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msc_logging.c
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/*
* ModSecurity for Apache 2.x, http://www.modsecurity.org/
* Copyright (c) 2004-2013 Trustwave Holdings, Inc. (http://www.trustwave.com/)
*
* 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
*
* If any of the files related to licensing are missing or if you have any
* other questions related to licensing please contact Trustwave Holdings, Inc.
* directly using the email address security@modsecurity.org.
*/
#include "modsecurity.h"
#include <sys/stat.h>
#include "re.h"
#include "msc_logging.h"
#include "httpd.h"
#include "apr_strings.h"
#include "apr_global_mutex.h"
#include "msc_util.h"
#include "apr_version.h"
#include <libxml/xmlversion.h>
#ifdef WITH_YAJL
#include <yajl/yajl_gen.h>
#include "msc_logging_json.h"
#endif
/**
* Write the supplied data to the audit log (if the FD is ready), update
* the size counters, update the hash context.
*/
static int sec_auditlog_write(modsec_rec *msr, const char *data, unsigned int len) {
apr_size_t nbytes_written, nbytes = len;
apr_status_t rc;
/* Do nothing if there's no data. */
if (data == NULL) return -1;
/* Update size counters and the hash calculation. We always do this,
* even in cases where write fails. That will make it easier to detect
* problems with partial writes.
*/
msr->new_auditlog_size += len;
apr_md5_update(&msr->new_auditlog_md5ctx, data, len);
/* Do not write if we do not have a file descriptor. */
if (msr->new_auditlog_fd == NULL) return -1;
/* Write data to file. */
rc = apr_file_write_full(msr->new_auditlog_fd, data, nbytes, &nbytes_written);
if (rc != APR_SUCCESS) {
char errstr[1024];
msr_log(msr, 1, "Audit log: Failed writing (requested %" APR_SIZE_T_FMT
" bytes, written %" APR_SIZE_T_FMT "): %s", nbytes, nbytes_written,
apr_strerror(rc, errstr, sizeof(errstr)));
/* Concurrent log format: don't leak file handle. */
if (msr->txcfg->auditlog_type == AUDITLOG_CONCURRENT) {
apr_file_close(msr->new_auditlog_fd);
}
/* Set to NULL to prevent more than one error message on
* out-of-disk-space events and to prevent further attempts
* to write to the same file in this request.
*
* Serial log format: Note that, as we opened the file through the
* pool mechanism of the APR, we do not need to close the file
* here. It will be closed automatically at the end of the request.
*/
msr->new_auditlog_fd = NULL;
return -1;
}
return 1;
}
/**
* Constructs a log line in vcombined log format trying to truncate
* some of the fields to make the log line shorter than _limit bytes.
*/
char *construct_log_vcombinedus_limited(modsec_rec *msr, int _limit, int *was_limited) {
char *hostname;
char *local_user, *remote_user;
char *referer, *user_agent, *uniqueid;
const char *sessionid;
char *the_request, *bytes_sent;
int limit = _limit;
/* hostname */
hostname = (msr->hostname == NULL ? "-" : log_escape_nq(msr->mp, msr->hostname));
/* remote log name */
if (msr->remote_user == NULL) remote_user = "-";
else remote_user = log_escape_nq(msr->mp, msr->remote_user);
/* authenticated user */
if (msr->local_user == NULL) local_user = "-";
else local_user = log_escape_nq(msr->mp, msr->local_user);
/* unique id */
if (msr->txid == NULL) uniqueid = "-";
else uniqueid = log_escape(msr->mp, msr->txid);
/* referer */
referer = "-";
/*
referer = (char *)apr_table_get(msr->request_headers, "Referer");
if (referer == NULL) referer = "-";
else referer = log_escape(msr->mp, referer);
*/
/* user agent */
user_agent = "-";
/*
user_agent = (char *)apr_table_get(msr->request_headers, "User-Agent");
if (user_agent == NULL) user_agent = "-";
else user_agent = log_escape(msr->mp, user_agent);
*/
/* sessionid */
sessionid = (msr->sessionid == NULL) ? "-" : log_escape(msr->mp, msr->sessionid);
the_request = (msr->request_line == NULL) ? "" : log_escape(msr->mp, msr->request_line);
bytes_sent = apr_psprintf(msr->mp, "%" APR_OFF_T_FMT, msr->bytes_sent);
/* first take away the size of the
* information we must log
*/
limit -= 22; /* spaces and double quotes */
limit -= strlen(hostname); /* server name or IP */
limit -= strlen(msr->remote_addr); /* remote IP */
limit -= 28; /* current_logtime */
limit -= 3; /* status */
limit -= strlen(bytes_sent); /* bytes sent */
limit -= strlen(uniqueid); /* unique id */
limit -= strlen(sessionid); /* session id */
if (limit <= 0) {
msr_log(msr, 1, "GuardianLog: Atomic pipe write size too small: %d", PIPE_BUF);
return NULL;
}
/* we hope to be able to squeeze everything in */
if (limit < (int)(strlen(remote_user) + strlen(local_user) + strlen(referer)
+ strlen(user_agent) + strlen(the_request)))
{
/* Boo hoo hoo, there's not enough space available. */
*was_limited = 1;
/* Let's see if we can reduce the size of something. This
* is a very crude approach but it seems to work for our
* needs.
