PR 11786

* solib-svr4.c (svr4_exec_displacement): Ignore filesz, memsz, flags and align fields for PT_GNU_RELRO segments. testsuite/ * gdb.base/gcore-relro-pie.c: New file. * gdb.base/gcore-relro-pie.exp: New file.
13 years ago · 204b53315d
5 changed files with 172 additions and 0 deletions
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@ -1,3 +1,9 @@
+2013-11-07  Doug Evans  <dje@google.com>
+
+	PR 11786
+	*  solib-svr4.c (svr4_exec_displacement): Ignore filesz, memsz, flags
+	and align fields for PT_GNU_RELRO segments.
+
 2013-11-07  Phil Muldoon  <pmuldoon@redhat.com>

        PR python/15747
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@ -2604,6 +2604,28 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
 		  if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
 		    continue;

+		  /* Strip modifies the flags and alignment of PT_GNU_RELRO.
+		     CentOS-5 has problems with filesz, memsz as well.
+		     See PR 11786.  */
+		  if (phdr2[i].p_type == PT_GNU_RELRO)
+		    {
+		      Elf32_External_Phdr tmp_phdr = *phdrp;
+		      Elf32_External_Phdr tmp_phdr2 = *phdr2p;
+
+		      memset (tmp_phdr.p_filesz, 0, 4);
+		      memset (tmp_phdr.p_memsz, 0, 4);
+		      memset (tmp_phdr.p_flags, 0, 4);
+		      memset (tmp_phdr.p_align, 0, 4);
+		      memset (tmp_phdr2.p_filesz, 0, 4);
+		      memset (tmp_phdr2.p_memsz, 0, 4);
+		      memset (tmp_phdr2.p_flags, 0, 4);
+		      memset (tmp_phdr2.p_align, 0, 4);
+
+		      if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
+			  == 0)
+			continue;
+		    }
+
 		  /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS.  */
 		  plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
 		  if (plt2_asect)
@ -2713,6 +2735,28 @@ svr4_exec_displacement (CORE_ADDR *displacementp)
 		  if (memcmp (phdrp, phdr2p, sizeof (*phdrp)) == 0)
 		    continue;

+		  /* Strip modifies the flags and alignment of PT_GNU_RELRO.
+		     CentOS-5 has problems with filesz, memsz as well.
+		     See PR 11786.  */
+		  if (phdr2[i].p_type == PT_GNU_RELRO)
+		    {
+		      Elf64_External_Phdr tmp_phdr = *phdrp;
+		      Elf64_External_Phdr tmp_phdr2 = *phdr2p;
+
+		      memset (tmp_phdr.p_filesz, 0, 8);
+		      memset (tmp_phdr.p_memsz, 0, 8);
+		      memset (tmp_phdr.p_flags, 0, 4);
+		      memset (tmp_phdr.p_align, 0, 8);
+		      memset (tmp_phdr2.p_filesz, 0, 8);
+		      memset (tmp_phdr2.p_memsz, 0, 8);
+		      memset (tmp_phdr2.p_flags, 0, 4);
+		      memset (tmp_phdr2.p_align, 0, 8);
+
+		      if (memcmp (&tmp_phdr, &tmp_phdr2, sizeof (tmp_phdr))
+			  == 0)
+			continue;
+		    }
+
 		  /* prelink can convert .plt SHT_NOBITS to SHT_PROGBITS.  */
 		  plt2_asect = bfd_get_section_by_name (exec_bfd, ".plt");
 		  if (plt2_asect)
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@ -1,3 +1,9 @@
+2013-11-07  Doug Evans  <dje@google.com>
+
+	PR 11786
+	* gdb.base/gcore-relro-pie.c: New file.
+	* gdb.base/gcore-relro-pie.exp: New file.
+
 2013-11-07  Phil Muldoon  <pmuldoon@redhat.com>

        * gdb.python/py-cmd.exp: Add COMPLETE_EXPRESSION tests.
--- a/gdb/testsuite/gdb.base/gcore-relro-pie.c
+++ b/gdb/testsuite/gdb.base/gcore-relro-pie.c
@ -0,0 +1,41 @@
+/* Copyright 2013 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+void
+break_here (void)
+{
+  *(int *) 0 = 0;
+}
+
+void
+foo (void)
+{
+  break_here ();
+}
+
+void
+bar (void)
+{
+  foo ();
+}
+
+int
+main (void)
+{
+  bar ();
+  return 0;
+}
--- a/gdb/testsuite/gdb.base/gcore-relro-pie.exp
+++ b/gdb/testsuite/gdb.base/gcore-relro-pie.exp
@ -0,0 +1,75 @@
+# Copyright 2013 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# PR 11786 (Gold and strip differ on flags,align fields of PT_GNU_RELRO).
+# Generate a core file from the stripped version of the program,
+# and then try to debug the core with the unstripped version.
+
+standard_testfile
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug additional_flags=-fpie "ldflags=-pie -Wl,-z,relro"}]} {
+    return -1
+}
+
+set stripped_binfile ${binfile}.stripped
+set gcorefile ${binfile}.gcore
+
+set strip_program [transform strip]
+remote_file host delete ${stripped_binfile}
+if [run_on_host "strip" "$strip_program" "-g -o ${stripped_binfile} $binfile"] {
+    return -1
+}
+
+# Workaround PR binutils/10802:
+# Preserve the 'x' bit also for PIEs (Position Independent Executables).
+set perm [file attributes ${binfile} -permissions]
+file attributes ${stripped_binfile} -permissions $perm
+
+clean_restart ${stripped_binfile}
+
+# Does this gdb support gcore?
+set test "help gcore"
+gdb_test_multiple $test $test {
+    -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {
+	# gcore command not supported -- nothing to test here.
+	unsupported "gdb does not support gcore on this target"
+	return -1
+    }
+    -re "Save a core file .*\r\n$gdb_prompt $" {
+	pass $test
+    }
+}
+
+# The binary is stripped of debug info, but not minsyms.
+if ![runto break_here] {
+    fail "Can't run to break_here"
+    return -1
+}
+
+if {![gdb_gcore_cmd $gcorefile "save a corefile"]} {
+    return -1
+}
+
+# Now restart gdb with the unstripped binary and load the corefile.
+
+clean_restart ${binfile}
+
+gdb_test "core ${gcorefile}" \
+    "Core was generated by .*" "re-load generated corefile"
+
+# Put $pc in gdb.log for debug purposes for comparison with stripped case.
+gdb_test "x/i \$pc" "break_here.*"
+
+gdb_test "frame" "#0 \[^\r\n\]* break_here .*" "unstripped + core ok"