source: otr.c @ 727a68b

/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/*
  OTR support (cf. http://www.cypherpunks.ca/otr/)

  (c) 2008-2011,2013 Sven Moritz Hallberg <pesco@khjk.org>
  funded by stonedcoder.org

  files used to store OTR data:
    <configdir>/<nick>.otr_keys
    <configdir>/<nick>.otr_fprints
    <configdir>/<nick>.otr_instags  <- don't copy this one between hosts

  top-level todos: (search for TODO for more ;-))
    integrate otr_load/otr_save with existing storage backends
    per-account policy settings
    per-user policy settings
    add a way to select recipient instance
*/

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program 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 General Public License for more details.

  You should have received a copy of the GNU General Public License with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "bitlbee.h"
#include "irc.h"
#include "otr.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <assert.h>
#include <signal.h>


/** OTR interface routines for the OtrlMessageAppOps struct: **/

OtrlPolicy op_policy(void *opdata, ConnContext *context);

void op_create_privkey(void *opdata, const char *accountname, const char *protocol);

int op_is_logged_in(void *opdata, const char *accountname, const char *protocol,
                    const char *recipient);

void op_inject_message(void *opdata, const char *accountname, const char *protocol,
                       const char *recipient, const char *message);

void op_new_fingerprint(void *opdata, OtrlUserState us, const char *accountname,
                        const char *protocol, const char *username, unsigned char fingerprint[20]);

void op_write_fingerprints(void *opdata);

void op_gone_secure(void *opdata, ConnContext *context);

void op_gone_insecure(void *opdata, ConnContext *context);

void op_still_secure(void *opdata, ConnContext *context, int is_reply);

void op_log_message(void *opdata, const char *message);

int op_max_message_size(void *opdata, ConnContext *context);

const char *op_account_name(void *opdata, const char *account, const char *protocol);

void op_create_instag(void *opdata, const char *account, const char *protocol);

void op_convert_msg(void *opdata, ConnContext *ctx, OtrlConvertType typ,
                    char **dst, const char *src);
void op_convert_free(void *opdata, ConnContext *ctx, char *msg);

void op_handle_smp_event(void *opdata, OtrlSMPEvent ev, ConnContext *ctx,
                         unsigned short percent, char *question);

void op_handle_msg_event(void *opdata, OtrlMessageEvent ev, ConnContext *ctx,
                         const char *message, gcry_error_t err);

const char *op_otr_error_message(void *opdata, ConnContext *ctx,
                                 OtrlErrorCode err_code);

/** otr sub-command handlers: **/

static void cmd_otr(irc_t *irc, char **args);
void cmd_otr_connect(irc_t *irc, char **args);
void cmd_otr_disconnect(irc_t *irc, char **args);
void cmd_otr_reconnect(irc_t *irc, char **args);
void cmd_otr_smp(irc_t *irc, char **args);
void cmd_otr_smpq(irc_t *irc, char **args);
void cmd_otr_trust(irc_t *irc, char **args);
void cmd_otr_info(irc_t *irc, char **args);
void cmd_otr_keygen(irc_t *irc, char **args);
void cmd_otr_forget(irc_t *irc, char **args);

const command_t otr_commands[] = {
        { "connect",     1, &cmd_otr_connect,    0 },
        { "disconnect",  1, &cmd_otr_disconnect, 0 },
        { "reconnect",   1, &cmd_otr_reconnect,  0 },
        { "smp",         2, &cmd_otr_smp,        0 },
        { "smpq",        3, &cmd_otr_smpq,       0 },
        { "trust",       6, &cmd_otr_trust,      0 },
        { "info",        0, &cmd_otr_info,       0 },
        { "keygen",      1, &cmd_otr_keygen,     0 },
        { "forget",      2, &cmd_otr_forget,     0 },
        { NULL }
};

typedef struct {
        void *fst;
        void *snd;
} pair_t;

static OtrlMessageAppOps otr_ops;   /* collects interface functions required by OTR */


/** misc. helpers/subroutines: **/

/* check whether we are already generating a key for a given account */
int keygen_in_progress(irc_t *irc, const char *handle, const char *protocol);

/* start background process to generate a (new) key for a given account */
void otr_keygen(irc_t *irc, const char *handle, const char *protocol);

/* main function for the forked keygen slave */
void keygen_child_main(OtrlUserState us, int infd, int outfd);

/* mainloop handler for when a keygen finishes */
gboolean keygen_finish_handler(gpointer data, gint fd, b_input_condition cond);

/* copy the contents of file a to file b, overwriting it if it exists */
void copyfile(const char *a, const char *b);

/* read one line of input from a stream, excluding trailing newline */
void myfgets(char *s, int size, FILE *stream);

/* some yes/no handlers */
void yes_keygen(void *data);
void yes_forget_fingerprint(void *data);
void yes_forget_context(void *data);
void yes_forget_key(void *data);

/* timeout handler that calls otrl_message_poll */
gboolean ev_message_poll(gpointer data, gint fd, b_input_condition cond);

/* helper to make sure accountname and protocol match the incoming "opdata" */
struct im_connection *check_imc(void *opdata, const char *accountname,
                                const char *protocol);

/* determine the nick for a given handle/protocol pair
   returns "handle/protocol" if not found */
const char *peernick(irc_t *irc, const char *handle, const char *protocol);

/* turn a hexadecimal digit into its numerical value */
int hexval(char a);

/* determine the irc_user_t for a given handle/protocol pair
   returns NULL if not found */
irc_user_t *peeruser(irc_t *irc, const char *handle, const char *protocol);

/* show an otr-related message to the user */
void display_otr_message(void *opdata, ConnContext *ctx, const char *fmt, ...);

/* write an otr-related message to the system log */
void log_otr_message(void *opdata, const char *fmt, ...);

/* combined handler for the 'otr smp' and 'otr smpq' commands */
void otr_smp_or_smpq(irc_t *irc, const char *nick, const char *question,
                     const char *secret);

/* update flags within the irc_user structure to reflect OTR status of context */
void otr_update_uflags(ConnContext *context, irc_user_t *u);

/* update op/voice flag of given user according to encryption state and settings
   returns 0 if neither op_buddies nor voice_buddies is set to "encrypted",
   i.e. msgstate should be announced separately */
int otr_update_modeflags(irc_t *irc, irc_user_t *u);

/* show general info about the OTR subsystem; called by 'otr info' */
void show_general_otr_info(irc_t *irc);

/* show info about a given OTR context and subcontexts/instances. bestctx
   may be either NULL or preferred destination context (this is hilighted
   in the output as being the target for a message) */
void show_otr_context_info(irc_t *irc, ConnContext *ctx, ConnContext *bestctx);

/* show the list of fingerprints associated with a given context */
void show_fingerprints(irc_t *irc, ConnContext *ctx);

/* find a fingerprint by prefix (given as any number of hex strings) */
Fingerprint *match_fingerprint(irc_t *irc, ConnContext *ctx, const char **args);

/* find a private key by fingerprint prefix (given as any number of hex strings) */
OtrlPrivKey *match_privkey(irc_t *irc, const char **args);

/* check whether a string is safe to use in a path component */
int strsane(const char *s);

/* close the OTR connection with the given buddy */
gboolean otr_disconnect_user(irc_t *irc, irc_user_t *u);

/* close all active OTR connections */
void otr_disconnect_all(irc_t *irc);

/* modifies string in-place, replacing \x03 with '?',
   as a quick way to prevent remote users from messing with irc colors */
static char *otr_filter_colors(char *msg);

/* functions to be called for certain events */
static const struct irc_plugin otr_plugin;

#define OTR_COLOR_TRUSTED "03"     /* green */
#define OTR_COLOR_UNTRUSTED "05"   /* red */

/*** routines declared in otr.h: ***/

#ifdef OTR_BI
#define init_plugin otr_init
#endif

void init_plugin(void)
{
        OTRL_INIT;

        /* fill global OtrlMessageAppOps */
        otr_ops.policy = &op_policy;
        otr_ops.create_privkey = &op_create_privkey;
        otr_ops.is_logged_in = &op_is_logged_in;
        otr_ops.inject_message = &op_inject_message;
        otr_ops.update_context_list = NULL;
        otr_ops.new_fingerprint = &op_new_fingerprint;
        otr_ops.write_fingerprints = &op_write_fingerprints;
        otr_ops.gone_secure = &op_gone_secure;
        otr_ops.gone_insecure = &op_gone_insecure;
        otr_ops.still_secure = &op_still_secure;
        otr_ops.max_message_size = &op_max_message_size;
        otr_ops.account_name = &op_account_name;
        otr_ops.account_name_free = NULL;

