From d4d80b38aa85eccb26e3c61b04d16e8ca5de76fe Mon Sep 17 00:00:00 2001
From: Breno Silva <breno.silva@gmail.com>
Date: Mon, 4 Mar 2013 16:54:20 -0400
Subject: [PATCH] Added SecXmlExternalEntity

---
 apache2/apache2_config.c | 48 ++++++++++++++++++++++++++++++++++++++--
 apache2/modsecurity.h    |  3 +++
 apache2/msc_xml.c        | 11 +++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/apache2/apache2_config.c b/apache2/apache2_config.c
index 7437ffbdc..188af59cb 100644
--- a/apache2/apache2_config.c
+++ b/apache2/apache2_config.c
@@ -156,6 +156,9 @@ void *create_directory_config(apr_pool_t *mp, char *path)
     dcfg->crypto_hash_framesrc_pm = NOT_SET;
 
 
+    /* xml external entity */
+    dcfg->xml_external_entity = NOT_SET;
+
     return dcfg;
 }
 
@@ -591,6 +594,10 @@ void *merge_directory_configs(apr_pool_t *mp, void *_parent, void *_child)
     merged->crypto_hash_framesrc_pm = (child->crypto_hash_framesrc_pm == NOT_SET
         ? parent->crypto_hash_framesrc_pm : child->crypto_hash_framesrc_pm);
 
+    /* xml external entity */
+    merged->xml_external_entity = (child->xml_external_entity == NOT_SET
+        ? parent->xml_external_entity : child->xml_external_entity);
+
     return merged;
 }
 
@@ -711,6 +718,9 @@ void init_directory_config(directory_config *dcfg)
     if (dcfg->crypto_hash_iframesrc_pm == NOT_SET) dcfg->crypto_hash_iframesrc_pm = 0;
     if (dcfg->crypto_hash_framesrc_pm == NOT_SET) dcfg->crypto_hash_framesrc_pm = 0;
 
+    /* xml external entity */
+    if (dcfg->xml_external_entity == NOT_SET) dcfg->xml_external_entity = 0;
+
 }
 
 /**
@@ -2282,9 +2292,35 @@ static const char *cmd_sensor_id(cmd_parms *cmd, void *_dcfg, const char *p1)
     return NULL;
 }
 
+/**
+* \brief Add SecXmlExternalEntity configuration option
+*
+* \param cmd Pointer to configuration data
+* \param _dcfg Pointer to directory configuration
+* \param p1 Pointer to configuration option
+*
+* \retval NULL On failure
+* \retval apr_psprintf On Success
+*/
+static const char *cmd_xml_external_entity(cmd_parms *cmd, void *_dcfg, const char *p1)
+{
+    directory_config *dcfg = (directory_config *)_dcfg;
+    if (dcfg == NULL) return NULL;
+
+    if (strcasecmp(p1, "on") == 0)  {
+        dcfg->xml_external_entity = 1;
+    }
+    else if (strcasecmp(p1, "off") == 0)    {
+        dcfg->xml_external_entity = 0;
+    }
+    else return apr_psprintf(cmd->pool, "ModSecurity: Invalid value for SecXmlExternalEntity: %s", p1);
+
+    return NULL;
+}
+
 
 /**
-* \brief Add SecHash configuration option
+* \brief Add SecHashEngine configuration option
 *
 * \param cmd Pointer to configuration data
 * \param _dcfg Pointer to directory configuration
@@ -2306,7 +2342,7 @@ static const char *cmd_hash_engine(cmd_parms *cmd, void *_dcfg, const char *p1)
         dcfg->hash_is_enabled = HASH_DISABLED;
         dcfg->hash_enforcement = HASH_DISABLED;
     }
-    else return apr_psprintf(cmd->pool, "ModSecurity: Invalid value for SecRuleEngine: %s", p1);
+    else return apr_psprintf(cmd->pool, "ModSecurity: Invalid value for SexHashEngine: %s", p1);
 
     return NULL;
 }
@@ -3223,6 +3259,14 @@ const command_rec module_directives[] = {
         "On or Off"
     ),
 
+    AP_INIT_TAKE1 (
+        "SecXmlExternalEntity",
+        cmd_xml_external_entity,
+        NULL,
+        CMD_SCOPE_ANY,
+        "On or Off"
+    ),
+
     AP_INIT_FLAG (
         "SecRuleInheritance",
         cmd_rule_inheritance,
diff --git a/apache2/modsecurity.h b/apache2/modsecurity.h
index 3f210b753..cb1a8d188 100644
--- a/apache2/modsecurity.h
+++ b/apache2/modsecurity.h
@@ -595,6 +595,9 @@ struct directory_config {
     int                 crypto_hash_location_pm;
     int                 crypto_hash_iframesrc_pm;
     int                 crypto_hash_framesrc_pm;
+
+    /* xml */
+    int                 xml_external_entity;
 };
 
 struct error_message_t {
diff --git a/apache2/msc_xml.c b/apache2/msc_xml.c
index d9cb09cc8..87ab967e7 100644
--- a/apache2/msc_xml.c
+++ b/apache2/msc_xml.c
@@ -14,17 +14,28 @@
 
 #include "msc_xml.h"
 
+static xmlParserInputBufferPtr
+xml_unload_external_entity(const char *URI, xmlCharEncoding enc)    {
+    return NULL;
+}
+
 
 /**
  * Initialise XML parser.
  */
 int xml_init(modsec_rec *msr, char **error_msg) {
+    xmlParserInputBufferCreateFilenameFunc entity;
+
     if (error_msg == NULL) return -1;
     *error_msg = NULL;
 
     msr->xml = apr_pcalloc(msr->mp, sizeof(xml_data));
     if (msr->xml == NULL) return -1;
 
+    if(msr->txcfg->xml_external_entity == 0)    {
+        entity = xmlParserInputBufferCreateFilenameDefault(xml_unload_external_entity);
+    }
+
     return 1;
 }