X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=secnet.git;a=blobdiff_plain;f=site.c;h=567b85f85d26d97947f11d1447f2330822ff14c4;hp=2b51a5d0c6b41941ab89640de4c1f0e0545d4daa;hb=b1a0f651d803e1c1ff50f559b50de5c2dd6236d4;hpb=ff05a229397c75142725f45cad191ce4a00625ce diff --git a/site.c b/site.c index 2b51a5d..567b85f 100644 --- a/site.c +++ b/site.c @@ -16,6 +16,7 @@ #include "secnet.h" #include #include +#include #include #include @@ -28,7 +29,7 @@ #define DEFAULT_KEY_LIFETIME 3600000 /* One hour */ #define DEFAULT_KEY_RENEGOTIATE_GAP 300000 /* Five minutes */ #define DEFAULT_SETUP_RETRIES 5 -#define DEFAULT_SETUP_TIMEOUT 1000 +#define DEFAULT_SETUP_TIMEOUT 2000 #define DEFAULT_WAIT_TIME 20000 /* Each site can be in one of several possible states. */ @@ -78,7 +79,7 @@ #define SITE_SENTMSG5 7 #define SITE_WAIT 8 -static string_t state_name(uint32_t state) +static cstring_t state_name(uint32_t state) { switch (state) { case 0: return "STOP"; @@ -144,19 +145,19 @@ struct site { struct dh_if *dh; struct hash_if *hash; - 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 key_renegotiate_time; /* If we see traffic (or a keepalive) + int32_t setup_retries; /* How many times to send setup packets */ + int32_t setup_timeout; /* Initial timeout for setup packets */ + int32_t wait_timeout; /* How long to wait if setup unsuccessful */ + 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 */ bool_t keepalive; /* Send keepalives to detect peer failure (not yet implemented) */ uint8_t *setupsig; /* Expected signature of incoming MSG1 packets */ - uint32_t setupsiglen; /* Allows us to discard packets quickly if - they are not for us */ + int32_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; @@ -186,17 +187,17 @@ struct site { 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 */ + int32_t retries; /* Number of retries remaining */ uint64_t timeout; /* Timeout for current state */ uint8_t *dhsecret; uint8_t *sharedsecret; struct transform_inst_if *new_transform; /* For key setup/verify */ }; -static void slog(struct site *st, uint32_t event, string_t msg, ...) +static void slog(struct site *st, uint32_t event, cstring_t msg, ...) { va_list ap; - uint8_t buf[240]; + char buf[240]; uint32_t class; va_start(ap,msg); @@ -223,8 +224,8 @@ static void slog(struct site *st, uint32_t event, string_t msg, ...) } static void set_link_quality(struct site *st); -static void delete_key(struct site *st, string_t reason, uint32_t loglevel); -static bool_t initiate_key_setup(struct site *st, string_t reason); +static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel); +static bool_t initiate_key_setup(struct site *st, cstring_t reason); static void enter_state_run(struct site *st); static bool_t enter_state_resolve(struct site *st); static bool_t enter_new_state(struct site *st,uint32_t next); @@ -241,25 +242,25 @@ struct msg { uint8_t *hashstart; uint32_t dest; uint32_t source; - uint32_t remlen; + int32_t remlen; uint8_t *remote; - uint32_t loclen; + int32_t loclen; uint8_t *local; uint8_t *nR; uint8_t *nL; - uint32_t pklen; + int32_t pklen; uint8_t *pk; - uint32_t hashlen; - uint32_t siglen; + int32_t hashlen; + int32_t siglen; uint8_t *sig; }; /* 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, string_t what) +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; @@ -275,15 +276,20 @@ static bool_t generate_msg(struct site *st, uint32_t type, string_t what) 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; + 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; } @@ -330,7 +336,7 @@ static bool_t unpick_msg(struct site *st, uint32_t type, } static bool_t check_msg(struct site *st, uint32_t type, struct msg *m, - string_t *error) + cstring_t *error) { if (type==LABEL_MSG1) return True; @@ -392,7 +398,7 @@ static bool_t process_msg2(struct site *st, struct buffer_if *msg2, struct sockaddr_in *src) { struct msg m; - string_t err; + cstring_t err; if (!unpick_msg(st,LABEL_MSG2,msg2,&m)) return False; if (!check_msg(st,LABEL_MSG2,&m,&err)) { @@ -416,9 +422,9 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, struct sockaddr_in *src) { struct msg m; - uint8_t *hash=alloca(st->hash->len); + uint8_t *hash; void *hst; - string_t err; + cstring_t err; if (!unpick_msg(st,LABEL_MSG3,msg3,&m)) return False; if (!check_msg(st,LABEL_MSG3,&m,&err)) { @@ -427,6 +433,7 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, } /* Check signature and store g^x mod m */ + hash=safe_malloc(st->hash->len, "process_msg3"); hst=st->hash->init(); st->hash->update(hst,m.hashstart,m.hashlen); st->hash->final(hst,hash); @@ -434,8 +441,10 @@ static bool_t process_msg3(struct site *st, struct buffer_if *msg3, m.sig[m.siglen]=0; if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { slog(st,LOG_SEC,"msg3 signature failed check!"); + free(hash); return False; } + free(hash); /* Terminate their DH public key with a '0' */ m.pk[m.pklen]=0; @@ -464,9 +473,9 @@ static bool_t process_msg4(struct site *st, struct buffer_if *msg4, struct sockaddr_in *src) { struct msg m; - uint8_t *hash=alloca(st->hash->len); + uint8_t *hash; void *hst; - string_t err; + cstring_t err; if (!unpick_msg(st,LABEL_MSG4,msg4,&m)) return False; if (!check_msg(st,LABEL_MSG4,&m,&err)) { @@ -475,6 +484,7 @@ static bool_t process_msg4(struct site *st, struct buffer_if *msg4, } /* Check signature and store g^x mod m */ + hash=safe_malloc(st->hash->len, "process_msg4"); hst=st->hash->init(); st->hash->update(hst,m.hashstart,m.hashlen); st->hash->final(hst,hash); @@ -482,8 +492,10 @@ static bool_t process_msg4(struct site *st, struct buffer_if *msg4, m.sig[m.siglen]=0; if (!st->pubkey->check(st->pubkey->st,hash,st->hash->len,m.sig)) { slog(st,LOG_SEC,"msg4 signature failed check!"); + free(hash); return False; } + free(hash); /* Terminate their DH public key with a '0' */ m.pk[m.pklen]=0; @@ -518,7 +530,7 @@ static bool_t unpick_msg0(struct site *st, struct buffer_if *msg0, static bool_t generate_msg5(struct site *st) { - string_t transform_err; + cstring_t transform_err; BUF_ALLOC(&st->buffer,"site:MSG5"); /* We are going to add four words to the message */ @@ -541,7 +553,7 @@ static bool_t process_msg5(struct site *st, struct buffer_if *msg5, struct sockaddr_in *src) { struct msg0 m; - string_t transform_err; + cstring_t transform_err; if (!unpick_msg0(st,msg5,&m)) return False; @@ -567,7 +579,7 @@ static bool_t process_msg5(struct site *st, struct buffer_if *msg5, static bool_t generate_msg6(struct site *st) { - string_t transform_err; + cstring_t transform_err; BUF_ALLOC(&st->buffer,"site:MSG6"); /* We are going to add four words to the message */ @@ -590,7 +602,7 @@ static bool_t process_msg6(struct site *st, struct buffer_if *msg6, struct sockaddr_in *src) { struct msg0 m; - string_t transform_err; + cstring_t transform_err; if (!unpick_msg0(st,msg6,&m)) return False; @@ -618,7 +630,7 @@ static bool_t process_msg0(struct site *st, struct buffer_if *msg0, struct sockaddr_in *src) { struct msg0 m; - string_t transform_err; + cstring_t transform_err; uint32_t type; if (!st->current_valid) { @@ -663,9 +675,9 @@ static void dump_packet(struct site *st, struct buffer_if *buf, uint32_t msgtype=ntohl(*(uint32_t *)(buf->start+8)); if (st->log_events & LOG_DUMP) - log(st->log,M_DEBUG,"%s: %s: %08x<-%08x: %08x:", - st->tunname,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) @@ -710,7 +722,7 @@ static void site_resolve_callback(void *sst, struct in_addr *address) } } -static bool_t initiate_key_setup(struct site *st,string_t reason) +static bool_t initiate_key_setup(struct site *st, cstring_t reason) { if (st->state!