diff options
Diffstat (limited to 'comm/third_party/libotr/src/context.c')
| -rw-r--r-- | comm/third_party/libotr/src/context.c | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/comm/third_party/libotr/src/context.c b/comm/third_party/libotr/src/context.c new file mode 100644 index 0000000000..44d8b860f7 --- /dev/null +++ b/comm/third_party/libotr/src/context.c @@ -0,0 +1,547 @@ +/* + * Off-the-Record Messaging library + * Copyright (C) 2004-2014 Ian Goldberg, David Goulet, Rob Smits, + * Chris Alexander, Willy Lew, Lisa Du, + * Nikita Borisov + * <otr@cypherpunks.ca> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of version 2.1 of the GNU Lesser General + * Public License as published by the Free Software Foundation. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/* system headers */ +#include <stdlib.h> +#include <assert.h> + +/* libgcrypt headers */ +#include <gcrypt.h> + +/* libotr headers */ +#include "context.h" +#include "instag.h" + +#if OTRL_DEBUGGING +#include <stdio.h> + +void otrl_auth_dump(FILE *f, const OtrlAuthInfo *auth); +void otrl_sm_dump(FILE *f, const OtrlSMState *sm); + +/* Dump the contents of a context to the FILE *f. */ +void otrl_context_dump(FILE *f, const ConnContext *context) +{ + const Fingerprint *fing; + + fprintf(f, "Context %p:\n\n", context); + + fprintf(f, " Username: %s\n", context->username); + fprintf(f, " Accountname: %s\n", context->accountname); + fprintf(f, " Protocol: %s\n\n", context->protocol); + fprintf(f, " Master context: %p%s\n", context->m_context, + context->m_context == context ? " IS MASTER" : ""); + fprintf(f, " Recent recv child: %p\n", context->recent_rcvd_child); + fprintf(f, " Recent sent child: %p\n", context->recent_sent_child); + fprintf(f, " Recent child: %p\n\n", context->recent_child); + fprintf(f, " Our instance: %08x\n", context->our_instance); + fprintf(f, " Their instance: %08x\n\n", context->their_instance); + fprintf(f, " Msgstate: %d (%s)\n\n", context->msgstate, + context->msgstate == OTRL_MSGSTATE_PLAINTEXT ? "PLAINTEXT" : + context->msgstate == OTRL_MSGSTATE_ENCRYPTED ? "ENCRYPTED" : + context->msgstate == OTRL_MSGSTATE_FINISHED ? "FINISHED" : + "INVALID"); + otrl_auth_dump(f, &context->auth); + fprintf(f, "\n Fingerprints:\n"); + for (fing = context->fingerprint_root.next; fing; fing = fing->next) { + fprintf(f, " %p ", fing); + if (fing->fingerprint == NULL) { + fprintf(f, "(null)"); + } else { + int i; + for (i=0;i<20;++i) { + fprintf(f, "%02x", fing->fingerprint[i]); + } + } + fprintf(f, " %p", fing->context); + if (fing->trust && fing->trust[0]) { + fprintf(f, " %s", fing->trust); + } + fprintf(f, "\n"); + } + fprintf(f, "\n Active fingerprint: %p\n\n", context->active_fingerprint); + fprintf(f, " Protocol version: %d\n", context->protocol_version); + fprintf(f, " OTR offer: %d (%s)\n\n", context->otr_offer, + context->otr_offer == OFFER_NOT ? "NOT" : + context->otr_offer == OFFER_SENT ? "SENT" : + context->otr_offer == OFFER_REJECTED ? "REJECTED" : + context->otr_offer == OFFER_ACCEPTED ? "ACCEPTED" : + "INVALID"); + + fprintf(f, " Application data: %p\n", context->app_data); + if (context->smstate == NULL) { + fprintf(f, " SM state: NULL\n"); + } else { + otrl_sm_dump(f, context->smstate); + } + fprintf(f, "\n"); +} + +/* Dump the master context of this context, and all of its children. */ +void otrl_context_siblings_dump(FILE *f, const ConnContext *context) +{ + const ConnContext *citer; + for (citer = context->m_context; + citer && citer->m_context == context->m_context; + citer = citer->next) { + if (citer == context) { + fprintf(f, "*** "); + } + otrl_context_dump(f, citer); + } +} + +/* Dump all contexts. */ +void otrl_context_all_dump(FILE *f, OtrlUserState us) +{ + const ConnContext *citer; + unsigned int ctxnum = 1; + for (citer = us->context_root; citer; citer = citer->next, ++ctxnum) { + fprintf(f, "%u. ", ctxnum); + otrl_context_dump(f, citer); + } +} +#endif + +/* Create a new connection context. */ +static ConnContext * new_context(const char * user, const char * accountname, + const char * protocol) +{ + ConnContext * context; + OtrlSMState *smstate; + + context = malloc(sizeof(ConnContext)); + assert(context != NULL); + + context->username = strdup(user); + context->accountname = strdup(accountname); + context->protocol = strdup(protocol); + + context->msgstate = OTRL_MSGSTATE_PLAINTEXT; + otrl_auth_new(context); + + smstate = malloc(sizeof(OtrlSMState)); + assert(smstate != NULL); + otrl_sm_state_new(smstate); + context->smstate = smstate; + + context->our_instance = 0; + context->their_instance = OTRL_INSTAG_MASTER; + context->fingerprint_root.fingerprint = NULL; + context->fingerprint_root.context = context; + context->fingerprint_root.next = NULL; + context->fingerprint_root.tous = NULL; + context->active_fingerprint = NULL; + memset(context->sessionid, 0, 20); + context->sessionid_len = 0; + context->protocol_version = 0; + context->otr_offer = OFFER_NOT; + context->app_data = NULL; + context->app_data_free = NULL; + context->context_priv = otrl_context_priv_new(); + assert(context->context_priv != NULL); + context->next = NULL; + context->m_context = context; + context->recent_rcvd_child = NULL; + context->recent_sent_child = NULL; + context->recent_child = NULL; + + return context; +} + +ConnContext * otrl_context_find_recent_instance(ConnContext * context, + otrl_instag_t recent_instag) { + ConnContext * m_context; + + if (!context) return NULL; + + m_context = context->m_context; + + if (!m_context) return NULL; + + switch(recent_instag) { + case OTRL_INSTAG_RECENT: + return m_context->recent_child; + case OTRL_INSTAG_RECENT_RECEIVED: + return m_context->recent_rcvd_child; + case OTRL_INSTAG_RECENT_SENT: + return m_context->recent_sent_child; + default: + return NULL; + } +} + +/* Find the instance of this context that has the best security level, + and for which we have most recently received a message from. Note that most + recent in this case is limited to a one-second resolution. */ +ConnContext * otrl_context_find_recent_secure_instance(ConnContext * context) +{ + ConnContext *curp; /* for iteration */ + ConnContext *m_context; /* master */ + ConnContext *cresult = context; /* best so far */ + + if (!context) { + return cresult; + } + + m_context = context->m_context; + + for (curp = m_context; curp && curp->m_context == m_context; + curp = curp->next) { + int msgstate_improved = 0; /* 0 == same, 1 == improved */ + int trust_improved = 0; /* (will immediately 'continue' if worse + * than) */ + + if (cresult->msgstate == curp->msgstate) { + msgstate_improved = 0; + } else if (curp->msgstate == OTRL_MSGSTATE_ENCRYPTED || + (cresult->msgstate == OTRL_MSGSTATE_PLAINTEXT && + curp->msgstate == OTRL_MSGSTATE_FINISHED)) { + msgstate_improved = 1; + } else { + continue; + } + + + if (otrl_context_is_fingerprint_trusted(cresult->active_fingerprint) == + otrl_context_is_fingerprint_trusted(curp->active_fingerprint)) { + + trust_improved = 0; + } else if + (otrl_context_is_fingerprint_trusted(curp->active_fingerprint)){ + + trust_improved = 1; + } else { + continue; + } + + if (msgstate_improved || trust_improved || + (!msgstate_improved && !trust_improved && + curp->context_priv->lastrecv >= + cresult->context_priv->lastrecv)) { + cresult = curp; + } + } + + return cresult; +} + +/* Look up a connection context by name/account/protocol/instag from the given + * OtrlUserState. If add_if_missing is true, allocate and return a new + * context if one does not currently exist. In that event, call + * add_app_data(data, context) so that app_data and app_data_free can be + * filled in by the application, and set *addedp to 1. + * In the 'their_instance' field note that you can also specify a 'meta- + * instance' value such as OTRL_INSTAG_MASTER, OTRL_INSTAG_RECENT, + * OTRL_INSTAG_RECENT_RECEIVED and OTRL_INSTAG_RECENT_SENT. */ +ConnContext * otrl_context_find(OtrlUserState us, const char *user, + const char *accountname, const char *protocol, + otrl_instag_t their_instance, int add_if_missing, int *addedp, + void (*add_app_data)(void *data, ConnContext *context), void *data) +{ + ConnContext ** curp; + int usercmp = 1, acctcmp = 1, protocmp = 1; + if (addedp) *addedp = 