Lua: Added support for scripting to @inspectFile.

apache2/apache2_config.c

@@ -9,7 +9,6 @@
  *
  */
 #include <limits.h>
-#include <apr_lib.h>
 
 #include "modsecurity.h"
 #include "msc_logging.h"
@@ -18,15 +17,6 @@
 
 #include "msc_lua.h"
 
-static const char *configuration_relative_path(apr_pool_t *pool, const char *parent_filename, const char *filename) {
-    if (filename == NULL) return NULL;
-    // TODO Support paths on operating systems other than Unix.
-    if (filename[0] == '/') return filename;
-
-    return apr_pstrcat(pool, apr_pstrndup(pool, parent_filename,
-        strlen(parent_filename) - strlen(apr_filepath_name_get(parent_filename))),
-        filename, NULL);
-}
 
 /* -- Directory context creation and initialisation -- */
 
@@ -1297,7 +1287,7 @@ static const char *cmd_rule_inheritance(cmd_parms *cmd, void *_dcfg, int flag) {
 static const char *cmd_rule_script(cmd_parms *cmd, void *_dcfg, const char *p1,
     const char *p2)
 {
-    const char *filename = configuration_relative_path(cmd->pool, cmd->directive->filename, p1);
+    const char *filename = resolve_relative_path(cmd->pool, cmd->directive->filename, p1);
     return add_rule(cmd, (directory_config *)_dcfg, RULE_TYPE_LUA, filename, p2, NULL);
 }
 #endif

apache2/msc_lua.c

@@ -244,7 +244,7 @@ static const struct luaL_Reg mylib[] = {
 /**
  *
  */
-int lua_execute(msc_script *script, modsec_rec *msr, msre_rule *rule, char **error_msg) {
+int lua_execute(msc_script *script, char *param, modsec_rec *msr, msre_rule *rule, char **error_msg) {
     apr_time_t time_before;
     lua_State *L = NULL;
     int rc;
@@ -288,7 +288,12 @@ int lua_execute(msc_script *script, modsec_rec *msr, msre_rule *rule, char **err
     /* Execute main() */
     lua_getglobal(L, "main");
 
-    if (lua_pcall(L, 0, 1, 0)) {
+    /* Put the parameter on the stack. */
+    if (param != NULL) {
+        lua_pushlstring(L, param, strlen(param));
+    }
+
+    if (lua_pcall(L, ((param != NULL) ? 1 : 0), 1, 0)) {
         *error_msg = apr_psprintf(msr->mp, "Lua: Script execution failed: %s", lua_tostring(L, -1));
         return -1;
     }

apache2/msc_lua.h

@@ -36,7 +36,7 @@ struct msc_script_part {
 
 char DSOLOCAL *lua_compile(msc_script **script, const char *filename, apr_pool_t *pool);
 
-int DSOLOCAL lua_execute(msc_script *script, modsec_rec *msr, msre_rule *rule, char **error_msg);
+int DSOLOCAL lua_execute(msc_script *script, char *param, modsec_rec *msr, msre_rule *rule, char **error_msg);
 
 #endif
 #endif

apache2/msc_util.c

@@ -16,6 +16,8 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#include <apr_lib.h>
+
 /* NOTE: Be careful as these can ONLY be used on static values for X.
  * (i.e. VALID_HEX(c++) will NOT work)
  */
@@ -1176,3 +1178,28 @@ char *modsec_build(apr_pool_t *mp) {
                             build_type,
                             atoi(MODSEC_VERSION_RELEASE));
 }
+
+int is_empty_string(const char *string) {
+    unsigned int i;
+
+    if (string == NULL) return 1;
+    if (strlen(string) == 0) return 1;
+
+    for(i = 0; i < strlen(string); i++) {
+        if (!isspace(string[i])) {
+            return 0;
+        }
+    }        
+
+    return 1;
+}
+
+char *resolve_relative_path(apr_pool_t *pool, const char *parent_filename, const char *filename) {
+    if (filename == NULL) return NULL;
+    // TODO Support paths on operating systems other than Unix.
+    if (filename[0] == '/') return (char *)filename;
+
+    return apr_pstrcat(pool, apr_pstrndup(pool, parent_filename,
+        strlen(parent_filename) - strlen(apr_filepath_name_get(parent_filename))),
+        filename, NULL);
+}

apache2/msc_util.h

@@ -78,4 +78,8 @@ int DSOLOCAL ansi_c_sequences_decode_inplace(unsigned char *input, int len);
 
 char DSOLOCAL *modsec_build(apr_pool_t *mp);
 