        /* stuff added with libotr 4.0.0 */
        otr_ops.received_symkey = NULL;         /* we don't use the extra key */
        otr_ops.otr_error_message = &op_otr_error_message;
        otr_ops.otr_error_message_free = NULL;
        otr_ops.resent_msg_prefix = NULL;       /* default: [resent] */
        otr_ops.resent_msg_prefix_free = NULL;
        otr_ops.handle_smp_event = &op_handle_smp_event;
        otr_ops.handle_msg_event = &op_handle_msg_event;
        otr_ops.create_instag = &op_create_instag;
        otr_ops.convert_msg = &op_convert_msg;
        otr_ops.convert_free = &op_convert_free;
        otr_ops.timer_control = NULL;           /* we just poll */

        root_command_add("otr", 1, cmd_otr, 0);
        register_irc_plugin(&otr_plugin);
}

#ifndef OTR_BI
struct plugin_info *init_plugin_info(void)
{
        static struct plugin_info info = {
                BITLBEE_ABI_VERSION_CODE,
                "otr",
                BITLBEE_VERSION,
                "Off-the-Record communication",
                NULL,
                NULL
        };

        return &info;
}
#endif

gboolean otr_irc_new(irc_t *irc)
{
        set_t *s;
        GSList *l;

        irc->otr = g_new0(otr_t, 1);
        irc->otr->us = otrl_userstate_create();

        s = set_add(&irc->b->set, "otr_color_encrypted", "true", set_eval_bool, irc);

        s = set_add(&irc->b->set, "otr_policy", "opportunistic", set_eval_list, irc);
        l = g_slist_prepend(NULL, "never");
        l = g_slist_prepend(l, "opportunistic");
        l = g_slist_prepend(l, "manual");
        l = g_slist_prepend(l, "always");
        s->eval_data = l;

        s = set_add(&irc->b->set, "otr_does_html", "true", set_eval_bool, irc);

        /* regularly call otrl_message_poll */
        gint definterval = otrl_message_poll_get_default_interval(irc->otr->us);
        irc->otr->timer = b_timeout_add(definterval, ev_message_poll, irc->otr);

        return TRUE;
}

void otr_irc_free(irc_t *irc)
{
        set_t *s;
        otr_t *otr = irc->otr;

        otr_disconnect_all(irc);
        b_event_remove(otr->timer);
        otrl_userstate_free(otr->us);

        s = set_find(&irc->b->set, "otr_policy");
        g_slist_free(s->eval_data);

        if (otr->keygen) {
                kill(otr->keygen, SIGTERM);
                waitpid(otr->keygen, NULL, 0);
                /* TODO: remove stale keygen tempfiles */
        }
        if (otr->to) {
                fclose(otr->to);
        }
        if (otr->from) {
                fclose(otr->from);
        }
        while (otr->todo) {
                kg_t *p = otr->todo;
                otr->todo = p->next;
                g_free(p);
        }
        g_free(otr);
}

void otr_load(irc_t *irc)
{
        char s[512];
        account_t *a;
        gcry_error_t e;
        gcry_error_t enoent = gcry_error_from_errno(ENOENT);
        int kg = 0;

        if (strsane(irc->user->nick)) {
                g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, irc->user->nick);
                e = otrl_privkey_read(irc->otr->us, s);
                if (e && e != enoent) {
                        irc_rootmsg(irc, "otr load: %s: %s", s, gcry_strerror(e));
                }
                g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, irc->user->nick);
                e = otrl_privkey_read_fingerprints(irc->otr->us, s, NULL, NULL);
                if (e && e != enoent) {
                        irc_rootmsg(irc, "otr load: %s: %s", s, gcry_strerror(e));
                }
                g_snprintf(s, 511, "%s%s.otr_instags", global.conf->configdir, irc->user->nick);
                e = otrl_instag_read(irc->otr->us, s);
                if (e && e != enoent) {
                        irc_rootmsg(irc, "otr load: %s: %s", s, gcry_strerror(e));
                }
        }

        /* check for otr keys on all accounts */
        for (a = irc->b->accounts; a; a = a->next) {
                kg = otr_check_for_key(a) || kg;
        }
        if (kg) {
                irc_rootmsg(irc, "Notice: "
                            "The accounts above do not have OTR encryption keys associated with them, yet. "
                            "These keys are now being generated in the background. "
                            "You will be notified as they are completed. "
                            "It is not necessary to wait; "
                            "BitlBee can be used normally during key generation. "
                            "You may safely ignore this message if you don't know what OTR is. ;)");
        }
}

void otr_save(irc_t *irc)
{
        char s[512];
        gcry_error_t e;

        if (strsane(irc->user->nick)) {
                g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, irc->user->nick);
                e = otrl_privkey_write_fingerprints(irc->otr->us, s);
                if (e) {
                        irc_rootmsg(irc, "otr save: %s: %s", s, gcry_strerror(e));
                }
                chmod(s, 0600);
        }
}

void otr_remove(const char *nick)
{
        char s[512];

        if (strsane(nick)) {
                g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, nick);
                unlink(s);
                g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, nick);
                unlink(s);
        }
}

void otr_rename(const char *onick, const char *nnick)
{
        char s[512], t[512];

        if (strsane(nnick) && strsane(onick)) {
                g_snprintf(s, 511, "%s%s.otr_keys", global.conf->configdir, onick);
                g_snprintf(t, 511, "%s%s.otr_keys", global.conf->configdir, nnick);
                rename(s, t);
                g_snprintf(s, 511, "%s%s.otr_fprints", global.conf->configdir, onick);
                g_snprintf(t, 511, "%s%s.otr_fprints", global.conf->configdir, nnick);
                rename(s, t);
        }
}

int otr_check_for_key(account_t *a)
{
        irc_t *irc = a->bee->ui_data;
        OtrlPrivKey *k;

        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if (a->prpl->options & OPT_NOOTR) {
                return 0;
        }

        k = otrl_privkey_find(irc->otr->us, a->user, a->prpl->name);
        if (k) {
                irc_rootmsg(irc, "otr: %s/%s ready", a->user, a->prpl->name);
                return 0;
        }
        if (keygen_in_progress(irc, a->user, a->prpl->name)) {
                irc_rootmsg(irc, "otr: keygen for %s/%s already in progress", a->user, a->prpl->name);
                return 0;
        } else {
                irc_rootmsg(irc, "otr: starting background keygen for %s/%s", a->user, a->prpl->name);
                otr_keygen(irc, a->user, a->prpl->name);
                return 1;
        }
}

char *otr_filter_msg_in(irc_user_t *iu, char *msg, int flags)
{
        int ignore_msg;
        char *newmsg = NULL;
        OtrlTLV *tlvs = NULL;
        irc_t *irc = iu->irc;
        struct im_connection *ic = iu->bu->ic;

        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if (ic->acc->prpl->options & OPT_NOOTR ||
            iu->bu->flags & BEE_USER_NOOTR) {
                return msg;
        }

        ignore_msg = otrl_message_receiving(irc->otr->us, &otr_ops, ic,
                                            ic->acc->user, ic->acc->prpl->name, iu->bu->handle, msg, &newmsg,
                                            &tlvs, NULL, NULL, NULL);

        if (tlvs) {
                otrl_tlv_free(tlvs);
        }

        if (ignore_msg) {
                /* this was an internal OTR protocol message */
                return NULL;
        } else if (!newmsg) {
                /* this was a non-OTR message */
                return otr_filter_colors(msg);
        } else {
                /* we're done with the original msg, which will be caller-freed. */
                return newmsg;
        }
}

char *otr_filter_msg_out(irc_user_t *iu, char *msg, int flags)
{
        int st;
        char *otrmsg = NULL;
        ConnContext *ctx = NULL;
        irc_t *irc = iu->irc;
        struct im_connection *ic = iu->bu->ic;
        otrl_instag_t instag = OTRL_INSTAG_BEST; // XXX?

        /* NB: in libotr 4.0.0 OTRL_INSTAG_RECENT will cause a null-pointer deref
         * in otrl_message_sending with newly-added OTR contexts.
         */

        /* don't do OTR on certain (not classic IM) protocols, e.g. twitter */
        if (ic->acc->prpl->options & OPT_NOOTR ||
            iu->bu->flags & BEE_USER_NOOTR) {
                return msg;
        }

        st = otrl_message_sending(irc->otr->us, &otr_ops, ic,
                                  ic->acc->user, ic->acc->prpl->name, iu->bu->handle, instag,
                                  msg, NULL, &otrmsg, OTRL_FRAGMENT_SEND_ALL_BUT_LAST, &ctx, NULL, NULL);

        if (otrmsg && otrmsg != msg) {
                /* libotr wants us to replace our message */
                /* NB: caller will free old msg */
                msg = st ? NULL : g_strdup(otrmsg);
                otrl_message_free(otrmsg);
        }

        if (st) {
                irc_usernotice(iu, "otr: error handling outgoing message: %d", st);
                msg = NULL;     /* do not send plaintext! */
        }

        return msg;
}

static const struct irc_plugin otr_plugin =
{
        otr_irc_new,
        otr_irc_free,
        otr_filter_msg_out,
        otr_filter_msg_in,
        otr_load,
        otr_save,
        otr_remove,
};

static void cmd_otr(irc_t *irc, char **args)
{
        const command_t *cmd;

        if (!args[0]) {
                return;
        }

        if (!args[1]) {
                return;
        }

        for (cmd = otr_commands; cmd->command; cmd++) {
                if (strcmp(cmd->command, args[1]) == 0) {
                        break;
                }
        }

        if (!cmd->command) {
                irc_rootmsg(irc, "%s: unknown subcommand \"%s\", see \x02help otr\x02",
                            args[0], args[1]);
                return;
        }

        if (!args[cmd->required_parameters + 1]) {
                irc_rootmsg(irc, "%s %s: not enough arguments (%d req.)",
                            args[0], args[1], cmd->required_parameters);
                return;
        }

        cmd->execute(irc, args + 1);
}


/*** OTR "MessageAppOps" callbacks for global.otr_ui: ***/

OtrlPolicy op_policy(void *opdata, ConnContext *context)
{
        struct im_connection *ic = check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        const char *p;

