Bug 29878 - Out of bound read at `case DST__K_RTNBEG` handler in function `parse_module`
Summary: Out of bound read at `case DST__K_RTNBEG` handler in function `parse_module`
Status: RESOLVED FIXED
Alias: None
Product: binutils
Classification: Unclassified
Component: binutils (show other bugs)
Version: 2.40
: P2 normal
Target Milestone: 2.40
Assignee: Alan Modra
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-12-12 03:32 UTC by 2019
Modified: 2022-12-12 09:02 UTC (History)
0 users

See Also:
Host:
Target:
Build:
Last reconfirmed: 2022-12-12 00:00:00
Project(s) to access:
ssh public key:

Attachments
PoC (3.66 KB, model/x.stl-binary)
2022-12-12 03:32 UTC, 2019 		Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description 2019 2022-12-12 03:32:10 UTC 
Created attachment 14499 [details]
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 8
binutils/addr2line: unknown source command 130
binutils/addr2line: unknown source command 130
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 79
binutils/addr2line: unknown source command 255
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 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 246
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 240
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 240
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 64
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 114
binutils/addr2line: unknown source command 118
binutils/addr2line: unknown source command 77
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 108
binutils/addr2line: unknown source command 255
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 8
binutils/addr2line: unknown source command 0
binutils/addr2line: unknown source command 255
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
=================================================================
==178722==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61a000000b88 at pc 0x5620f46e597c bp 0x7ffc73d6b330 sp 0x7ffc73d6b320
READ of size 1 at 0x61a000000b88 thread T0
    #0 0x5620f46e597b in _bfd_vms_save_counted_string ../../bfd/vms-misc.c:170
    #1 0x5620f403e062 in parse_module ../../bfd/vms-alpha.c:4404
    #2 0x5620f403ffad in module_find_nearest_line ../../bfd/vms-alpha.c:4902
    #3 0x5620f4040911 in _bfd_vms_find_nearest_line ../../bfd/vms-alpha.c:4982
    #4 0x5620f3a6cb1e in find_address_in_section ../../binutils/addr2line.c:197
    #5 0x5620f3a87f43 in bfd_map_over_sections ../../bfd/section.c:1366
    #6 0x5620f3a6d8eb in translate_addresses ../../binutils/addr2line.c:337
    #7 0x5620f3a6dfbc in process_file ../../binutils/addr2line.c:470
    #8 0x5620f3a6e5b1 in main ../../binutils/addr2line.c:579
    #9 0x7fb86c693d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #10 0x7fb86c693e3f in __libc_start_main_impl ../csu/libc-start.c:392
    #11 0x5620f3a6c244 in _start (/binutils-gdb/build/binutils/addr2line+0x343244)

0x61a000000b88 is located 8 bytes to the right of 1280-byte region [0x61a000000680,0x61a000000b80)
allocated by thread T0 here:
    #0 0x7fb86c946867 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x5620f3a7e8d5 in bfd_malloc ../../bfd/libbfd.c:289
    #2 0x5620f402913a in _bfd_malloc_and_read ../../bfd/libbfd.h:970
    #3 0x5620f403ff77 in module_find_nearest_line ../../bfd/vms-alpha.c:4896
    #4 0x5620f4040911 in _bfd_vms_find_nearest_line ../../bfd/vms-alpha.c:4982
    #5 0x5620f3a6cb1e in find_address_in_section ../../binutils/addr2line.c:197
    #6 0x5620f3a87f43 in bfd_map_over_sections ../../bfd/section.c:1366
    #7 0x5620f3a6d8eb in translate_addresses ../../binutils/addr2line.c:337
    #8 0x5620f3a6dfbc in process_file ../../binutils/addr2line.c:470
    #9 0x5620f3a6e5b1 in main ../../binutils/addr2line.c:579
    #10 0x7fb86c693d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

SUMMARY: AddressSanitizer: heap-buffer-overflow ../../bfd/vms-misc.c:170 in _bfd_vms_save_counted_string
Shadow bytes around the buggy address:
  0x0c347fff8120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c347fff8160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c347fff8170: fa[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff8180: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff8190: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff81a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff81b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c347fff81c0: 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
==178722==ABORTING
Aborted (core dumped)
```

# Analysis

`ptr + DST_S_B_RTNBEG_NAME` is accessed via `_bfd_vms_save_counted_string` without bound check, which can actually be larger than `maxptr`.
Comment 1 Sourceware Commits 2022-12-12 08:59:43 UTC 
The master branch has been updated by Alan Modra <amodra@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=77c225bdeb410cf60da804879ad41622f5f1aa44

commit 77c225bdeb410cf60da804879ad41622f5f1aa44
Author: Alan Modra <amodra@gmail.com>
Date:   Mon Dec 12 18:28:49 2022 +1030

    Lack of bounds checking in vms-alpha.c parse_module
    
            PR 29873
            PR 29874
            PR 29875
            PR 29876
            PR 29877
            PR 29878
            PR 29879
            PR 29880
            PR 29881
            PR 29882
            PR 29883
            PR 29884
            PR 29885
            PR 29886
            PR 29887
            PR 29888
            PR 29889
            PR 29890
            PR 29891
            * vms-alpha.c (parse_module): Make length param bfd_size_type.
            Delete length == -1 checks.  Sanity check record_length.
            Sanity check DST__K_MODBEG, DST__K_RTNBEG, DST__K_RTNEND lengths.
            Sanity check DST__K_SOURCE and DST__K_LINE_NUM elements
            before accessing.
            (build_module_list): Pass dst_section size to parse_module.
Comment 2 Alan Modra 2022-12-12 09:02:51 UTC 
.