libxml2 – xmlParserPrintFileContextInternal Heap Buffer Overread

• Exploit Database
• 12 阅读

• 作者： Google Security Research
  日期： 2016-02-24
• 类别：

  • dos
  平台：

  • linux
• 来源：https://www.exploit-db.com/exploits/39493/

• Source: https://code.google.com/p/google-security-research/issues/detail?id=639
  
  The following crash due to a heap-based out-of-bounds memory read can be observed in an ASAN build of latest stable libxml2 (2.9.3, released 4 days ago), by feeding a malformed file to xmllint ("$ ./xmllint /path/to/file"):
  
  --- cut ---
  ==4210==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6290000051ff at pc 0x000000533c8f bp 0x7ffdb38c4830 sp 0x7ffdb38c4828
  READ of size 1 at 0x6290000051ff thread T0
  #0 0x533c8e in xmlParserPrintFileContextInternal libxml2-2.9.3/error.c:192:6
  #1 0x54088a in xmlReportError libxml2-2.9.3/error.c:406:9
  #2 0x53884f in __xmlRaiseError libxml2-2.9.3/error.c:633:2
  #3 0x56f0ec in xmlFatalErr libxml2-2.9.3/parser.c:540:5
  #4 0x569c98 in xmlGROW libxml2-2.9.3/parser.c:2077:9
  #5 0x62bcb3 in xmlParseEndTag2 libxml2-2.9.3/parser.c:9846:5
  #6 0x61d620 in xmlParseElement libxml2-2.9.3/parser.c:10238:2
  #7 0x63be9b in xmlParseDocument libxml2-2.9.3/parser.c:10912:2
  #8 0x672b74 in xmlDoRead libxml2-2.9.3/parser.c:15390:5
  #9 0x673041 in xmlReadFile libxml2-2.9.3/parser.c:15452:13
  #10 0x4f5b60 in parseAndPrintFile libxml2-2.9.3/xmllint.c:2401:9
  #11 0x4ebe8f in main libxml2-2.9.3/xmllint.c:3759:7
  
  0x6290000051ff is located 1 bytes to the left of 16384-byte region [0x629000005200,0x629000009200)
  allocated by thread T0 here:
  #0 0x4b8b68 in malloc llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:40
  #1 0x7f4df5219729(/lib/x86_64-linux-gnu/libz.so.1+0xf729)
  
  SUMMARY: AddressSanitizer: heap-buffer-overflow libxml2-2.9.3/error.c:192:6 in xmlParserPrintFileContextInternal
  Shadow bytes around the buggy address:
  0x0c527fff89e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c527fff89f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c527fff8a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c527fff8a10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c527fff8a20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  =>0x0c527fff8a30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa]
  0x0c527fff8a40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c527fff8a50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c527fff8a60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c527fff8a70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c527fff8a80: 00 00 00 00 00 00 00 00 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
  Container overflow:fc
  Array cookie:ac
  Intra object redzone:bb
  ASan internal: fe
  Left alloca redzone: ca
  Right alloca redzone:cb
  ==4210==ABORTING
  --- cut ---
  
  The crash was reported at https://bugzilla.gnome.org/show_bug.cgi?id=758588. Attached is an XML file which triggers the crash.
  
  
  Proof of Concept:
  https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39493.zip