[PATCH] D40359: [ELF] Give error message when relro sections are not contiguous.

[Peter Smith via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL318920: [ELF] Give error message when relro sections are not contiguous. (authored by psmith).

Changed prior to commit:
  https://reviews.llvm.org/D40359?vs=123946&id=124077#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D40359

Files:
  lld/trunk/ELF/Writer.cpp
  lld/trunk/test/ELF/relro-non-contiguous.s


Index: lld/trunk/test/ELF/relro-non-contiguous.s
===================================================================
--- lld/trunk/test/ELF/relro-non-contiguous.s
+++ lld/trunk/test/ELF/relro-non-contiguous.s
@@ -0,0 +1,28 @@
+// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/shared.s -o %t.o
+// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/copy-in-shared.s -o %t2.o
+// RUN: ld.lld -shared %t.o %t2.o -o %t.so
+
+// Place the .got.plt (non relro) immediately after .dynamic. This is the
+// reverse order of the non-linker script case. The linker created .bss.rel.ro
+// section will be placed after .got.plt causing the relro to be non-contiguous.
+// RUN: echo "SECTIONS { \
+// RUN: .dynamic : { *(.dynamic) } \
+// RUN: .got.plt : { *(.got.plt) } \
+// RUN: } " > %t.script
+// RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t3.o
+
+// Expect error for non-contiguous relro
+// RUN: not ld.lld %t3.o %t.so -z relro -o %t --script=%t.script 2>&1 | FileCheck %s
+// No error when we do not request relro.
+// RUN: ld.lld %t3.o %t.so -z norelro -o %t --script=%t.script
+// REQUIRES: x86
+
+// CHECK: error: section: .bss.rel.ro is not contiguous with other relro sections
+        .section .text, "ax", @progbits
+        .global _start
+        .global bar
+        .global foo
+_start:
+        .quad bar
+        .quad foo
+
Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -1511,10 +1511,26 @@
 
   // PT_GNU_RELRO includes all sections that should be marked as
   // read-only by dynamic linker after proccessing relocations.
+  // Current dynamic loaders only support one PT_GNU_RELRO PHDR, give
+  // an error message if more than one PT_GNU_RELRO PHDR is required.
   PhdrEntry *RelRo = make<PhdrEntry>(PT_GNU_RELRO, PF_R);
-  for (OutputSection *Sec : OutputSections)
-    if (needsPtLoad(Sec) && isRelroSection(Sec))
-      RelRo->add(Sec);
+  bool InRelroPhdr = false;
+  bool IsRelroFinished = false;
+  for (OutputSection *Sec : OutputSections) {
+    if (!needsPtLoad(Sec))
+      continue;
+    if (isRelroSection(Sec)) {
+      InRelroPhdr = true;
+      if (!IsRelroFinished)
+        RelRo->add(Sec);
+      else
+        error("section: " + Sec->Name + " is not contiguous with other relro" +
+              " sections");
+    } else if (InRelroPhdr) {
+      InRelroPhdr = false;
+      IsRelroFinished = true;
+    }
+  }
   if (RelRo->FirstSec)
     Ret.push_back(RelRo);
 


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