[Bug binutils/29887] New: Out of bound read when accessing `file_table` at `case DST__K_SRC_SETFILE` handler in function `parse_module`

[r3tr0spect2019 at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=29887

            Bug ID: 29887
           Summary: Out of bound read when accessing `file_table` at `case
                    DST__K_SRC_SETFILE` handler in function `parse_module`
           Product: binutils
           Version: 2.40 (HEAD)
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: binutils
          Assignee: unassigned at sourceware dot org
          Reporter: r3tr0spect2019 at gmail dot com
  Target Milestone: ---

Created attachment 14508
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14508&action=edit
PoC

# Reproduce

```bash
cd binutils-gdb
git reset --hard f2f58a399cf3f946983398cdfe52d0eaa72bf877
mkdir build && cd build
../configure --disable-gdb --disable-gdbserver --disable-gdbsupport
--disable-libdecnumber --disable-readline --disable-sim --disable-libbacktrace
--disable-gas --disable-ld --disable-werror --enable-targets=all
CPPFLAGS=-DDEBUG CFLAGS="-g -O0 -fsanitize=address"
make all-binutils MAKEINFO=true && true
binutils/addr2line -e poc.bin 0
```

# Output

```
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 119
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 212
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 44
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 116
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 68
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 176
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 137
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 248
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 177
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 64
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 219
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 48
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 26
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 188
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 243
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 60
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 18
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 70
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 8
=================================================================
==174360==ERROR: AddressSanitizer: heap-buffer-overflow on address
0x61100003e388 at pc 0x564c5ffffb6f bp 0x7fff1ab016b0 sp 0x7fff1ab016a0
READ of size 4 at 0x61100003e388 thread T0
    #0 0x564c5ffffb6e in parse_module ../../bfd/vms-alpha.c:4521
    #1 0x564c60000fad in module_find_nearest_line ../../bfd/vms-alpha.c:4902
    #2 0x564c60001911 in _bfd_vms_find_nearest_line ../../bfd/vms-alpha.c:4982
    #3 0x564c5fa2db1e in find_address_in_section ../../binutils/addr2line.c:197
    #4 0x564c5fa48f43 in bfd_map_over_sections ../../bfd/section.c:1366
    #5 0x564c5fa2e8eb in translate_addresses ../../binutils/addr2line.c:337
    #6 0x564c5fa2efbc in process_file ../../binutils/addr2line.c:470
    #7 0x564c5fa2f5b1 in main ../../binutils/addr2line.c:579
    #8 0x7fa61c10ad8f in __libc_start_call_main
../sysdeps/nptl/libc_start_call_main.h:58
    #9 0x7fa61c10ae3f in __libc_start_main_impl ../csu/libc-start.c:392
    #10 0x564c5fa2d244 in _start
(/binutils-gdb/build/binutils/addr2line+0x343244)

Address 0x61100003e388 is a wild pointer.
SUMMARY: AddressSanitizer: heap-buffer-overflow ../../bfd/vms-alpha.c:4521 in
parse_module
Shadow bytes around the buggy address:
  0x0c227ffffc20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc50: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc60: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c227ffffc70: fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffc90: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffca0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffcb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227ffffcc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==174360==ABORTING
Aborted (core dumped)
```

# Analysis

Variable `data` is obtained from `src_ptr + DST_S_W_SRC_UNSWORD`[1], which can
be controlled by file content, and then this variable is used to access
`file_table`[2] without any check, so out-of-bound read is triggered.

[1]
https://github.com/bminor/binutils-gdb/blob/85f9067d3a47d51a46ba369c60fdec752da0f885/bfd/vms-alpha.c#L4519
[2]
https://github.com/bminor/binutils-gdb/blob/85f9067d3a47d51a46ba369c60fdec752da0f885/bfd/vms-alpha.c#L4521

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