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Snort_AIPreproc/spp_ai.c
BlackLight a1d157487c 16 ago 2010 commit
2010-08-16 22:09:34 +02:00

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/*
* =====================================================================================
*
* Filename: spp_ai.c
*
* Description: Main file for the spp_ai Snort preprocessor module
*
* Version: 0.1
* Created: 26/07/2010 11:00:41
* Revision: none
* Compiler: gcc
*
* Author: BlackLight (http://0x00.ath.cx), <blacklight@autistici.org>
* Licence: GNU GPL v.3
* Company: DO WHAT YOU WANT CAUSE A PIRATE IS FREE, YOU ARE A PIRATE!
*
* =====================================================================================
*/
#include "spp_ai.h"
#include "sfPolicyUserData.h"
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
tSfPolicyUserContextId ex_config = NULL;
#ifdef SNORT_RELOAD
tSfPolicyUserContextId ex_swap_config = NULL;
#endif
static void AI_init(char *);
static void AI_process(void *, void *);
static AI_config * AI_parse(char *);
#ifdef SNORT_RELOAD
static void AI_reload(char *);
static int AI_reloadSwapPolicyFree(tSfPolicyUserContextId, tSfPolicyId, void *);
static void * AI_reloadSwap(void);
static void AI_reloadSwapFree(void *);
#endif
/**
* FUNCTION: AI_setup
* \brief Set up the preprocessor module
*/
void AI_setup(void)
{
#ifndef SNORT_RELOAD
_dpd.registerPreproc("ai", AI_init);
#else
_dpd.registerPreproc("ai", AI_init, AI_reload,
AI_reloadSwap, AI_reloadSwapFree);
#endif
DEBUG_WRAP(_dpd.debugMsg(DEBUG_PLUGIN, "Preprocessor: AI is setup\n"););
} /* ----- end of function AI_setup ----- */
/**
* FUNCTION: AI_init
* \brief Initialize the preprocessor module
* \param args Configuration arguments passed to the module
*/
static void AI_init(char *args)
{
AI_config *config;
pthread_t cleanup_thread,
logparse_thread;
tSfPolicyId policy_id = _dpd.getParserPolicy();
_dpd.logMsg("AI dynamic preprocessor configuration\n");
if (ex_config == NULL)
{
ex_config = sfPolicyConfigCreate();
if (ex_config == NULL)
_dpd.fatalMsg("Could not allocate configuration struct.\n");
}
config = AI_parse(args);
sfPolicyUserPolicySet(ex_config, policy_id);
sfPolicyUserDataSetCurrent(ex_config, config);
/* If the hash_cleanup_interval of stream_expire_interval options are set to zero,
* no cleanup will be made on the streams */
if ( config->hashCleanupInterval != 0 && config->streamExpireInterval != 0 )
{
if ( pthread_create ( &cleanup_thread, NULL, AI_hashcleanup_thread, config ) != 0 )
{
_dpd.fatalMsg ( "Failed to create the hash cleanup thread\n" );
}
}
if ( strlen ( config->alertfile ) > 0 )
{
if ( pthread_create ( &logparse_thread, NULL, AI_alertparser_thread, config ) != 0 )
{
_dpd.fatalMsg ( "Failed to create the alert parser thread\n" );
}
}
/* Register the preprocessor function, Transport layer, ID 10000 */
_dpd.addPreproc(AI_process, PRIORITY_TRANSPORT, 10000, PROTO_BIT__TCP | PROTO_BIT__UDP);
DEBUG_WRAP(_dpd.debugMsg(DEBUG_PLUGIN, "Preprocessor: AI is initialized\n"););
} /* ----- end of function AI_init ----- */
/**
* FUNCTION: AI_config
* \brief Parse the arguments passed to the module saving them to a valid configuration struct
* \param args Arguments passed to the module
* \return Pointer to AI_config keeping the configuration for the module
*/
static AI_config * AI_parse(char *args)
{
char *arg;
char *match;
char alertfile[1024] = { 0 };
char clusterfile[1024] = { 0 };
char **matches = NULL;
int nmatches = 0;
int i;
int offset;
int len;
uint32_t netmask;
int min_val;
int max_val;
char label[256];
cluster_type type;
hierarchy_node **hierarchy_nodes = NULL;
int n_hierarchy_nodes = 0;
unsigned long cleanup_interval = 0,
stream_expire_interval = 0,
alertfile_len = 0,
clusterfile_len = 0,
alert_clustering_interval = 0;
BOOL has_cleanup_interval = false,
has_stream_expire_interval = false,
