /* Transform it and send it */ - *(uint32_t *)buf_prepend(buf,4)=LABEL_MSG9; - st->current_transform->forwards(st->current_transform->st, - buf, &transform_err); - *(uint32_t *)buf_prepend(buf,4)=LABEL_MSG0; - *(uint32_t *)buf_prepend(buf,4)=(uint32_t)st; - *(uint32_t *)buf_prepend(buf,4)=st->remote_session_id; - st->comm->sendmsg(st->comm->st,buf,&st->peer); + if (buf->size>0) { + buf_prepend_uint32(buf,LABEL_MSG9); + 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; } - if (st->state==SITE_RUN) { - BUF_FREE(buf); /* We throw the outgoing packet away */ - slog(st,LOG_SETUP_INIT,"initiating key exchange"); - enter_state_resolve(st); - return; - } - - /* Otherwise we're in the middle of key setup or a wait - just - throw the outgoing packet away */ - slog(st,LOG_DROP,"discarding outgoing packet"); + slog(st,LOG_DROP,"discarding outgoing packet of size %d",buf->size); BUF_FREE(buf); - return; + initiate_key_setup(st,"outgoing packet",0); +} + +static bool_t named_for_us(struct site *st, const struct buffer_if *buf_in, + uint32_t type, struct msg *m) + /* For packets which are identified by the local and remote names. + * If it has our name and our peer's name in it it's for us. */ +{ + struct buffer_if buf[1]; + buffer_readonly_clone(buf,buf_in); + return unpick_msg(st,type,buf,m) + && name_matches(&m->remote,st->remotename) + && name_matches(&m->local,st->localname); } /* This function is called by the communication device to deliver - packets from our peers. */ + packets from our peers. + It should return True if the packet is recognised as being for + this current site instance (and should therefore not be processed + by other sites), even if the packet was otherwise ignored. */ static bool_t site_incoming(void *sst, struct buffer_if *buf, - struct sockaddr_in *source) + const struct comm_addr *source) { struct site *st=sst; - uint32_t dest=*(uint32_t *)buf->start; - - if (dest==0) { - if (buf->size<(st->setupsiglen+8+NONCELEN)) return False; - /* It could be for any site - it should have LABEL_MSG1 and - might have our name and our peer's name in it */ - if (memcmp(buf->start+8,st->setupsig,st->setupsiglen)==0) { - dump_packet(st,buf,source,True); - /* It's addressed to us. Decide what to do about it. */ - if (st->state==SITE_RUN || st->state==SITE_RESOLVE || - st->state==SITE_WAIT) { - /* We should definitely process it */ - if (process_msg1(st,buf,source)) { - slog(st,LOG_SETUP_INIT,"key setup initiated by peer"); - enter_state_sentmsg2(st); - } else { - slog(st,LOG_ERROR,"failed to process incoming msg1"); - } + + if (buf->size < 12) return False; + + uint32_t dest=get_uint32(buf->start); + uint32_t msgtype=get_uint32(buf->start+8); + struct msg named_msg; + + if (msgtype==LABEL_MSG1) { + if (!named_for_us(st,buf,msgtype,&named_msg)) + return False; + /* It's a MSG1 addressed to us. Decide what to do about it. */ + dump_packet(st,buf,source,True); + if (st->state==SITE_RUN || st->state==SITE_RESOLVE || + st->state==SITE_WAIT) { + /* We should definitely process it */ + transport_record_peer(st,&st->setup_peers,source,"msg1"); + if (process_msg1(st,buf,source,&named_msg)) { + slog(st,LOG_SETUP_INIT,"key setup initiated by peer"); + bool_t entered=enter_new_state(st,SITE_SENTMSG2); + if (entered && st->address && st->local_mobile) + /* We must do this as the very last thing, because + the resolver callback might reenter us. */ + ensure_resolving(st); + } else { + slog(st,LOG_ERROR,"failed to process incoming msg1"); + } + BUF_FREE(buf); + return True; + } else if (st->state==SITE_SENTMSG1) { + /* We've just sent a message 1! They may have crossed on + the wire. If we have priority then we ignore the + incoming one, otherwise we process it as usual. */ + if (st->setup_priority) { BUF_FREE(buf); + slog(st,LOG_DUMP,"crossed msg1s; we are higher " + "priority => ignore incoming msg1"); return True; - } - if (st->state==SITE_SENTMSG1) { - /* We've just sent a message 1! They may have crossed on - the wire. If we have priority then we ignore the - incoming one, otherwise we process it as usual. */ - if (st->setup_priority) { - BUF_FREE(buf); - slog(st,LOG_DUMP,"crossed msg1s; we are higher " - "priority => ignore incoming msg1"); - return True; + } else { + slog(st,LOG_DUMP,"crossed msg1s; we are lower " + "priority => use incoming msg1"); + if (process_msg1(st,buf,source,&named_msg)) { + BUF_FREE(&st->buffer); /* Free our old message 1 */ + transport_setup_msgok(st,source); + enter_new_state(st,SITE_SENTMSG2); } else { - slog(st,LOG_DUMP,"crossed msg1s; we are lower " - "priority => use incoming msg1"); - if (process_msg1(st,buf,source)) { - BUF_FREE(&st->buffer); /* Free our old message 1 */ - enter_state_sentmsg2(st); - } else { - slog(st,LOG_ERROR,"failed to process an incoming " - "crossed msg1 (we have low priority)"); - } - BUF_FREE(buf); - return True; + slog(st,LOG_ERROR,"failed to process an incoming " + "crossed msg1 (we have low priority)"); } + BUF_FREE(buf); + return True; } - /* The message 1 was received at an unexpected stage of the - key setup. XXX POLICY - what do we do? */ - slog(st,LOG_UNEXPECTED,"unexpected incoming message 1"); - BUF_FREE(buf); - return True; } - return False; /* Not for us. */ + /* The message 1 was received at an unexpected stage of the + key setup. XXX POLICY - what do we do? */ + slog(st,LOG_UNEXPECTED,"unexpected incoming message 1"); + BUF_FREE(buf); + return True; + } + if (msgtype==LABEL_PROD) { + if (!named_for_us(st,buf,msgtype,&named_msg)) + return False; + dump_packet(st,buf,source,True); + if (st->state!=SITE_RUN) { + slog(st,LOG_DROP,"ignoring PROD when not in state RUN"); + } else if (current_valid(st)) { + slog(st,LOG_DROP,"ignoring PROD when we think we have a key"); + } else { + initiate_key_setup(st,"peer sent PROD packet",source); + } + BUF_FREE(buf); + return True; } - if (dest==(uint32_t)st) { - uint32_t msgtype=*(uint32_t *)(buf->start+8); + if (dest==st->index) { /* Explicitly addressed to us */ if (msgtype!=LABEL_MSG0) dump_packet(st,buf,source,True); switch (msgtype) { + case LABEL_NAK: + /* If the source is our current peer then initiate a key setup, + because our peer's forgotten the key */ + if (get_uint32(buf->start+4)==st->current.remote_session_id) { + bool_t initiated; + initiated = initiate_key_setup(st,"received a NAK",0); + if (!initiated) generate_send_prod(st,source); + } else { + slog(st,LOG_SEC,"bad incoming NAK"); + } + break; case LABEL_MSG0: process_msg0(st,buf,source); break; case LABEL_MSG1: /* Setup packet: should not have been explicitly addressed to us */ - slog(st,LOG_SECURITY,"incoming explicitly addressed msg1"); + slog(st,LOG_SEC,"incoming explicitly addressed msg1"); break; case LABEL_MSG2: /* Setup packet: expected only in state SENTMSG1 */ if (st->state!