Re: PATCH: PR ld/14215: ld creates bad GNU_RELRO segment

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Sat, Jun 9, 2012 at 2:06 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Hi,
>
> We should check if .got.plt section exists before putting the first N
> bytes in PT_GNU_RELRO segment. ?OK to install?
>
> Thanks.
>
>
> H.J.
> --
> ld/
>
> 2012-06-09 ?H.J. Lu ?<hongjiu.lu@intel.com>
>
> ? ? ? ?PR ld/14215
> ? ? ? ?* ldexp.c (fold_binary): Check if .got.plt section exists
> ? ? ? ?before putting the first N bytes in PT_GNU_RELRO segment.
>

Here is the updated patch to check .got.plt section only if
expld.result.value isn't 0.   OK to install.


-- 
H.J.
---
ld/

2012-06-10  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/14215
	* ldexp.c (fold_binary): Check if .got.plt section exists
	before putting the first N bytes of .got.plt section in
	PT_GNU_RELRO segment.

ld/testsuite/

2012-06-10  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/14215
	* ld-i386/i386.exp: Run pr14215.
	* ld-x86-64/x86-64.exp: Likewise.

	* ld-i386/pr14215.d: New file.
	* ld-i386/pr14215.s: Likewise.
	* ld-x86-64/pr14215.d: Likewise.
	* ld-x86-64/pr14215.s: Likewise.

diff --git a/ld/ldexp.c b/ld/ldexp.c
index 3bddc81..c1ec92c 100644
--- a/ld/ldexp.c
+++ b/ld/ldexp.c
@@ -487,9 +487,23 @@ fold_binary (etree_type *tree)
 		   || expld.dataseg.phase == exp_dataseg_relro_adjust
 		   || expld.dataseg.phase == exp_dataseg_done)
 	    {
+	      bfd_vma value = expld.result.value;
+	      if (value != 0)
+		{
+		  /* Check if .got.plt section exists before putting the
+		     first VALUE bytes of .got.plt section in PT_GNU_RELRO
+		     segment.  */
+		  asection *gotplt;
+		  gotplt = bfd_get_section_by_name (link_info.output_bfd,
+						    ".got.plt");
+		  if (gotplt == NULL
+		      || (gotplt->rawsize == 0
+			  && (gotplt->flags & SEC_KEEP) == 0))
+		    value = 0;
+		}
 	      if (expld.dataseg.phase == exp_dataseg_align_seen
 		  || expld.dataseg.phase == exp_dataseg_relro_adjust)
-		expld.dataseg.relro_end = lhs.value + expld.result.value;
+		expld.dataseg.relro_end = lhs.value + value;

 	      if (expld.dataseg.phase == exp_dataseg_relro_adjust
 		  && (expld.dataseg.relro_end
@@ -497,8 +511,7 @@ fold_binary (etree_type *tree)
 		{
 		  expld.dataseg.relro_end += expld.dataseg.pagesize - 1;
 		  expld.dataseg.relro_end &= ~(expld.dataseg.pagesize - 1);
-		  expld.result.value = (expld.dataseg.relro_end
-					- expld.result.value);
+		  expld.result.value = expld.dataseg.relro_end - value;
 		}
 	      else
 		expld.result.value = lhs.value;
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 47f918f..03367ca 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -245,3 +245,4 @@ if { !([istarget "i?86-*-linux*"]
 run_dump_test "compressed1"
 run_dump_test "pr12627"
 run_dump_test "pr13302"
+run_dump_test "pr14215"
diff --git a/ld/testsuite/ld-i386/pr14215.d b/ld/testsuite/ld-i386/pr14215.d
new file mode 100644
index 0000000..78ec994
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr14215.d
@@ -0,0 +1,9 @@
+#name: PR ld/14215
+#as: --32
+#ld: -melf_i386 -shared -z relro
+#readelf: -l --wide
+
+#failif
+#...
+   03     .dynamic .got .data
+#...
diff --git a/ld/testsuite/ld-i386/pr14215.s b/ld/testsuite/ld-i386/pr14215.s
new file mode 100644
index 0000000..df0cbc2
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr14215.s
@@ -0,0 +1,4 @@
+	.section .got
+	.space 0x2a8, 4
+	.data
+	.zero 12
diff --git a/ld/testsuite/ld-x86-64/pr14215.d b/ld/testsuite/ld-x86-64/pr14215.d
new file mode 100644
index 0000000..7d8e90d
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr14215.d
@@ -0,0 +1,9 @@
+#name: PR ld/14215
+#as: --64
+#ld: -melf_x86_64 -shared -z relro
+#readelf: -l --wide
+
+#failif
+#...
+   03     .dynamic .got .data
+#...
diff --git a/ld/testsuite/ld-x86-64/pr14215.s b/ld/testsuite/ld-x86-64/pr14215.s
new file mode 100644
index 0000000..281b638
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr14215.s
@@ -0,0 +1,4 @@
+	.section .got
+	.space 0x2a8, 4
+	.data
+	.zero 24
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp
b/ld/testsuite/ld-x86-64/x86-64.exp
index 7d2934f..b9af8de 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -208,6 +208,7 @@ run_dump_test "pr12921"
 run_dump_test "pr13947"
 run_dump_test "pr12570a"
 run_dump_test "pr12570b"
+run_dump_test "pr14215"

 if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
     return