        /* policy override during keygen: if we're missing the key for context but are currently
           generating it, then that's as much as we can do. => temporarily return NEVER. */
        if (keygen_in_progress(irc, context->accountname, context->protocol) &&
            !otrl_privkey_find(irc->otr->us, context->accountname, context->protocol)) {
                return OTRL_POLICY_NEVER;
        }

        p = set_getstr(&ic->bee->set, "otr_policy");
        if (!strcmp(p, "never")) {
                return OTRL_POLICY_NEVER;
        }
        if (!strcmp(p, "opportunistic")) {
                return OTRL_POLICY_OPPORTUNISTIC;
        }
        if (!strcmp(p, "manual")) {
                return OTRL_POLICY_MANUAL;
        }
        if (!strcmp(p, "always")) {
                return OTRL_POLICY_ALWAYS;
        }

        return OTRL_POLICY_OPPORTUNISTIC;
}

void op_create_privkey(void *opdata, const char *accountname,
                       const char *protocol)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;

        /* will fail silently if keygen already in progress */
        otr_keygen(irc, accountname, protocol);
}

int op_is_logged_in(void *opdata, const char *accountname,
                    const char *protocol, const char *recipient)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        bee_user_t *bu;

        /* lookup the irc_user_t for the given recipient */
        bu = bee_user_by_handle(ic->bee, ic, recipient);
        if (bu) {
                if (bu->flags & BEE_USER_ONLINE) {
                        return 1;
                } else {
                        return 0;
                }
        } else {
                return -1;
        }
}

void op_inject_message(void *opdata, const char *accountname,
                       const char *protocol, const char *recipient, const char *message)
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;

        if (strcmp(accountname, recipient) == 0) {
                /* huh? injecting messages to myself? */
                irc_rootmsg(irc, "note to self: %s", message);
        } else {
                /* need to drop some consts here :-( */
                /* TODO: get flags into op_inject_message?! */
                ic->acc->prpl->buddy_msg(ic, (char *) recipient, (char *) message, 0);
                /* ignoring return value :-/ */
        }
}

void op_new_fingerprint(void *opdata, OtrlUserState us,
                        const char *accountname, const char *protocol,
                        const char *username, unsigned char fingerprint[20])
{
        struct im_connection *ic = check_imc(opdata, accountname, protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u = peeruser(irc, username, protocol);
        char hunam[45];         /* anybody looking? ;-) */

        otrl_privkey_hash_to_human(hunam, fingerprint);
        if (u) {
                irc_usernotice(u, "new fingerprint: %s", hunam);
        } else {
                /* this case shouldn't normally happen */
                irc_rootmsg(irc, "new fingerprint for %s/%s: %s",
                            username, protocol, hunam);
        }
}

void op_write_fingerprints(void *opdata)
{
        struct im_connection *ic = (struct im_connection *) opdata;
        irc_t *irc = ic->bee->ui_data;

        otr_save(irc);
}

void op_gone_secure(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_user_t *u;
        irc_t *irc = ic->bee->ui_data;

        u = peeruser(irc, context->username, context->protocol);
        if (!u) {
                log_message(LOGLVL_ERROR,
                            "BUG: otr.c: op_gone_secure: irc_user_t for %s/%s/%s not found!",
                            context->username, context->protocol, context->accountname);
                return;
        }

        otr_update_uflags(context, u);
        if (!otr_update_modeflags(irc, u)) {
                char *trust = u->flags & IRC_USER_OTR_TRUSTED ? "trusted" : "untrusted!";
                irc_usernotice(u, "conversation is now off the record (%s)", trust);
        }
}

void op_gone_insecure(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u;

        u = peeruser(irc, context->username, context->protocol);
        if (!u) {
                log_message(LOGLVL_ERROR,
                            "BUG: otr.c: op_gone_insecure: irc_user_t for %s/%s/%s not found!",
                            context->username, context->protocol, context->accountname);
                return;
        }
        otr_update_uflags(context, u);
        if (!otr_update_modeflags(irc, u)) {
                irc_usernotice(u, "conversation is now in cleartext");
        }
}

void op_still_secure(void *opdata, ConnContext *context, int is_reply)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u;

        u = peeruser(irc, context->username, context->protocol);
        if (!u) {
                log_message(LOGLVL_ERROR,
                            "BUG: otr.c: op_still_secure: irc_user_t for %s/%s/%s not found!",
                            context->username, context->protocol, context->accountname);
                return;
        }

        otr_update_uflags(context, u);
        if (!otr_update_modeflags(irc, u)) {
                char *trust = u->flags & IRC_USER_OTR_TRUSTED ? "trusted" : "untrusted!";
                irc_usernotice(u, "otr connection has been refreshed (%s)", trust);
        }
}

int op_max_message_size(void *opdata, ConnContext *context)
{
        struct im_connection *ic =
                check_imc(opdata, context->accountname, context->protocol);

        return ic->acc->prpl->mms;
}

const char *op_account_name(void *opdata, const char *account, const char *protocol)
{
        struct im_connection *ic = (struct im_connection *) opdata;
        irc_t *irc = ic->bee->ui_data;

        return peernick(irc, account, protocol);
}

void op_create_instag(void *opdata, const char *account, const char *protocol)
{
        struct im_connection *ic =
                check_imc(opdata, account, protocol);
        irc_t *irc = ic->bee->ui_data;
        gcry_error_t e;
        char s[512];

        g_snprintf(s, 511, "%s%s.otr_instags", global.conf->configdir,
                   irc->user->nick);
        e = otrl_instag_generate(irc->otr->us, s, account, protocol);
        if (e) {
                irc_rootmsg(irc, "otr: %s/%s: otrl_instag_generate failed: %s",
                            account, protocol, gcry_strerror(e));
        }
}

static char *otr_filter_colors(char *msg)
{
        return str_reject_chars(msg, "\x02\x03", '?');
}

/* returns newly allocated string */
static char *otr_color_encrypted(char *msg, char *color, gboolean is_query) {
        char **lines;
        GString *out;
        int i;

        lines = g_strsplit(msg, "\n", -1);

        /* up to 4 extra chars per line (e.g., '\x03' + ("03"|"05") + ' ') */
        out = g_string_sized_new(strlen(msg) + g_strv_length(lines) * 4);
        
        for (i = 0; lines[i]; i++) {
                char *line = lines[i];

                if (i != 0) {
                        g_string_append_c(out, '\n');

                } else if (is_query && g_strncasecmp(line, "/me ", 4) == 0) {
                        /* in a query window, keep "/me " uncolored at the beginning */
                        line += 4;
                        g_string_append(out, "/me ");
                }

                g_string_append_c(out, '\x03');
                g_string_append(out, color);

                /* comma in first place could mess with the color code */
                if (line[0] == ',') {
                        /* insert a space between color spec and message */
                        g_string_append_c(out, ' ');
                }

                g_string_append(out, otr_filter_colors(line));
        }

        g_strfreev(lines);

        return g_string_free(out, FALSE);
}

void op_convert_msg(void *opdata, ConnContext *ctx, OtrlConvertType typ,
                    char **dst, const char *src)
{
        struct im_connection *ic =
                check_imc(opdata, ctx->accountname, ctx->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *iu = peeruser(irc, ctx->username, ctx->protocol);

        if (typ == OTRL_CONVERT_RECEIVING) {
                char *msg = g_strdup(src);

                /* HTML decoding */
                if (set_getbool(&ic->bee->set, "otr_does_html") &&
                    !(ic->flags & OPT_DOES_HTML) &&
                    set_getbool(&ic->bee->set, "strip_html")) {
                        strip_html(msg);

                        /* msg is borrowed by *dst (unless the next if decides to color it) */
                        *dst = msg;
                }

                /* coloring */
                if (set_getbool(&ic->bee->set, "otr_color_encrypted")) {
                        const char *trust = ctx->active_fingerprint->trust;
                        char *color = (trust && *trust) ? OTR_COLOR_TRUSTED : OTR_COLOR_UNTRUSTED;
                        gboolean is_query = (irc_user_msgdest(iu) == irc->user->nick);

