From 7de4fc78131a5aeeb619e0559a57582105ac278b Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@rspamd.com>
Date: Thu, 25 Sep 2025 10:40:22 +0100
Subject: [PATCH] [Fix] Fix XML prolog detection in lua_magic

---
 lualib/lua_magic/patterns.lua | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/lualib/lua_magic/patterns.lua b/lualib/lua_magic/patterns.lua
index b51deab7f6..df524f177c 100644
--- a/lualib/lua_magic/patterns.lua
+++ b/lualib/lua_magic/patterns.lua
@@ -448,14 +448,24 @@ local patterns = {
       {
         -- Case-insensitive <svg ...> in the first chunk
         string = [[(?i)<svg\b]],
-        position = { '>=', 0 },
+        position = { '<=', 4096 },
+        weight = 40,
+      },
+      {
+        -- Case-insensitive <!DOCTYPE svg ...> within the first 4KiB
+        string = [[(?i)<!doctype\s+svg]],
+        position = { '<=', 4096 },
         weight = 40,
       },
+    }
+  },
+  xml = {
+    matches = {
       {
-        -- XML prolog hints
-        string = [[<\?xml\b]],
+        -- XML prolog
+        string = [[<\?xml\b.+\?>]],
         position = { '>=', 0 },
-        weight = 20,
+        weight = 30,
       },
     }
   },
-- 
2.47.3