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/*-
* Copyright 2016 Vsevolod Stakhov
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/***MODULE:chartable
* rspamd module that make marks based on symbol chains
*
* Allowed options:
* - symbol (string): symbol to insert (default: 'R_BAD_CHARSET')
* - threshold (double): value that would be used as threshold in expression characters_changed / total_characters
* (e.g. if threshold is 0.1 than charset change should occure more often than in 10 symbols), default: 0.1
*/
#include "config.h"
#include "libmime/message.h"
#include "rspamd.h"
#include "libstat/stat_api.h"
#include "libstat/tokenizers/tokenizers.h"
#include "unicode/utf8.h"
#include "unicode/uchar.h"
#define DEFAULT_SYMBOL "R_MIXED_CHARSET"
#define DEFAULT_URL_SYMBOL "R_MIXED_CHARSET_URL"
#define DEFAULT_THRESHOLD 0.1
#define msg_err_chartable(...) rspamd_default_log_function (G_LOG_LEVEL_CRITICAL, \
"chartable", task->task_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
#define msg_warn_chartable(...) rspamd_default_log_function (G_LOG_LEVEL_WARNING, \
"chartable", task->task_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
#define msg_info_chartable(...) rspamd_default_log_function (G_LOG_LEVEL_INFO, \
"chartable", task->task_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
#define msg_debug_chartable(...) rspamd_default_log_function (G_LOG_LEVEL_DEBUG, \
"chartable", task->task_pool->tag.uid, \
G_STRFUNC, \
__VA_ARGS__)
/* Initialization */
gint chartable_module_init (struct rspamd_config *cfg, struct module_ctx **ctx);
gint chartable_module_config (struct rspamd_config *cfg);
gint chartable_module_reconfig (struct rspamd_config *cfg);
module_t chartable_module = {
"chartable",
chartable_module_init,
chartable_module_config,
chartable_module_reconfig,
NULL,
RSPAMD_MODULE_VER
};
struct chartable_ctx {
struct module_ctx ctx;
const gchar *symbol;
const gchar *url_symbol;
double threshold;
guint max_word_len;
rspamd_mempool_t *chartable_pool;
};
static struct chartable_ctx *chartable_module_ctx = NULL;
static void chartable_symbol_callback (struct rspamd_task *task, void *unused);
static void chartable_url_symbol_callback (struct rspamd_task *task, void *unused);
gint
chartable_module_init (struct rspamd_config *cfg, struct module_ctx **ctx)
{
if (chartable_module_ctx == NULL) {
chartable_module_ctx = g_malloc (sizeof (struct chartable_ctx));
chartable_module_ctx->chartable_pool = rspamd_mempool_new (rspamd_mempool_suggest_size (), NULL);
chartable_module_ctx->max_word_len = 10;
}
*ctx = (struct module_ctx *)chartable_module_ctx;
return 0;
}
gint
chartable_module_config (struct rspamd_config *cfg)
{
const ucl_object_t *value;
gint res = TRUE;
if (!rspamd_config_is_module_enabled (cfg, "chartable")) {
return TRUE;
}
if ((value =
rspamd_config_get_module_opt (cfg, "chartable", "symbol")) != NULL) {
chartable_module_ctx->symbol = ucl_obj_tostring (value);
}
else {
chartable_module_ctx->symbol = DEFAULT_SYMBOL;
}
if ((value =
rspamd_config_get_module_opt (cfg, "chartable", "url_symbol")) != NULL) {
chartable_module_ctx->url_symbol = ucl_obj_tostring (value);
}
else {
chartable_module_ctx->url_symbol = DEFAULT_URL_SYMBOL;
}
if ((value =
rspamd_config_get_module_opt (cfg, "chartable", "threshold")) != NULL) {
if (!ucl_obj_todouble_safe (value, &chartable_module_ctx->threshold)) {
msg_warn_config ("invalid numeric value");