                        /* the return value of otr_color_encrypted() is borrowed by *dst */
                        *dst = otr_color_encrypted(msg, color, is_query);

                        /* this branch doesn't need msg */
                        g_free(msg);
                }
        } else {
                /* HTML encoding */
                /* consider OTR plaintext to be HTML if otr_does_html is set */
                if (ctx && ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED &&
                    set_getbool(&ic->bee->set, "otr_does_html") &&
                    (g_strncasecmp(src, "<html>", 6) != 0)) {
                        *dst = escape_html(src);
                }
        }
}

void op_convert_free(void *opdata, ConnContext *ctx, char *msg)
{
        g_free(msg);
}

/* Socialist Millionaires' Protocol */
void op_handle_smp_event(void *opdata, OtrlSMPEvent ev, ConnContext *ctx,
                         unsigned short percent, char *question)
{
        struct im_connection *ic =
                check_imc(opdata, ctx->accountname, ctx->protocol);
        irc_t *irc = ic->bee->ui_data;
        OtrlUserState us = irc->otr->us;
        irc_user_t *u = peeruser(irc, ctx->username, ctx->protocol);

        if (!u) {
                return;
        }

        switch (ev) {
        case OTRL_SMPEVENT_ASK_FOR_SECRET:
                irc_rootmsg(irc, "smp: initiated by %s"
                            " - respond with \x02otr smp %s <secret>\x02",
                            u->nick, u->nick);
                break;
        case OTRL_SMPEVENT_ASK_FOR_ANSWER:
                irc_rootmsg(irc, "smp: initiated by %s with question: \x02\"%s\"\x02", u->nick,
                            question);
                irc_rootmsg(irc, "smp: respond with \x02otr smp %s <answer>\x02",
                            u->nick);
                break;
        case OTRL_SMPEVENT_CHEATED:
                irc_rootmsg(irc, "smp %s: opponent violated protocol, aborting",
                            u->nick);
                otrl_message_abort_smp(us, &otr_ops, u->bu->ic, ctx);
                otrl_sm_state_free(ctx->smstate);
                break;
        case OTRL_SMPEVENT_NONE:
                break;
        case OTRL_SMPEVENT_IN_PROGRESS:
                break;
        case OTRL_SMPEVENT_SUCCESS:
                if (ctx->smstate->received_question) {
                        irc_rootmsg(irc, "smp %s: correct answer, you are trusted",
                                    u->nick);
                } else {
                        irc_rootmsg(irc, "smp %s: secrets proved equal, fingerprint trusted",
                                    u->nick);
                }
                otrl_sm_state_free(ctx->smstate);
                break;
        case OTRL_SMPEVENT_FAILURE:
                if (ctx->smstate->received_question) {
                        irc_rootmsg(irc, "smp %s: wrong answer, you are not trusted",
                                    u->nick);
                } else {
                        irc_rootmsg(irc, "smp %s: secrets did not match, fingerprint not trusted",
                                    u->nick);
                }
                otrl_sm_state_free(ctx->smstate);
                break;
        case OTRL_SMPEVENT_ABORT:
                irc_rootmsg(irc, "smp: received abort from %s", u->nick);
                otrl_sm_state_free(ctx->smstate);
                break;
        case OTRL_SMPEVENT_ERROR:
                irc_rootmsg(irc, "smp %s: protocol error, aborting",
                            u->nick);
                otrl_message_abort_smp(us, &otr_ops, u->bu->ic, ctx);
                otrl_sm_state_free(ctx->smstate);
                break;
        }
}

void op_handle_msg_event(void *opdata, OtrlMessageEvent ev, ConnContext *ctx,
                         const char *message, gcry_error_t err)
{
        switch (ev) {
        case OTRL_MSGEVENT_ENCRYPTION_REQUIRED:
                display_otr_message(opdata, ctx,
                                    "policy requires encryption - message not sent");
                break;
        case OTRL_MSGEVENT_ENCRYPTION_ERROR:
                display_otr_message(opdata, ctx,
                                    "error during encryption - message not sent");
                break;
        case OTRL_MSGEVENT_CONNECTION_ENDED:
                display_otr_message(opdata, ctx,
                                    "other end has disconnected OTR - "
                                    "close connection or reconnect!");
                break;
        case OTRL_MSGEVENT_SETUP_ERROR:
                display_otr_message(opdata, ctx,
                                    "OTR connection failed: %s", gcry_strerror(err));
                break;
        case OTRL_MSGEVENT_MSG_REFLECTED:
                display_otr_message(opdata, ctx,
                                    "received our own OTR message (!?)");
                break;
        case OTRL_MSGEVENT_MSG_RESENT:
                display_otr_message(opdata, ctx,
                                    "the previous message was resent");
                break;
        case OTRL_MSGEVENT_RCVDMSG_NOT_IN_PRIVATE:
                display_otr_message(opdata, ctx,
                                    "unexpected encrypted message received");
                break;
        case OTRL_MSGEVENT_RCVDMSG_UNREADABLE:
                display_otr_message(opdata, ctx,
                                    "unreadable encrypted message received");
                break;
        case OTRL_MSGEVENT_RCVDMSG_MALFORMED:
                display_otr_message(opdata, ctx,
                                    "malformed OTR message received");
                break;
        case OTRL_MSGEVENT_LOG_HEARTBEAT_RCVD:
                if (global.conf->verbose) {
                        log_otr_message(opdata, "%s/%s: heartbeat received",
                                        ctx->accountname, ctx->protocol);
                }
                break;
        case OTRL_MSGEVENT_LOG_HEARTBEAT_SENT:
                if (global.conf->verbose) {
                        log_otr_message(opdata, "%s/%s: heartbeat sent",
                                        ctx->accountname, ctx->protocol);
                }
                break;
        case OTRL_MSGEVENT_RCVDMSG_GENERAL_ERR:
                display_otr_message(opdata, ctx,
                                    "OTR error message received: %s", message);
                break;
        case OTRL_MSGEVENT_RCVDMSG_UNENCRYPTED:
                display_otr_message(opdata, ctx,
                                    "unencrypted message received: %s", message);
                break;
        case OTRL_MSGEVENT_RCVDMSG_UNRECOGNIZED:
                display_otr_message(opdata, ctx,
                                    "unrecognized OTR message received");
                break;
        case OTRL_MSGEVENT_RCVDMSG_FOR_OTHER_INSTANCE:
                display_otr_message(opdata, ctx,
                                    "OTR message for a different instance received");
                break;
        default:
                /* shouldn't happen */
                break;
        }
}

const char *op_otr_error_message(void *opdata, ConnContext *ctx,
                                 OtrlErrorCode err_code)
{
        switch (err_code) {
        case OTRL_ERRCODE_ENCRYPTION_ERROR:
                return "i failed to encrypt a message";
        case OTRL_ERRCODE_MSG_NOT_IN_PRIVATE:
                return "you sent an encrypted message i didn't expect";
        case OTRL_ERRCODE_MSG_UNREADABLE:
                return "could not read encrypted message";
        case OTRL_ERRCODE_MSG_MALFORMED:
                return "you sent a malformed OTR message";
        default:
                return "i suffered an unexpected OTR error";
        }
}



/*** OTR sub-command handlers ***/

void cmd_otr_reconnect(irc_t *irc, char **args)
{
        cmd_otr_disconnect(irc, args);
        cmd_otr_connect(irc, args);
}

void cmd_otr_disconnect(irc_t *irc, char **args)
{
        irc_user_t *u;

        if (!strcmp("*", args[1])) {
                otr_disconnect_all(irc);
                irc_rootmsg(irc, "all conversations are now in cleartext");
        } else {
                u = irc_user_by_name(irc, args[1]);
                if (otr_disconnect_user(irc, u)) {
                        irc_usernotice(u, "conversation is now in cleartext");
                } else {
                        irc_rootmsg(irc, "%s: unknown user", args[1]);
                }
        }
}

void cmd_otr_connect(irc_t *irc, char **args)
{
        irc_user_t *u;
        char *msg, *query = "?OTR?";

        u = irc_user_by_name(irc, args[1]);
        if (!u || !u->bu || !u->bu->ic) {
                irc_rootmsg(irc, "%s: unknown user", args[1]);
                return;
        }
        if (!(u->bu->flags & BEE_USER_ONLINE)) {
                irc_rootmsg(irc, "%s is offline", args[1]);
                return;
        }

        /* passing this through the filter so it goes through libotr which
         * will replace the simple query string with a proper one */
        msg = otr_filter_msg_out(u, query, 0);

