gdb/SOURCES/gdb-rhbz2018504-do-not-update-elf-headers.patch
2022-03-29 11:08:56 +00:00

115 lines
4.0 KiB
Diff

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