[PATCH] D25472: [ELF] - Implemented -z wxneeded.

[George Rimar via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL284226: [ELF] - Implemented -z wxneeded. (authored by grimar).

Changed prior to commit:
  https://reviews.llvm.org/D25472?vs=74358&id=74653#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D25472

Files:
  lld/trunk/ELF/Config.h
  lld/trunk/ELF/Driver.cpp
  lld/trunk/ELF/LinkerScript.cpp
  lld/trunk/ELF/Writer.cpp
  lld/trunk/test/ELF/linkerscript/openbsd-wxneeded.s
  lld/trunk/test/ELF/openbsd-wxneeded.s


Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -1109,6 +1109,13 @@
       Hdr.H.p_memsz = Config->ZStackSize;
   }
 
+  // PT_OPENBSD_WXNEEDED is a OpenBSD-specific header to mark the executable
+  // is expected to perform W^X violations, such as calling mprotect(2) or
+  // mmap(2) with PROT_WRITE | PROT_EXEC, which is prohibited by default on
+  // OpenBSD.
+  if (Config->ZWxneeded)
+    AddHdr(PT_OPENBSD_WXNEEDED, PF_X);
+
   if (Note.First)
     Ret.push_back(std::move(Note));
   return Ret;
Index: lld/trunk/ELF/LinkerScript.cpp
===================================================================
--- lld/trunk/ELF/LinkerScript.cpp
+++ lld/trunk/ELF/LinkerScript.cpp
@@ -1720,6 +1720,7 @@
                      .Case("PT_GNU_EH_FRAME", PT_GNU_EH_FRAME)
                      .Case("PT_GNU_STACK", PT_GNU_STACK)
                      .Case("PT_GNU_RELRO", PT_GNU_RELRO)
+                     .Case("PT_OPENBSD_WXNEEDED", PT_OPENBSD_WXNEEDED)
                      .Default(-1);
 
   if (Ret == (unsigned)-1) {
Index: lld/trunk/ELF/Config.h
===================================================================
--- lld/trunk/ELF/Config.h
+++ lld/trunk/ELF/Config.h
@@ -126,6 +126,7 @@
   bool ZNow;
   bool ZOrigin;
   bool ZRelro;
+  bool ZWxneeded;
   DiscardPolicy Discard;
   SortSectionPolicy SortSection;
   StripPolicy Strip = StripPolicy::None;
Index: lld/trunk/ELF/Driver.cpp
===================================================================
--- lld/trunk/ELF/Driver.cpp
+++ lld/trunk/ELF/Driver.cpp
@@ -494,6 +494,7 @@
   Config->ZNow = hasZOption(Args, "now");
   Config->ZOrigin = hasZOption(Args, "origin");
   Config->ZRelro = !hasZOption(Args, "norelro");
+  Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
   if (!Config->Relocatable)
     Config->Strip = getStripOption(Args);
Index: lld/trunk/test/ELF/openbsd-wxneeded.s
===================================================================
--- lld/trunk/test/ELF/openbsd-wxneeded.s
+++ lld/trunk/test/ELF/openbsd-wxneeded.s
@@ -0,0 +1,17 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
+# RUN: ld.lld -z wxneeded %t -o %t.out
+# RUN: llvm-readobj --program-headers %t.out | FileCheck %s
+
+# CHECK:      ProgramHeader {
+# CHECK:        Type:  (0x65A3DBE7)
+# CHECK-NEXT:   Offset: 0x0
+# CHECK-NEXT:   VirtualAddress: 0x0
+# CHECK-NEXT:   PhysicalAddress: 0x0
+# CHECK-NEXT:   FileSize: 0
+# CHECK-NEXT:   MemSize: 0
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:     PF_X
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Alignment: 0
+# CHECK-NEXT: }
Index: lld/trunk/test/ELF/linkerscript/openbsd-wxneeded.s
===================================================================
--- lld/trunk/test/ELF/linkerscript/openbsd-wxneeded.s
+++ lld/trunk/test/ELF/linkerscript/openbsd-wxneeded.s
@@ -0,0 +1,17 @@
+# RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %s -o %t.o
+# RUN: echo "PHDRS { text PT_LOAD FILEHDR PHDRS; wxneeded PT_OPENBSD_WXNEEDED; }" > %t.script
+# RUN: ld.lld -z wxneeded --script %t.script %t.o -o %t
+# RUN: llvm-readobj --program-headers %t | FileCheck %s
+
+# CHECK:      ProgramHeader {
+# CHECK:        Type:  (0x65A3DBE7)
+# CHECK-NEXT:   Offset: 0x0
+# CHECK-NEXT:   VirtualAddress: 0x0
+# CHECK-NEXT:   PhysicalAddress: 0x0
+# CHECK-NEXT:   FileSize: 0
+# CHECK-NEXT:   MemSize: 0
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:     PF_R
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Alignment: 0
+# CHECK-NEXT: }


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