        /* send the message */
        if (msg) {
                u->bu->ic->acc->prpl->buddy_msg(u->bu->ic, u->bu->handle, msg, 0);  /* XXX flags? */
                /* XXX error message? */

                if (msg != query) {
                        g_free(msg);
                }
        }
}

void cmd_otr_smp(irc_t *irc, char **args)
{
        otr_smp_or_smpq(irc, args[1], NULL, args[2]);   /* no question */
}

void cmd_otr_smpq(irc_t *irc, char **args)
{
        otr_smp_or_smpq(irc, args[1], args[2], args[3]);
}

void cmd_otr_trust(irc_t *irc, char **args)
{
        irc_user_t *u;
        ConnContext *ctx;
        unsigned char raw[20];
        Fingerprint *fp;
        int i, j;

        u = irc_user_by_name(irc, args[1]);
        if (!u || !u->bu || !u->bu->ic) {
                irc_rootmsg(irc, "%s: unknown user", args[1]);
                return;
        }

        ctx = otrl_context_find(irc->otr->us, u->bu->handle,
                                u->bu->ic->acc->user, u->bu->ic->acc->prpl->name, OTRL_INSTAG_MASTER, 0, NULL, NULL,
                                NULL);
        if (!ctx) {
                irc_rootmsg(irc, "%s: no otr context with user", args[1]);
                return;
        }

        /* convert given fingerprint to raw representation */
        for (i = 0; i < 5; i++) {
                for (j = 0; j < 4; j++) {
                        char *p = args[2 + i] + (2 * j);
                        char *q = p + 1;
                        int x, y;

                        if (!*p || !*q) {
                                irc_rootmsg(irc, "failed: truncated fingerprint block %d", i + 1);
                                return;
                        }

                        x = hexval(*p);
                        y = hexval(*q);
                        if (x < 0) {
                                irc_rootmsg(irc, "failed: %d. hex digit of block %d out of range", 2 * j + 1, i + 1);
                                return;
                        }
                        if (y < 0) {
                                irc_rootmsg(irc, "failed: %d. hex digit of block %d out of range", 2 * j + 2, i + 1);
                                return;
                        }

                        raw[i * 4 + j] = x * 16 + y;
                }
        }
        fp = otrl_context_find_fingerprint(ctx, raw, 0, NULL);
        if (!fp) {
                irc_rootmsg(irc, "failed: no such fingerprint for %s", args[1]);
        } else {
                char *trust = args[7] ? args[7] : "affirmed";
                otrl_context_set_trust(fp, trust);
                irc_rootmsg(irc, "fingerprint match, trust set to \"%s\"", trust);
                if (u->flags & IRC_USER_OTR_ENCRYPTED) {
                        u->flags |= IRC_USER_OTR_TRUSTED;
                }
                otr_update_modeflags(irc, u);
        }
}

void cmd_otr_info(irc_t *irc, char **args)
{
        if (!args[1]) {
                show_general_otr_info(irc);
        } else {
                char *arg = g_strdup(args[1]);
                char *myhandle, *handle = NULL, *protocol;
                ConnContext *bestctx = NULL, *ctx;

                /* interpret arg as 'user/protocol/account' if possible */
                protocol = strchr(arg, '/');
                myhandle = NULL;
                if (protocol) {
                        *(protocol++) = '\0';
                        myhandle = strchr(protocol, '/');
                }
                if (protocol && myhandle) {
                        *(myhandle++) = '\0';
                        handle = arg;
                        ctx = otrl_context_find(irc->otr->us, handle, myhandle, protocol, OTRL_INSTAG_MASTER, 0, NULL,
                                                NULL, NULL);
                        if (!ctx) {
                                irc_rootmsg(irc, "no such context");
                                g_free(arg);
                                return;
                        }
                } else {
                        irc_user_t *u = irc_user_by_name(irc, args[1]);
                        if (!u || !u->bu || !u->bu->ic) {
                                irc_rootmsg(irc, "%s: unknown user", args[1]);
                                g_free(arg);
                                return;
                        }
                        ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                                                u->bu->ic->acc->prpl->name, OTRL_INSTAG_MASTER, 0, NULL, NULL, NULL);
                        if (!ctx) {
                                irc_rootmsg(irc, "no otr context with %s", args[1]);
                                g_free(arg);
                                return;
                        }
                        /* This does no harm if it returns NULL */
                        bestctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                                                    u->bu->ic->acc->prpl->name, OTRL_INSTAG_BEST, 0, NULL, NULL, NULL);
                }

                /* show how we resolved the (nick) argument, if we did */
                if (handle != arg) {
                        irc_rootmsg(irc, "%s:", args[1]);
                        irc_rootmsg(irc, "  they are: %s/%s", ctx->username, ctx->protocol);
                        irc_rootmsg(irc, "  we are: %s/%s", ctx->accountname, ctx->protocol);
                }
                show_otr_context_info(irc, ctx, bestctx);
                g_free(arg);
        }
}

void cmd_otr_keygen(irc_t *irc, char **args)
{
        account_t *a;

        if ((a = account_get(irc->b, args[1])) == NULL) {
                irc_rootmsg(irc, "Could not find account `%s'.", args[1]);
                return;
        }

        if (keygen_in_progress(irc, a->user, a->prpl->name)) {
                irc_rootmsg(irc, "keygen for account `%s' already in progress", a->tag);
                return;
        }

        if (otrl_privkey_find(irc->otr->us, a->user, a->prpl->name)) {
                char *s = g_strdup_printf("account `%s' already has a key, replace it?", a->tag);
                query_add(irc, NULL, s, yes_keygen, NULL, NULL, a);
                g_free(s);
        } else {
                otr_keygen(irc, a->user, a->prpl->name);
        }
}

void yes_forget_fingerprint(void *data)
{
        pair_t *p = (pair_t *) data;
        irc_t *irc = (irc_t *) p->fst;
        Fingerprint *fp = (Fingerprint *) p->snd;

        g_free(p);

        if (fp == fp->context->active_fingerprint) {
                irc_rootmsg(irc, "that fingerprint is active, terminate otr connection first");
                return;
        }

        otrl_context_forget_fingerprint(fp, 0);
}

void yes_forget_context(void *data)
{
        pair_t *p = (pair_t *) data;
        irc_t *irc = (irc_t *) p->fst;
        ConnContext *ctx = (ConnContext *) p->snd;

        g_free(p);

        // XXX forget all contexts

        if (ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                irc_rootmsg(irc, "active otr connection with %s, terminate it first",
                            peernick(irc, ctx->username, ctx->protocol));
                return;
        }

        if (ctx->msgstate == OTRL_MSGSTATE_FINISHED) {
                otrl_context_force_plaintext(ctx);
        }
        otrl_context_forget(ctx);
}

void yes_forget_key(void *data)
{
        OtrlPrivKey *key = (OtrlPrivKey *) data;

        otrl_privkey_forget(key);
        /* Hm, libotr doesn't seem to offer a function for explicitly /writing/
           keyfiles. So the key will be back on the next load... */
        /* TODO: Actually erase forgotten keys from storage? */
}

void cmd_otr_forget(irc_t *irc, char **args)
{
        if (!strcmp(args[1], "fingerprint")) {
                irc_user_t *u;
                ConnContext *ctx;
                Fingerprint *fp;
                char human[54];
                char *s;
                pair_t *p;

                if (!args[3]) {
                        irc_rootmsg(irc, "otr %s %s: not enough arguments (2 req.)", args[0], args[1]);
                        return;
                }

                /* TODO: allow context specs ("user/proto/account") in 'otr forget fingerprint'? */
                u = irc_user_by_name(irc, args[2]);
                if (!u || !u->bu || !u->bu->ic) {
                        irc_rootmsg(irc, "%s: unknown user", args[2]);
                        return;
                }

                ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                                        u->bu->ic->acc->prpl->name, OTRL_INSTAG_MASTER, 0, NULL, NULL, NULL);
                if (!ctx) {
                        irc_rootmsg(irc, "no otr context with %s", args[2]);
                        return;
                }

                fp = match_fingerprint(irc, ctx, ((const char **) args) + 3);
                if (!fp) {
                        /* match_fingerprint does error messages */
                        return;
                }

                if (fp == ctx->active_fingerprint) {
                        irc_rootmsg(irc, "that fingerprint is active, terminate otr connection first");
                        return;
                }

                otrl_privkey_hash_to_human(human, fp->fingerprint);
                s = g_strdup_printf("about to forget fingerprint %s, are you sure?", human);
                p = g_malloc(sizeof(pair_t));
                if (!p) {
                        return;
                }
                p->fst = irc;
                p->snd = fp;
                query_add(irc, NULL, s, yes_forget_fingerprint, NULL, NULL, p);
                g_free(s);
        } else if (!strcmp(args[1], "context")) {
                irc_user_t *u;
                ConnContext *ctx;
                char *s;
                pair_t *p;