chartable_module_ctx->threshold = DEFAULT_THRESHOLD;
}
}
else {
chartable_module_ctx->threshold = DEFAULT_THRESHOLD;
}
if ((value =
rspamd_config_get_module_opt (cfg, "chartable", "max_word_len")) != NULL) {
chartable_module_ctx->max_word_len = ucl_object_toint (value);
}
else {
chartable_module_ctx->threshold = DEFAULT_THRESHOLD;
}
rspamd_symbols_cache_add_symbol (cfg->cache,
chartable_module_ctx->symbol,
0,
chartable_symbol_callback,
NULL,
SYMBOL_TYPE_NORMAL,
-1);
rspamd_symbols_cache_add_symbol (cfg->cache,
chartable_module_ctx->url_symbol,
0,
chartable_url_symbol_callback,
NULL,
SYMBOL_TYPE_NORMAL,
-1);
msg_info_config ("init internal chartable module");
return res;
}
gint
chartable_module_reconfig (struct rspamd_config *cfg)
{
rspamd_mempool_delete (chartable_module_ctx->chartable_pool);
chartable_module_ctx->chartable_pool = rspamd_mempool_new (1024, NULL);
return chartable_module_config (cfg);
}
static gdouble
rspamd_chartable_process_word_utf (struct rspamd_task *task,
rspamd_stat_token_t *w,
gboolean is_url)
{
const gchar *p, *end;
gdouble badness = 0.0;
UChar32 uc;
UBlockCode sc, last_sc;
guint same_script_count = 0, nsym = 0, i = 0;
enum {
start_process = 0,
got_alpha,
got_digit,
got_unknown,
} state = start_process, prev_state = start_process;
p = w->begin;
end = p + w->len;
last_sc = 0;
/* We assume that w is normalized */
while (p + i < end) {
U8_NEXT_UNSAFE (p, i, uc);
if (u_isalpha (uc)) {
sc = ublock_getCode (uc);
if (sc <= UBLOCK_LATIN_EXTENDED_B) {
/* Assume all latin characters as basic latin */
sc = UBLOCK_BASIC_LATIN;
}
if (state == got_digit) {
/* Penalize digit -> alpha translations */
if (!is_url && sc != UBLOCK_BASIC_LATIN &&
prev_state != start_process) {
badness += 1.0;
}
}
else if (state == got_alpha) {
/* Check script */
if (same_script_count > 0) {
if (sc != last_sc) {
badness += 1.0 / (gdouble)same_script_count;
last_sc = sc;
same_script_count = 1;
}
else {
same_script_count ++;
}
}
else {
last_sc = sc;
same_script_count = 1;
}
}
prev_state = state;
state = got_alpha;
}
else if (u_isdigit (uc)) {
if (state != got_digit) {
prev_state = state;
}
state = got_digit;
same_script_count = 0;
}
else {
/* We don't care about unknown characters here */
if (state != got_unknown) {
prev_state = state;
}
state = got_unknown;
same_script_count = 0;
}
nsym ++;
}
/* Try to avoid FP for long words */
if (nsym > chartable_module_ctx->max_word_len) {
badness = 0;
}
else {
if (badness > 4.0) {
badness = 4.0;
}
}
msg_debug_chartable ("word %*s, badness: %.2f", (gint)w->len, w->begin,
badness);
return badness;
}
static gdouble
rspamd_chartable_process_word_ascii (struct rspamd_task *task,
rspamd_stat_token_t *w,
gboolean is_url)
{
const guchar *p, *end;
gdouble badness = 0.0;
enum {
ascii = 1,
non_ascii
} sc, last_sc;
gint same_script_count = 0, seen_alpha = FALSE;
enum {
start_process = 0,
got_alpha,
got_digit,
got_unknown,
} state = start_process;
p = w->begin;
end = p + w->len;
last_sc = 0;
if (w->len > chartable_module_ctx->max_word_len) {
return 0.0;
}
/* We assume that w is normalized */
while (p < end) {
if (g_ascii_isalpha (*p) || *p > 0x7f) {
if (state == got_digit) {
/* Penalize digit -> alpha translations */
if (seen_alpha && !is_url && !g_ascii_isxdigit (*p)) {
badness += 1.0;
}
}
else if (state == got_alpha) {
/* Check script */
sc = (*p > 0x7f) ? ascii : non_ascii;
if (same_script_count > 0) {
if (sc != last_sc) {
