[Valgrind-developers] valgrind: r13368: Pay attention to PT_GNU_STACK when deciding what permissions to

[<sv...@va...>]

tom	2013-04-17 11:08:04 +0100 (Wed, 17 Apr 2013)

  New Revision: 13368

  Log:
    Pay attention to PT_GNU_STACK when deciding what permissions to
    use for the client stack.

  Modified files:
    trunk/coregrind/m_initimg/initimg-linux.c
    trunk/coregrind/m_ume/elf.c
    trunk/coregrind/pub_core_ume.h


  Modified: trunk/coregrind/m_initimg/initimg-linux.c (+1 -1)
===================================================================
--- trunk/coregrind/m_initimg/initimg-linux.c	2013-04-11 18:55:39 +01:00 (rev 13367)
+++ trunk/coregrind/m_initimg/initimg-linux.c	2013-04-17 11:08:04 +01:00 (rev 13368)
@@ -557,7 +557,7 @@
         res = VG_(am_mmap_anon_fixed_client)(
                  anon_start -inner_HACK,
                  anon_size +inner_HACK,
-	         VKI_PROT_READ|VKI_PROT_WRITE|VKI_PROT_EXEC
+	         info->stack_prot
 	      );
      }
      if ((!ok) || sr_isError(res)) {

  Modified: trunk/coregrind/m_ume/elf.c (+7 -0)
===================================================================
--- trunk/coregrind/m_ume/elf.c	2013-04-11 18:55:39 +01:00 (rev 13367)
+++ trunk/coregrind/m_ume/elf.c	2013-04-17 11:08:04 +01:00 (rev 13368)
@@ -354,6 +354,7 @@
    info->phnum = e->e.e_phnum;
    info->entry = e->e.e_entry + ebase;
    info->phdr = 0;
+   info->stack_prot = VKI_PROT_READ|VKI_PROT_WRITE|VKI_PROT_EXEC;
 
    for (i = 0; i < e->e.e_phnum; i++) {
       ESZ(Phdr) *ph = &e->p[i];
@@ -416,6 +417,12 @@
          }
          break;
 
+      case PT_GNU_STACK:
+         if ((ph->p_flags & PF_X) == 0) info->stack_prot &= ~VKI_PROT_EXEC;
+         if ((ph->p_flags & PF_W) == 0) info->stack_prot &= ~VKI_PROT_WRITE;
+         if ((ph->p_flags & PF_R) == 0) info->stack_prot &= ~VKI_PROT_READ;
+         break;
+
       default:
          // do nothing
          break;

  Modified: trunk/coregrind/pub_core_ume.h (+1 -0)
===================================================================
--- trunk/coregrind/pub_core_ume.h	2013-04-11 18:55:39 +01:00 (rev 13367)
+++ trunk/coregrind/pub_core_ume.h	2013-04-17 11:08:04 +01:00 (rev 13368)
@@ -52,6 +52,7 @@
 #if !defined(VGO_darwin)
       Addr phdr;         // OUT: address phdr was mapped at
       Int  phnum;        // OUT: number of phdrs
+      UInt stack_prot;   // OUT: stack permissions
       Addr interp_base;  // OUT: where interpreter (ld.so) was mapped
 #else
       Addr  stack_start;      // OUT: address of start of stack segment (hot)