                /* TODO: allow context specs ("user/proto/account") in 'otr forget contex'? */
                u = irc_user_by_name(irc, args[2]);
                if (!u || !u->bu || !u->bu->ic) {
                        irc_rootmsg(irc, "%s: unknown user", args[2]);
                        return;
                }

                ctx = otrl_context_find(irc->otr->us, u->bu->handle, u->bu->ic->acc->user,
                                        u->bu->ic->acc->prpl->name, OTRL_INSTAG_MASTER, 0, NULL, NULL, NULL);
                if (!ctx) {
                        irc_rootmsg(irc, "no otr context with %s", args[2]);
                        return;
                }

                if (ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                        irc_rootmsg(irc, "active otr connection with %s, terminate it first", args[2]);
                        return;
                }

                s = g_strdup_printf("about to forget otr data about %s, are you sure?", args[2]);
                p = g_malloc(sizeof(pair_t));
                if (!p) {
                        return;
                }
                p->fst = irc;
                p->snd = ctx;
                query_add(irc, NULL, s, yes_forget_context, NULL, NULL, p);
                g_free(s);
        } else if (!strcmp(args[1], "key")) {
                OtrlPrivKey *key;
                char *s;

                key = match_privkey(irc, ((const char **) args) + 2);
                if (!key) {
                        /* match_privkey does error messages */
                        return;
                }

                s = g_strdup_printf("about to forget the private key for %s/%s, are you sure?",
                                    key->accountname, key->protocol);
                query_add(irc, NULL, s, yes_forget_key, NULL, NULL, key);
                g_free(s);
        } else {
                irc_rootmsg(irc, "otr %s: unknown subcommand \"%s\", see \x02help otr forget\x02",
                            args[0], args[1]);
        }
}


/*** local helpers / subroutines: ***/

void log_otr_message(void *opdata, const char *fmt, ...)
{
        va_list va;

        va_start(va, fmt);
        char *msg = g_strdup_vprintf(fmt, va);
        va_end(va);

        log_message(LOGLVL_INFO, "otr: %s", msg);

        g_free(msg);
}

void display_otr_message(void *opdata, ConnContext *ctx, const char *fmt, ...)
{
        char *msg_, *msg;
        struct im_connection *ic =
                check_imc(opdata, ctx->accountname, ctx->protocol);
        irc_t *irc = ic->bee->ui_data;
        irc_user_t *u = peeruser(irc, ctx->username, ctx->protocol);
        va_list va;

        va_start(va, fmt);
        msg_ = g_strdup_vprintf(fmt, va);
        va_end(va);

        msg = word_wrap(msg_, IRC_WORD_WRAP);

        if (u) {
                /* just show this as a regular message */
                irc_usermsg(u, "<<\002OTR\002>> %s", msg);
        } else {
                irc_rootmsg(irc, "[otr] %s", msg);
        }

        g_free(msg_);
        g_free(msg);
}

/* combined handler for the 'otr smp' and 'otr smpq' commands */
void otr_smp_or_smpq(irc_t *irc, const char *nick, const char *question,
                     const char *secret)
{
        irc_user_t *u;
        ConnContext *ctx;
        otrl_instag_t instag = OTRL_INSTAG_BEST;  // XXX

        u = irc_user_by_name(irc, nick);
        if (!u || !u->bu || !u->bu->ic) {
                irc_rootmsg(irc, "%s: unknown user", nick);
                return;
        }
        if (!(u->bu->flags & BEE_USER_ONLINE)) {
                irc_rootmsg(irc, "%s is offline", nick);
                return;
        }

        ctx = otrl_context_find(irc->otr->us, u->bu->handle,
                                u->bu->ic->acc->user, u->bu->ic->acc->prpl->name, instag, 0, NULL, NULL, NULL);
        if (!ctx || ctx->msgstate != OTRL_MSGSTATE_ENCRYPTED) {
                irc_rootmsg(irc, "smp: otr inactive with %s, try \x02otr connect"
                            " %s\x02", nick, nick);
                return;
        }

        if (ctx->smstate->nextExpected != OTRL_SMP_EXPECT1) {
                log_message(LOGLVL_INFO,
                            "SMP already in phase %d, sending abort before reinitiating",
                            ctx->smstate->nextExpected + 1);
                otrl_message_abort_smp(irc->otr->us, &otr_ops, u->bu->ic, ctx);
                otrl_sm_state_free(ctx->smstate);
        }

        if (question) {
                /* this was 'otr smpq', just initiate */
                irc_rootmsg(irc, "smp: initiating with %s...", u->nick);
                otrl_message_initiate_smp_q(irc->otr->us, &otr_ops, u->bu->ic, ctx,
                                            question, (unsigned char *) secret, strlen(secret));
                /* smp is now in EXPECT2 */
        } else {
                /* this was 'otr smp', initiate or reply */
                /* warning: the following assumes that smstates are cleared whenever an SMP
                   is completed or aborted! */
                if (ctx->smstate->secret == NULL) {
                        irc_rootmsg(irc, "smp: initiating with %s...", u->nick);
                        otrl_message_initiate_smp(irc->otr->us, &otr_ops,
                                                  u->bu->ic, ctx, (unsigned char *) secret, strlen(secret));
                        /* smp is now in EXPECT2 */
                } else {
                        /* if we're still in EXPECT1 but smstate is initialized, we must have
                           received the SMP1, so let's issue a response */
                        irc_rootmsg(irc, "smp: responding to %s...", u->nick);
                        otrl_message_respond_smp(irc->otr->us, &otr_ops,
                                                 u->bu->ic, ctx, (unsigned char *) secret, strlen(secret));
                        /* smp is now in EXPECT3 */
                }
        }
}

/* timeout handler that calls otrl_message_poll */
gboolean ev_message_poll(gpointer data, gint fd, b_input_condition cond)
{
        otr_t *otr = data;

        if (otr && otr->us) {
                otrl_message_poll(otr->us, &otr_ops, NULL);
        }

        return TRUE;    /* cycle timer */
}

/* helper to assert that account and protocol names given to ops below always
   match the im_connection passed through as opdata */
struct im_connection *check_imc(void *opdata, const char *accountname,
                                const char *protocol)
{
        struct im_connection *ic = (struct im_connection *) opdata;

        /* libotr 4.0.0 has a bug where it doesn't set opdata, so we catch
         * that and try to find the desired connection in the global list. */
        if (!ic) {
                GSList *l;
                for (l = get_connections(); l; l = l->next) {
                        ic = l->data;
                        if (strcmp(accountname, ic->acc->user) == 0 &&
                            strcmp(protocol, ic->acc->prpl->name) == 0) {
                                break;
                        }
                }
                assert(l != NULL);  /* a match should always be found */
                if (!l) {
                        return NULL;
                }
        }

        if (strcmp(accountname, ic->acc->user) != 0) {
                log_message(LOGLVL_WARNING,
                            "otr: internal account name mismatch: '%s' vs '%s'",
                            accountname, ic->acc->user);
        }
        if (strcmp(protocol, ic->acc->prpl->name) != 0) {
                log_message(LOGLVL_WARNING,
                            "otr: internal protocol name mismatch: '%s' vs '%s'",
                            protocol, ic->acc->prpl->name);
        }

        return ic;
}

irc_user_t *peeruser(irc_t *irc, const char *handle, const char *protocol)
{
        GSList *l;

        for (l = irc->b->users; l; l = l->next) {
                bee_user_t *bu = l->data;
                struct prpl *prpl;
                if (!bu->ui_data || !bu->ic || !bu->handle) {
                        continue;
                }
                prpl = bu->ic->acc->prpl;
                if (strcmp(prpl->name, protocol) == 0
                    && prpl->handle_cmp(bu->handle, handle) == 0) {
                        return bu->ui_data;
                }
        }

        return NULL;
}

int hexval(char a)
{
        int x = g_ascii_tolower(a);

        if (x >= 'a' && x <= 'f') {
                x = x - 'a' + 10;
        } else if (x >= '0' && x <= '9') {
                x = x - '0';
        } else {
                return -1;
        }

        return x;
}

const char *peernick(irc_t *irc, const char *handle, const char *protocol)
{
        static char fallback[512];

        irc_user_t *u = peeruser(irc, handle, protocol);

        if (u) {
                return u->nick;
        } else {
                g_snprintf(fallback, 511, "%s/%s", handle, protocol);
                return fallback;
        }
}

void otr_update_uflags(ConnContext *context, irc_user_t *u)
{
        const char *trust;

        if (context->active_fingerprint) {
                u->flags |= IRC_USER_OTR_ENCRYPTED;

                trust = context->active_fingerprint->trust;
                if (trust && trust[0]) {
                        u->flags |= IRC_USER_OTR_TRUSTED;
                } else {
                        u->flags &= ~IRC_USER_OTR_TRUSTED;
                }
        } else {
                u->flags &= ~IRC_USER_OTR_ENCRYPTED;
        }
}

int otr_update_modeflags(irc_t *irc, irc_user_t *u)
{
        return 0;
}

void show_fingerprints(irc_t *irc, ConnContext *ctx)
{
        char human[45];
        Fingerprint *fp;
        const char *trust;
        int count = 0;