*/
if (strlen(remote_user) > 32) {
msr_log(msr, 9, "GuardianLog: Reduced remote_user to 32.");
remote_user[32] = '\0';
}
limit -= strlen(remote_user);
if (strlen(local_user) > 32) {
msr_log(msr, 9, "GuardianLog: Reduced local_user to 32.");
local_user[32] = '\0';
}
limit -= strlen(local_user);
if (strlen(referer) > 64) {
msr_log(msr, 9, "GuardianLog: Reduced referer to 64.");
referer[64] = '\0';
}
limit -= strlen(referer);
if (strlen(user_agent) > 64) {
msr_log(msr, 9, "GuardianLog: Reduced user_agent to 64.");
user_agent[64] = '\0';
}
limit -= strlen(user_agent);
if (limit <= 0) {
msr_log(msr, 1, "GuardianLog: Atomic pipe write size too small: %d.", PIPE_BUF);
return NULL;
}
/* use what's left for the request line */
if ((int)strlen(the_request) > limit) {
the_request[limit] = '\0';
msr_log(msr, 9, "GuardianLog: Reduced the_request to %d bytes.", limit);
}
} else {
/* Yay! We have enough space! */
*was_limited = 0;
}
return apr_psprintf(msr->mp, "%s %s %s %s [%s] \"%s\" %u %s \"%s\" \"%s\" %s \"%s\"",
hostname, msr->remote_addr, remote_user,
local_user, current_logtime(msr->mp), the_request,
msr->response_status, bytes_sent, referer, user_agent,
uniqueid, sessionid
);
}
/**
* Checks if the provided string is a valid audit log parts specification.
*/
int is_valid_parts_specification(char *p) {
char c, *t = p;
while((c = *(t++)) != '\0') {
if ((c != AUDITLOG_PART_ENDMARKER)&&((c < AUDITLOG_PART_FIRST)||(c > AUDITLOG_PART_LAST))) {
return 0;
}
}
return 1;
}
/**
* Constructs a filename that will be used to store an
* audit log entry.
*/
static char *construct_auditlog_filename(apr_pool_t *mp, const char *uniqueid) {
apr_time_exp_t t;
char tstr[300];
apr_size_t len;
apr_time_exp_lt(&t, apr_time_now());
apr_strftime(tstr, &len, 299, "/%Y%m%d/%Y%m%d-%H%M/%Y%m%d-%H%M%S", &t);
return apr_psprintf(mp, "%s-%s", tstr, uniqueid);
}
/**
* Creates a random 8-character string that
* consists of hexadecimal numbers, to be used
* as an audit log boundary.
*/
static char *create_auditlog_boundary(request_rec *r) {
#ifdef LINUX_S390
int data = swap_int32(rand());
#else
unsigned long data = rand();
#endif
/* Do note that I tried using apr_generate_random_bytes but it turned
* out to be terribly slow for some reason. Needs further investigation.
*/
return bytes2hex(r->pool, (void *)&data, 4);
}
/**
* Sanitises the request line by removing the parameters
* that have been marked as sensitive.
