Add libotr/etc sources

1 files changed, 547 insertions, 0 deletions

diff --git a/libotr/libotr-4.1.1/src/context.c b/libotr/libotr-4.1.1/src/context.c
new file mode 100644
index 0000000..44d8b86
--- /dev/null
+++ b/libotr/libotr-4.1.1/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);
+    }
+}