ld of binutils-2.21.1 and 2.21.1a has a bug when compiling (some) pie
code, see
https://bugs.launchpad.net/ubuntu/+source/binutils/+bug/663294
This is fixed in 2.22.
I updated the binutils patch and crosschecked my doing with
63_all_binutils-2.22-pt-pax-flags-20111121.patch of gentoo.
Using this patch with binutils-2.22 makes it possible to compile firefox
with pie enabled, which resulted in a not starting firefox when using
2.21.1*
diff -Naur binutils-2.22-orig/bfd/elf-bfd.h binutils-2.22-my/bfd/elf-bfd.h
--- binutils-2.22-orig/bfd/elf-bfd.h 2011-08-17 02:39:38.000000000 +0200
+++ binutils-2.22-my/bfd/elf-bfd.h 2012-02-08 11:45:03.132972358 +0100
@@ -1600,6 +1600,9 @@
/* Segment flags for the PT_GNU_STACK segment. */
unsigned int stack_flags;
+ /* Segment flags for the PT_PAX_FLAGS segment. */
+ unsigned int pax_flags;
+
/* Symbol version definitions in external objects. */
Elf_Internal_Verdef *verdef;
diff -Naur binutils-2.22-orig/bfd/elf.c binutils-2.22-my/bfd/elf.c
--- binutils-2.22-orig/bfd/elf.c 2011-07-03 15:37:06.000000000 +0200
+++ binutils-2.22-my/bfd/elf.c 2012-02-08 11:45:03.132972358 +0100
@@ -1158,6 +1158,7 @@
case PT_GNU_EH_FRAME: pt = "EH_FRAME"; break;
case PT_GNU_STACK: pt = "STACK"; break;
case PT_GNU_RELRO: pt = "RELRO"; break;
+ case PT_PAX_FLAGS: pt = "PAX_FLAGS"; break;
default: pt = NULL; break;
}
return pt;
@@ -2484,6 +2485,9 @@
case PT_GNU_RELRO:
return _bfd_elf_make_section_from_phdr (abfd, hdr, hdr_index, "relro");
+ case PT_PAX_FLAGS:
+ return _bfd_elf_make_section_from_phdr (abfd, hdr, hdr_index,
"pax_flags");
+
default:
/* Check for any processor-specific program segment types. */
bed = get_elf_backend_data (abfd);
@@ -3558,6 +3562,11 @@
++segs;
}
+ {
+ /* We need a PT_PAX_FLAGS segment. */
+ ++segs;
+ }
+
for (s = abfd->sections; s != NULL; s = s->next)
{
if ((s->flags & SEC_LOAD) != 0
@@ -4160,6 +4169,20 @@
}
}
+ {
+ amt = sizeof (struct elf_segment_map);
+ m = bfd_zalloc (abfd, amt);
+ if (m == NULL)
+ goto error_return;
+ m->next = NULL;
+ m->p_type = PT_PAX_FLAGS;
+ m->p_flags = elf_tdata (abfd)->pax_flags;
+ m->p_flags_valid = 1;
+
+ *pm = m;
+ pm = &m->next;
+ }
+
free (sections);
elf_tdata (abfd)->segment_map = mfirst;
}
@@ -5434,7 +5457,8 @@
6. PT_TLS segment includes only SHF_TLS sections.
7. SHF_TLS sections are only in PT_TLS or PT_LOAD segments.
8. PT_DYNAMIC should not contain empty sections at the beginning
- (with the possible exception of .dynamic). */
+ (with the possible exception of .dynamic).