*/
static void sanitize_request_line(modsec_rec *msr) {
const apr_array_header_t *tarr = NULL;
const apr_table_entry_t *telts = NULL;
const apr_array_header_t *tarr_pattern = NULL;
const apr_table_entry_t *telts_pattern = NULL;
msc_parm *mparm = NULL;
int i, k;
char *qspos;
char *buf = NULL;
int sanitized_partial = 0;
int sanitize_matched = 0;
/* Locate the query string. */
qspos = strstr(msr->request_line, "?");
if (qspos == NULL) return;
qspos++;
/* Loop through the list of sensitive parameters. */
tarr = apr_table_elts(msr->arguments_to_sanitize);
telts = (const apr_table_entry_t*)tarr->elts;
for (i = 0; i < tarr->nelts; i++) {
msc_arg *arg = (msc_arg *)telts[i].val;
/* Only look at the parameters that appeared in the query string. */
if (strcmp(arg->origin, "QUERY_STRING") == 0) {
char *pat = NULL;
char *p;
int j, arg_min, arg_max;
/* Go to the beginning of the parameter. */
p = qspos;
j = arg->value_origin_offset;
while((*p != '\0')&&(j--)) p++;
if (*p == '\0') {
msr_log(msr, 1, "Unable to sanitize variable \"%s\" at offset %u of QUERY_STRING"
"because the request line is too short.",
log_escape_ex(msr->mp, arg->name, arg->name_len),
arg->value_origin_offset);
continue;
}
tarr_pattern = apr_table_elts(msr->pattern_to_sanitize);
telts_pattern = (const apr_table_entry_t*)tarr_pattern->elts;
sanitized_partial = 0;
sanitize_matched = 0;
buf = apr_psprintf(msr->mp, "%s",p);
for ( k = 0; k < tarr_pattern->nelts; k++) {
if(strncmp(telts_pattern[k].key,arg->name,strlen(arg->name)) ==0 ) {
mparm = (msc_parm *)telts_pattern[k].val;
pat = strstr(buf,mparm->value);
if(mparm->pad_1 == -1)
sanitize_matched = 1;
if (pat != NULL) {
j = strlen(mparm->value);
arg_min = j;
arg_max = 1;
while((*pat != '\0')&&(j--)) {
if(arg_max > mparm->pad_2) {
int off = (strlen(mparm->value) - arg_max);
int pos = (mparm->pad_1-1);
if(off > pos) {
*pat = '*';
}
}
arg_max++;
arg_min--;
pat++;
}
}
sanitized_partial = 1;
}
}
if(sanitized_partial == 1 && sanitize_matched == 0) {
while(*buf != '\0') {
*p++ = *buf++;
}
continue;
} else {
/* Write over the value. */
j = arg->value_origin_len;
while((*p != '\0')&&(j--)) {
*p++ = '*';
}
if (*p == '\0') {
msr_log(msr, 1, "Unable to sanitize variable \"%s\" at offset %u (size %d) "
"of QUERY_STRING because the request line is too short.",
log_escape_ex(msr->mp, arg->name, arg->name_len),
arg->value_origin_offset, arg->value_origin_len);
continue;
}
}
}
}
}
/**
* Output the Producer header.