        /* Is this a subcontext? If so, only list the active fingerprint */
        if (ctx->m_context != ctx) {
                fp = ctx->active_fingerprint;
        } else {
                fp = &ctx->fingerprint_root;
        }

        while (fp) {
                if (!fp->fingerprint) {
                        fp = fp->next;
                        continue;
                }
                count++;
                otrl_privkey_hash_to_human(human, fp->fingerprint);
                if (!fp->trust || fp->trust[0] == '\0') {
                        trust = "untrusted";
                } else {
                        trust = fp->trust;
                }
                if (fp == ctx->active_fingerprint) {
                        irc_rootmsg(irc, "      \x02%s (%s)\x02", human, trust);
                } else {
                        irc_rootmsg(irc, "      %s (%s)", human, trust);
                }

                /* Break if this is a subcontext - we only print active fp */
                if (ctx->m_context != ctx) {
                        break;
                }
                fp = fp->next;
        }
        if (count == 0) {
                irc_rootmsg(irc, "      (none)");
        }
}

Fingerprint *match_fingerprint(irc_t *irc, ConnContext *ctx, const char **args)
{
        Fingerprint *fp, *fp2;
        char human[45];
        char prefix[45], *p;
        int n;
        int i, j;

        /* assemble the args into a prefix in standard "human" form */
        n = 0;
        p = prefix;
        for (i = 0; args[i]; i++) {
                for (j = 0; args[i][j]; j++) {
                        char c = g_ascii_toupper(args[i][j]);

                        if (n >= 40) {
                                irc_rootmsg(irc, "too many fingerprint digits given, expected at most 40");
                                return NULL;
                        }

                        if ((c >= 'A' && c <= 'F') || (c >= '0' && c <= '9')) {
                                *(p++) = c;
                        } else {
                                irc_rootmsg(irc, "invalid hex digit '%c' in block %d", args[i][j], i + 1);
                                return NULL;
                        }

                        n++;
                        if (n % 8 == 0) {
                                *(p++) = ' ';
                        }
                }
        }
        *p = '\0';

        /* find first fingerprint with the given prefix */
        n = strlen(prefix);
        for (fp = &ctx->fingerprint_root; fp; fp = fp->next) {
                if (!fp->fingerprint) {
                        continue;
                }
                otrl_privkey_hash_to_human(human, fp->fingerprint);
                if (!strncmp(prefix, human, n)) {
                        break;
                }
        }
        if (!fp) {
                irc_rootmsg(irc, "%s: no match", prefix);
                return NULL;
        }

        /* make sure the match, if any, is unique */
        for (fp2 = fp->next; fp2; fp2 = fp2->next) {
                if (!fp2->fingerprint) {
                        continue;
                }
                otrl_privkey_hash_to_human(human, fp2->fingerprint);
                if (!strncmp(prefix, human, n)) {
                        break;
                }
        }
        if (fp2) {
                irc_rootmsg(irc, "%s: multiple matches", prefix);
                return NULL;
        }

        return fp;
}

OtrlPrivKey *match_privkey(irc_t *irc, const char **args)
{
        OtrlPrivKey *k, *k2;
        char human[45];
        char prefix[45], *p;
        int n;
        int i, j;

        /* assemble the args into a prefix in standard "human" form */
        n = 0;
        p = prefix;
        for (i = 0; args[i]; i++) {
                for (j = 0; args[i][j]; j++) {
                        char c = g_ascii_toupper(args[i][j]);

                        if (n >= 40) {
                                irc_rootmsg(irc, "too many fingerprint digits given, expected at most 40");
                                return NULL;
                        }

                        if ((c >= 'A' && c <= 'F') || (c >= '0' && c <= '9')) {
                                *(p++) = c;
                        } else {
                                irc_rootmsg(irc, "invalid hex digit '%c' in block %d", args[i][j], i + 1);
                                return NULL;
                        }

                        n++;
                        if (n % 8 == 0) {
                                *(p++) = ' ';
                        }
                }
        }
        *p = '\0';

        /* remove trailing whitespace */
        g_strchomp(prefix);

        /* find first key which matches the given prefix */
        n = strlen(prefix);
        for (k = irc->otr->us->privkey_root; k; k = k->next) {
                p = otrl_privkey_fingerprint(irc->otr->us, human, k->accountname, k->protocol);
                if (!p) { /* gah! :-P */
                        continue;
                }
                if (!strncmp(prefix, human, n)) {
                        break;
                }
        }
        if (!k) {
                irc_rootmsg(irc, "%s: no match", prefix);
                return NULL;
        }

        /* make sure the match, if any, is unique */
        for (k2 = k->next; k2; k2 = k2->next) {
                p = otrl_privkey_fingerprint(irc->otr->us, human, k2->accountname, k2->protocol);
                if (!p) { /* gah! :-P */
                        continue;
                }
                if (!strncmp(prefix, human, n)) {
                        break;
                }
        }
        if (k2) {
                irc_rootmsg(irc, "%s: multiple matches", prefix);
                return NULL;
        }

        return k;
}

void show_general_otr_info(irc_t *irc)
{
        ConnContext *ctx;
        OtrlPrivKey *key;
        char human[45];
        kg_t *kg;

        /* list all privkeys (including ones being generated) */
        irc_rootmsg(irc, "\x1fprivate keys:\x1f");
        for (key = irc->otr->us->privkey_root; key; key = key->next) {
                const char *hash;

                switch (key->pubkey_type) {
                case OTRL_PUBKEY_TYPE_DSA:
                        irc_rootmsg(irc, "  %s/%s - DSA", key->accountname, key->protocol);
                        break;
                default:
                        irc_rootmsg(irc, "  %s/%s - type %d", key->accountname, key->protocol,
                                    key->pubkey_type);
                }

                /* No, it doesn't make much sense to search for the privkey again by
                   account/protocol, but libotr currently doesn't provide a direct routine
                   for hashing a given 'OtrlPrivKey'... */
                hash = otrl_privkey_fingerprint(irc->otr->us, human, key->accountname, key->protocol);
                if (hash) { /* should always succeed */
                        irc_rootmsg(irc, "    %s", human);
                }
        }
        if (irc->otr->sent_accountname) {
                irc_rootmsg(irc, "  %s/%s - DSA", irc->otr->sent_accountname,
                            irc->otr->sent_protocol);
                irc_rootmsg(irc, "    (being generated)");
        }
        for (kg = irc->otr->todo; kg; kg = kg->next) {
                irc_rootmsg(irc, "  %s/%s - DSA", kg->accountname, kg->protocol);
                irc_rootmsg(irc, "    (queued)");
        }
        if (key == irc->otr->us->privkey_root &&
            !irc->otr->sent_accountname &&
            kg == irc->otr->todo) {
                irc_rootmsg(irc, "  (none)");
        }

        /* list all contexts */
        /* XXX remove this, or split off as its own command */
        irc_rootmsg(irc, "%s", "");
        irc_rootmsg(irc, "\x1f" "connection contexts:\x1f (bold=currently encrypted)");

        ctx = irc->otr->us->context_root;
        while (ctx) {
                ConnContext *subctx;
                irc_user_t *u;
                char *userstring;
                char encrypted = 0;

                u = peeruser(irc, ctx->username, ctx->protocol);
                if (u) {
                        userstring = g_strdup_printf("%s/%s/%s (%s)",
                                                     ctx->username, ctx->protocol, ctx->accountname, u->nick);
                } else {
                        userstring = g_strdup_printf("%s/%s/%s",
                                                     ctx->username, ctx->protocol, ctx->accountname);
                }

                subctx = ctx;
                while (subctx && subctx->m_context == ctx) {
                        if (subctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                                encrypted = 1;
                        }
                        subctx = subctx->next;
                }

                if(encrypted) {
                        irc_rootmsg(irc, "  \x02%s\x02", userstring);
                } else {
                        irc_rootmsg(irc, "  %s", userstring);
                }

                /* Skip subcontexts/instances from output */
                ctx = subctx;

                g_free(userstring);
        }

        if (ctx == irc->otr->us->context_root) {
                irc_rootmsg(irc, "  (none)");
        }
}

void show_otr_context_info(irc_t *irc, ConnContext *ctx, ConnContext *bestctx)
{
        ConnContext *subctx;
        int instcount = 0;

        subctx = ctx;
        while (subctx && subctx->m_context == ctx) {
                if (subctx->m_context == subctx) {
                        if (subctx == bestctx) {
                                irc_rootmsg(irc, "  \x02master context (target):\x02");
                        } else {
                                irc_rootmsg(irc, "  master context:");
                        }
                        irc_rootmsg(irc, "    known fingerprints (bold = active for v1 or v2):");
                } else {
                        if (subctx == bestctx) {
                                irc_rootmsg(irc, "  \x02instance %d (target):\x02", instcount);
                        } else {
                                irc_rootmsg(irc, "  instance %d:", instcount);
                        }
                        irc_rootmsg(irc, "    active fingerprint:");
                        instcount++;
                }

                show_fingerprints(irc, subctx);

                switch (subctx->msgstate) {
                case OTRL_MSGSTATE_PLAINTEXT:
                        irc_rootmsg(irc, "    connection state: cleartext");
                        break;
                case OTRL_MSGSTATE_ENCRYPTED:
                        irc_rootmsg(irc, "    connection state: encrypted (v%d)", subctx->protocol_version);
                        break;
                case OTRL_MSGSTATE_FINISHED:
                        irc_rootmsg(irc, "    connection state: shut down");
                        break;
                default:
                        irc_rootmsg(irc, "    connection state: %d", subctx->msgstate);
                }

                subctx = subctx->next;
        }
}

int keygen_in_progress(irc_t *irc, const char *handle, const char *protocol)
{
        kg_t *kg;

        if (!irc->otr->sent_accountname || !irc->otr->sent_protocol) {
                return 0;
        }

