From 891859f9c5a4f130e118bdf34398d75eea41e726 Mon Sep 17 00:00:00 2001
From: brectanus <brectanus@9017d574-64ec-4062-9424-5e00b32a252b>
Date: Tue, 27 Mar 2007 15:32:53 +0000
Subject: [PATCH] Revert back to using captured regex execution as it seems to
 be more effecient as the ovector can be used for working space even if it is
 not used for captures. Warn when captures are used in the regex, but
 "capture" not specified.

---
 CHANGES                |  3 ++-
 apache2/msc_pcre.c     |  8 ++++++++
 apache2/msc_pcre.h     |  2 ++
 apache2/re_operators.c | 21 +++++++++++----------
 4 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/CHANGES b/CHANGES
index 6ec934d5..1ff92d19 100644
--- a/CHANGES
+++ b/CHANGES
@@ -8,7 +8,8 @@
 
 * Do not log 'allow' action as intercepted in the debug log.
 
-* Optimize regex execution to not capture unless 'capture' action used.
+* Warn if a regular expression captures subexpressions, but the
+  "capture" action was not specified.
 
 * Performance improvements in memory management.
 
diff --git a/apache2/msc_pcre.c b/apache2/msc_pcre.c
index 4729d3b9..11fd9e72 100644
--- a/apache2/msc_pcre.c
+++ b/apache2/msc_pcre.c
@@ -91,3 +91,11 @@ int msc_regexec(msc_regex_t *regex, const char *s, unsigned int slen,
 
     return msc_regexec_capture(regex, s, slen, NULL, 0, error_msg);
 }
+
+/**
+ * Gets info on a compiled regex.
+ */
+int msc_fullinfo(msc_regex_t *regex, int what, void *where)
+{
+    return pcre_fullinfo(regex->re, regex->pe, what, where);
+}
diff --git a/apache2/msc_pcre.h b/apache2/msc_pcre.h
index 8cc9dc33..d9af38b5 100644
--- a/apache2/msc_pcre.h
+++ b/apache2/msc_pcre.h
@@ -36,4 +36,6 @@ int DSOLOCAL msc_regexec_capture(msc_regex_t *regex, const char *s,
 int DSOLOCAL msc_regexec(msc_regex_t *regex, const char *s, unsigned int slen,
     char **error_msg);
 
+int DSOLOCAL msc_fullinfo(msc_regex_t *regex, int what, void *where);
+
 #endif
diff --git a/apache2/re_operators.c b/apache2/re_operators.c
index ff595e4f..30fb62aa 100644
--- a/apache2/re_operators.c
+++ b/apache2/re_operators.c
@@ -108,18 +108,19 @@ static int msre_op_rx_execute(modsec_rec *msr, msre_rule *rule, msre_var *var, c
     /* 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.");
+    /* Warn when the regex captures but "capture" is not set */
+    if (msr->txcfg->debuglog_level >= 2) {
+        int capcount;
+        rc = msc_fullinfo(regex, PCRE_INFO_CAPTURECOUNT, &capcount);
+        if ((capture == 0) && (capcount > 0)) {
+            msr_log(msr, 2, "Warning. regex captures, but \"capture\" action not set.");
         }
-        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);
     }
+
+    /* We always use capture so that ovector can be used as working space
+     * and no memory has to be allocated for any backreferences.
+     */
+    rc = msc_regexec_capture(regex, target, target_length, ovector, 30, &my_error_msg);
     if (rc < -1) {
         *error_msg = apr_psprintf(msr->mp, "Regex execution failed: %s", my_error_msg);
         return -1;