+int DSOLOCAL is_empty_string(const char *string);
+
+char DSOLOCAL *resolve_relative_path(apr_pool_t *pool, const char *parent_filename, const char *filename);
+
 #endif

apache2/re.c

@@ -1966,7 +1966,7 @@ static apr_status_t msre_rule_process_lua(msre_rule *rule, modsec_rec *msr) {
         acting_actionset = rule->chain_starter->actionset;
     }
 
-    rc = lua_execute(rule->script, msr, rule, &my_error_msg);
+    rc = lua_execute(rule->script, NULL, msr, rule, &my_error_msg);
     if (rc < 0) {
         msr_log(msr, 1, "%s", my_error_msg);
         return -1;

apache2/re_actions.c

@@ -1484,7 +1484,7 @@ static apr_status_t msre_action_exec_execute(modsec_rec *msr, apr_pool_t *mptmp,
         msc_script *script = (msc_script *)action->param_data;
         char *my_error_msg = NULL;
 
-        if (lua_execute(script, msr, rule, &my_error_msg) < 0) {
+        if (lua_execute(script, NULL, msr, rule, &my_error_msg) < 0) {
             msr_log(msr, 1, "%s", my_error_msg);
             return 0;
         }

apache2/re_operators.c

@@ -1237,44 +1237,99 @@ static int msre_op_rbl_execute(modsec_rec *msr, msre_rule *rule, msre_var *var,
 }
 
 /* inspectFile */
-static int msre_op_inspectFile_execute(modsec_rec *msr, msre_rule *rule, msre_var *var,
-    char **error_msg)
-{
-    char *script_output = NULL;
-    char const *argv[5];
-    const char *approver_script = rule->op_param;
-    const char *target_file = apr_pstrmemdup(msr->mp, var->value, var->value_len);
+
+static int msre_op_inspectFile_init(msre_rule *rule, char **error_msg) {
+    char *filename = (char *)rule->op_param;
 
     if (error_msg == NULL) return -1;
     *error_msg = NULL;
 
-    msr_log(msr, 4, "Executing %s to inspect %s.", approver_script, target_file);
-
-    argv[0] = approver_script;
-    argv[1] = target_file;
-    argv[2] = NULL;    
-
-    if (apache2_exec(msr, approver_script, (const char **)argv, &script_output) <= 0) {
-        *error_msg = apr_psprintf(msr->mp, "Execution of the approver script \"%s\" failed (invocation failed).",
-            log_escape(msr->mp, approver_script));
+    if ((filename == NULL)||(is_empty_string(filename))) {
+        *error_msg = apr_psprintf(rule->ruleset->mp, "Operator @inspectFile requires parameter.");
         return -1;
     }
 
-    if (script_output == NULL) {
-        *error_msg = apr_psprintf(msr->mp, "Execution of the approver script \"%s\" failed (no output).",
-            log_escape(msr->mp, approver_script));
-        return -1;
+    filename = resolve_relative_path(rule->ruleset->mp, rule->filename, filename);
+
+    #ifdef WITH_LUA
+    // TODO Write & use string_ends(s, e).
+    if (strlen(rule->op_param) > 4) {
+        char *p = filename + strlen(filename) - 4;
+        if ((p[0] == '.')&&(p[1] == 'l')&&(p[2] == 'u')&&(p[3] == 'a'))
+        {
+            msc_script *script = NULL;
+
+            /* Compile script. */
+            *error_msg = lua_compile(&script, filename, rule->ruleset->mp);
+            if (*error_msg != NULL) return -1;
+
+            rule->op_param_data = script;
+        }
+    }
+    #endif
+
+    if (rule->op_param_data == NULL) {
+        // TODO Verify the script exists and that we have
+        // the rights to execute it.
     }
 