*/
static void sec_auditlog_write_producer_header(modsec_rec *msr) {
char **signatures = NULL;
char *text = NULL;
int i;
/* Try to write everything in one go. */
if (msr->txcfg->component_signatures->nelts == 0) {
text = apr_psprintf(msr->mp, "Producer: %s.\n", MODSEC_MODULE_NAME_FULL);
sec_auditlog_write(msr, text, strlen(text));
return;
}
/* Start with the ModSecurity signature. */
text = apr_psprintf(msr->mp, "Producer: %s", MODSEC_MODULE_NAME_FULL);
sec_auditlog_write(msr, text, strlen(text));
/* Then loop through the components and output individual signatures. */
signatures = (char **)msr->txcfg->component_signatures->elts;
for(i = 0; i < msr->txcfg->component_signatures->nelts; i++) {
text = apr_psprintf(msr->mp, "; %s", (char *)signatures[i]);
sec_auditlog_write(msr, text, strlen(text));
}
sec_auditlog_write(msr, ".\n", 2);
}
#ifdef WITH_YAJL
/**
* Ouput the Producer header into a JSON generator
*/
static void sec_auditlog_write_producer_header_json(modsec_rec *msr, yajl_gen g) {
char **signatures = NULL;
int i;
// this is written no matter what
yajl_string(g, "producer");
/* Try to write verything in one go. */
if (msr->txcfg->component_signatures->nelts == 0) {
yajl_string(g, MODSEC_MODULE_NAME_FULL);
return;
}
// we'll need an array if there are component signatures
yajl_gen_array_open(g);
/* Start with the ModSecurity signature. */
yajl_string(g, MODSEC_MODULE_NAME_FULL);
/* Then loop through the components and output individual signatures. */
signatures = (char **)msr->txcfg->component_signatures->elts;
for(i = 0; i < msr->txcfg->component_signatures->nelts; i++) {
yajl_string(g, (char *)signatures[i]);
}
yajl_gen_array_close(g); // array for producers is finished
}
#endif
/*
* \brief This function will returns the next chain node
*
* \param current Pointer to current chined rule
* \param msr Pointer to modsec_rec
*
* \retval NULL On failure
* \retval next_rule On Success
*/
static msre_rule *return_chained_rule(const msre_rule *current, modsec_rec *msr) {
apr_array_header_t *arr = NULL;
msre_rule **rules = NULL;
msre_rule *rule = NULL, *next_rule = NULL;
int i;
int phase;
if (current == NULL || current->actionset == NULL || current->ruleset == NULL)
return NULL;
phase = current->actionset->phase;
switch (phase) {
case PHASE_REQUEST_HEADERS :
arr = current->ruleset->phase_request_headers;
break;
case PHASE_REQUEST_BODY :
arr = current->ruleset->phase_request_body;
break;
case PHASE_RESPONSE_HEADERS :
arr = current->ruleset->phase_response_headers;
break;
case PHASE_RESPONSE_BODY :
arr = current->ruleset->phase_response_body;
break;
case PHASE_LOGGING :
arr = current->ruleset->phase_logging;
break;
default :
msr_log(msr, 1, "Logging: Invalid phase %d",phase);
return NULL;
}
rules = (msre_rule **)arr->elts;
for (i = 0; i < arr->nelts; i++) {
rule = rules[i];
if (rule != NULL) {
if (strncmp(current->unparsed,rule->unparsed,strlen(current->unparsed)) == 0) {
if (i < arr->nelts -1) {
next_rule = rules[i+1];
} else {
next_rule = rules[i];
}
if (next_rule == NULL || next_rule->chain_starter == NULL)
return NULL;
if(current->chain_starter == NULL && next_rule->chain_starter != NULL) {
if (strncmp(current->unparsed, next_rule->chain_starter->unparsed, strlen(current->unparsed)) != 0)
return NULL;
}
if(current->chain_starter != NULL && next_rule->chain_starter != NULL) {
if (strncmp(current->chain_starter->unparsed, rule->chain_starter->unparsed, strlen(current->chain_starter->unparsed)) != 0)
return NULL;
}
return next_rule;
}
}
}
return NULL;
}
/*
* \brief This function will check if a chained rule
* appears into matched array.