+ 9. PT_PAX_FLAGS segments do not include any sections. */
#define IS_SECTION_IN_INPUT_SEGMENT(section, segment, bed) \
((((segment->p_paddr \
? IS_CONTAINED_BY_LMA (section, segment, segment->p_paddr) \
@@ -5442,6 +5466,7 @@
&& (section->flags & SEC_ALLOC) != 0) \
|| IS_NOTE (segment, section)) \
&& segment->p_type != PT_GNU_STACK \
+ && segment->p_type != PT_PAX_FLAGS \
&& (segment->p_type != PT_TLS \
|| (section->flags & SEC_THREAD_LOCAL)) \
&& (segment->p_type == PT_LOAD \
diff -Naur binutils-2.22-orig/bfd/elflink.c binutils-2.22-my/bfd/elflink.c
--- binutils-2.22-orig/bfd/elflink.c 2011-11-21 10:29:26.000000000 +0100
+++ binutils-2.22-my/bfd/elflink.c 2012-02-08 11:45:03.136974359 +0100
@@ -5531,16 +5531,30 @@
return TRUE;
bed = get_elf_backend_data (output_bfd);
+
+ elf_tdata (output_bfd)->pax_flags = PF_NORANDEXEC;
+ if (info->execheap)
+ elf_tdata (output_bfd)->pax_flags |= PF_NOMPROTECT;
+ else if (info->noexecheap)
+ elf_tdata (output_bfd)->pax_flags |= PF_MPROTECT;
+
if (info->execstack)
- elf_tdata (output_bfd)->stack_flags = PF_R | PF_W | PF_X;
+ {
+ elf_tdata (output_bfd)->stack_flags = PF_R | PF_W | PF_X;
+ elf_tdata (output_bfd)->pax_flags |= PF_EMUTRAMP;
+ }
else if (info->noexecstack)
- elf_tdata (output_bfd)->stack_flags = PF_R | PF_W;
+ {
+ elf_tdata (output_bfd)->stack_flags = PF_R | PF_W;
+ elf_tdata (output_bfd)->pax_flags |= PF_NOEMUTRAMP;
+ }
else
{
bfd *inputobj;
asection *notesec = NULL;
int exec = 0;
+ elf_tdata (output_bfd)->pax_flags |= PF_NOEMUTRAMP;
for (inputobj = info->input_bfds;
inputobj;
inputobj = inputobj->link_next)
@@ -5554,7 +5568,11 @@
if (s)
{
if (s->flags & SEC_CODE)
- exec = PF_X;
+ {
+ elf_tdata (output_bfd)->pax_flags &= ~PF_NOEMUTRAMP;
+ elf_tdata (output_bfd)->pax_flags |= PF_EMUTRAMP;
+ exec = PF_X;
+ }
notesec = s;
}
else if (bed->default_execstack)
diff -Naur binutils-2.22-orig/binutils/readelf.c
binutils-2.22-my/binutils/readelf.c
--- binutils-2.22-orig/binutils/readelf.c 2011-09-21 22:49:13.000000000
+0200
+++ binutils-2.22-my/binutils/readelf.c 2012-02-08 11:45:03.140976361 +0100
@@ -2786,6 +2786,7 @@
return "GNU_EH_FRAME";
case PT_GNU_STACK: return "GNU_STACK";
case PT_GNU_RELRO: return "GNU_RELRO";
+ case PT_PAX_FLAGS: return "PAX_FLAGS";
default:
if ((p_type >= PT_LOPROC) && (p_type <= PT_HIPROC))
diff -Naur binutils-2.22-orig/include/bfdlink.h
binutils-2.22-my/include/bfdlink.h
--- binutils-2.22-orig/include/bfdlink.h 2011-11-21 10:29:37.000000000
+0100
+++ binutils-2.22-my/include/bfdlink.h 2012-02-08 11:45:19.148976824 +0100
@@ -330,6 +330,14 @@
/* TRUE if PT_GNU_RELRO segment should be created. */
unsigned int relro: 1;
+ /* TRUE if PT_PAX_FLAGS segment should be created with PF_NOMPROTECT
+ flags. */
+ unsigned int execheap: 1;
+
+ /* TRUE if PT_PAX_FLAGS segment should be created with PF_MPROTECT
+ flags. */
+ unsigned int noexecheap: 1;
+
/* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
should be created. */
unsigned int eh_frame_hdr: 1;
diff -Naur binutils-2.22-orig/include/elf/common.h
binutils-2.22-my/include/elf/common.h
--- binutils-2.22-orig/include/elf/common.h 2011-07-22 22:22:36.000000000