=SITE_SENTMSG1) { slog(st,LOG_UNEXPECTED,"unexpected MSG2"); - } else if (process_msg2(st,buf,source)) - enter_state_sentmsg3(st); - else { - slog(st,LOG_SECURITY,"invalid MSG2"); + } else if (process_msg2(st,buf,source)) { + transport_setup_msgok(st,source); + enter_new_state(st,SITE_SENTMSG3); + } else { + slog(st,LOG_SEC,"invalid MSG2"); } break; case LABEL_MSG3: + case LABEL_MSG3BIS: /* Setup packet: expected only in state SENTMSG2 */ if (st->state!=SITE_SENTMSG2) { slog(st,LOG_UNEXPECTED,"unexpected MSG3"); - } else if (process_msg3(st,buf,source)) - enter_state_sentmsg4(st); - else { - slog(st,LOG_SECURITY,"invalid MSG3"); + } else if (process_msg3(st,buf,source,msgtype)) { + transport_setup_msgok(st,source); + enter_new_state(st,SITE_SENTMSG4); + } else { + slog(st,LOG_SEC,"invalid MSG3"); } break; case LABEL_MSG4: /* Setup packet: expected only in state SENTMSG3 */ if (st->state!=SITE_SENTMSG3) { slog(st,LOG_UNEXPECTED,"unexpected MSG4"); - } else if (process_msg4(st,buf,source)) - enter_state_sentmsg5(st); - else { - slog(st,LOG_SECURITY,"invalid MSG4"); + } else if (process_msg4(st,buf,source)) { + transport_setup_msgok(st,source); + enter_new_state(st,SITE_SENTMSG5); + } else { + slog(st,LOG_SEC,"invalid MSG4"); } break; case LABEL_MSG5: /* Setup packet: expected only in state SENTMSG4 */ /* (may turn up in state RUN if our return MSG6 was lost and the new key has already been activated. In that - case we should treat it as an ordinary PING packet. We - can't pass it to process_msg5() because the - new_transform will now be null. XXX) */ - if (st->state!=SITE_SENTMSG4) { - slog(st,LOG_UNEXPECTED,"unexpected MSG5"); - } else if (process_msg5(st,buf,source)) { - send_msg6(st); + case we discard it. The peer will realise that we + are using the new key when they see our data packets. + Until then the peer's data packets to us get discarded. */ + if (st->state==SITE_SENTMSG4) { + if (process_msg5(st,buf,source,st->new_transform)) { + transport_setup_msgok(st,source); + enter_new_state(st,SITE_RUN); + } else { + slog(st,LOG_SEC,"invalid MSG5"); + } + } else if (st->state==SITE_RUN) { + if (process_msg5(st,buf,source,st->current.transform)) { + slog(st,LOG_DROP,"got MSG5, retransmitting MSG6"); + transport_setup_msgok(st,source); + create_msg6(st,st->current.transform, + st->current.remote_session_id); + transport_xmit(st,&st->peers,&st->buffer,True); + BUF_FREE(&st->buffer); + } else { + slog(st,LOG_SEC,"invalid MSG5 (in state RUN)"); + } } else { - slog(st,LOG_SECURITY,"invalid MSG5"); + slog(st,LOG_UNEXPECTED,"unexpected MSG5"); } break; case LABEL_MSG6: @@ -1034,17 +1779,14 @@ static bool_t site_incoming(void *sst, struct buffer_if *buf, slog(st,LOG_UNEXPECTED,"unexpected MSG6"); } else if (process_msg6(st,buf,source)) { BUF_FREE(&st->buffer); /* Free message 5 */ + transport_setup_msgok(st,source); activate_new_key(st); } else { - slog(st,LOG_SECURITY,"invalid MSG6"); + slog(st,LOG_SEC,"invalid MSG6"); } break; - case LABEL_MSG8: - /* NAK packet: enter state where we ping and check for response */ - slog(st,LOG_ERROR,"received