-    if (script_output[0] != '1') {
-        *error_msg = apr_psprintf(msr->mp, "File \"%s\" rejected by the approver script \"%s\": %s",
-            log_escape(msr->mp, target_file), log_escape(msr->mp, approver_script),
-            log_escape_nq(msr->mp,  script_output));
-        return 1; /* Match. */
-    }
+    return 1;
+}
 
-    /* No match. */
-    return 0;
+static int msre_op_inspectFile_execute(modsec_rec *msr, msre_rule *rule, msre_var *var,
+    char **error_msg)
+{
+    if (error_msg == NULL) return -1;
+    *error_msg = NULL;
+
+    if (rule->op_param_data == NULL) {
+        /* Execute externally, as native binary/shell script. */
+        char *script_output = NULL;
+        char const *argv[5];
+        const char *approver_script = rule->op_param;
+        const char *target_file = apr_pstrmemdup(msr->mp, var->value, var->value_len);
+
+        msr_log(msr, 4, "Executing %s to inspect %s.", approver_script, target_file);
+
+        argv[0] = approver_script;
+        argv[1] = target_file;
+        argv[2] = NULL;    
+
+        if (apache2_exec(msr, approver_script, (const char **)argv, &script_output) <= 0) {
+            *error_msg = apr_psprintf(msr->mp, "Execution of the approver script \"%s\" failed (invocation failed).",
+                log_escape(msr->mp, approver_script));
+            return -1;
+        }
+
+        if (script_output == NULL) {
+            *error_msg = apr_psprintf(msr->mp, "Execution of the approver script \"%s\" failed (no output).",
+                log_escape(msr->mp, approver_script));
+            return -1;
+        }
+
+        if (script_output[0] != '1') {
+            *error_msg = apr_psprintf(msr->mp, "File \"%s\" rejected by the approver script \"%s\": %s",
+                log_escape(msr->mp, target_file), log_escape(msr->mp, approver_script),
+                log_escape_nq(msr->mp,  script_output));
+            return 1; /* Match. */
+        }
+
+        /* No match. */
+        return 0;
+    } else {
+        /* Execute internally, as Lua script. */
+        char *target = apr_pstrmemdup(msr->mp, var->value, var->value_len);
+        msc_script *script = (msc_script *)rule->op_param_data;
+        int rc;
+
+        rc = lua_execute(script, target, msr, rule, error_msg);
+        if (rc < 0) {
+            /* Error. */
+            return -1;
+        }
+
+        return rc;
+    }
 }
 
 /* validateByteRange */
@@ -1867,7 +1922,7 @@ void msre_engine_register_default_operators(msre_engine *engine) {
     /* inspectFile */
     msre_engine_op_register(engine,
         "inspectFile",
-        NULL,
+        msre_op_inspectFile_init,
         msre_op_inspectFile_execute
     );
 

doc/modsecurity2-apache-reference.xml

@@ -339,9 +339,8 @@
       </listitem>
 
       <listitem>
-        <para>Add one line to your configuration to load libxml2:
-        <filename moreinfo="none">LoadFile
-        /usr/lib/libxml2.so</filename></para>
+        <para>Add one line to your configuration to load libxml2: <filename
+        moreinfo="none">LoadFile /usr/lib/libxml2.so</filename></para>
       </listitem>
 
       <listitem>
@@ -420,13 +419,13 @@
     "allow" rules or to correct any false positives in the Core rules as they
     are applied to your site.</para>
 
-    <para><emphasis>Note</emphasis></para>
-
-    <para>It is highly encouraged that you do not edit the Core rules files
-    themselves but rather place all changes (such as
-    <literal>SecRuleRemoveByID</literal>, etc...) in your custom rules file.
-    This will allow for easier upgrading as newer Core rules are released by
-    Breach Security on the ModSecurity website.</para>
+    <note>
+      <para>It is highly encouraged that you do not edit the Core rules files
+      themselves but rather place all changes (such as
+      <literal>SecRuleRemoveByID</literal>, etc...) in your custom rules file.
+      This will allow for easier upgrading as newer Core rules are released by
+      Breach Security on the ModSecurity website.</para>
+    </note>
 
