heap overflow (write) in r_print_randomart

[hannob]

Input script:
https://crashes.fuzzing-project.org/radare2-script-heap-overflow-write-r_print_randomart
Contains the command "pk@4000000000000".

Address Sanitizer:

=================================================================
==26187==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61100000525c at pc 0x7f087e25fdff bp 0x7ffc4de25970 sp 0x7ffc4de25960
WRITE of size 1 at 0x61100000525c thread T0
    #0 0x7f087e25fdfe in r_print_randomart /f/radare2/radare2/libr/util/randomart.c:113
    #1 0x7f0883456d0c in cmd_print /f/radare2/radare2/libr/core/cmd_print.c:2850
    #2 0x7f08834c5eee in r_core_cmd_subst_i /f/radare2/radare2/libr/core/cmd.c:1578
    #3 0x7f08834259ac in r_core_cmd_subst /f/radare2/radare2/libr/core/cmd.c:1084
    #4 0x7f0883426b53 in r_core_cmd /f/radare2/radare2/libr/core/cmd.c:1947
    #5 0x7f0883429a7c in r_core_cmd_lines /f/radare2/radare2/libr/core/cmd.c:1998
    #6 0x7f0883429cb4 in r_core_cmd_file /f/radare2/radare2/libr/core/cmd.c:2010
    #7 0x7f088342c9ee in r_core_run_script /f/radare2/radare2/libr/core/cmd.c:373
    #8 0x405236 in main /f/radare2/radare2/binr/radare2/radare2.c:729
    #9 0x7f087d983f9f in __libc_start_main (/lib64/libc.so.6+0x1ff9f)
    #10 0x409e6d (/mnt/ram/r2/radare2+0x409e6d)

0x61100000525c is located 0 bytes to the right of 220-byte region [0x611000005180,0x61100000525c)
allocated by thread T0 here:
    #0 0x7f0883b586f7 in malloc (/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.2/libasan.so.1+0x576f7)
    #1 0x7f087e25e12a in r_print_randomart /f/radare2/radare2/libr/util/randomart.c:50

SUMMARY: AddressSanitizer: heap-buffer-overflow /f/radare2/radare2/libr/util/randomart.c:113 r_print_randomart
Shadow bytes around the buggy address:
  0x0c227fff89f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8a10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8a20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8a30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c227fff8a40: 00 00 00 00 00 00 00 00 00 00 00[04]fa fa fa fa
  0x0c227fff8a50: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c227fff8a60: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c227fff8a70: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa
  0x0c227fff8a80: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c227fff8a90: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Contiguous container OOB:fc
  ASan internal:           fe
==26187==ABORTING

[neuschaefer]

@hannob The randomart code seems to be originally from OpenSSH, which may be worth checking, too.