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heap-buffer-overflow read in visible_length() #73

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kcwu opened this issue Dec 7, 2016 · 4 comments
Closed

heap-buffer-overflow read in visible_length() #73

kcwu opened this issue Dec 7, 2016 · 4 comments

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@kcwu
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kcwu commented Dec 7, 2016 •
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similar to issue #57

input (xxd cases/tats-w3m-73)

00000000: 3c74 6162 6c65 3e26 8c3c                 <table>&.<

how to reproduce:

ASAN_OPTIONS=abort_on_error=1:detect_leaks=0 LD_LIBRARY_PATH=./notgc ./w3m-tats.asan -T text/html -dump cases/tats-w3m-73

stderr:

=================================================================
==827466==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60300000d110 at pc 0x0000005f7370 bp 0x7fff6568cf30 sp 0x7fff6568cf28
READ of size 1 at 0x60300000d110 thread T0
    #0 0x5f736f in visible_length /targets/w3m-tats/table.c:432:12
    #1 0x616c31 in feed_table /targets/w3m-tats/table.c:3250:23
    #2 0x591c7c in HTMLlineproc0 /targets/w3m-tats/file.c:6434:14
    #3 0x5a5d4c in loadHTMLstream /targets/w3m-tats/file.c:7265:2
    #4 0x55bbf8 in loadHTMLBuffer /targets/w3m-tats/file.c:6794:5
    #5 0x55ee64 in loadSomething /targets/w3m-tats/file.c:224:16
    #6 0x5535ac in loadGeneralFile /targets/w3m-tats/file.c:2241:6
    #7 0x4f9202 in main /targets/w3m-tats/main.c:1017:12
    #8 0x7fed79631f44 in __libc_start_main /build/eglibc-oGUzwX/eglibc-2.19/csu/libc-start.c:287
    #9 0x41bf25 in _start (/w3m-tats.asan+0x41bf25)

0x60300000d110 is located 0 bytes to the right of 32-byte region [0x60300000d0f0,0x60300000d110)
allocated by thread T0 here:
    #0 0x4c6288 in __interceptor_malloc (/w3m-tats.asan+0x4c6288)
    #1 0x7fed7ad7fc21 in GC_malloc_atomic /notgc/notgc.c:275
    #2 0x615121 in feed_table /targets/w3m-tats/table.c:3191:8
    #3 0x591c7c in HTMLlineproc0 /targets/w3m-tats/file.c:6434:14
    #4 0x5a5d4c in loadHTMLstream /targets/w3m-tats/file.c:7265:2
    #5 0x55bbf8 in loadHTMLBuffer /targets/w3m-tats/file.c:6794:5
    #6 0x55ee64 in loadSomething /targets/w3m-tats/file.c:224:16
    #7 0x5535ac in loadGeneralFile /targets/w3m-tats/file.c:2241:6
    #8 0x4f9202 in main /targets/w3m-tats/main.c:1017:12
    #9 0x7fed79631f44 in __libc_start_main /build/eglibc-oGUzwX/eglibc-2.19/csu/libc-start.c:287

SUMMARY: AddressSanitizer: heap-buffer-overflow /targets/w3m-tats/table.c:432:12 in visible_length
Shadow bytes around the buggy address:
  0x0c067fff99d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff99e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff99f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c067fff9a10: fa fa fa fa fa fa fa fa 00 00 00 00 fa fa 00 00
=>0x0c067fff9a20: 00 00[fa]fa 00 00 00 00 fa fa 00 00 00 00 fa fa
  0x0c067fff9a30: 00 00 00 02 fa fa 00 00 00 fa fa fa 00 00 00 00
  0x0c067fff9a40: fa fa 00 00 00 00 fa fa 00 00 00 00 fa fa fd fd
  0x0c067fff9a50: fd fd fa fa 00 00 00 00 fa fa 00 00 00 00 fa fa
  0x0c067fff9a60: 00 00 00 fa fa fa 00 00 00 00 fa fa 00 00 02 fa
  0x0c067fff9a70: fa fa 00 00 02 fa fa fa 00 00 00 00 fa fa 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
==827466==ABORTING