0; + if (!user || !accountname || !protocol) return NULL; + + for (curp = &(us->context_root); *curp; curp = &((*curp)->next)) { + if ((usercmp = strcmp((*curp)->username, user)) > 0 || + (usercmp == 0 && + (acctcmp = strcmp((*curp)->accountname, accountname)) > 0) || + (usercmp == 0 && acctcmp == 0 && + (protocmp = strcmp((*curp)->protocol, protocol)) > 0) || + (usercmp == 0 && acctcmp == 0 && protocmp == 0 + && (their_instance < OTRL_MIN_VALID_INSTAG || + ((*curp)->their_instance >= their_instance)))) + /* We're at the right place in the list. We've either found + * it, or gone too far. */ + break; + } + + if (usercmp == 0 && acctcmp == 0 && protocmp == 0 && *curp && + (their_instance < OTRL_MIN_VALID_INSTAG || + (their_instance == (*curp)->their_instance))) { + /* Found one! */ + if (their_instance >= OTRL_MIN_VALID_INSTAG || + their_instance == OTRL_INSTAG_MASTER) { + return *curp; + } + + /* We need to go back and check more values in the context */ + switch(their_instance) { + case OTRL_INSTAG_BEST: + return otrl_context_find_recent_secure_instance(*curp); + case OTRL_INSTAG_RECENT: + case OTRL_INSTAG_RECENT_RECEIVED: + case OTRL_INSTAG_RECENT_SENT: + return otrl_context_find_recent_instance(*curp, their_instance); + default: + return NULL; + } + } + + if (add_if_missing) { + ConnContext *newctx; + OtrlInsTag *our_instag = (OtrlInsTag *)otrl_instag_find(us, accountname, + protocol); + + if (addedp) *addedp = 1; + newctx = new_context(user, accountname, protocol); + newctx->next = *curp; + if (*curp) { + (*curp)->tous = &(newctx->next); + } + *curp = newctx; + newctx->tous = curp; + if (add_app_data) { + add_app_data(data, *curp); + } + + /* Initialize specified instance tags */ + if (our_instag) { + newctx->our_instance = our_instag->instag; + } + + if (their_instance >= OTRL_MIN_VALID_INSTAG || + their_instance == OTRL_INSTAG_MASTER) { + newctx->their_instance = their_instance; + } + + if (their_instance >= OTRL_MIN_VALID_INSTAG) { + newctx->m_context = otrl_context_find(us, user, accountname, + protocol, OTRL_INSTAG_MASTER, 1, NULL, add_app_data, data); + } + + if (their_instance == OTRL_INSTAG_MASTER) { + /* if we're adding a master, there are no children, so the most + * recent context is the one we add. */ + newctx->recent_child = newctx; + newctx->recent_rcvd_child = newctx; + newctx->recent_sent_child = newctx; + } + + return *curp; + } + return NULL; +} + +/* Return true iff the given fingerprint is marked as trusted. */ +int otrl_context_is_fingerprint_trusted(Fingerprint *fprint) { + return fprint && fprint->trust && fprint->trust[0] != '\0'; +} + +/* This method gets called after sending or receiving a message, to + * update the master context's "recent context" pointers. */ +void otrl_context_update_recent_child(ConnContext *context, + unsigned int sent_msg) { + ConnContext *m_context = context->m_context; + + if (sent_msg) { + m_context->recent_sent_child = context; + } else { + m_context->recent_rcvd_child = context; + } + + m_context->recent_child = context; + +} + +/* Find a fingerprint in a given context, perhaps adding it if not + * present. */ +Fingerprint *otrl_context_find_fingerprint(ConnContext *context, + unsigned char fingerprint[20], int add_if_missing, int *addedp) +{ + Fingerprint *f; + if (addedp) *addedp = 0; + + if (!context || !context->m_context) return NULL; + + context = context->m_context; + + f = context->fingerprint_root.next; + while(f) { + if (!memcmp(f->fingerprint, fingerprint, 20)) return f; + f = f->next; + } + + /* Didn't find it. */ + if (add_if_missing) { + if (addedp) *addedp = 1; + f = malloc(sizeof(*f)); + assert(f != NULL); + f->fingerprint = malloc(20); + assert(f->fingerprint != NULL); + memmove(f->fingerprint, fingerprint, 20); + f->context = context; + f->trust = NULL; + f->next = context->fingerprint_root.next; + if (f->next) { + f->next->tous = &(f->next); + } + context->fingerprint_root.next = f; + f->tous = &(context->fingerprint_root.next); + return f; + } + return NULL; +} + +/* Set the trust level for a given fingerprint */ +void otrl_context_set_trust(Fingerprint *fprint, const