*
* \param msr Pointer to modsec_rec
* \param next_rule Pointer to chained rule
*
* \retval 0 On failure
* \retval 1 On Success
*/
static int chained_is_matched(modsec_rec *msr, const msre_rule *next_rule) {
int i = 0;
const msre_rule *rule = NULL;
for (i = 0; i < msr->matched_rules->nelts; i++) {
rule = ((msre_rule **)msr->matched_rules->elts)[i];
if (rule != NULL && (strncmp(rule->unparsed,next_rule->unparsed,strlen(rule->unparsed)) == 0)) {
return 1;
}
}
return 0;
}
#ifdef WITH_YAJL
/**
* Write detailed information about performance metrics into a JSON generator
*/
static void format_performance_variables_json(modsec_rec *msr, yajl_gen g) {
yajl_string(g, "stopwatch");
yajl_gen_map_open(g);
yajl_kv_int(g, "p1", msr->time_phase1);
yajl_kv_int(g, "p2", msr->time_phase2);
yajl_kv_int(g, "p3", msr->time_phase3);
yajl_kv_int(g, "p4", msr->time_phase4);
yajl_kv_int(g, "p5", msr->time_phase5);
yajl_kv_int(g, "sr", msr->time_storage_read);
yajl_kv_int(g, "sw", msr->time_storage_write);
yajl_kv_int(g, "l", msr->time_logging);
yajl_kv_int(g, "gc", msr->time_gc);
yajl_gen_map_close(g);
}
/**
* Write detailed information about a rule and its actionset into a JSON generator
*/
static void write_rule_json(modsec_rec *msr, const msre_rule *rule, yajl_gen g) {
const apr_array_header_t *tarr;
const apr_table_entry_t *telts;
int been_opened = 0;
int k;
yajl_gen_map_open(g);
yajl_string(g, "actionset");
yajl_gen_map_open(g);
if (rule->actionset->id) {
yajl_kv_string(g, "id", log_escape(msr->mp, rule->actionset->id));
}
if (rule->actionset->rev) {
yajl_kv_string(g, "rev", log_escape(msr->mp, rule->actionset->rev));
}
if (rule->actionset->msg) {
msc_string *var = (msc_string *)apr_palloc(msr->mp, sizeof(msc_string));
var->value = (char *)rule->actionset->msg;
var->value_len = strlen(rule->actionset->msg);
expand_macros(msr, var, NULL, msr->mp);
yajl_kv_string(g, "msg", log_escape_ex(msr->mp, var->value, var->value_len));
}
if (rule->actionset->version) {
yajl_kv_string(g, "version", log_escape(msr->mp, rule->actionset->version));
}
if (rule->actionset->logdata) {
msc_string *var = (msc_string *)apr_pcalloc(msr->mp, sizeof(msc_string));
var->value = (char *)rule->actionset->logdata;
var->value_len = strlen(rule->actionset->logdata);
expand_macros(msr, var, NULL, msr->mp);
char *logdata = apr_pstrdup(msr->mp, log_escape_hex(msr->mp, (unsigned char *)var->value, var->value_len));
// if it is > 512 bytes, then truncate at 512 with ellipsis.
if (strlen(logdata) > 515) {
logdata[512] = '.';
logdata[513] = '.';
logdata[514] = '.';
logdata[515] = '\0';
}
yajl_kv_string(g, "logdata", logdata);
}
if (rule->actionset->severity != NOT_SET) {
yajl_kv_int(g, "severity", rule->actionset->severity);
}
if (rule->actionset->accuracy != NOT_SET) {
yajl_kv_int(g, "accuracy", rule->actionset->accuracy);
}
if (rule->actionset->maturity != NOT_SET) {
yajl_kv_int(g, "maturity", rule->actionset->maturity);
}
if (rule->actionset->phase != NOT_SET) {
yajl_kv_int(g, "phase", rule->actionset->phase);
}
yajl_kv_bool(g, "is_chained", rule->actionset->is_chained || (rule->chain_starter != NULL));
if (rule->actionset->is_chained && (rule->chain_starter == NULL)) {
yajl_kv_bool(g, "chain_starter", 1);
}
// tags, lazily opened
tarr = apr_table_elts(rule->actionset->actions);
telts = (const apr_table_entry_t*)tarr->elts;
for (k = 0; k < tarr->nelts; k++) {
msre_action *action = (msre_action *)telts[k].val;
if (strcmp(telts[k].key, "tag") == 0) {
if (been_opened == 0) {
yajl_string(g, "tags");
yajl_gen_array_open(g);
been_opened = 1;
}
// expand variables in the tag
msc_string *var = (msc_string *)apr_pcalloc(msr->mp, sizeof(msc_string));
var->value = (char *)action->param;
var->value_len = strlen(action->param);
expand_macros(msr, var, NULL, msr->mp);
yajl_string(g, log_escape(msr->mp, var->value));
}
}
if (been_opened == 1) {
yajl_gen_array_close(g);
}
yajl_gen_map_close(g);
yajl_string(g, "operator");
yajl_gen_map_open(g);
yajl_kv_string(g, "operator", rule->op_name);
yajl_kv_string(g, "operator_param", rule->op_param);
yajl_kv_string(g, "target", rule->p1);
yajl_kv_bool(g, "negated", rule->op_negated);
yajl_gen_map_close(g);
yajl_string(g, "config");
yajl_gen_map_open(g);
yajl_kv_string(g, "filename", rule->filename);
yajl_kv_int(g, "line_num", rule->line_num);
yajl_gen_map_close(g);
yajl_kv_string(g, "unparsed", rule->unparsed);
yajl_kv_bool(g, "is_matched", chained_is_matched(msr, rule));
yajl_gen_map_close(g);
}
/*
* Produce an audit log entry in JSON format.
