Bug 29876 - Out of bound read at `case DST__K_LINE_NUM` handler in function `parse_module`
Summary: Out of bound read at `case DST__K_LINE_NUM` 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 03:30 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


Attachments
PoC (3.66 KB, model/x.stl-binary)
2022-12-12 03:30 UTC, 2019
Details

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Description 2019 2022-12-12 03:30:39 UTC
Created attachment 14497 [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
binutils/addr2line -e poc.bin 0
```

# Output

```
binutils/addr2line: DST__K_SET_PC not implemented
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: DST__K_SET_STMTNUM not implemented
binutils/addr2line: unknown line command 68
binutils/addr2line: unknown line command 83
binutils/addr2line: unknown line command 49
binutils/addr2line: DST__K_RESET_LINUM_INCR not implemented
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: unknown line command 87
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: unknown line command 32
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: unknown line command 45
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
binutils/addr2line: unknown line command 58
binutils/addr2line: DST__K_SET_LINUM_INCR not implemented
=================================================================
==174957==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x611000036868 at pc 0x55e028da0f5e bp 0x7ffe4823f1c0 sp 0x7ffe4823f1b0
READ of size 1 at 0x611000036868 thread T0
    #0 0x55e028da0f5d in parse_module ../../bfd/vms-alpha.c:4580
    #1 0x55e028da1fad in module_find_nearest_line ../../bfd/vms-alpha.c:4902
    #2 0x55e028da2911 in _bfd_vms_find_nearest_line ../../bfd/vms-alpha.c:4982
    #3 0x55e0287ceb1e in find_address_in_section ../../binutils/addr2line.c:197
    #4 0x55e0287e9f43 in bfd_map_over_sections ../../bfd/section.c:1366
    #5 0x55e0287cf8eb in translate_addresses ../../binutils/addr2line.c:337
    #6 0x55e0287cffbc in process_file ../../binutils/addr2line.c:470
    #7 0x55e0287d05b1 in main ../../binutils/addr2line.c:579
    #8 0x7f127bbffd8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #9 0x7f127bbffe3f in __libc_start_main_impl ../csu/libc-start.c:392
    #10 0x55e0287ce244 in _start (/binutils-gdb/build/binutils/addr2line+0x343244)

0x611000036868 is located 0 bytes to the right of 232-byte region [0x611000036780,0x611000036868)
allocated by thread T0 here:
    #0 0x7f127beb2867 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x55e0287e08d5 in bfd_malloc ../../bfd/libbfd.c:289
    #2 0x55e028d8b13a in _bfd_malloc_and_read ../../bfd/libbfd.h:970
    #3 0x55e028da1f77 in module_find_nearest_line ../../bfd/vms-alpha.c:4896
    #4 0x55e028da2911 in _bfd_vms_find_nearest_line ../../bfd/vms-alpha.c:4982
    #5 0x55e0287ceb1e in find_address_in_section ../../binutils/addr2line.c:197
    #6 0x55e0287e9f43 in bfd_map_over_sections ../../bfd/section.c:1366
    #7 0x55e0287cf8eb in translate_addresses ../../binutils/addr2line.c:337
    #8 0x55e0287cffbc in process_file ../../binutils/addr2line.c:470
    #9 0x55e0287d05b1 in main ../../binutils/addr2line.c:579
    #10 0x7f127bbffd8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

SUMMARY: AddressSanitizer: heap-buffer-overflow ../../bfd/vms-alpha.c:4580 in parse_module
Shadow bytes around the buggy address:
  0x0c227fffecb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c227fffecc0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c227fffecd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c227fffece0: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa
  0x0c227fffecf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c227fffed00: 00 00 00 00 00 00 00 00 00 00 00 00 00[fa]fa fa
  0x0c227fffed10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fffed20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fffed30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fffed40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fffed50: 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
==174957==ABORTING
Aborted (core dumped)
```

# Analysis

`((signed char *)pcl_ptr)[0]` is accessed[1], which is only ensured to be smaller than `ptr + rec_length`. However, `rec_length` can be controlled by file content[2] and can be larger than actual buffer size. Therefore, out-of-bound read can occur.

[1] https://github.com/bminor/binutils-gdb/blob/85f9067d3a47d51a46ba369c60fdec752da0f885/bfd/vms-alpha.c#L4580
[2] https://github.com/bminor/binutils-gdb/blob/85f9067d3a47d51a46ba369c60fdec752da0f885/bfd/vms-alpha.c#L4372
Comment 1 Sourceware Commits 2022-12-12 08:59:42 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 09:02:10 UTC
.