[Bug-tar] Heap-based buffer overflow in transform.c:276:parse_transform_expr().

[x ksi]

Hi All,

I'd like to report a defect in tar v1.30.

Execution of the following command will cause a heap-based buffer overflow:

-- cut --
$ ~/tar-asan/src/tar --transform="s///"
=================================================================
==4615==ERROR: AddressSanitizer: heap-buffer-overflow on address
0x60200000066f at pc 0x55fcbf10c3dd bp 0x7ffe443251d0 sp
0x7ffe443251c8
READ of size 1 at 0x60200000066f thread T0
    #0 0x55fcbf10c3dc in parse_transform_expr
/home/s1m0n/tar/tar-asan/src/transform.c:276
    #1 0x55fcbf10c4c9 in set_transform_expr
/home/s1m0n/tar/tar-asan/src/transform.c:414
    #2 0x55fcbf101ecf in parse_opt /home/s1m0n/tar/tar-asan/src/tar.c:1947
    #3 0x55fcbf164ac6 in group_parse
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:234
    #4 0x55fcbf164ac6 in parser_parse_opt
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:749
    #5 0x55fcbf164ac6 in parser_parse_next
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:860
    #6 0x55fcbf164ac6 in argp_parse
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:928
    #7 0x55fcbf01664e in decode_options /home/s1m0n/tar/tar-asan/src/tar.c:2312
    #8 0x55fcbf01664e in main /home/s1m0n/tar/tar-asan/src/tar.c:2698
    #9 0x7f6afb635b16 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x22b16)
    #10 0x55fcbf01faa9 in _start (/home/s1m0n/tar/tar-asan/src/tar+0x9eaa9)
0x60200000066f is located 1 bytes to the left of 1-byte region
[0x602000000670,0x602000000671)
allocated by thread T0 here:
    #0 0x7f6afb8b8ed0 in __interceptor_malloc
../../../../src/libsanitizer/asan/asan_malloc_linux.cc:86
    #1 0x55fcbf1d35f8 in xmalloc /home/s1m0n/tar/tar-asan/gnu/xmalloc.c:41
    #2 0x55fcbf1096df in parse_transform_expr
/home/s1m0n/tar/tar-asan/src/transform.c:263
    #3 0x55fcbf10c4c9 in set_transform_expr
/home/s1m0n/tar/tar-asan/src/transform.c:414
    #4 0x55fcbf101ecf in parse_opt /home/s1m0n/tar/tar-asan/src/tar.c:1947
    #5 0x55fcbf164ac6 in group_parse
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:234
    #6 0x55fcbf164ac6 in parser_parse_opt
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:749
    #7 0x55fcbf164ac6 in parser_parse_next
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:860
    #8 0x55fcbf164ac6 in argp_parse
/home/s1m0n/tar/tar-asan/gnu/argp-parse.c:928
    #9 0x55fcbf01664e in decode_options /home/s1m0n/tar/tar-asan/src/tar.c:2312
    #10 0x55fcbf01664e in main /home/s1m0n/tar/tar-asan/src/tar.c:2698
    #11 0x7f6afb635b16 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x22b16)
SUMMARY: AddressSanitizer: heap-buffer-overflow
/home/s1m0n/tar/tar-asan/src/transform.c:276 in parse_transform_expr
Shadow bytes around the buggy address:
  0x0c047fff8070: fa fa fd fa fa fa fd fa fa fa 00 03 fa fa 00 03
  0x0c047fff8080: fa fa fd fa fa fa fd fa fa fa 00 03 fa fa 00 03
  0x0c047fff8090: fa fa fd fa fa fa fd fa fa fa 00 03 fa fa 00 03
  0x0c047fff80a0: fa fa fd fa fa fa fd fa fa fa 00 03 fa fa 00 03
  0x0c047fff80b0: fa fa fd fa fa fa fd fa fa fa 00 03 fa fa 00 03
=>0x0c047fff80c0: fa fa 00 03 fa fa 04 fa fa fa 00 00 fa[fa]01 fa
  0x0c047fff80d0: fa fa 00 00 fa fa 00 fa fa fa fd fa fa fa fd fa
  0x0c047fff80e0: fa fa 00 fa fa fa fd fa fa fa 00 fa fa fa 00 fa
  0x0c047fff80f0: fa fa 00 00 fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8100: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8110: 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
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  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
==4615==ABORTING
-- cut --

Please let me know if you have any questions.


Thanks,
Filip Palian