Out of bounds call to __strlen in Elf64_r_bin_elf_get_symbols

[hannob]

An invalid input file can cause an out of bounds read access in radare2. Example file:
https://crashes.fuzzing-project.org/radare2-oob-heap-read-Elf64_r_bin_elf_get_symbols

Can be seen with address sanitizer. This was found with the tool american fuzzy lop.

Address sanitizer output:

==21442==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x607000006206 at pc 0x7f36e084ced0 bp 0x7fffdbfd7c50 sp 0x7fffdbfd7c40
READ of size 1 at 0x607000006206 thread T0
    #0 0x7f36e084cecf in __strnlen /f/radare2/radare2/libr/..//libr/bin/p/../format/elf/elf.c:12
    #1 0x7f36e084cecf in Elf64_r_bin_elf_get_symbols /f/radare2/radare2/libr/..//libr/bin/p/../format/elf/elf.c:1605
    #2 0x7f36e08258c5 in symbols /f/radare2/radare2/libr/..//libr/bin/p/bin_elf.c:249
    #3 0x7f36e07563fe in r_bin_object_set_items /f/radare2/radare2/libr/bin/bin.c:421
    #4 0x7f36e07563fe in r_bin_object_new /f/radare2/radare2/libr/bin/bin.c:945
    #5 0x7f36e075c83b in r_bin_file_new_from_bytes /f/radare2/radare2/libr/bin/bin.c:1056
    #6 0x7f36e075c83b in r_bin_load_io_at_offset_as_sz /f/radare2/radare2/libr/bin/bin.c:644
    #7 0x7f36e075e0ca in r_bin_load_io_at_offset_as /f/radare2/radare2/libr/bin/bin.c:666
    #8 0x7f36e075f575 in r_bin_load_io /f/radare2/radare2/libr/bin/bin.c:546
    #9 0x7f36e17b5b0d in r_core_file_do_load_for_io_plugin /f/radare2/radare2/libr/core/file.c:350
    #10 0x7f36e17b5b0d in r_core_bin_load /f/radare2/radare2/libr/core/file.c:487
    #11 0x405a3d in main /f/radare2/radare2/binr/radare2/radare2.c:585
    #12 0x7f36dbca0f9f in __libc_start_main (/lib64/libc.so.6+0x1ff9f)
    #13 0x40a0dd (/mnt/ram/radare2/radare2+0x40a0dd)

0x607000006206 is located 15 bytes to the right of 71-byte region [0x6070000061b0,0x6070000061f7)
allocated by thread T0 here:
    #0 0x7f36e1e2d855 in calloc (/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.2/libasan.so.1+0x57855)
    #1 0x7f36e084c713 in Elf64_r_bin_elf_get_symbols /f/radare2/radare2/libr/..//libr/bin/p/../format/elf/elf.c:1474

SUMMARY: AddressSanitizer: heap-buffer-overflow /f/radare2/radare2/libr/..//libr/bin/p/../format/elf/elf.c:12 __strnlen
Shadow bytes around the buggy address:
  0x0c0e7fff8bf0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8c00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8c10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8c20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c0e7fff8c30: fa fa fa fa fa fa 00 00 00 00 00 00 00 00 07 fa
=>0x0c0e7fff8c40:[fa]fa fa fa fd fd fd fd fd fd fd fd fd fa fa fa
  0x0c0e7fff8c50: fa fa 00 00 00 00 00 00 00 00 00 fa fa fa fa fa
  0x0c0e7fff8c60: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa 00 00
  0x0c0e7fff8c70: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00
  0x0c0e7fff8c80: 00 00 00 00 00 00 fa fa fa fa 00 00 00 00 00 00
  0x0c0e7fff8c90: 00 00 00 00 fa fa fa fa 00 00 00 00 00 00 00 00
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
==21442==ABORTING