a NAK"); - break; default: - slog(st,LOG_SECURITY,"received message of unknown type 0x%08x", + slog(st,LOG_SEC,"received message of unknown type 0x%08x", msgtype); break; } @@ -1062,12 +1804,22 @@ static void site_control(void *vst, bool_t run) else enter_state_stop(st); } +static void site_phase_hook(void *sst, uint32_t newphase) +{ + struct site *st=sst; + + /* The program is shutting down; tell our peer */ + send_msg7(st,"shutting down"); +} + static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, list_t *args) { + static uint32_t index_sequence; struct site *st; item_t *item; dict_t *dict; + int i; st=safe_malloc(sizeof(*st),"site_apply"); @@ -1085,89 +1837,338 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, cfgfatal(loc,"site","parameter must be a dictionary\n"); dict=item->data.dict; - st->netlink=find_cl_if(dict,"netlink",CL_NETLINK,True,"site",loc); - st->comm=find_cl_if(dict,"comm",CL_COMM,True,"site",loc); + st->localname=dict_read_string(dict, "local-name", True, "site", loc); + st->remotename=dict_read_string(dict, "name", True, "site", loc); + + st->peer_mobile=dict_read_bool(dict,"mobile",False,"site",loc,False); + st->local_mobile= + dict_read_bool(dict,"local-mobile",False,"site",loc,False); + + /* Sanity check (which also allows the 'sites' file to include + site() closures for all sites including our own): refuse to + talk to ourselves */ + if (strcmp(st->localname,st->remotename)==0) { + Message(M_DEBUG,"site %s: local-name==name -> ignoring this site\n", + st->localname); + if (st->peer_mobile != st->local_mobile) + cfgfatal(loc,"site","site %s's peer-mobile=%d" + " but our local-mobile=%d\n", + st->localname, st->peer_mobile, st->local_mobile); + free(st); + return NULL; + } + if (st->peer_mobile && st->local_mobile) { + Message(M_WARNING,"site %s: site is mobile but so are we" + " -> ignoring this site\n", st->remotename); + free(st); + return NULL; + } + + assert(index_sequence < 0xffffffffUL); + st->index = ++index_sequence; + st->local_capabilities = 0; + st->netlink=find_cl_if(dict,"link",CL_NETLINK,True,"site",loc); + +#define GET_CLOSURE_LIST(dictkey,things,nthings,CL_TYPE) do{ \ + list_t *things##_cfg=dict_lookup(dict,dictkey); \ + if (!things##_cfg) \ + cfgfatal(loc,"site","closure list \"%s\" not found\n",dictkey); \ + st->nthings=list_length(things##_cfg); \ + st->things=safe_malloc_ary(sizeof(*st->things),st->nthings,dictkey "s"); \ + assert(st->nthings); \ + for (i=0; inthings; i++) { \ + item_t *item=list_elem(things##_cfg,i); \ + if (item->type!=t_closure) \ + cfgfatal(loc,"site","%s is not a closure\n",dictkey); \ + closure_t *cl=item->data.closure; \ + if (cl->type!=CL_TYPE) \ + cfgfatal(loc,"site","%s closure wrong type\n",dictkey); \ + st->things[i]=cl->interface; \ + } \ +}while(0) + + GET_CLOSURE_LIST("comm",comms,ncomms,CL_COMM); + st->resolver=find_cl_if(dict,"resolver",CL_RESOLVER,True,"site",loc); 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->localname=dict_read_string(dict, "local-name", True, "site", loc); st->privkey=find_cl_if(dict,"local-key",CL_RSAPRIVKEY,True,"site",loc); - st->remoteport=dict_read_number(dict,"port",True,"site",loc,0); - - st->remotename=dict_read_string(dict, "name", True, "site", loc); st->address=dict_read_string(dict, "address", False, "site", loc); - dict_read_subnet_list(dict, "networks", True, "site", loc, - &st->remotenets); + if (st->address) + 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->transform= - find_cl_if(dict,"transform",CL_TRANSFORM,True,"site",loc); + GET_CLOSURE_LIST("transform",transforms,ntransforms,CL_TRANSFORM); st->dh=find_cl_if(dict,"dh",CL_DH,True,"site",loc); st->hash=find_cl_if(dict,"hash",CL_HASH,True,"site",loc); - st->key_lifetime=dict_read_number(dict,"key-lifetime", - False,"site",loc,DEFAULT_KEY_LIFETIME); - st->setup_retries=dict_read_number(dict,"setup-retries", - False,"site",loc,DEFAULT_SETUP_RETRIES); - st->setup_timeout=dict_read_number(dict,"setup-timeout", - False,"site",loc,DEFAULT_SETUP_TIMEOUT); - st->wait_timeout=dict_read_number(dict,"wait-time", - False,"site",loc,DEFAULT_WAIT_TIME); - /* XXX should be configurable */ - st->log_events=LOG_SECURITY|LOG_ERROR| - LOG_ACTIVATE_KEY|LOG_TIMEOUT_KEY|LOG_SETUP_INIT|LOG_SETUP_TIMEOUT; +#define DEFAULT(D) (st->peer_mobile || st->local_mobile \ + ? DEFAULT_MOBILE_##D : DEFAULT_##D) +#define CFG_NUMBER(k,D) dict_read_number(dict,(k),False,"site",loc,DEFAULT(D)); + + 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->mtu_target= dict_read_number(dict,"mtu-target",False,"site",loc,0); + + st->mobile_peer_expiry= dict_read_number( + dict,"mobile-peer-expiry",False,"site",loc,DEFAULT_MOBILE_PEER_EXPIRY); + + st->transport_peers_max= !st->peer_mobile ? 1 : dict_read_number( + dict,"mobile-peers-max",False,"site",loc,DEFAULT_MOBILE_PEERS_MAX); + if (st->transport_peers_max<1 || + st->transport_peers_max>=MAX_MOBILE_PEERS_MAX) { + cfgfatal(loc,"site","mobile-peers-max must be in range 1.." + STRING(MAX_MOBILE_PEERS_MAX) "\n"); + } + + if (st->key_lifetime < DEFAULT(KEY_RENEGOTIATE_GAP)*2) + st->key_renegotiate_time=st->key_lifetime/2; + else + st->key_renegotiate_time=st->key_lifetime-DEFAULT(KEY_RENEGOTIATE_GAP); + st->key_renegotiate_time=dict_read_number( + dict,"renegotiate-time",False,"site",loc,st->key_renegotiate_time); + if (st->key_renegotiate_time > st->key_lifetime) { + cfgfatal(loc,"site", + "renegotiate-time must be less than key-lifetime\n"); + } + + st->log_events=string_list_to_word(dict_lookup(dict,"log-events"), + log_event_table,"site"); + + st->resolving=False; + st->allow_send_prod=0; st->tunname=safe_malloc(strlen(st->localname)+strlen(st->remotename)+5, "site_apply"); sprintf(st->tunname,"%s<->%s",st->localname,st->remotename); /* The information we expect to see in incoming messages of type 1 */ - st->setupsiglen=strlen(st->remotename)+strlen(st->localname)+8; - st->setupsig=safe_malloc(st->setupsiglen,"site_apply"); - *(uint32_t *)&(st->setupsig[0])=LABEL_MSG1; - *(uint16_t *)&(st->setupsig[4])=htons(strlen(st->remotename)); - memcpy(&st->setupsig[6],st->remotename,strlen(st->remotename)); - *(uint16_t *)&(st->setupsig[6+strlen(st->remotename)])= - htons(strlen(st->localname)); - memcpy(&st->setupsig[8+strlen(st->remotename)],st->localname, - strlen(st->localname)); + /* fixme: lots of unchecked overflows here, but the results are only + corrupted packets rather than undefined behaviour */ st->setup_priority=(strcmp(st->localname,st->remotename)>0); buffer_new(&st->buffer,SETUP_BUFFER_LEN); + buffer_new(&st->scratch,SETUP_BUFFER_LEN); + BUF_ALLOC(&st->scratch,"site:scratch"); + /* We