     <section>
       <title><literal>SecAction</literal></title>
@@ -690,7 +689,7 @@ SecAuditLogStorageDir logs/audit
         <listitem>
           <para><literal moreinfo="none">K</literal> - This part contains a
           full list of every rule that matched (one per line) in the order
-          they were matched.</para>
+          they were matched. Supported as of v2.5.0</para>
         </listitem>
 
         <listitem>
@@ -1798,8 +1797,13 @@ ServerAlias www.app2.com
       optional parameter is the list of actions whose meaning is identical to
       that of <literal>SecRule</literal>.</para>
 
-      <para><emphasis>Syntax:</emphasis> SecRuleScript /path/to/script.lua
-      [ACTIONS]</para>
+      <para><emphasis>Syntax:</emphasis> <literal>SecRuleScript
+      /path/to/script.lua [ACTIONS]</literal></para>
+
+      <para>The first parameter, path to the script, can be absolute or
+      relative to the configuration file in which
+      <literal>SecRuleScript</literal> resides. This allows you to place your
+      script in the same folder as the configuration files using them.</para>
 
       <para>Example script:</para>
 
@@ -1819,8 +1823,10 @@ function main()
     var2 = m.getvar("REQUEST_URI", "normalisePath");
 
     -- Retrieve one variable, applying several transformation functions.
-    -- Notice how the second parameter is now a list.
-    var3 = m.getvar("ARGS:p", { "lowercase", "compressWhitespace" } );
+    -- The second parameter is now a list. You should note that m.getvar()
+    -- requires the use of comma to separate collection names from
+    -- variable names. This is because only one variable is returned.
+    var3 = m.getvar("ARGS.p", { "lowercase", "compressWhitespace" } );
 
     -- If you want this rule to match return a string
     -- containing the error message. It is a good idea to mention
@@ -1830,6 +1836,13 @@ function main()
     -- Otherwise, simply return null.
     return null;
 end</programlisting>
+
+      <note>
+        <para>Go to <ulink url="http://www.lua.org">http://www.lua.org</ulink>
+        to find more about the Lua programming language. The reference manual
+        too is available online, at <ulink
+        url="http://www.lua.org/manual/5.1/">http://www.lua.org/manual/5.1/</ulink>.</para>
+      </note>
     </section>
 
     <section>
@@ -2412,7 +2425,7 @@ SecRule <emphasis>ENV:tag</emphasis> "suspicious"</programlisting>
 
       <para>Example:</para>
 
-      <programlisting format="linespecific">SecRule REMOTE_ADDR "<emphasis>@geoLookup</emphasis>" chain,drop,msg:'Non-UK IP address'
+      <programlisting format="linespecific">SecRule REMOTE_ADDR "<emphasis>@geoLookup</emphasis>" "chain,drop,msg:'Non-UK IP address'"
 SecRule GEO:COUNTRY_CODE "!@streq UK"</programlisting>
     </section>
 
@@ -3913,27 +3926,42 @@ SecRule IP:AUTH_ATTEMPT "@gt 25" \
       <title><literal>exec</literal></title>
 
       <para><emphasis>Description:</emphasis> Executes an external
-      script/binary supplied as parameter.</para>
+      script/binary supplied as parameter. As of v2.5, when the support for
+      Lua scripting is enabled, and the parameter supplied to
+      <literal>exec</literal> is a Lua script (detected by the
+      <filename>.lua</filename> extension) the script will be processed
+      <emphasis>internally</emphasis>. This means you will get direct access
+      to the internal request context from the script. Please read the
+      <literal>SecRuleScript</literal> documentation for more details on how
+      to write Lua scripts.</para>
 
