[Bug binutils/27879] New: stash-buffer-overflow on sysdump

[shaohua.li at inf dot ethz.ch]

https://sourceware.org/bugzilla/show_bug.cgi?id=27879

            Bug ID: 27879
           Summary: stash-buffer-overflow on sysdump
           Product: binutils
           Version: 2.37 (HEAD)
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: binutils
          Assignee: unassigned at sourceware dot org
          Reporter: shaohua.li at inf dot ethz.ch
  Target Milestone: ---

Created attachment 13456
  --> https://sourceware.org/bugzilla/attachment.cgi?id=13456&action=edit
poc

Hi there,

I found a stack-buffer-overflow on sysdump with a fuzzer. I attached the poc
file.

Compiler: clang12

Compile args: -fsanitize=address

Reproduce: `sysdump poc`

AddressSanitizer output:

==30955==ERROR: AddressSanitizer: stack-buffer-overflow on address
0x7ffeaa74a95f at pc 0x000000496b07 bp 0x7ffeaa74a830 sp 0x7ffeaa749ff8
READ of size 255 at 0x7ffeaa74a95f thread T0
    #0 0x496b06 in __asan_memcpy
(/data/clean/binutils-gdb-asan/binutils/sysdump+0x496b06)
    #1 0x4d9725 in getBARRAY
/data/clean/binutils-gdb-asan/binutils/sysdump.c:146:17
    #2 0x4d9725 in sysroff_swap_ob_in
/data/clean/binutils-gdb-asan/binutils/./sysroff.c:1296:15
    #3 0x4e4839 in getone
/data/clean/binutils-gdb-asan/binutils/sysdump.c:419:2
    #4 0x4e4839 in module
/data/clean/binutils-gdb-asan/binutils/sysdump.c:618:10
    #5 0x4e4839 in main /data/clean/binutils-gdb-asan/binutils/sysdump.c:709:3
    #6 0x7fd3cf0db0b2 in __libc_start_main
/build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #7 0x41c4fd in _start
(/data/clean/binutils-gdb-asan/binutils/sysdump+0x41c4fd)

Address 0x7ffeaa74a95f is located in stack of thread T0 at offset 287 in frame
    #0 0x4d935f in sysroff_swap_ob_in
/data/clean/binutils-gdb-asan/binutils/./sysroff.c:1280

  This frame has 2 object(s):
    [32, 287) 'raw' (line 1281)
    [352, 356) 'idx' (line 1282) <== Memory access at offset 287 partially
underflows this variable
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism, swapcontext or vfork
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow
(/data/clean/binutils-gdb-asan/binutils/sysdump+0x496b06) in __asan_memcpy
Shadow bytes around the buggy address:
  0x1000554e14d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000554e14e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000554e14f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1000554e1500: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
  0x1000554e1510: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x1000554e1520: 00 00 00 00 00 00 00 00 00 00 00[07]f2 f2 f2 f2
  0x1000554e1530: f2 f2 f2 f2 04 f3 f3 f3 00 00 00 00 00 00 00 00
  0x1000554e1540: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
  0x1000554e1550: f8 f2 f8 f2 f8 f2 f8 f2 f8 f2 f8 f8 f8 f8 f8 f8
  0x1000554e1560: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
  0x1000554e1570: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f2 f2 f2 f2 f2 f2
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
==30955==ABORTING

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