        /* are we currently working on this key? */
        if (!strcmp(handle, irc->otr->sent_accountname) &&
            !strcmp(protocol, irc->otr->sent_protocol)) {
                return 1;
        }

        /* do we have it queued for later? */
        for (kg = irc->otr->todo; kg; kg = kg->next) {
                if (!strcmp(handle, kg->accountname) &&
                    !strcmp(protocol, kg->protocol)) {
                        return 1;
                }
        }

        return 0;
}

void otr_keygen(irc_t *irc, const char *handle, const char *protocol)
{
        /* do nothing if a key for the requested account is already being generated */
        if (keygen_in_progress(irc, handle, protocol)) {
                return;
        }

        /* see if we already have a keygen child running. if not, start one and put a
           handler on its output. */
        if (!irc->otr->keygen || waitpid(irc->otr->keygen, NULL, WNOHANG)) {
                pid_t p;
                int to[2], from[2];
                FILE *tof, *fromf;

                if (pipe(to) < 0 || pipe(from) < 0) {
                        irc_rootmsg(irc, "otr keygen: couldn't create pipe: %s", strerror(errno));
                        return;
                }

                tof = fdopen(to[1], "w");
                fromf = fdopen(from[0], "r");
                if (!tof || !fromf) {
                        irc_rootmsg(irc, "otr keygen: couldn't streamify pipe: %s", strerror(errno));
                        return;
                }

                p = fork();
                if (p < 0) {
                        irc_rootmsg(irc, "otr keygen: couldn't fork: %s", strerror(errno));
                        return;
                }

                if (!p) {
                        /* child process */
                        signal(SIGTERM, exit);
                        keygen_child_main(irc->otr->us, to[0], from[1]);
                        exit(0);
                }

                irc->otr->keygen = p;
                irc->otr->to = tof;
                irc->otr->from = fromf;
                irc->otr->sent_accountname = NULL;
                irc->otr->sent_protocol = NULL;
                irc->otr->todo = NULL;
                b_input_add(from[0], B_EV_IO_READ, keygen_finish_handler, irc);
        }

        /* is the keygen slave currently working? */
        if (irc->otr->sent_accountname) {
                /* enqueue our job for later transmission */
                kg_t **kg = &irc->otr->todo;
                while (*kg) {
                        kg = &((*kg)->next);
                }
                *kg = g_new0(kg_t, 1);
                (*kg)->accountname = g_strdup(handle);
                (*kg)->protocol = g_strdup(protocol);
        } else {
                /* send our job over and remember it */
                fprintf(irc->otr->to, "%s\n%s\n", handle, protocol);
                fflush(irc->otr->to);
                irc->otr->sent_accountname = g_strdup(handle);
                irc->otr->sent_protocol = g_strdup(protocol);
        }
}

void keygen_child_main(OtrlUserState us, int infd, int outfd)
{
        FILE *input, *output;
        char filename[128], accountname[512], protocol[512];
        gcry_error_t e;
        int tempfd;

        input = fdopen(infd, "r");
        output = fdopen(outfd, "w");

        while (!feof(input) && !ferror(input) && !feof(output) && !ferror(output)) {
                myfgets(accountname, 512, input);
                myfgets(protocol, 512, input);

                strncpy(filename, "/tmp/bitlbee-XXXXXX", 128);
                tempfd = mkstemp(filename);
                close(tempfd);

                e = otrl_privkey_generate(us, filename, accountname, protocol);
                if (e) {
                        fprintf(output, "\n");  /* this means failure */
                        fprintf(output, "otr keygen: %s\n", gcry_strerror(e));
                        unlink(filename);
                } else {
                        fprintf(output, "%s\n", filename);
                        fprintf(output, "otr keygen for %s/%s complete\n", accountname, protocol);
                }
                fflush(output);
        }

        fclose(input);
        fclose(output);
}

gboolean keygen_finish_handler(gpointer data, gint fd, b_input_condition cond)
{
        irc_t *irc = (irc_t *) data;
        char filename[512], msg[512];

        myfgets(filename, 512, irc->otr->from);
        myfgets(msg, 512, irc->otr->from);

        irc_rootmsg(irc, "%s", msg);
        if (filename[0]) {
                if (strsane(irc->user->nick)) {
                        char *kf = g_strdup_printf("%s%s.otr_keys", global.conf->configdir, irc->user->nick);
                        char *tmp = g_strdup_printf("%s.new", kf);
                        copyfile(filename, tmp);
                        unlink(filename);
                        rename(tmp, kf);
                        otrl_privkey_read(irc->otr->us, kf);
                        g_free(kf);
                        g_free(tmp);
                } else {
                        otrl_privkey_read(irc->otr->us, filename);
                        unlink(filename);
                }
        }

        /* forget this job */
        g_free(irc->otr->sent_accountname);
        g_free(irc->otr->sent_protocol);
        irc->otr->sent_accountname = NULL;
        irc->otr->sent_protocol = NULL;

        /* see if there are any more in the queue */
        if (irc->otr->todo) {
                kg_t *p = irc->otr->todo;
                /* send the next one over */
                fprintf(irc->otr->to, "%s\n%s\n", p->accountname, p->protocol);
                fflush(irc->otr->to);
                irc->otr->sent_accountname = p->accountname;
                irc->otr->sent_protocol = p->protocol;
                irc->otr->todo = p->next;
                g_free(p);
                return TRUE;   /* keep watching */
        } else {
                /* okay, the slave is idle now, so kill him */
                fclose(irc->otr->from);
                fclose(irc->otr->to);
                irc->otr->from = irc->otr->to = NULL;
                kill(irc->otr->keygen, SIGTERM);
                waitpid(irc->otr->keygen, NULL, 0);
                irc->otr->keygen = 0;
                return FALSE;  /* unregister ourselves */
        }
}

void copyfile(const char *a, const char *b)
{
        int fda, fdb;
        int n;
        char buf[1024];

        fda = open(a, O_RDONLY);
        fdb = open(b, O_WRONLY | O_CREAT | O_TRUNC, 0600);

        while ((n = read(fda, buf, 1024)) > 0) {
                write(fdb, buf, n);
        }

        close(fda);
        close(fdb);
}

void myfgets(char *s, int size, FILE *stream)
{
        if (!fgets(s, size, stream)) {
                s[0] = '\0';
        } else {
                int n = strlen(s);
                if (n > 0 && s[n - 1] == '\n') {
                        s[n - 1] = '\0';
                }
        }
}

void yes_keygen(void *data)
{
        account_t *acc = (account_t *) data;
        irc_t *irc = acc->bee->ui_data;

        if (keygen_in_progress(irc, acc->user, acc->prpl->name)) {
                irc_rootmsg(irc, "keygen for %s/%s already in progress",
                            acc->user, acc->prpl->name);
        } else {
                irc_rootmsg(irc, "starting background keygen for %s/%s",
                            acc->user, acc->prpl->name);
                irc_rootmsg(irc, "you will be notified when it completes");
                otr_keygen(irc, acc->user, acc->prpl->name);
        }
}

/* check whether a string is safe to use in a path component */
int strsane(const char *s)
{
        return strpbrk(s, "/\\") == NULL;
}

/* close the OTR connection with the given buddy */
gboolean otr_disconnect_user(irc_t *irc, irc_user_t *u)
{
        if (!u || !u->bu || !u->bu->ic) {
                return FALSE;
        }

        /* XXX we disconnect all instances; is that what we want? */
        otrl_message_disconnect_all_instances(irc->otr->us, &otr_ops,
                                              u->bu->ic, u->bu->ic->acc->user, u->bu->ic->acc->prpl->name,
                                              u->bu->handle);

        u->flags &= ~IRC_USER_OTR_TRUSTED;
        u->flags &= ~IRC_USER_OTR_ENCRYPTED;
        otr_update_modeflags(irc, u);

        return TRUE;
}

/* close all active OTR connections */
void otr_disconnect_all(irc_t *irc)
{
        irc_user_t *u;
        ConnContext *ctx;

        for (ctx = irc->otr->us->context_root; ctx; ctx = ctx->next) {
                if (ctx->msgstate == OTRL_MSGSTATE_ENCRYPTED) {
                        u = peeruser(irc, ctx->username, ctx->protocol);
                        (void) otr_disconnect_user(irc, u);
                }
        }
}