       <para><emphasis>Action Group:</emphasis> Non-Disruptive</para>
 
       <para>Example:</para>
 
-      <programlisting format="linespecific">SecRule REQUEST_URI "^/cgi-bin/script\.pl" \
-    "log,<emphasis>exec:/usr/local/apache/bin/test.sh</emphasis>,phase:1"</programlisting>
+      <programlisting format="linespecific"># The following is going to execute /usr/local/apache/bin/test.sh
+# as a shell script on rule match.
+SecRule REQUEST_URI "^/cgi-bin/script\.pl" \
+    "log,<emphasis>exec:/usr/local/apache/bin/test.sh</emphasis>"
 
-      <para><emphasis>Note</emphasis></para>
+# The following is going to process /usr/local/apache/conf/exec.lua
+# internally as a Lua script on rule match, provided ModSecurity was
+# compiled with Lua support enabled.
+SecRule ARGS:p attack log,<emphasis>exec:/usr/local/apache/conf/exec.lua</emphasis></programlisting>
 
-      <para>This directive does not effect a primary action if it exists. This
-      action will always call script with no parameters, but providing all
-      information in the environment. All the usual CGI environment variables
-      will be there. You can have one binary executed per filter match.
-      Execution will add the header mod_security-executed to the list of
-      request headers. You should be aware that forking a threaded process
-      results in all threads being replicated in the new process. Forking can
-      therefore incur larger overhead in multithreaded operation. The script
-      you execute must write something (anything) to stdout. If it doesn't
-      ModSecurity will assume execution didn't work.</para>
+      <note>
+        <para>This directive does not effect a primary action if it exists.
+        This action will always call script with no parameters, but providing
+        all information in the environment. All the usual CGI environment
+        variables will be there. You can have one binary executed per filter
+        match. Execution will add the header mod_security-executed to the list
+        of request headers. You should be aware that forking a threaded
+        process results in all threads being replicated in the new process.
+        Forking can therefore incur larger overhead in multithreaded
+        operation. The script you execute must write something (anything) to
+        stdout. If it doesn't ModSecurity will assume execution didn't
+        work.</para>
+      </note>
     </section>
 
     <section>
@@ -4847,11 +4875,37 @@ SecRule ARGS:route "!<emphasis>@endsWith %{REQUEST_ADDR}</emphasis>" t:none,deny
 
       <para><emphasis>Description:</emphasis> Executes the external
       script/binary given as parameter to the operator against every file
-      extracted from the request.</para>
+      extracted from the request. As of v2.5, if the supplied filename is not
+      absolute it is treated as relative to the directory in which the
+      configuration file resides. Also as of v2.5 if the filename is
+      determined to be a Lua script (based on its extension) and the Lua
+      support is compiled in, the script will be processed by the internal
+      engine. As such it will have full access to the ModSecurity
+      context.</para>
 
-      <para>Example:</para>
+      <para>Example of using an external binary/script:</para>
 
-      <programlisting format="linespecific">SecRule FILES_TMPNAMES "<emphasis>@inspectFile</emphasis> /opt/apache/bin/inspect_script.pl"</programlisting>
+      <programlisting format="linespecific"># Execute external script to validate uploaded files.
+SecRule FILES_TMPNAMES "<emphasis>@inspectFile</emphasis> /opt/apache/bin/inspect_script.pl"</programlisting>
+
+      <para>Example of using Lua script:</para>
+
+      <programlisting>SecRule FILES_TMPNANMES "@inspectFile <emphasis>inspect.lua</emphasis>"</programlisting>
+
+      <para>Script <filename>inspect.lua</filename>:</para>
+
+      <programlisting>function main(filename)
+    -- Do something to the file to verify it. In this example, we
+    -- read up to 10 characters from the beginning of the file.
+    local f = io.open(filename, "rb");
+    local d = f:read(10);
+    f:close();
+   
+    -- Return null if there is no reason to believe there is ansything
+    -- wrong with the file (no match). Returning any text will be taken
+    -- to mean a match should be trigerred.
+    return null;
+end</programlisting>
     </section>
 
     <section>
@@ -5269,4 +5323,4 @@ SecRule REQUEST_METHOD "!<emphasis>@within %{tx.allowed_methods}</emphasis>" t:l
       </section>
     </section>
   </section>
-</article>
+</article>