From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Jozef Lawrynowicz <jozef.l@mittosystems.com>

Date: Mon, 6 Dec 2021 12:56:59 -0500

Subject: gdb-rhbz2018504-do-not-update-elf-headers.patch

;; Backport gdb/20948 (--write option to GDB causes segfault)

;; (Jozef Lawrynowicz, RHBZ 2018504)

Fix PR gdb/20948: --write option to GDB causes segmentation fault

When opening a BFD for update, as gdb --write does, modifications to

anything but the contents of sections is restricted.

Do not try to write back any ELF headers in this case.

diff --git a/bfd/elf.c b/bfd/elf.c

--- a/bfd/elf.c

+++ b/bfd/elf.c

@@ -6418,6 +6418,18 @@ _bfd_elf_write_object_contents (bfd *abfd)

   if (! abfd->output_has_begun

       && ! _bfd_elf_compute_section_file_positions (abfd, NULL))

     return FALSE;

+  /* Do not rewrite ELF data when the BFD has been opened for update.

+     abfd->output_has_begun was set to TRUE on opening, so creation of new

+     sections, and modification of existing section sizes was restricted.

+     This means the ELF header, program headers and section headers can't have

+     changed.

+     If the contents of any sections has been modified, then those changes have

+     already been written to the BFD.  */

+  else if (abfd->direction == both_direction)

+    {

+      BFD_ASSERT (abfd->output_has_begun);

+      return TRUE;

+    }

   i_shdrp = elf_elfsections (abfd);

diff --git a/gdb/testsuite/gdb.base/write_mem.c b/gdb/testsuite/gdb.base/write_mem.c

new file mode 100644

--- /dev/null

+++ b/gdb/testsuite/gdb.base/write_mem.c

@@ -0,0 +1,20 @@

+/* Copyright (C) 2018 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/>.  */

+

+int main (void)

+{

+  while (1);

+  return 0;

+}

diff --git a/gdb/testsuite/gdb.base/write_mem.exp b/gdb/testsuite/gdb.base/write_mem.exp

new file mode 100644

--- /dev/null

+++ b/gdb/testsuite/gdb.base/write_mem.exp

@@ -0,0 +1,47 @@

+# Copyright (C) 2018 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/>.

+

+# Contributed by Jozef Lawrynowicz (jozef.l@mittosystems.com)

+

+# Test for PR gdb/20948

+# Verify that invoking gdb with the --write argument works as expected

+

+global GDBFLAGS

+standard_testfile

+

+if {[build_executable $testfile.exp $testfile \

+	$srcfile [list debug nowarnings] ] == -1} {

+    untested $testfile.exp

+    return -1

+}

+

+set old_gdbflags $GDBFLAGS

+

+# Expect a failure before --write has been added to the command line

+set GDBFLAGS "$old_gdbflags $binfile"

+clean_restart

+test_print_reject "set {int}main = 0x4242" "Cannot access memory at address"

+

+# Setting memory should now work correctly after adding --write

+set GDBFLAGS "$old_gdbflags --write $binfile"

+clean_restart

+gdb_test_no_output "set {int}main = 0x4242"

+

+# Check that memory write persists after quitting GDB

+gdb_exit

+gdb_start

+gdb_test "x /xh main" "<main>:.*4242"

+

+set GDBFLAGS $old_gdbflags