has_alertfile = false,
has_clusterfile = false,
has_clustering = false;
AI_config *config = NULL;
if ( !( config = ( AI_config* ) malloc ( sizeof( AI_config )) ))
_dpd.fatalMsg("Could not allocate configuration struct.\n");
memset ( config, 0, sizeof ( AI_config ));
/* Parsing the hashtable_cleanup_interval option */
if (( arg = (char*) strcasestr( args, "hashtable_cleanup_interval" ) ))
{
has_cleanup_interval = true;
for ( arg += strlen("hashtable_cleanup_interval");
*arg && (*arg < '0' || *arg > '9');
arg++ );
if ( !(*arg) )
{
_dpd.fatalMsg("AIPreproc: hashtable_cleanup_interval option used but "
"no value specified\n");
}
cleanup_interval = strtoul(arg, NULL, 10);
config->hashCleanupInterval = cleanup_interval;
_dpd.logMsg(" Hash table cleanup interval: %d\n", config->hashCleanupInterval);
}
/* Parsing the tcp_stream_expire_interval option */
if (( arg = (char*) strcasestr( args, "tcp_stream_expire_interval" ) ))
{
has_stream_expire_interval = true;
for ( arg += strlen("tcp_stream_expire_interval");
*arg && (*arg < '0' || *arg > '9');
arg++ );
if ( !(*arg) )
{
_dpd.fatalMsg("AIPreproc: tcp_stream_expire_interval option used but "
"no value specified\n");
}
stream_expire_interval = strtoul(arg, NULL, 10);
config->streamExpireInterval = stream_expire_interval;
_dpd.logMsg(" TCP stream expire interval: %d\n", config->streamExpireInterval);
}
/* Parsing the alert_clustering_interval option */
if (( arg = (char*) strcasestr( args, "alert_clustering_interval" ) ))
{
for ( arg += strlen("alert_clustering_interval");
*arg && (*arg < '0' || *arg > '9');
arg++ );
if ( !(*arg) )
{
_dpd.fatalMsg("AIPreproc: alert_clustering_interval option used but "
"no value specified\n");
}
alert_clustering_interval = strtoul(arg, NULL, 10);
config->alertClusteringInterval = alert_clustering_interval;
_dpd.logMsg(" Alert clustering interval: %d\n", config->alertClusteringInterval);
}
/* Parsing the alertfile option */
if (( arg = (char*) strcasestr( args, "alertfile" ) ))
{
for ( arg += strlen("alertfile");
*arg && *arg != '"';
arg++ );
if ( !(*(arg++)) )
{
_dpd.fatalMsg("AIPreproc: alertfile option used but no filename specified\n");
}
for ( alertfile[ (++alertfile_len)-1 ] = *arg;
*arg && *arg != '"' && alertfile_len < 1024;
arg++, alertfile[ (++alertfile_len)-1 ] = *arg );
if ( alertfile[0] == 0 || alertfile_len <= 1 ) {
has_alertfile = false;
} else {
if ( alertfile_len >= 1024 ) {
_dpd.fatalMsg("AIPreproc: alertfile path too long ( >= 1024 )\n");
} else if ( strlen( alertfile ) == 0 ) {
has_alertfile = false;
} else {
has_alertfile = true;
alertfile[ alertfile_len-1 ] = 0;
strncpy ( config->alertfile, alertfile, alertfile_len );
_dpd.logMsg(" alertfile path: %s\n", config->alertfile);
}
}
}
/* Parsing the clusterfile option */
if (( arg = (char*) strcasestr( args, "clusterfile" ) ))
{
for ( arg += strlen("clusterfile");
*arg && *arg != '"';
arg++ );
if ( !(*(arg++)) )
{
_dpd.fatalMsg("AIPreproc: clusterfile option used but no filename specified\n");
}
for ( clusterfile[ (++clusterfile_len)-1 ] = *arg;
*arg && *arg != '"' && clusterfile_len < 1024;
arg++, clusterfile[ (++clusterfile_len)-1 ] = *arg );
if ( clusterfile[0] == 0 || clusterfile_len <= 1 ) {
has_clusterfile = false;
} else {
if ( clusterfile_len >= 1024 ) {
_dpd.fatalMsg("AIPreproc: clusterfile path too long ( >= 1024 )\n");
} else if ( strlen( clusterfile ) == 0 ) {
has_clusterfile = false;
} else {
has_clusterfile = true;
clusterfile[ clusterfile_len-1 ] = 0;
strncpy ( config->clusterfile, clusterfile, clusterfile_len );
_dpd.logMsg(" clusterfile path: %s\n", config->clusterfile);
}
}
}
/* Parsing cluster options */
while ( preg_match ( "\\s*(cluster\\s*\\(\\s*)([^\\)]+)\\)", args, &matches, &nmatches ) > 0 )
{
if ( ! has_clustering )
has_clustering = true;
memset ( label, 0, sizeof(label) );
min_val = -1;
max_val = -1;
type = none;