*/
void sec_audit_logger_json(modsec_rec *msr) {
const apr_array_header_t *arr = NULL;
apr_table_entry_t *te = NULL;
const apr_array_header_t *tarr_pattern = NULL;
const apr_table_entry_t *telts_pattern = NULL;
char *str1 = NULL, *str2 = NULL, *text = NULL;
const msre_rule *rule = NULL, *next_rule = NULL;
apr_size_t nbytes, nbytes_written;
unsigned char md5hash[APR_MD5_DIGESTSIZE];
int was_limited = 0;
int present = 0;
int wrote_response_body = 0;
char *entry_filename, *entry_basename;
apr_status_t rc;
int i, limit, k, sanitized_partial, j;
char *buf = NULL, *pat = NULL;
msc_parm *mparm = NULL;
int arg_min, arg_max, sanitize_matched;
yajl_gen g;
int been_opened = 0; // helper flag for conditionally opening maps
/* Return silently if we don't have a request line. This
* means we will not be logging request timeouts.
*/
if (msr->request_line == NULL) {
msr_log(msr, 4, "Audit log: Skipping request whose request_line is null.");
return;
}
/* Also return silently if we don't have a file descriptor. */
if (msr->txcfg->auditlog_fd == NULL) {
msr_log(msr, 4, "Audit log: Skipping request since there is nowhere to write to.");
return;
}
if (msr->txcfg->auditlog_type != AUDITLOG_CONCURRENT) {
/* Serial logging - we already have an open file
* descriptor to write to.
*/
msr->new_auditlog_fd = msr->txcfg->auditlog_fd;
} else {
/* Concurrent logging - we need to create a brand
* new file for this request.
*/
apr_md5_init(&msr->new_auditlog_md5ctx);
msr->new_auditlog_filename = construct_auditlog_filename(msr->mp, msr->txid);
if (msr->new_auditlog_filename == NULL) return;
/* The audit log storage directory should be explicitly
* defined. But if it isn't try to write to the same
* directory where the index file is placed. Of course,
* it is *very* bad practice to allow the Apache user
* to write to the same directory where a root user is
* writing to but it's not us that's causing the problem
* and there isn't anything we can do about that.
*
* ENH Actually there is something we can do! We will make
* SecAuditStorageDir mandatory, ask the user to explicitly
* define the storage location *and* refuse to work if the
* index and the storage location are in the same folder.
*/
if (msr->txcfg->auditlog_storage_dir == NULL) {
entry_filename = file_dirname(msr->mp, msr->txcfg->auditlog_name);
}
else {
entry_filename = msr->txcfg->auditlog_storage_dir;
}
if (entry_filename == NULL) return;
entry_filename = apr_psprintf(msr->mp, "%s%s", entry_filename, msr->new_auditlog_filename);
if (entry_filename == NULL) return;
entry_basename = file_dirname(msr->mp, entry_filename);
if (entry_basename == NULL) return;
/* IMP1 Surely it would be more efficient to check the folders for
* the audit log repository base path in the configuration phase, to reduce
* the work we do on every request. Also, since our path depends on time,
* we could cache the time we last checked and don't check if we know
* the folder is there.
