out of bounds heap read in r_mem_copyendian

[hannob]

This script will cause a heap oob:
https://crashes.fuzzing-project.org/radare2-oob-heap-read-r_mem_copyendian
Contains the string "pt@!"

It must be tested with a real executable, however it seems any 64 bit elf will do.
Test: radare2 -q -i [script] [elf_file]

Found with american fuzzy lop. Address Sanitizer trace:

==9520==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000416d0 at pc 0x7f3558e41103 bp 0x7ffc7a950240 sp 0x7ffc7a950230
READ of size 4 at 0x6020000416d0 thread T0
    #0 0x7f3558e41102 in memmove /usr/include/bits/string3.h:57
    #1 0x7f3558e41102 in r_mem_copyendian /f/radare2/radare2/libr/util/mem.c:157
    #2 0x7f3558ef84a7 in r_print_date_unix /f/radare2/radare2/libr/util/p_date.c:40
    #3 0x7f355e12cda1 in cmd_print /f/radare2/radare2/libr/core/cmd_print.c:2891
    #4 0x7f355e18dac6 in r_core_cmd_subst_i /f/radare2/radare2/libr/core/cmd.c:1569
    #5 0x7f355e0ee8c4 in r_core_cmd_subst /f/radare2/radare2/libr/core/cmd.c:1081
    #6 0x7f355e0efaa3 in r_core_cmd /f/radare2/radare2/libr/core/cmd.c:1938
    #7 0x7f355e0f28f4 in r_core_cmd_lines /f/radare2/radare2/libr/core/cmd.c:1989
    #8 0x7f355e0f2b64 in r_core_cmd_file /f/radare2/radare2/libr/core/cmd.c:2001
    #9 0x7f355e0f5ba3 in r_core_run_script /f/radare2/radare2/libr/core/cmd.c:373
    #10 0x405572 in main /f/radare2/radare2/binr/radare2/radare2.c:729
    #11 0x7f3558656f9f in __libc_start_main (/lib64/libc.so.6+0x1ff9f)
    #12 0x40a333 (/mnt/ram/radare2/radare2+0x40a333)

0x6020000416d2 is located 0 bytes to the right of 2-byte region [0x6020000416d0,0x6020000416d2)
allocated by thread T0 here:
    #0 0x7f355e8209d6 in __interceptor_realloc (/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.2/libasan.so.1+0x579d6)
    #1 0x7f355e0a1100 in r_core_block_size /f/radare2/radare2/libr/core/core.c:1108

SUMMARY: AddressSanitizer: heap-buffer-overflow /usr/include/bits/string3.h:57 memmove
Shadow bytes around the buggy address:
  0x0c0480000280: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0480000290: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c04800002a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c04800002b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c04800002c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
=>0x0c04800002d0: fa fa fa fa fa fa fa fa fa fa[02]fa fa fa 01 fa
  0x0c04800002e0: fa fa 05 fa fa fa 05 fa fa fa 05 fa fa fa fd fa
  0x0c04800002f0: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd
  0x0c0480000300: fa fa fd fa fa fa fd fd fa fa 02 fa fa fa fd fd
  0x0c0480000310: fa fa fd fd fa fa fd fd fa fa fd fd fa fa fd fd
  0x0c0480000320: fa fa fd fd fa fa fd fd fa fa fd fd fa fa 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
==9520==ABORTING