match = strdup ( matches[1] );
offset = (int) strcasestr ( args, matches[0] ) - (int) args;
len = strlen ( matches[0] );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
if ( preg_match ( "class\\s*=\\s*\"([^\"]+)\"", match, &matches, &nmatches ) > 0 )
{
if ( !strcasecmp ( matches[0], "src_port" ))
type = src_port;
else if ( !strcasecmp ( matches[0], "dst_port" ))
type = dst_port;
else if ( !strcasecmp ( matches[0], "src_addr" ))
type = src_addr;
else if ( !strcasecmp ( matches[0], "dst_addr" ))
type = dst_addr;
else
_dpd.fatalMsg ( "AIPreproc: Unknown class type in configuration: '%s'\n", matches[0] );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
}
if ( preg_match ( "name\\s*=\\s*\"([^\"]+)\"", match, &matches, &nmatches ) > 0 )
{
if ( strlen( matches[0] ) > sizeof(label) )
_dpd.fatalMsg ( "AIPreproc: Label name too long in configuration: '%s' (maximum allowed length: %d)\n",
matches[0], sizeof(label) );
strncpy ( label, matches[0], sizeof(label) );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
}
if ( preg_match ( "range\\s*=\\s*\"([^\"]+)\"", match, &matches, &nmatches ) > 0 )
{
arg = strdup ( matches[0] );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
switch ( type )
{
case src_port:
case dst_port:
if ( preg_match ( "^([0-9]+)-([0-9]+)$", arg, &matches, &nmatches ) > 0 )
{
min_val = strtoul ( matches[0], NULL, 10 );
max_val = strtoul ( matches[1], NULL, 10 );
if ( min_val > max_val )
{
_dpd.fatalMsg ( "AIPreproc: Parse error in configuration: '%s', minval > maxval\n", arg );
}
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
} else if ( preg_match ( "^([0-9]+)$", arg, &matches, &nmatches ) > 0 ) {
min_val = strtoul ( matches[0], NULL, 10 );
max_val = min_val;
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
} else {
_dpd.fatalMsg ( "AIPreproc: Unallowed format for a port range in configuration file: '%s'\n", arg );
}
break;
case src_addr:
case dst_addr:
if ( preg_match ( "^([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3})/([0-9]{1,2})$", arg, &matches, &nmatches ) > 0 )
{
if (( min_val = inet_addr ( matches[0] )) == INADDR_NONE )
{
_dpd.fatalMsg ( "AIPreproc: Unallowed IPv4 format in configuration: '%s'\n", matches[0] );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
}
netmask = strtoul ( matches[1], NULL, 10 );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
if ( netmask > 32 )
{
_dpd.fatalMsg ( "AIPreproc: The netmask number of bits should be in [0,32] in '%s'\n", arg );
}
netmask = 1 << (( 8*sizeof ( uint32_t )) - netmask );
min_val = ntohl ( min_val ) & (~(netmask - 1));
max_val = min_val | (netmask - 1);
} else if ( preg_match ( "^([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3})$", arg, &matches, &nmatches ) > 0 ) {
if (( min_val = inet_addr ( matches[0] )) == INADDR_NONE )
{
_dpd.fatalMsg ( "AIPreproc: Unallowed IPv4 format in configuration: '%s'\n", matches[0] );
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
}
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
min_val = ntohl ( min_val );
max_val = min_val;
} else {
_dpd.fatalMsg ( "AIPreproc: Invalid value for an IP address or a subnet in configuration: '%s'\n", arg );
}
break;
/* TODO Manage ranges and clusters for timestamps (and more?) here */
default:
break;
}
if ( matches )
{
for ( i=0; i < nmatches; i++ )
free ( matches[i] );
free ( matches );
matches = NULL;
}
if ( arg )
{
free ( arg );
arg = NULL;
}
}
for ( i=offset; i <= strlen(args); i++ )
args[i] = args[ i+len ];
if ( min_val == -1 || max_val == -1 || type == none || strlen ( label ) == 0 )
{
_dpd.fatalMsg ( "AIPreproc: Invalid cluster in configuration: '%s'\nAll of the following fields are required: class, range, name\n", match );
free ( match );
match = NULL;
}
if ( !( hierarchy_nodes = ( hierarchy_node** ) realloc ( hierarchy_nodes, (++n_hierarchy_nodes) * sizeof(hierarchy_node) )) )
