fileext: make case insensitive

Change keyword to be case insensitive when matching.

Ticket #597.

src/detect-fileext.c

@@ -110,8 +110,9 @@ static int DetectFileextMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx,
 
     int offset = file->name_len - fileext->len;
 
+    /* fileext->ext is already in lowercase, as SCMemcmpLowercase requires */
     if (file->name[offset - 1] == '.' &&
-        SCMemcmp(file->name + offset, fileext->ext, fileext->len) == 0)
+        SCMemcmpLowercase(fileext->ext, file->name + offset, fileext->len) == 0)
     {
         if (!(fileext->flags & DETECT_CONTENT_NEGATED)) {
             ret = 1;
@@ -149,6 +150,9 @@ static DetectFileextData *DetectFileextParse (char *str)
     if (DetectContentDataParse("fileext", str, &fileext->ext, &fileext->len, &fileext->flags) == -1) {
         goto error;
     }
+    uint16_t u;
+    for (u = 0; u < fileext->len; u++)
+        fileext->ext[u] = tolower(fileext->ext[u]);
 
     SCLogDebug("flags %02X", fileext->flags);
     if (fileext->flags & DETECT_CONTENT_NEGATED) {