Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

nickserv/enforce: REGAIN: fix race condition #850

Draft
wants to merge 1 commit into
base: master
Choose a base branch
from
Draft

nickserv/enforce: REGAIN: fix race condition #850

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
110 changes: 109 additions & 1 deletion modules/nickserv/enforce.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,13 +25,23 @@ struct enforce_timeout
mowgli_node_t node;
};

struct pending_regain
{
char nick[NICKLEN + 1];
stringref client;
time_t client_ts;
};

static mowgli_heap_t *pending_regain_heap = NULL;
static mowgli_heap_t *enforce_timeout_heap = NULL;
static mowgli_eventloop_timer_t *enforce_timeout_check_timer = NULL;
static mowgli_eventloop_timer_t *enforce_remove_enforcers_timer = NULL;

static mowgli_list_t enforce_list;
static time_t enforce_next;

static mowgli_patricia_t *pending_regains;

static mowgli_patricia_t **ns_set_cmdtree;

// logs a released nickname out
Expand Down Expand Up @@ -229,6 +239,65 @@ check_enforce_all(struct myuser *mu)
}
}

static void
destroy_pending_regain(const char ATHEME_VATTR_UNUSED *key, void *data, void ATHEME_VATTR_UNUSED *privdata)
{
struct pending_regain *regain = data;

strshare_unref(regain->client);
mowgli_heap_free(pending_regain_heap, regain);
}

static void
check_pending_regain(const char *nick)
{
struct pending_regain *data = mowgli_patricia_delete(pending_regains, nick);
if (!data)
return;

slog(LG_DEBUG, "%s: found %s -> %s", MOWGLI_FUNC_NAME, data->client, data->nick);

struct user *u = user_find(data->client);
struct mynick *mn = mynick_find(data->nick);

if (!mn)
{
slog(LG_DEBUG, "%s: dropping regain attempt (nick dropped)", MOWGLI_FUNC_NAME);
}
// Make sure they haven't changed nick themselves (or if the protocol
// doesn't support UIDs, someone else might now be using their nick)
else if (!u)
{
slog(LG_DEBUG, "%s: dropping regain attempt (source user gone)", MOWGLI_FUNC_NAME);
}
else if (u->ts != data->client_ts)
{
slog(LG_DEBUG, "%s: dropping regain attempt (source user nickTS mismatch)", MOWGLI_FUNC_NAME);
}
else
{
notice(nicksvs.nick, u->nick, _("\2%s\2 has been regained."), data->nick);
fnc_sts(nicksvs.me->me, u, data->nick, FNC_FORCE);
// Clear ircd-side nick enforcement; this avoids users being unable
// to change the casing of their nick post-REGAIN while on the regained nick
holdnick_sts(nicksvs.me->me, 0, data->nick, mn->owner);
}

destroy_pending_regain(nick, data, NULL);
}

static void
pending_regain_nickchange(struct hook_user_nick *data)
{
check_pending_regain(data->oldnick);
}

static void
pending_regain_delete(struct user *u)
{
check_pending_regain(u->nick);
}

static void
ns_cmd_set_enforce(struct sourceinfo *si, int parc, char *parv[])
{
Expand Down Expand Up @@ -539,10 +608,33 @@ ns_cmd_regain(struct sourceinfo *si, int parc, char *parv[])
{
if (ircd->flags & IRCD_HOLDNICK)
holdnick_sts(nicksvs.me->me, SECONDS_PER_MINUTE + atheme_random_uniform(SECONDS_PER_MINUTE), u->nick, mn->owner);

struct pending_regain *old = mowgli_patricia_delete(pending_regains, u->nick);

if (old)
{
// We might want to avoid re-FNCing the target, too;
// this just avoids leaking memory
slog(LG_DEBUG, "%s: overwriting existing pending regain %s -> %s", MOWGLI_FUNC_NAME, old->client, old->nick);
destroy_pending_regain(old->nick, old, NULL);
}

struct pending_regain *data = mowgli_heap_alloc(pending_regain_heap);
mowgli_strlcpy(data->nick, target, sizeof data->nick);
data->client = strshare_ref(CLIENT_NAME(si->su));
data->client_ts = si->su->ts;

mowgli_patricia_add(pending_regains, u->nick, data);
slog(LG_DEBUG, "%s: added pending regain %s -> %s", MOWGLI_FUNC_NAME, data->client, data->nick);

guest_nickname(u);
}
else
{
holdnick_sts(si->service->me, 0, target, mn->owner);
fnc_sts(nicksvs.me->me, si->su, target, FNC_FORCE);
command_success_nodata(si, _("\2%s\2 has been regained."), target);
}
fnc_sts(nicksvs.me->me, si->su, target, FNC_FORCE);
}

return;
Expand Down Expand Up @@ -670,6 +762,16 @@ mod_init(struct module *const restrict m)
return;
}

pending_regain_heap = mowgli_heap_create(sizeof(struct pending_regain), 32, BH_NOW);
if (pending_regain_heap == NULL)
{
mowgli_heap_destroy(enforce_timeout_heap);
m->mflags |= MODFLAG_FAIL;
return;
}

pending_regains = mowgli_patricia_create(&irccasecanon);

enforce_remove_enforcers_timer = mowgli_timer_add(base_eventloop, "enforce_remove_enforcers", enforce_remove_enforcers, NULL, 5 * SECONDS_PER_MINUTE);

service_named_bind_command("nickserv", &ns_release);
Expand All @@ -678,6 +780,8 @@ mod_init(struct module *const restrict m)
hook_add_user_info(show_enforce);
hook_add_nick_can_register(check_registration);
hook_add_nick_enforce(check_enforce);
hook_add_user_nickchange(pending_regain_nickchange);
hook_add_user_delete(pending_regain_delete);
}

static void
Expand All @@ -696,7 +800,11 @@ mod_deinit(const enum module_unload_intent ATHEME_VATTR_UNUSED intent)
hook_del_user_info(show_enforce);
hook_del_nick_can_register(check_registration);
hook_del_nick_enforce(check_enforce);
hook_del_user_nickchange(pending_regain_nickchange);
hook_del_user_delete(pending_regain_delete);
mowgli_patricia_destroy(pending_regains, &destroy_pending_regain, NULL);
mowgli_heap_destroy(enforce_timeout_heap);
mowgli_heap_destroy(pending_regain_heap);
}

SIMPLE_DECLARE_MODULE_V1("nickserv/enforce", MODULE_UNLOAD_CAPABILITY_OK)