[PATCH] PR ld/17618: Check PC-relative offset overflow in PLT entry

H.J. Lu hongjiu.lu@intel.com
Tue Nov 18 19:11:00 GMT 2014


Hi,

I checked in this patch to check PC-relative offset overflow in pushq
instruction in x86-64 PLT entry.


H.J.
--
bfd/

	PR ld/17618
	* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Check
	PC-relative offset overflow in PLT entry.

ld/testsuite/

	PR ld/17618
	* ld-x86-64/x86-64.exp: Run pr17618 for Linux target.

	* ld-x86-64/pr17618.d: New file.
	* ld-x86-64/pr17618.s: Likewise.
---
 bfd/ChangeLog                     |  6 ++++++
 bfd/elf64-x86-64.c                | 27 +++++++++++++++++++--------
 ld/testsuite/ChangeLog            |  8 ++++++++
 ld/testsuite/ld-x86-64/pr17618.d  |  4 ++++
 ld/testsuite/ld-x86-64/pr17618.s  | 18 ++++++++++++++++++
 ld/testsuite/ld-x86-64/x86-64.exp |  7 +++++++
 6 files changed, 62 insertions(+), 8 deletions(-)
 create mode 100644 ld/testsuite/ld-x86-64/pr17618.d
 create mode 100644 ld/testsuite/ld-x86-64/pr17618.s

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f606e15..579cca2 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2014-11-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/17618
+	* elf64-x86-64.c (elf_x86_64_finish_dynamic_symbol): Check
+	PC-relative offset overflow in PLT entry.
+
 2014-11-18  Nick Clifton  <nickc@redhat.com>
 
 	PR binutils/17512
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 20f45a9..432ab58 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -4749,6 +4749,8 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
       bfd_byte *loc;
       asection *plt, *gotplt, *relplt, *resolved_plt;
       const struct elf_backend_data *bed;
+      bfd_boolean gotplt_after_plt;
+      int32_t plt_got_pcrel_offset;
 
       /* When building a static executable, use .iplt, .igot.plt and
 	 .rela.iplt sections for STT_GNU_IFUNC symbols.  */
@@ -4853,14 +4855,23 @@ elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
 
       /* Put offset the PC-relative instruction referring to the GOT entry,
 	 subtracting the size of that instruction.  */
-      bfd_put_32 (output_bfd,
-		  (gotplt->output_section->vma
-		   + gotplt->output_offset
-		   + got_offset
-		   - resolved_plt->output_section->vma
-		   - resolved_plt->output_offset
-		   - plt_offset
-		   - plt_got_insn_size),
+      plt_got_pcrel_offset = (gotplt->output_section->vma
+			      + gotplt->output_offset
+			      + got_offset
+			      - resolved_plt->output_section->vma
+			      - resolved_plt->output_offset
+			      - plt_offset
+			      - plt_got_insn_size);
+
+      /* Check PC-relative offset overflow in PLT entry.  */
+      gotplt_after_plt = (gotplt->output_section->vma
+			  > resolved_plt->output_section->vma);
+      if ((gotplt_after_plt && plt_got_pcrel_offset < 0)
+	  || (!gotplt_after_plt && plt_got_pcrel_offset > 0))
+	info->callbacks->einfo (_("%F%B: PC-relative offset overflow in PLT entry for `%s'\n"),
+				output_bfd, h->root.root.string);
+
+      bfd_put_32 (output_bfd, plt_got_pcrel_offset,
 		  resolved_plt->contents + plt_offset + plt_got_offset);
 
       /* Fill in the entry in the global offset table, initially this
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index a8aa37d..72b4bb9 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,5 +1,13 @@
 2014-11-18  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/17618
+	* ld-x86-64/x86-64.exp: Run pr17618 for Linux target.
+
+	* ld-x86-64/pr17618.d: New file.
+	* ld-x86-64/pr17618.s: Likewise.
+
+2014-11-18  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* ld-x86-64/mpx.exp: Always run mpx3 and mpx4 tests in 64-bit.
 
 2014-11-18  Igor Zamyatin  <igor.zamyatin@intel.com>
diff --git a/ld/testsuite/ld-x86-64/pr17618.d b/ld/testsuite/ld-x86-64/pr17618.d
new file mode 100644
index 0000000..e640b40
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr17618.d
@@ -0,0 +1,4 @@
+#name: PLT PC-relative offset overflow check
+#as: --64
+#ld: -shared -melf_x86_64
+#error: .*PC-relative offset overflow in PLT entry for `bar'
diff --git a/ld/testsuite/ld-x86-64/pr17618.s b/ld/testsuite/ld-x86-64/pr17618.s
new file mode 100644
index 0000000..39102e0
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pr17618.s
@@ -0,0 +1,18 @@
+	.text
+	.globl	foo
+	.type	foo, @function
+foo:
+	call bar@PLT
+	.size	foo, .-foo
+
+	.globl	gap
+	.type	gap, @function
+gap:
+	jmp .L0
+	.space 0x40000000, 0x90
+.L0:
+	jmp .L2
+	.space 0x3fdfff14, 0x90
+.L2:
+	.size	gap, .-gap
+	.section	.note.GNU-stack,"",@progbits
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index a9b68ff..7f09458 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -333,3 +333,10 @@ if { [isnative] && [which $CC] != 0 } {
 	{dummy.s} {{readelf {-s --wide} x86-64-x32.rd}} "x86-64-x32"}
     }
 }
+
+if { ![istarget "x86_64-*-linux*"]} {
+    return
+}
+
+# Linux only tests
+run_dump_test "pr17618"
-- 
1.9.3



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