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Add bypass capability to spamfilter #456

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17 changes: 17 additions & 0 deletions doc/reference.conf
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Original file line number Diff line number Diff line change
Expand Up @@ -1535,6 +1535,23 @@ general {
* requires extensions/drain to be loaded.
*/
drain_reason = "This server is not accepting connections.";

/* filter_sees_user_info: Whether the filter is given the nick!user@host of message senders.
* If set to NO, the filter is given a literal "*!*@*" instead.
* Requires extension/filter to be loaded.
*/
#filter_sees_user_info = no;

/* filter_bypass_all: If set to NO, the only filter action that can bypass +u is DROP when paired with BYPASS.
* If set to YES, all filter actions can bypass +u when paired with BYPASS.
* Requires extension/filter to be loaded.
*/
#filter_bypass_all = no;

/* filter_exit_message: The QUIT message shown when a user is disconnected due to the filter KILL action.
* Requires extension/filter to be loaded.
*/
#filter_exit_message = "Connection closed";
};

modules {
Expand Down
2 changes: 2 additions & 0 deletions doc/server-version-info.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@
+----------------------------+
| 'e' | USE_EXCEPT |
|------+---------------------|
| 'F' | FILTER_CAN_SPY |
|------+---------------------|
| 'I' | USE_INVEX |
|------+---------------------|
| 'K' | USE_KNOCK |
Expand Down
173 changes: 129 additions & 44 deletions extensions/filter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
#include "numeric.h"
#include "send.h"
#include "s_newconf.h"
#include "s_conf.h"
#include "s_serv.h"
#include "s_user.h"
#include "msg.h"
Expand All @@ -41,22 +42,27 @@
#include "operhash.h"
#include "inline/stringops.h"
#include "msgbuf.h"
#include "newconf.h"

#include <hs_common.h>
#include <hs_runtime.h>

#define FILTER_NICK 0
#define FILTER_USER 0
#define FILTER_HOST 0

#define FILTER_EXIT_MSG "Connection closed"
#define FILTER_DEFAULT_EXIT_MSG "Connection closed"

static const char filter_desc[] = "Filter messages using a precompiled Hyperscan database";

static int modinit(void);
static void moddeinit(void);
static void filter_msg_user(void *data);
static void filter_msg_channel(void *data);
static void filter_client_quit(void *data);
static void on_client_exit(void *data);
static void filter_init_conf(void *data);
static void filter_conf_info(void *data);
static void filter_version_info(void *data);
static void filter_conf_set_sees_user_info(void *data);
static void filter_conf_set_bypass_all(void *data);
static void filter_conf_set_exit_message(void *data);

static void mo_setfilter(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
static void me_setfilter(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
Expand All @@ -67,6 +73,9 @@ static hs_database_t *filter_db;
static hs_scratch_t *filter_scratch;

static int filter_enable = 1;
static int filter_sees_user_info = 0;
static int filter_bypass_all = 0;
static char *filter_exit_message = NULL;

static const char *cmdname[MESSAGE_TYPE_COUNT] = {
[MESSAGE_TYPE_PRIVMSG] = "PRIVMSG",
Expand All @@ -81,9 +90,15 @@ enum filter_state {
FILTER_LOADED
};

struct match_context {
unsigned int actions;
bool require_bypass;
};

#define ACT_DROP (1 << 0)
#define ACT_KILL (1 << 1)
#define ACT_ALARM (1 << 2)
#define ACT_BYPASS (1 << 3)

static enum filter_state state = FILTER_EMPTY;
static char check_str[21] = "";
Expand All @@ -95,21 +110,30 @@ mapi_hfn_list_av1 filter_hfnlist[] = {
{ "privmsg_channel", filter_msg_channel },
{ "client_quit", filter_client_quit },
{ "client_exit", on_client_exit },
{ "conf_read_start", filter_init_conf },
{ "doing_info_conf", filter_conf_info },
{ "doing_version_confopts", filter_version_info },
{ NULL, NULL }
};


struct Message setfilter_msgtab = {
"SETFILTER", 0, 0, 0, 0,
{mg_unreg, mg_not_oper, mg_ignore, mg_ignore, {me_setfilter, 2}, {mo_setfilter, 2}}
};

mapi_clist_av1 filter_clist[] = { &setfilter_msgtab, NULL };

