From a5f5e7fc7378925b78e9d0dadb0e7f5415930dd4 Mon Sep 17 00:00:00 2001
From: John Reiser <jreiser@BitWagon.com>
Date: Fri, 24 Oct 2025 08:35:20 -0700
Subject: [PATCH] WinPE: Require --strip-relocs if relocating compressed data

Thanks to @bitraid for investigating and suggestions.
https://github.com/upx/upx/issues/880
	modified:   pefile.cpp
---
 src/pefile.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/pefile.cpp b/src/pefile.cpp
index ffd8ecda..ab974526 100644
--- a/src/pefile.cpp
+++ b/src/pefile.cpp
@@ -1502,8 +1502,12 @@ void PeFile::processTls2(Reloc *const rel, const Interval *const iv, unsigned ne
             kc += newaddr + sizeof(tls) - tlsp->datastart;
             *p = kc + imagebase;
             rel->add_reloc(kc, iv->ivarr[ic].len);
-        } else
-            rel->add_reloc(kc - imagebase, iv->ivarr[ic].len);
+        } else {
+            unsigned const a = kc - imagebase;
+            if (a < newaddr && !opt->win32_pe.strip_relocs)
+                throwCantPack("relocation too low (%#x < %#x); try --strip-relocs", a, newaddr);
+            rel->add_reloc(a, iv->ivarr[ic].len);
+        }
     }
 
     const unsigned tls_data_size = tlsp->dataend - tlsp->datastart;