bugfix: lua panic handling in ngx.socket.tcp

If luaL_pushresult() encounters a buffer larger than 2GB, it triggers a
Lua panic. This panic is handled by ngx_http_lua_atpanic(), which
performs a longjmp() back to the last setjmp() call point (e.g.,
ngx_http_lua_log_by_chunk()), potentially causing a SEGFAULT or ABORT
signal if stack protection is enabled.

The fix sets the handler that manages Lua panics directly within
ngx_http_lua_socket_push_input_data().

src/ngx_http_lua_socket_tcp.c

@@ -13,6 +13,7 @@
 #include "ngx_http_lua_socket_tcp.h"
 #include "ngx_http_lua_input_filters.h"
 #include "ngx_http_lua_util.h"
+#include "ngx_http_lua_exception.h"
 #include "ngx_http_lua_uthread.h"
 #include "ngx_http_lua_output.h"
 #include "ngx_http_lua_contentby.h"
@@ -5950,7 +5951,16 @@ ngx_http_lua_socket_push_input_data(ngx_http_request_t *r,
         nbufs++;
     }
 
-    luaL_pushresult(&luabuf);
+    /* set Lua VM panic handler */
+    lua_atpanic(L, ngx_http_lua_atpanic);
+
+    NGX_LUA_EXCEPTION_TRY {
+
+        luaL_pushresult(&luabuf);
+
+    } NGX_LUA_EXCEPTION_CATCH {
+        dd("nginx execution restored");
+    }
 
 #if (DDEBUG)
     dd("size: %d, nbufs: %d", (int) size, (int) nbufs);