+0200
+++ binutils-2.22-my/include/elf/common.h 2012-02-08 11:45:03.152982363
+0100
@@ -430,6 +430,7 @@
#define PT_SUNW_EH_FRAME PT_GNU_EH_FRAME /* Solaris uses the same value */
#define PT_GNU_STACK (PT_LOOS + 0x474e551) /* Stack flags */
#define PT_GNU_RELRO (PT_LOOS + 0x474e552) /* Read-only after relocation */
+#define PT_PAX_FLAGS (PT_LOOS + 0x5041580) /* PaX flags */
/* Program segment permissions, in program header p_flags field. */
@@ -440,6 +441,21 @@
#define PF_MASKOS 0x0FF00000 /* New value, Oct 4, 1999 Draft */
#define PF_MASKPROC 0xF0000000 /* Processor-specific reserved bits */
+/* Flags to control PaX behavior. */
+
+#define PF_PAGEEXEC (1 << 4) /* Enable PAGEEXEC */
+#define PF_NOPAGEEXEC (1 << 5) /* Disable PAGEEXEC */
+#define PF_SEGMEXEC (1 << 6) /* Enable SEGMEXEC */
+#define PF_NOSEGMEXEC (1 << 7) /* Disable SEGMEXEC */
+#define PF_MPROTECT (1 << 8) /* Enable MPROTECT */
+#define PF_NOMPROTECT (1 << 9) /* Disable MPROTECT */
+#define PF_RANDEXEC (1 << 10) /* Enable RANDEXEC */
+#define PF_NORANDEXEC (1 << 11) /* Disable RANDEXEC */
+#define PF_EMUTRAMP (1 << 12) /* Enable EMUTRAMP */
+#define PF_NOEMUTRAMP (1 << 13) /* Disable EMUTRAMP */
+#define PF_RANDMMAP (1 << 14) /* Enable RANDMMAP */
+#define PF_NORANDMMAP (1 << 15) /* Disable RANDMMAP */
+
/* Values for section header, sh_type field. */
#define SHT_NULL 0 /* Section header table entry unused */
diff -Naur binutils-2.22-orig/ld/emultempl/elf32.em
binutils-2.22-my/ld/emultempl/elf32.em
--- binutils-2.22-orig/ld/emultempl/elf32.em 2011-11-21 10:29:39.000000000
+0100
+++ binutils-2.22-my/ld/emultempl/elf32.em 2012-02-08 11:45:03.152982363
+0100
@@ -2285,6 +2285,16 @@
link_info.noexecstack = TRUE;
link_info.execstack = FALSE;
}
+ else if (strcmp (optarg, "execheap") == 0)
+ {
+ link_info.execheap = TRUE;
+ link_info.noexecheap = FALSE;
+ }
+ else if (strcmp (optarg, "noexecheap") == 0)
+ {
+ link_info.noexecheap = TRUE;
+ link_info.execheap = FALSE;
+ }
EOF
if test x"$GENERATE_SHLIB_SCRIPT" = xyes; then
fragment <<EOF
@@ -2402,6 +2412,8 @@
-z defs Report unresolved symbols in object files.\n"));
fprintf (file, _("\
-z execstack Mark executable as requiring executable
stack\n"));
+ fprintf (file, _("\
+ -z execheap Mark executable as requiring executable
heap\n"));
EOF
if test x"$GENERATE_SHLIB_SCRIPT" = xyes; then
@@ -2443,6 +2455,8 @@
fragment <<EOF
fprintf (file, _("\
-z noexecstack Mark executable as not requiring executable
stack\n"));
+ fprintf (file, _("\
+ -z noexecheap Mark executable as not requiring executable
heap\n"));
EOF
if test x"$GENERATE_SHLIB_SCRIPT" = xyes; then
fragment <<EOF
diff -Naur binutils-2.22-orig/ld/ldgram.y binutils-2.22-my/ld/ldgram.y
--- binutils-2.22-orig/ld/ldgram.y 2011-07-11 17:03:09.000000000 +0200
+++ binutils-2.22-my/ld/ldgram.y 2012-02-08 11:45:03.152982363 +0100
@@ -1215,6 +1215,8 @@
$$ = exp_intop (0x6474e550);
else if (strcmp (s, "PT_GNU_STACK") == 0)
$$ = exp_intop (0x6474e551);
+ else if (strcmp (s, "PT_PAX_FLAGS") == 0)
+ $$ = exp_intop (0x65041580);
else
{
einfo (_("\
--
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