=SITE_RUN) return False; slog(st,LOG_SETUP_INIT,"initiating key exchange (%s)",reason); @@ -749,7 +761,7 @@ static void activate_new_key(struct site *st) enter_state_run(st); } -static void delete_key(struct site *st, string_t reason, uint32_t loglevel) +static void delete_key(struct site *st, cstring_t reason, uint32_t loglevel) { if (st->current_valid) { slog(st,loglevel,"session closed (%s)",reason); @@ -763,7 +775,7 @@ static void delete_key(struct site *st, string_t reason, uint32_t loglevel) 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) @@ -820,6 +832,8 @@ static bool_t enter_state_resolve(struct site *st) static bool_t enter_new_state(struct site *st, uint32_t next) { bool_t (*gen)(struct site *st); + int r; + slog(st,LOG_STATE,"entering state %s",state_name(next)); switch(next) { case SITE_SENTMSG1: @@ -853,11 +867,19 @@ static bool_t enter_new_state(struct site *st, uint32_t next) break; default: gen=NULL; - fatal("enter_new_state(%s): invalid new state\n",state_name(next)); + fatal("enter_new_state(%s): invalid new state",state_name(next)); break; } - if (gen(st) && send_msg(st)) { + if (hacky_par_start_failnow()) return False; + + r= gen(st) && send_msg(st); + + hacky_par_end(&r, + st->setup_retries, st->setup_timeout, + send_msg, st); + + if (r) { st->state=next; if (next==SITE_RUN) { BUF_FREE(&st->buffer); /* Never reused */ @@ -875,9 +897,9 @@ static bool_t enter_new_state(struct site *st, uint32_t next) } /* msg7 tells our peer that we're about to forget our key */ -static bool_t send_msg7(struct site *st,string_t reason) +static bool_t send_msg7(struct site *st, cstring_t reason) { - string_t transform_err; + cstring_t transform_err; if (st->current_valid && st->peer_valid && st->buffer.free) { BUF_ALLOC(&st->buffer,"site:MSG7"); @@ -910,9 +932,19 @@ static void enter_state_wait(struct site *st) /* XXX Erase keys etc. */ } +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; @@ -922,28 +954,24 @@ static int site_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, /* Work out when our next timeout is. The earlier of 'timeout' or '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); return 0; /* success */ } /* 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) { 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", @@ -961,7 +989,7 @@ static void site_afterpoll(void *sst, struct pollfd *fds, int nfds, 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); @@ -1210,18 +1238,19 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, st->key_lifetime=dict_read_number( dict,"key-lifetime",False,"site",loc,DEFAULT_KEY_LIFETIME); - if (st->key_lifetime < DEFAULT_KEY_RENEGOTIATE_GAP) - st->key_renegotiate_time=st->key_lifetime/2; - else - st->key_renegotiate_time=st->key_lifetime-DEFAULT_KEY_RENEGOTIATE_GAP; 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); + + 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_lifetime); + 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"); @@ -1236,6 +1265,8 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, sprintf(st->tunname,"%s<->%s",st->localname,st->remotename); /* The information we expect to see in incoming messages of type 1 */ + /* fixme: lots of unchecked overflows here, but the results are only + corrupted packets rather than undefined behaviour */ st->setupsiglen=strlen(st->remotename)+strlen(st->localname)+8; st->setupsig=safe_malloc(st->setupsiglen,"site_apply"); put_uint32(st->setupsig+0,LABEL_MSG1); @@ -1278,7 +1309,6 @@ static list_t *site_apply(closure_t *self, struct cloc loc, dict_t *context, return new_closure(&st->cl); } -init_module site_module; void site_module(dict_t *dict) { add_closure(dict,"site",site_apply);