Heap out of bounds read in yara_yyparse()

[fumfel]

Heap out of bounds read in yara_yyparse()

Git HEAD: 5a8f180

To reproduce: yara yara_hoobr_yyparse_l833.yar strings

Payload

ASAN:

==16721==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60d00000cff1 at pc 0x0000004251cf bp 0x7ffdd8257230 sp 0x7ffdd82569d8
READ of size 130 at 0x60d00000cff1 thread T0
    #0 0x4251ce in __interceptor_strlen /home/llvm/clang-3.9/final/llvm.src/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:227:5
    #1 0x578166 in yara_yyparse XYZ/yara/libyara/grammar.y:833:13
    #2 0x50c590 in yr_lex_parse_rules_file XYZ/yara/libyara/lexer.l:822:3
    #3 0x4f094e in yr_compiler_add_file XYZ/yara/libyara/compiler.c:357:12
    #4 0x4ee094 in main XYZ/yara/yara.c:1124:17
    #5 0x7f6f1b58782f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
    #6 0x41a408 in _start (/usr/local/bin/yara+0x41a408)

0x60d00000cff1 is located 0 bytes to the right of 129-byte region [0x60d00000cf70,0x60d00000cff1)
allocated by thread T0 here:
    #0 0x4b8c1c in malloc /home/llvm/clang-3.9/final/llvm.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:64:3
    #1 0x5770ea in yara_yyparse XYZ/yara/libyara/grammar.y:808:36
    #2 0x50c590 in yr_lex_parse_rules_file XYZ/yara/libyara/lexer.l:822:3

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/llvm/clang-3.9/final/llvm.src/projects/compiler-rt/lib/asan/../sanitizer_common/sanitizer_common_interceptors.inc:227:5 in __interceptor_strlen
Shadow bytes around the buggy address:
  0x0c1a7fff99a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff99e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa 00 00
=>0x0c1a7fff99f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[01]fa
  0x0c1a7fff9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1a7fff9a40: 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
  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
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==16721==ABORTING

[plusvic]

Fixed in ab906da

[fgeek]

CVE-2017-5923 has been assigned for this issue.