char *trust) +{ + if (fprint == NULL) return; + + free(fprint->trust); + fprint->trust = trust ? strdup(trust) : NULL; +} + +/* Force a context into the OTRL_MSGSTATE_FINISHED state. */ +void otrl_context_force_finished(ConnContext *context) +{ + context->msgstate = OTRL_MSGSTATE_FINISHED; + otrl_auth_clear(&(context->auth)); + context->active_fingerprint = NULL; + memset(context->sessionid, 0, 20); + context->sessionid_len = 0; + context->protocol_version = 0; + otrl_sm_state_free(context->smstate); + otrl_context_priv_force_finished(context->context_priv); +} + +/* Force a context into the OTRL_MSGSTATE_PLAINTEXT state. */ +void otrl_context_force_plaintext(ConnContext *context) +{ + /* First clean up everything we'd need to do for the FINISHED state */ + otrl_context_force_finished(context); + + /* And just set the state properly */ + context->msgstate = OTRL_MSGSTATE_PLAINTEXT; +} + +/* Forget a fingerprint (so long as it's not the active one. If it's a + * fingerprint_root, forget the whole context (as long as + * and_maybe_context is set, and it's PLAINTEXT). Also, if it's not + * the fingerprint_root, but it's the only fingerprint, and we're + * PLAINTEXT, forget the whole context if and_maybe_context is set. */ +void otrl_context_forget_fingerprint(Fingerprint *fprint, + int and_maybe_context) +{ + ConnContext *context = fprint->context; + if (fprint == &(context->fingerprint_root)) { + if (context->msgstate == OTRL_MSGSTATE_PLAINTEXT && + and_maybe_context) { + otrl_context_forget(context); + } + } else { + if (context->msgstate != OTRL_MSGSTATE_PLAINTEXT || + context->active_fingerprint != fprint) { + + free(fprint->fingerprint); + free(fprint->trust); + *(fprint->tous) = fprint->next; + if (fprint->next) { + fprint->next->tous = fprint->tous; + } + free(fprint); + if (context->msgstate == OTRL_MSGSTATE_PLAINTEXT && + context->fingerprint_root.next == NULL && + and_maybe_context) { + /* We just deleted the only fingerprint. Forget the + * whole thing. */ + otrl_context_forget(context); + } + } + } +} + +/* Forget a whole context, so long as it's PLAINTEXT. If a context has child + * instances, don't remove this instance unless children are also all in + * PLAINTEXT state. In this case, the children will also be removed. + * Returns 0 on success, 1 on failure. */ +int otrl_context_forget(ConnContext *context) +{ + if (context->msgstate != OTRL_MSGSTATE_PLAINTEXT) return 1; + + if (context->their_instance == OTRL_INSTAG_MASTER) { + ConnContext *c_iter; + + for (c_iter = context; c_iter && + c_iter->m_context == context->m_context; + c_iter = c_iter->next) { + if (c_iter->msgstate != OTRL_MSGSTATE_PLAINTEXT) return 1; + } + + c_iter = context->next; + while (c_iter && c_iter->m_context == context->m_context) { + if (!otrl_context_forget(c_iter)) { + c_iter = context->next; + } else { + return 1; + } + } + + } + + /* Just to be safe, force to plaintext. This also frees any + * extraneous data lying around. */ + otrl_context_force_plaintext(context); + + /* First free all the Fingerprints */ + while(context->fingerprint_root.next) { + otrl_context_forget_fingerprint(context->fingerprint_root.next, 0); + } + /* Now free all the dynamic info here */ + free(context->username); + free(context->accountname); + free(context->protocol); + free(context->smstate); + context->username = NULL; + context->accountname = NULL; + context->protocol = NULL; + context->smstate = NULL; + + /* Free the application data, if it exists */ + if (context->app_data && context->app_data_free) { + (context->app_data_free)(context->app_data); + context->app_data = NULL; + } + + /* Fix the list linkages */ + *(context->tous) = context->next; + if (context->next) { + context->next->tous = context->tous; + } + + free(context); + return 0; +} + +/* Forget all the contexts in a given OtrlUserState. */ +void otrl_context_forget_all(OtrlUserState us) +{ + ConnContext *c_iter; + + for (c_iter = us->context_root; c_iter; c_iter = c_iter->next) { + otrl_context_force_plaintext(c_iter); + } + + while (us->context_root) { + otrl_context_forget(us->context_root); + } +} |