This is detected with help of dummy libgc wrapper. See http://github.com/kcwu/fuzzing-w3m/notgc for detail.
More detail to reproduce please see http://github.com/kcwu/fuzzing-w3m

For your convenience,
gdbline:
LD_LIBRARY_PATH=./notgc ASAN_OPTIONS=abort_on_error=1:detect_leaks=0 gdb --args ./w3m-tats.asan -T text/html -dump cases/tats-w3m-73

this is found by afl-fuzz
@kcwu
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kcwu commented Dec 7, 2016

table.c

437             n = get_mclen(str);
...
494             str += n;

n=3, str jump beyond the end of string.

This was referenced Dec 7, 2016
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@kcwu
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kcwu commented Dec 7, 2016

Given issue 73,74,75. I'd suggest to review all caller of get_mclen() in w3m.

tats added a commit that referenced this issue Dec 8, 2016
@tats
Prevent overflow beyond the end of string in visible_length()
a932f78 
Bug-Debian: #73
@tats
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tats commented Dec 8, 2016

Fixed, thank you.

@tats tats closed this as completed Dec 8, 2016
@kcwu kcwu mentioned this issue Dec 9, 2016
Closed
tats added a commit that referenced this issue Dec 15, 2016
@tats
Prevent overflow beyond the end of string in caller of get_mclen()
6eea841 
Bug-Debian: #59
Bug-Debian: #73
Bug-Debian: #74
Bug-Debian: #76
Bug-Debian: #79
Bug-Debian: #80
Bug-Debian: #83
Bug-Debian: #84
@tats
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tats commented Dec 15, 2016

Patch updated.

tats added a commit that referenced this issue May 5, 2017
@tats
Fix multiple vulnerabilities (closes: #850432)
d73f74e 
- New patch 934_menu.patch to fix buffer overflow (#49)
- New patch 935_shiftanchor.patch to fix buffer overflow (#62)
- New patch 936_metarefresh.patch to fix buffer overflow (#63)
- New patch 937_lineproc0.patch to fix buffer overflow (#67)
- New patch 938_lineproc2body.patch to fix buffer overflow (#61)
- New patch 939_textarea.patch to fix buffer overflow (#58)
- New patch 940_tabattr.patch to fix buffer overflow (#60)
- New patch 941_integeredwidth.patch to fix buffer overflow (#70)
- New patch 942_tridvalue.patch to fix buffer overflow (#71)
- New patch 943_pushlink.patch to fix buffer overflow (#64, #66)
- New patch 944_lineproc0.patch to fix use after free (#65)
- New patch 945_wtfstrwidth.patch to fix buffer overflow (#57)
- New patch 946_strnewsize.patch to fix buffer overflow (#72)
- New patch 947_realcolumn.patch to fix buffer overflow (#69)
- New patch 948_getmclen.patch to fix buffer overflow
  (#59, #73, #74, #75, #76, #78, #79, #80, #83, #84)
- New patch 949_wtftowcs.patch to fix buffer overflow (#77)
- New patch 950_textarea.patch to fix infinite loop (#85)
- New patch 951_lineproc0.patch to fix use after free (#81)
- New patch 952_formupdatebuffer.patch to fix buffer overflow (#82)
- New patch 953_formupdateline.patch to fix buffer overflow
  (#68#issuecomment-266214643)
- New patch 954_wtfparse1.patch to fix buffer overflow (#68)
tats added a commit that referenced this issue May 5, 2017
@tats
Prevent overflow beyond the end of string in caller of get_mclen()
047640e 
Bug-Debian: #59
Bug-Debian: #73
Bug-Debian: #74
Bug-Debian: #75
Bug-Debian: #76
Bug-Debian: #78
Bug-Debian: #79
Bug-Debian: #80
Bug-Debian: #83
Bug-Debian: #84
Origin: https://anonscm.debian.org/cgit/collab-maint/w3m.git/commit/?id=6eea841d3a0f8dc539584dc67b15f585a8213775
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