are interested in poll(), but only for timeouts. We don't have any fds of our own. */ register_for_poll(st, site_beforepoll, site_afterpoll, 0, "site"); st->timeout=0; - st->current_valid=False; - st->current_key_timeout=0; - st->peer_valid=False; + st->remote_capabilities=0; + st->chosen_transform=0; + st->current.key_timeout=0; + st->auxiliary_key.key_timeout=0; + transport_peers_clear(st,&st->peers); + transport_peers_clear(st,&st->setup_peers); /* XXX mlock these */ st->dhsecret=safe_malloc(st->dh->len,"site:dhsecret"); - st->sharedsecret=safe_malloc(st->transform->keylen,"site:sharedsecret"); + 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; + } /* We need to register the remote networks with the netlink device */ - st->netlink_cid=st->netlink->regnets(st->netlink->st, &st->remotenets, - site_outgoing, st, - st->transform->max_start_pad+(4*4), - st->transform->max_end_pad, - st->tunname); - - st->comm->request_notify(st->comm->st, st, site_incoming); + uint32_t netlink_mtu; /* local virtual interface mtu */ + st->netlink->reg(st->netlink->st, site_outgoing, st, &netlink_mtu); + if (!st->mtu_target) + st->mtu_target=netlink_mtu; + + 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->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); + add_hook(PHASE_SHUTDOWN,site_phase_hook,st); + return new_closure(&st->cl); } -init_module site_module; void site_module(dict_t *dict) { add_closure(dict,"site",site_apply); } + + +/***** TRANSPORT PEERS definitions *****/ + +static void transport_peers_debug(struct site *st, transport_peers *dst, + const char *didwhat, + int nargs, const struct comm_addr *args, + size_t stride) { + int i; + char *argp; + + if (!(st->log_events & LOG_PEER_ADDRS)) + return; /* an optimisation */ + + slog(st, LOG_PEER_ADDRS, "peers (%s) %s nargs=%d => npeers=%d", + (dst==&st->peers ? "data" : + dst==&st->setup_peers ? "setup" : "UNKNOWN"), + didwhat, nargs, dst->npeers); + + for (i=0, argp=(void*)args; + inpeers; i++) { + struct timeval diff; + timersub(tv_now,&dst->peers[i].last,&diff); + const struct comm_addr *ca=&dst->peers[i].addr; + slog(st, LOG_PEER_ADDRS, " peers: addrs[%d]=%s T-%ld.%06ld", + i, comm_addr_to_string(ca), + (unsigned long)diff.tv_sec, (unsigned long)diff.tv_usec); + } +} + +static int transport_peer_compar(const void *av, const void *bv) { + const transport_peer *a=av; + const transport_peer *b=bv; + /* put most recent first in the array */ + if (timercmp(&a->last, &b->last, <)) return +1; + if (timercmp(&a->last, &b->last, >)) return -11; + return 0; +} + +static void transport_peers_expire(struct site *st, transport_peers *peers) { + /* peers must be sorted first */ + int previous_peers=peers->npeers; + struct timeval oldest; + oldest.tv_sec = tv_now->tv_sec - st->mobile_peer_expiry; + oldest.tv_usec = tv_now->tv_usec; + while (peers->npeers>1 && + timercmp(&peers->peers[peers->npeers-1].last, &oldest, <)) + peers->npeers--; + if (peers->npeers != previous_peers) + transport_peers_debug(st,peers,"expire", 0,0,0); +} + +static void transport_record_peer(struct site *st, transport_peers *peers, + const struct comm_addr *addr, const char *m) { + int slot, changed=0; + + for (slot=0; slotnpeers; slot++) + if (!memcmp(&peers->peers[slot].addr, addr, sizeof(*addr))) + goto found; + + changed=1; + if (peers->npeers==st->transport_peers_max) + slot=st->transport_peers_max-1; + else + slot=peers->npeers++; + + found: + peers->peers[slot].addr=*addr; + peers->peers[slot].last=*tv_now; + + if (peers->npeers>1) + qsort(peers->peers, peers->npeers, + sizeof(*peers->peers), transport_peer_compar); + + if (changed || peers->npeers!