From bf931df30385ee064a6d5cd98b2d4049e4b75efc Mon Sep 17 00:00:00 2001
From: Romain Thomas <me@romainthomas.fr>
Date: Sat, 14 Sep 2024 06:31:20 +0200
Subject: [PATCH] Fix error when rewriting an ELF with `DT_RELR` relocations

---
 doc/sphinx/changelog.rst           |  2 ++
 src/ELF/Binary.tcc                 | 17 -----------------
 tests/elf/test_relr_relocations.py |  8 ++++++++
 3 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/doc/sphinx/changelog.rst b/doc/sphinx/changelog.rst
index dc036a38a9..44dd417ba9 100644
--- a/doc/sphinx/changelog.rst
+++ b/doc/sphinx/changelog.rst
@@ -56,6 +56,8 @@ Changelog
 
 :ELF:
 
+  * Fix a critical error when rewriting ELF file with ``DT_RELR`` relocations.
+    This error leads to a crash of the modified binary.
   * Fix error while (re)generating ELF's RELR relocations (:issue:`1097`)
   * Add support for RISC-V architecture
   * Fix bug when trying to remove a dynamic symbol that is associated with
diff --git a/src/ELF/Binary.tcc b/src/ELF/Binary.tcc
index 81f7930939..bf31e38ee9 100644
--- a/src/ELF/Binary.tcc
+++ b/src/ELF/Binary.tcc
@@ -44,10 +44,6 @@ void Binary::patch_relocations<ARCH::ARM>(uint64_t from, uint64_t shift) {
       relocation.address(relocation.address() + shift);
     }
 
-    if (relocation.encoding() == Relocation::ENCODING::RELR) {
-      continue;
-    }
-
     const Relocation::TYPE type = relocation.type();
 
     switch (type) {
@@ -82,10 +78,6 @@ void Binary::patch_relocations<ARCH::AARCH64>(uint64_t from, uint64_t shift) {
       relocation.address(relocation.address() + shift);
     }
 
-    if (relocation.encoding() == Relocation::ENCODING::RELR) {
-      continue;
-    }
-
     const Relocation::TYPE type = relocation.type();
 
     switch (type) {
@@ -153,11 +145,6 @@ void Binary::patch_relocations<ARCH::I386>(uint64_t from, uint64_t shift) {
       //shift_code(relocation.address(), shift, relocation.size() / 8);
       relocation.address(relocation.address() + shift);
     }
-
-    if (relocation.encoding() == Relocation::ENCODING::RELR) {
-      continue;
-    }
-
     const Relocation::TYPE type = relocation.type();
 
     switch (type) {
@@ -196,10 +183,6 @@ void Binary::patch_relocations<ARCH::X86_64>(uint64_t from, uint64_t shift) {
       relocation.address(relocation.address() + shift);
     }
 
-    if (relocation.encoding() == Relocation::ENCODING::RELR) {
-      continue;
-    }
-
     const Relocation::TYPE type = relocation.type();
 
     switch (type) {
diff --git a/tests/elf/test_relr_relocations.py b/tests/elf/test_relr_relocations.py
index 5c7ebe2911..f423e6b041 100644
--- a/tests/elf/test_relr_relocations.py
+++ b/tests/elf/test_relr_relocations.py
@@ -41,3 +41,11 @@ def test_relr_relocations(tmp_path: Path):
         lib = ctypes.cdll.LoadLibrary(out.as_posix())
         assert lib.cos is not None
 
+def test_relr_addend(tmp_path: Path):
+    elf = lief.ELF.parse(get_sample("ELF/ls-glibc2.40-relr.elf"))
+    elf.relocate_phdr_table()
+    out = tmp_path / "out.elf"
+    elf.write(out.as_posix())
+
+    new_elf = lief.ELF.parse(out)
+    assert new_elf.get_int_from_virtual_address(0x21f40, 8) == 0xa680