{
_dpd.fatalMsg ( "Fatal dynamic memory allocation failure at %s:%d\n", __FILE__, __LINE__ );
free ( match );
match = NULL;
}
if ( !( hierarchy_nodes[ n_hierarchy_nodes - 1 ] = ( hierarchy_node* ) malloc ( sizeof(hierarchy_node) ) ))
{
_dpd.fatalMsg ( "Fatal dynamic memory allocation failure at %s:%d\n", __FILE__, __LINE__ );
free ( match );
match = NULL;
}
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->type = type;
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->min_val = min_val;
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->max_val = max_val;
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->nchildren = 0;
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->children = NULL;
hierarchy_nodes[ n_hierarchy_nodes - 1 ]->parent = NULL;
strncpy ( hierarchy_nodes[ n_hierarchy_nodes - 1 ]->label,
label,
sizeof ( hierarchy_nodes[ n_hierarchy_nodes - 1 ]->label ));
free ( match );
match = NULL;
}
if ( ! has_cleanup_interval )
{
config->hashCleanupInterval = DEFAULT_HASH_CLEANUP_INTERVAL;
}
if ( ! has_stream_expire_interval )
{
config->streamExpireInterval = DEFAULT_STREAM_EXPIRE_INTERVAL;
}
if ( ! has_alertfile )
{
strncpy ( config->alertfile, DEFAULT_ALERT_LOG_FILE, sizeof ( config->alertfile ));
}
if ( has_clustering )
{
if ( ! hierarchy_nodes )
{
_dpd.fatalMsg ( "AIPreproc: cluster file specified in the configuration but no clusters were specified\n" );
}
if ( ! has_clusterfile )
{
strncpy ( config->clusterfile, DEFAULT_CLUSTER_LOG_FILE, sizeof ( config->clusterfile ));
}
if ( ! alert_clustering_interval )
{
config->alertClusteringInterval = DEFAULT_ALERT_CLUSTERING_INTERVAL;
}
AI_hierarchies_build ( config, hierarchy_nodes, n_hierarchy_nodes );
}
return config;
} /* ----- end of function AI_config ----- */
/**
* FUNCTION: AI_process
* \brief Function executed every time the module receives a packet to be processed
* \param pkt void* pointer to the packet data
* \param context void* pointer to the context
*/
void AI_process(void *pkt, void *context)
{
SFSnortPacket *p = (SFSnortPacket *) pkt;
AI_config *config;
sfPolicyUserPolicySet(ex_config, _dpd.getRuntimePolicy());
config = (AI_config * ) sfPolicyUserDataGetCurrent (ex_config);
if (config == NULL)
return;
if (!p->ip4_header || p->ip4_header->proto != IPPROTO_TCP || !p->tcp_header)
{
/* Not for me, return */
return;
}
AI_pkt_enqueue ( pkt );
} /* ----- end of function AI_process ----- */
#ifdef SNORT_RELOAD
static void AI_reload(char *args)
{
AI_config *config;
tSfPolicyId policy_id = _dpd.getParserPolicy();
_dpd.logMsg("AI dynamic preprocessor configuration\n");
if (ex_swap_config == NULL)
{
ex_swap_config = sfPolicyConfigCreate();
if (ex_swap_config == NULL)
_dpd.fatalMsg("Could not allocate configuration struct.\n");
}
config = AI_parse(args);
sfPolicyUserPolicySet(ex_swap_config, policy_id);
sfPolicyUserDataSetCurrent(ex_swap_config, config);
/* Register the preprocessor function, Transport layer, ID 10000 */
_dpd.addPreproc(AI_process, PRIORITY_TRANSPORT, 10000, PROTO_BIT__TCP | PROTO_BIT__UDP);
DEBUG_WRAP(_dpd.debugMsg(DEBUG_PLUGIN, "Preprocessor: AI is initialized\n"););
}
static int AI_reloadSwapPolicyFree(tSfPolicyUserContextId config, tSfPolicyId policyId, void *data)
{
AI_config *policy_config = (AI_config *)data;
sfPolicyUserDataClear(config, policyId);
free(policy_config);
return 0;
}
static void * AI_reloadSwap(void)
{
tSfPolicyUserContextId old_config = ex_config;
if (ex_swap_config == NULL)
return NULL;
ex_config = ex_swap_config;
ex_swap_config = NULL;
return (void *)old_config;
}
static void AI_reloadSwapFree(void *data)
{
tSfPolicyUserContextId config = (tSfPolicyUserContextId)data;
if (data == NULL)
return;
sfPolicyUserDataIterate(config, AI_reloadSwapPolicyFree);
sfPolicyConfigDelete(config);
}
#endif
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