=1) + transport_peers_debug(st,peers,m, 1,addr,0); + transport_peers_expire(st, peers); +} + +static bool_t transport_compute_setupinit_peers(struct site *st, + const struct comm_addr *configured_addr /* 0 if none or not found */, + const struct comm_addr *prod_hint_addr /* 0 if none */) { + + if (!configured_addr && !prod_hint_addr && + !transport_peers_valid(&st->peers)) + return False; + + slog(st,LOG_SETUP_INIT, + "using:%s%s %d old peer address(es)", + configured_addr ? " configured address;" : "", + prod_hint_addr ? " PROD hint address;" : "", + st->peers.npeers); + + /* Non-mobile peers have st->peers.npeers==0 or ==1, since they + * have transport_peers_max==1. The effect is that this code + * always uses the configured address if supplied, or otherwise + * the address of the incoming PROD, or the existing data peer if + * one exists; this is as desired. */ + + transport_peers_copy(st,&st->setup_peers,&st->peers); + + if (prod_hint_addr) + transport_record_peer(st,&st->setup_peers,prod_hint_addr,"prod"); + + if (configured_addr) + transport_record_peer(st,&st->setup_peers,configured_addr,"setupinit"); + + assert(transport_peers_valid(&st->setup_peers)); + return True; +} + +static void transport_setup_msgok(struct site *st, const struct comm_addr *a) { + if (st->peer_mobile) + transport_record_peer(st,&st->setup_peers,a,"setupmsg"); +} +static void transport_data_msgok(struct site *st, const struct comm_addr *a) { + if (st->peer_mobile) + transport_record_peer(st,&st->peers,a,"datamsg"); +} + +static int transport_peers_valid(transport_peers *peers) { + return peers->npeers; +} +static void transport_peers_clear(struct site *st, transport_peers *peers) { + peers->npeers= 0; + transport_peers_debug(st,peers,"clear",0,0,0); +} +static void transport_peers_copy(struct site *st, transport_peers *dst, + const transport_peers *src) { + dst->npeers=src->npeers; + memcpy(dst->peers, src->peers, sizeof(*dst->peers) * dst->npeers); + transport_peers_debug(st,dst,"copy", + src->npeers, &src->peers->addr, sizeof(*src->peers)); +} + +static void transport_resolve_complete(struct site *st, + const struct comm_addr *ca_use) { + transport_record_peer(st,&st->peers,ca_use,"resolved data"); + transport_record_peer(st,&st->setup_peers,ca_use,"resolved setup"); +} + +static void transport_resolve_complete_tardy(struct site *st, + const struct comm_addr *ca_use) { + transport_record_peer(st,&st->peers,ca_use,"resolved tardily"); +} + +void transport_xmit(struct site *st, transport_peers *peers, + struct buffer_if *buf, bool_t candebug) { + int slot; + transport_peers_expire(st, peers); + for (slot=0; slotnpeers; slot++) { + transport_peer *peer=&peers->peers[slot]; + if (candebug) + dump_packet(st, buf, &peer->addr, False); + peer->addr.comm->sendmsg(peer->addr.comm->st, buf, &peer->addr); + } +} + +/***** END of transport peers declarations *****/