*/
rc = apr_dir_make_recursive(entry_basename, msr->txcfg->auditlog_dirperms, msr->mp);
if ((rc != APR_SUCCESS) && (rc != APR_EEXIST)) {
msr_log(msr, 1, "Audit log: Failed to create subdirectories: %s (%s)",
entry_basename, get_apr_error(msr->mp, rc));
return;
}
rc = apr_file_open(&msr->new_auditlog_fd, entry_filename,
APR_WRITE | APR_TRUNCATE | APR_CREATE | APR_BINARY | APR_FILE_NOCLEANUP,
msr->txcfg->auditlog_fileperms, msr->mp);
if (rc != APR_SUCCESS) {
msr_log(msr, 1, "Audit log: Failed to create file: %s (%s)",
entry_filename, get_apr_error(msr->mp, rc));
return;
}
}
/* Lock the mutex, but only if we are using serial format. */
if (msr->txcfg->auditlog_type != AUDITLOG_CONCURRENT) {
rc = apr_global_mutex_lock(msr->modsecurity->auditlog_lock);
if (rc != APR_SUCCESS) {
msr_log(msr, 1, "Audit log: Failed to lock global mutex: %s",
get_apr_error(msr->mp, rc));
}
}
/**
* allocate the buffer for the JSON generator
* passing null will force yajl to use malloc/realloc/free
* need to perf test using APR routines
*/
g = yajl_gen_alloc(NULL);
/**
* don't pretty print JSON
* this is harder to eyeball but much easier to parse programmatically
*/
yajl_gen_config(g, yajl_gen_beautify, 0);
yajl_gen_map_open(g); // IT BEGINS
/* AUDITLOG_PART_HEADER */
yajl_string(g, "transaction");
yajl_gen_map_open(g); // transaction top-level key
yajl_kv_string(g, "time", current_logtime(msr->mp));
yajl_kv_string(g, "transaction_id", msr->txid);
yajl_kv_string(g, "remote_address", msr->remote_addr);
yajl_kv_int(g, "remote_port", (int)msr->remote_port); // msr->remote_port is unsigned, yajl wants signed
yajl_kv_string(g, "local_address", msr->local_addr);
yajl_kv_int(g, "local_port", (int)msr->local_port);
yajl_gen_map_close(g); // transaction top-level key is finished
yajl_string(g, "request");
yajl_gen_map_open(g); // request top-level key
/* AUDITLOG_PART_REQUEST_HEADERS */
if (strchr(msr->txcfg->auditlog_parts, AUDITLOG_PART_REQUEST_HEADERS) != NULL) {
sanitize_request_line(msr);
yajl_kv_string(g, "request_line", msr->request_line);
yajl_string(g, "headers");
yajl_gen_map_open(g); // separate map for request headers
arr = apr_table_elts(msr->request_headers);
te = (apr_table_entry_t *)arr->elts;
tarr_pattern = apr_table_elts(msr->pattern_to_sanitize);
telts_pattern = (const apr_table_entry_t*)tarr_pattern->elts;
for (i = 0; i < arr->nelts; i++) {
sanitized_partial = 0;
sanitize_matched = 0;
text = apr_psprintf(msr->mp, "%s: %s\n", te[i].key, te[i].val);
// write the key no matter what
// since sanitization only occurs on the value
yajl_string(g, te[i].key);
if (apr_table_get(msr->request_headers_to_sanitize, te[i].key) != NULL) {
buf = apr_psprintf(msr->mp, "%s",text+strlen(te[i].key)+2);
for ( k = 0; k < tarr_pattern->nelts; k++) {
if(strncmp(telts_pattern[k].key,te[i].key,strlen(te[i].key)) ==0 ) {
mparm = (msc_parm *)telts_pattern[k].val;
if(mparm->pad_1 == -1)
sanitize_matched = 1;
pat = strstr(buf,mparm->value);
if (pat != NULL) {
j = strlen(mparm->value);
arg_min = j;
arg_max = 1;
while((*pat != '\0')&&(j--)) {
if(arg_max > mparm->pad_2) {
int off = strlen(mparm->value) - arg_max;
int pos = mparm->pad_1-1;
if(off > pos) {
*pat = '*';
}
}
arg_max++;
arg_min--;
pat++;
}
sanitized_partial = 1;
}
}
}
if(sanitized_partial == 1 && sanitize_matched == 0) {
yajl_string(g, buf);
} else {
memset(buf, '*', strlen(buf)); // strlen also includes the appended newline on the header
yajl_string(g, buf);
}
} else {
// we diverge from the original logic a bit because we always print the key
// at this no point sanitization had occured, so we just print the value
yajl_string(g, te[i].val);
}
}
yajl_gen_map_close(g); // request headers map is finished
}
/* AUDITLOG_PART_REQUEST_BODY */
/* Output this part of it was explicitly requested (C) or if it was the faked
* request body that was requested (I) but we have no reason to fake it (it's
* already in the correct format).