DECLARE_MODULE_AV2(filter, modinit, moddeinit, filter_clist, NULL, filter_hfnlist, NULL, "0.5", filter_desc);

static int
modinit(void)
{
filter_umode = user_modes['u'] = find_umode_slot();
construct_umodebuf();
filter_chmode = cflag_add('u', chm_simple);
add_conf_item("general", "filter_sees_user_info", CF_YESNO, filter_conf_set_sees_user_info);
add_conf_item("general", "filter_bypass_all", CF_YESNO, filter_conf_set_bypass_all);
add_conf_item("general", "filter_exit_message", CF_QSTRING, filter_conf_set_exit_message);
return 0;
}

Expand All @@ -128,12 +152,73 @@ moddeinit(void)
hs_free_database(filter_db);
if (filter_data)
rb_free(filter_data);
if (filter_exit_message)
rb_free(filter_exit_message);
remove_conf_item("general", "filter_sees_user_info");
remove_conf_item("general", "filter_bypass_all");
remove_conf_item("general", "filter_exit_message");
}

static void
filter_init_conf(void *data)
{
if (filter_exit_message)
{
rb_free(filter_exit_message);
filter_exit_message = NULL;
}
}

mapi_clist_av1 filter_clist[] = { &setfilter_msgtab, NULL };
static void
filter_conf_info(void *data_)
{
hook_data *data = data_;
sendto_one(data->client, ":%s %d %s :%-30s %-16s [%s]",
get_id(&me, data->client), RPL_INFO,
get_id(data->client, data->client),
"filter_sees_user_info",
filter_sees_user_info ? "YES" : "NO",
"Let the spamfilter engine see the hostmasks of senders");

sendto_one(data->client, ":%s %d %s :%-30s %-16s [%s]",
get_id(&me, data->client), RPL_INFO,
get_id(data->client, data->client),
"filter_bypass_all",
filter_bypass_all ? "YES" : "NO",
"Let the spamfilter BYPASS action work on KILL/ALARM in addition to DROP");

sendto_one(data->client, ":%s %d %s :%-30s %-16s [%s]",
get_id(&me, data->client), RPL_INFO,
get_id(data->client, data->client),
"filter_exit_message",
filter_exit_message != NULL ? filter_exit_message : FILTER_DEFAULT_EXIT_MSG,
"Message to quit users with if they hit a filter KILL action");
}

static void
filter_version_info(void *data)
{
if (filter_sees_user_info || filter_bypass_all)
((char *)data)['F'] = 1;
}

static void
filter_conf_set_sees_user_info(void *data)
{
filter_sees_user_info = *(int *)data;
}

DECLARE_MODULE_AV2(filter, modinit, moddeinit, filter_clist, NULL, filter_hfnlist, NULL, "0.4", filter_desc);
static void
filter_conf_set_bypass_all(void *data)
{
filter_bypass_all = *(int *)data;
}

static void
filter_conf_set_exit_message(void *data)
{
filter_exit_message = (char *)data;
}

static int
setfilter(const char *check, const char *data, const char **error)
Expand Down Expand Up @@ -313,8 +398,6 @@ me_setfilter(struct MsgBuf *msgbuf, struct Client *client_p, struct Client *sour
if (r) {
sendto_one_notice(source_p, ":SETFILTER failed: %s", error);
}

return;
}

/* will be called for every match
Expand All @@ -328,8 +411,17 @@ int match_callback(unsigned id,
unsigned flags,
void *context_)
{
unsigned *context = context_;
*context |= id;
struct match_context *context = context_;

if (context->require_bypass)
{
unsigned int bypass_mask = filter_bypass_all ? UINT_MAX : ACT_DROP;
if (id & ACT_BYPASS)
context->actions |= id & bypass_mask;
}
else
context->actions |= id;

return 0;
}

Expand All @@ -338,50 +430,42 @@ static char clean_buffer[BUFSIZE];

unsigned match_message(const char *prefix,
struct Client *source,
bool require_bypass,
const char *command,
const char *target,
const char *msg)
{
unsigned state = 0;
struct match_context ctx = { 0, require_bypass };

if (!filter_enable)
return 0;
if (!filter_db)
return 0;
if (!command)
return 0;

