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Andrew Burgess 44e4c7757a gdb: Handle malformed ELF, symbols in non-allocatable sections
I ended up debugging a malformed ELF where a section containing
executable code was not correctly marked as allocatable.  Before
realising the ELF was corrupted I tried to place a breakpoint on a
symbol in the non-allocatable, executable section, and GDB crashed.

Though trying to debug such an ELF clearly isn't going to go well I
would prefer, as far as possible, that any input, no matter how
corrupted, not crash GDB.

The crash occurs when trying to set a breakpoint on the name of a
function from the corrupted section.  GDB converts the symbol to a
symtab_and_line, and looks up a suitable section for this.

The problem is that the section is actually an obj_section, which is
stored in the table within the objfile, and we only initialise this
table for allocatable sections (see add_to_objfile_sections_full in
objfiles.c).  So, if the symbol is in a non-allocatable section then
we end up referencing an uninitialised obj_section.

Later we call get_sal_arch on the symtab_and_line, which calls
get_objfile_arch, which uses the objfile from the uninitialised
obj_section, which will be nullptr, at which point GDB crashes.

The fix I propose here is that when we setup the section references on
msymbols, we should check if the bfd_section being referenced is
allocatable or not.  If it is not then we should set the section
reference back to the default 0 section (see how MSYMBOL_OBJ_SECTION
and SYMBOL_OBJ_SECTION treat the 0 section index).

With this fix in place GDB no longer crashes.  Instead GDB creates the
breakpoint at the non-allocated address, and then fails, with an
error, when it tries to insert the breakpoint.

gdb/ChangeLog:

	* elfread.c (record_minimal_symbol): Set section index to 0 for
	non-allocatable sections.

gdb/testsuite/ChangeLog:

	* gdb.dwarf2/dw2-bad-elf-other.S: New file.
	* gdb.dwarf2/dw2-bad-elf.c: New file.
	* gdb.dwarf2/dw2-bad-elf.exp: New file.

Change-Id: Ie05436ab4c6a71440304d20ee639dfb021223f8b
2020-01-13 23:57:42 +00:00
bfd ubsan: alpha-vma: timeout 2020-01-13 12:12:05 +10:30
binutils Moev declaration of loop variable outside of the loop. 2020-01-13 17:28:41 +00:00
config Add support for debuginfod to the binutils (disable by default, enabled via a configure time option). 2020-01-09 13:19:20 +00:00
contrib contrib: Update dg-extract-results.* from gcc 2019-10-21 15:26:48 +01:00
cpu ubsan: fr30: left shift of negative value 2020-01-13 12:12:05 +10:30
elfcpp Re: Update year range in copyright notice of binutils files 2020-01-01 18:55:18 +10:30
etc Update year range in copyright notice of binutils files 2019-01-01 22:06:53 +10:30
gas [gas][aarch64] Turn on SVE when using f32mm or f64mm extensions 2020-01-13 15:31:39 +00:00
gdb gdb: Handle malformed ELF, symbols in non-allocatable sections 2020-01-13 23:57:42 +00:00
gnulib Update copyright year range in all GDB files. 2020-01-01 10:20:53 +04:00
gold Re: Update year range in copyright notice of binutils files 2020-01-01 18:55:18 +10:30
gprof Add support for the GBZ80, Z180, and eZ80 variants of the Z80 architecure. Add an ELF based target for these as well. 2020-01-02 14:14:59 +00:00
include [ARC][committed] Update ARC cpu list 2020-01-13 11:16:47 +02:00
intl Change version to 2.32.51 and regenerate configure and pot files. 2019-01-19 16:51:42 +00:00
ld Regen ld BLD-POTFILES.in 2020-01-13 22:45:36 +10:30
libctf Fix libctf ChangeLog date in most recent entry. 2020-01-05 09:53:14 +04:00
libdecnumber Merge config/ changes from GCC. 2018-10-31 17:16:41 +00:00
libiberty Synchronize libiberty sources with gcc mainline. 2019-08-09 16:16:18 +01:00
opcodes Add an option to objdump's disassembler to generate ascii art diagrams showing the destinations of flow control instructions. 2020-01-13 12:36:55 +00:00
readline Fix compilation of Readline on mingw.org's MinGW 2019-12-23 16:28:32 +02:00
sim Update copyright year range in all GDB files. 2020-01-01 10:20:53 +04:00
texinfo
zlib Merge config/ changes from GCC. 2018-10-31 17:16:41 +00:00
.cvsignore
.gitattributes
.gitignore Add profiling outputs to .gitignore 2019-12-26 06:54:58 +01:00
ar-lib Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ChangeLog oops - toplevel changelog entry for previous delta. 2020-01-09 13:37:26 +00:00
compile Update from upstream Automake 2014-11-16 13:43:48 +01:00
config-ml.in Update top level configure files by synchronizing them with gcc. 2018-01-10 15:29:21 +00:00
config.guess config.guess,config.sub: synchronize with config project master sources 2019-05-23 18:19:56 +02:00
config.rpath
config.sub config.guess,config.sub: synchronize with config project master sources 2019-05-23 18:19:56 +02:00
configure Add support for debuginfod to the binutils (disable by default, enabled via a configure time option). 2020-01-09 13:19:20 +00:00
configure.ac Add support for debuginfod to the binutils (disable by default, enabled via a configure time option). 2020-01-09 13:19:20 +00:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS Update the address of the FSF in the copyright notice of files which were using the old address. 2017-12-14 12:48:55 +00:00
COPYING.NEWLIB
depcomp Update from upstream Automake 2014-11-16 13:43:48 +01:00
djunpack.bat
install-sh Update from upstream Automake 2014-11-16 13:43:48 +01:00
libtool.m4 Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS Move gnulib to top level 2019-06-14 12:40:02 -06:00
Makefile.def gdb: CTF support 2019-10-07 02:26:27 +00:00
Makefile.in gdb: CTF support 2019-10-07 02:26:27 +00:00
Makefile.tpl Revert "Sync top level files with versions from gcc." 2019-05-30 11:17:19 +01:00
makefile.vms
missing Update from upstream Automake 2014-11-16 13:43:48 +01:00
mkdep
mkinstalldirs Update from upstream Automake 2014-11-16 13:43:48 +01:00
move-if-change Update `move-if-change' from gnulib 2014-11-16 17:04:02 +01:00
multilib.am Merge autoconf / automake update changes from GCC. 2018-10-31 17:10:56 +00:00
README
README-maintainer-mode Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
setup.com
src-release.sh Add libctf to src-release.sh:GDB_SUPPORT_DIRS 2019-10-17 14:00:51 -04:00
symlink-tree
test-driver Bump to autoconf 2.69 and automake 1.15.1 2018-06-19 16:55:06 -04:00
ylwrap Update from upstream Automake 2014-11-16 13:43:48 +01:00

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

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then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
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If you have more than one compiler on your system, it is often best to
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	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

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on where and how to report problems.