*/
if ( (strchr(msr->txcfg->auditlog_parts, AUDITLOG_PART_REQUEST_BODY) != NULL)
|| ( (strchr(msr->txcfg->auditlog_parts, AUDITLOG_PART_FAKE_REQUEST_BODY) != NULL)
&& (msr->mpd == NULL) ) )
{
if (msr->msc_reqbody_read) {
const apr_array_header_t *tarr;
const apr_table_entry_t *telts;
apr_array_header_t *sorted_args;
unsigned int offset = 0, last_offset = 0;
msc_arg *nextarg = NULL;
int sanitize = 0; /* IMP1 Use constants for "sanitize" values. */
char *my_error_msg = NULL;
sorted_args = apr_array_make(msr->mp, 25, sizeof(const msc_arg *));
/* First we need to sort the arguments that need to be
* sanitized in descending order (we are using a stack structure
* to store then so the order will be ascending when we start
* popping them out). This is because we will
* be reading the request body sequentially and must
* sanitize it as we go.
*/
for(;;) {
nextarg = NULL;
/* Find the next largest offset (excluding
* the ones we've used up already).
*/
tarr = apr_table_elts(msr->arguments_to_sanitize);
telts = (const apr_table_entry_t*)tarr->elts;
for(i = 0; i < tarr->nelts; i++) {
msc_arg *arg = (msc_arg *)telts[i].val;
if (arg->origin != NULL &&
strcmp(arg->origin, "BODY") != 0)
continue;
if (last_offset == 0) { /* The first time we're here. */
if (arg->value_origin_offset > offset) {
offset = arg->value_origin_offset;
nextarg = arg;
}
} else { /* Not the first time. */
if ((arg->value_origin_offset > offset)
&&(arg->value_origin_offset < last_offset))
{
offset = arg->value_origin_offset;
nextarg = arg;
}
}
}
/* If we don't have the next argument that means
* we're done here.
*/
if (nextarg == NULL) break;
sanitize = 2; /* Means time to pop the next argument out. */
last_offset = offset;
offset = 0;
{ /* IMP1 Fix this ugly bit here. */
msc_arg **x = apr_array_push(sorted_args);
*x = nextarg;
}
}
/* Now start retrieving the body chunk by chunk and
* sanitize data in pieces.
*/
rc = modsecurity_request_body_retrieve_start(msr, &my_error_msg);
if (rc < 0) {
msr_log(msr, 1, "Audit log: %s", my_error_msg);
} else {
msc_data_chunk *chunk = NULL;
unsigned int chunk_offset = 0;
unsigned int sanitize_offset = 0;
unsigned int sanitize_length = 0;
yajl_string(g, "body");
yajl_gen_array_open(g); // use an array here because we're writing in chunks
for(;;) {
rc = modsecurity_request_body_retrieve(msr, &chunk, -1, &my_error_msg);
if (chunk != NULL) {
/* Anything greater than 1 means we have more data to sanitize. */
while (sanitize > 1) {
msc_arg **arg = NULL;
if (sanitize == 2) {
/* Get the next argument from the stack. */
arg = (msc_arg **)apr_array_pop(sorted_args);
if (arg == NULL) sanitize = 0; /* We're done sanitising. */
else {
/* Continue with sanitation to process the
* retrieved argument.
*/
sanitize = 1;
sanitize_offset = (*arg)->value_origin_offset;
sanitize_length = (*arg)->value_origin_len;
}
}
if (sanitize) {
/* Check if the data we want to sanitize is
* stored in the current chunk.
*/
if (chunk_offset + chunk->length > sanitize_offset) {
unsigned int soff; /* data offset within chunk */
unsigned int len; /* amount in this chunk to sanitize */
soff = sanitize_offset - chunk_offset;
if (soff + sanitize_length <= chunk->length) {
/* The entire argument resides in the current chunk. */
len = sanitize_length;
sanitize = 2; /* Get another parameter to sanitize. */
} else {
/* Some work to do here but we'll need to seek
* another chunk.
*/
len = chunk->length - soff;
sanitize_offset += len;
sanitize_length -= len;
sanitize = 1; /* It's OK to go to the next chunk. */
}
/* Yes, we actually write over the original data.
* We shouldn't be needing it any more.
*/
if (soff + len <= chunk->length) { /* double check */
memset((char *)chunk->data + soff, '*', len);
}