snprintf(check_buffer, sizeof check_buffer, "%s:%s!%s@%s#%c %s%s%s :%s",
prefix,
#if FILTER_NICK
source->name,
#else
"*",
#endif
#if FILTER_USER
source->username,
#else
"*",
#endif
#if FILTER_HOST
source->host,
#else
"*",
#endif
filter_sees_user_info ? source->name : "*",
filter_sees_user_info ? source->username : "*",
filter_sees_user_info ? source->host : "*",
source->user && source->user->suser[0] != '\0' ? '1' : '0',
command,
target ? " " : "",
target ? target : "",
msg);
hs_error_t r = hs_scan(filter_db, check_buffer, strlen(check_buffer), 0, filter_scratch, match_callback, &state);
hs_error_t r = hs_scan(filter_db, check_buffer, strlen(check_buffer), 0, filter_scratch, match_callback, &ctx);
if (r != HS_SUCCESS && r != HS_SCAN_TERMINATED)
return 0;
return state;
return ctx.actions;
}

void
filter_msg_user(void *data_)
{
hook_data_privmsg_user *data = data_;
struct Client *s = data->source_p;

/* we only need to filter once */
if (!MyClient(s)) {
return;
Expand All @@ -392,14 +476,14 @@ filter_msg_user(void *data_)
if (IsOper(s) || IsOper(data->target_p)) {
return;
}
if (data->target_p->umodes & filter_umode) {
return;
}

bool require_bypass = (data->target_p->umodes & filter_umode) == filter_umode;
char *text = strcpy(clean_buffer, data->text);
strip_colour(text);
strip_unprintable(text);
unsigned r = match_message("0", s, cmdname[data->msgtype], "0", data->text) |
match_message("1", s, cmdname[data->msgtype], "0", text);
unsigned r = match_message("0", s, require_bypass, cmdname[data->msgtype], "0", data->text) |
match_message("1", s, require_bypass, cmdname[data->msgtype], "0", text);

if (r & ACT_DROP) {
if (data->msgtype == MESSAGE_TYPE_PRIVMSG) {
sendto_one_numeric(s, ERR_CANNOTSENDTOCHAN,
Expand All @@ -415,7 +499,7 @@ filter_msg_user(void *data_)
}
if (r & ACT_KILL) {
data->approved = 1;
exit_client(NULL, s, s, FILTER_EXIT_MSG);
exit_client(NULL, s, s, filter_exit_message != NULL ? filter_exit_message : FILTER_DEFAULT_EXIT_MSG);
}
}

Expand All @@ -424,6 +508,7 @@ filter_msg_channel(void *data_)
{
hook_data_privmsg_channel *data = data_;
struct Client *s = data->source_p;

/* we only need to filter once */
if (!MyClient(s)) {
return;
Expand All @@ -433,14 +518,14 @@ filter_msg_channel(void *data_)
if (IsOper(s)) {
return;
}
if (data->chptr->mode.mode & filter_chmode) {
return;
}

bool require_bypass = (data->chptr->mode.mode & filter_chmode) == filter_chmode;
char *text = strcpy(clean_buffer, data->text);
strip_colour(text);
strip_unprintable(text);
unsigned r = match_message("0", s, cmdname[data->msgtype], data->chptr->chname, data->text) |
match_message("1", s, cmdname[data->msgtype], data->chptr->chname, text);
unsigned r = match_message("0", s, require_bypass, cmdname[data->msgtype], data->chptr->chname, data->text) |
match_message("1", s, require_bypass, cmdname[data->msgtype], data->chptr->chname, text);

if (r & ACT_DROP) {
if (data->msgtype == MESSAGE_TYPE_PRIVMSG) {
sendto_one_numeric(s, ERR_CANNOTSENDTOCHAN,
Expand All @@ -456,7 +541,7 @@ filter_msg_channel(void *data_)
}
if (r & ACT_KILL) {
data->approved = 1;
exit_client(NULL, s, s, FILTER_EXIT_MSG);
exit_client(NULL, s, s, filter_exit_message != NULL ? filter_exit_message : FILTER_DEFAULT_EXIT_MSG);
}
}

Expand All @@ -471,8 +556,8 @@ filter_client_quit(void *data_)
char *text = strcpy(clean_buffer, data->orig_reason);
strip_colour(text);
strip_unprintable(text);
unsigned r = match_message("0", s, "QUIT", NULL, data->orig_reason) |
match_message("1", s, "QUIT", NULL, text);
unsigned r = match_message("0", s, false, "QUIT", NULL, data->orig_reason) |
match_message("1", s, false, "QUIT", NULL, text);
if (r & ACT_DROP) {
data->reason = NULL;
}
Expand Down