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Optimize regex execution to not capture unless 'capture' action used.

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This commit is contained in:
brectanus 2007-03-21 14:06:36 +00:00
parent 09b704f114
commit d1ada359dd
2 changed files with 44 additions and 39 deletions
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6
CHANGES
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@ -2,11 +2,17 @@
20 Mar 2007 - trunk
-------------------
* Optimize regex execution to not capture unless 'capture' action used.
* Performance improvements in memory management.
* Fixed some collection variable names not printing with the parameter
and/or counting operator in the debug log.
11 Mar 2007 - 2.1.1-rc1
-----------------------
* Fixed potential memory corruption when expanding macros.
* Fixed error when a collection var was fetched in the same second as creation

77
apache2/re_operators.c
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@ -82,6 +82,7 @@ static int msre_op_rx_execute(modsec_rec *msr, msre_rule *rule, msre_var *var, c
unsigned int target_length;
char *my_error_msg = NULL;
int ovector[33];
int capture = 0;
int rc;
if (error_msg == NULL) return -1;
@ -104,55 +105,51 @@ static int msre_op_rx_execute(modsec_rec *msr, msre_rule *rule, msre_var *var, c
target_length = var->value_len;
}
/* IMP1 Can we tell the regex engine not to do any captures if we have no use for them? */
rc = msc_regexec_capture(regex, target, target_length, ovector, 30, &my_error_msg);
/* Are we supposed to capture subexpressions? */
capture = apr_table_get(rule->actionset->actions, "capture") ? 1 : 0;
if (capture) {
if (msr->txcfg->debuglog_level >= 9) {
msr_log(msr, 9, "Using captured regex execution.");
}
rc = msc_regexec_capture(regex, target, target_length, ovector, 30, &my_error_msg);
}
else {
if (msr->txcfg->debuglog_level >= 9) {
msr_log(msr, 9, "Using uncaptured regex execution.");
}
rc = msc_regexec(regex, target, target_length, &my_error_msg);
}
if (rc < -1) {
*error_msg = apr_psprintf(msr->mp, "Regex execution failed: %s", my_error_msg);
return -1;
}
/* Handle captured subexpressions. */
if (rc > 0) {
int capture = 0;
const apr_array_header_t *tarr;
const apr_table_entry_t *telts;
if (capture && rc > 0) {
int i;
/* Are we supposed to store the captured subexpressions? */
/* IMP1 Can we use a flag to avoid having to iterate through the list every time. */
tarr = apr_table_elts(rule->actionset->actions);
telts = (const apr_table_entry_t*)tarr->elts;
for (i = 0; i < tarr->nelts; i++) {
msre_action *action = (msre_action *)telts[i].val;
if (strcasecmp(action->metadata->name, "capture") == 0) {
capture = 1;
break;
/* Use the available captures. */
for(i = 0; i < rc; i++) {
msc_string *s = (msc_string *)apr_pcalloc(msr->mp, sizeof(msc_string));
if (s == NULL) return -1;
s->name = apr_psprintf(msr->mp, "%i", i);
s->value = apr_pstrmemdup(msr->mp,
target + ovector[2*i], ovector[2*i + 1] - ovector[2*i]);
s->value_len = (ovector[2*i + 1] - ovector[2*i]);
if ((s->name == NULL)||(s->value == NULL)) return -1;
apr_table_setn(msr->tx_vars, s->name, (void *)s);
if (msr->txcfg->debuglog_level >= 9) {
msr_log(msr, 9, "Adding regex subexpression to TXVARS (%i): %s", i,
log_escape_nq(msr->mp, s->value));
}
}
if (capture) {
int k;
/* Use the available captures. */
for(k = 0; k < rc; k++) {
msc_string *s = (msc_string *)apr_pcalloc(msr->mp, sizeof(msc_string));
if (s == NULL) return -1;
s->name = apr_psprintf(msr->mp, "%i", k);
s->value = apr_pstrmemdup(msr->mp,
target + ovector[2*k], ovector[2*k + 1] - ovector[2*k]);
s->value_len = (ovector[2*k + 1] - ovector[2*k]);
if ((s->name == NULL)||(s->value == NULL)) return -1;
apr_table_setn(msr->tx_vars, s->name, (void *)s);
msr_log(msr, 9, "Adding regex subexpression to TXVARS (%i): %s", k,
log_escape_nq(msr->mp, s->value));
}
/* Unset the remaining ones (from previous invocations). */
for(k = rc; k <= 9; k++) {
char buf[24];
apr_snprintf(buf, sizeof(buf), "%i", k);
apr_table_unset(msr->tx_vars, buf);
}
/* Unset the remaining ones (from previous invocations). */
for(i = rc; i <= 9; i++) {
char buf[24];
apr_snprintf(buf, sizeof(buf), "%i", i);
apr_table_unset(msr->tx_vars, buf);
}
}
@ -518,7 +515,9 @@ static int msre_op_validateByteRange_execute(modsec_rec *msr, msre_rule *rule, m
for(i = 0; i < var->value_len; i++) {
int x = ((unsigned char *)var->value)[i];
if (!(table[x >> 3] & (1 << (x & 0x7)))) {
msr_log(msr, 9, "Value %i outside range: %s", x, rule->op_param);
if (msr->txcfg->debuglog_level >= 9) {
msr_log(msr, 9, "Value %i outside range: %s", x, rule->op_param);
}
count++;
}
}