badness += 1.0 / (gdouble)same_script_count;
last_sc = sc;
same_script_count = 1;
}
else {
same_script_count ++;
}
}
else {
last_sc = sc;
same_script_count = 1;
}
}
seen_alpha = TRUE;
state = got_alpha;
}
else if (g_ascii_isdigit (*p)) {
state = got_digit;
same_script_count = 0;
}
else {
/* We don't care about unknown characters here */
state = got_unknown;
same_script_count = 0;
}
p ++;
}
if (badness > 4.0) {
badness = 4.0;
}
msg_debug_chartable ("word %*s, badness: %.2f", (gint)w->len, w->begin,
badness);
return badness;
}
static void
rspamd_chartable_process_part (struct rspamd_task *task,
struct rspamd_mime_text_part *part)
{
rspamd_stat_token_t *w;
guint i;
gdouble cur_score = 0.0;
if (part == NULL || part->normalized_words == NULL ||
part->normalized_words->len == 0) {
return;
}
for (i = 0; i < part->normalized_words->len; i++) {
w = &g_array_index (part->normalized_words, rspamd_stat_token_t, i);
if (w->len > 0 && (w->flags & RSPAMD_STAT_TOKEN_FLAG_TEXT)) {
if (IS_PART_UTF (part)) {
cur_score += rspamd_chartable_process_word_utf (task, w, FALSE);
}
else {
cur_score += rspamd_chartable_process_word_ascii (task, w, FALSE);
}
}
}
cur_score /= (gdouble)part->normalized_words->len;
if (cur_score > 2.0) {
cur_score = 2.0;
}
if (cur_score > chartable_module_ctx->threshold) {
rspamd_task_insert_result (task, chartable_module_ctx->symbol,
cur_score, NULL);
}
}
static void
chartable_symbol_callback (struct rspamd_task *task, void *unused)
{
guint i;
struct rspamd_mime_text_part *part;
for (i = 0; i < task->text_parts->len; i ++) {
part = g_ptr_array_index (task->text_parts, i);
rspamd_chartable_process_part (task, part);
}
if (task->subject != NULL) {
GArray *words;
rspamd_stat_token_t *w;
guint i;
gdouble cur_score = 0.0;
words = rspamd_tokenize_text (task->subject, strlen (task->subject),
TRUE,
NULL,
NULL,
FALSE,
NULL);
if (words) {
for (i = 0; i < words->len; i++) {
w = &g_array_index (words, rspamd_stat_token_t, i);
cur_score += rspamd_chartable_process_word_utf (task, w, FALSE);
}
}
cur_score /= (gdouble)part->normalized_words->len;
if (cur_score > 2.0) {
cur_score = 2.0;
}
if (cur_score > chartable_module_ctx->threshold) {
rspamd_task_insert_result (task, chartable_module_ctx->symbol,
cur_score, "subject");
}
}
}
static void
chartable_url_symbol_callback (struct rspamd_task *task, void *unused)
{
struct rspamd_url *u;
GHashTableIter it;
gpointer k, v;
rspamd_stat_token_t w;
gdouble cur_score = 0.0;
g_hash_table_iter_init (&it, task->urls);
while (g_hash_table_iter_next (&it, &k, &v)) {
u = v;
if (cur_score > 2.0) {
cur_score = 2.0;
break;
}
if (u->hostlen > 0) {
w.begin = u->host;
w.len = u->hostlen;
if (g_utf8_validate (w.begin, w.len, NULL)) {
cur_score += rspamd_chartable_process_word_utf (task, &w, TRUE);
}
else {
cur_score += rspamd_chartable_process_word_ascii (task, &w, TRUE);
}
}
}
g_hash_table_iter_init (&it, task->emails);
while (g_hash_table_iter_next (&it, &k, &v)) {
u = v;
if (cur_score > 2.0) {
cur_score = 2.0;
break;
}
if (u->hostlen > 0) {
w.begin = u->host;
w.len = u->hostlen;
if (g_utf8_validate (w.begin, w.len, NULL)) {
cur_score += rspamd_chartable_process_word_utf (task, &w, TRUE);
}
else {
cur_score += rspamd_chartable_process_word_ascii (task, &w, TRUE);
}
}
}
if (cur_score > chartable_module_ctx->threshold) {
rspamd_task_insert_result (task, chartable_module_ctx->symbol,
cur_score, NULL);
}
}
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