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Heap-based Buffer Overflow in function ins_compl_add in vim/vim

Valid

Reported on

Jul 6th 2022

Description

Heap-based Buffer Overflow in function ins_compl_add at insexpand.c:751

vim version

git log
commit 324478037923feef1eb8a771648e38ade9e5e05a (HEAD -> master, tag: v9.0.0042, origin/master, origin/HEAD)

POC

./afl/src/vim -u NONE -i NONE -n -m -X -Z -e -s -S ./poc_hbor4_s.dat -c :qa!
=================================================================
==3114==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61e0000827cb at pc 0x0000009b3131 bp 0x7ffeee1a6850 sp 0x7ffeee1a6848
READ of size 1 at 0x61e0000827cb thread T0
    #0 0x9b3130 in ins_compl_add /home/fuzz/fuzz/vim/afl/src/insexpand.c:751:10
    #1 0x9b1294 in ins_compl_add_infercase /home/fuzz/fuzz/vim/afl/src/insexpand.c:697:12
    #2 0x9d137b in get_next_default_completion /home/fuzz/fuzz/vim/afl/src/insexpand.c:3629:6
    #3 0x9cc7f7 in get_next_completion_match /home/fuzz/fuzz/vim/afl/src/insexpand.c:3694:24
    #4 0x9c9a7e in ins_compl_get_exp /home/fuzz/fuzz/vim/afl/src/insexpand.c:3767:20
    #5 0x9c8438 in find_next_completion_match /home/fuzz/fuzz/vim/afl/src/insexpand.c:4002:21
    #6 0x9c0f04 in ins_compl_next /home/fuzz/fuzz/vim/afl/src/insexpand.c:4103:9
    #7 0x9c197c in ins_complete /home/fuzz/fuzz/vim/afl/src/insexpand.c:4954:9
    #8 0x674939 in edit /home/fuzz/fuzz/vim/afl/src/edit.c:1281:10
    #9 0xb989c7 in op_change /home/fuzz/fuzz/vim/afl/src/ops.c:1758:14
    #10 0xbb25f7 in do_pending_operator /home/fuzz/fuzz/vim/afl/src/ops.c:4041:7
    #11 0xb21ac3 in normal_cmd /home/fuzz/fuzz/vim/afl/src/normal.c:961:2
    #12 0x8156fe in exec_normal /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8814:6
    #13 0x814f28 in exec_normal_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8777:5
    #14 0x814ad9 in ex_normal /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8695:6
    #15 0x7dda59 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
    #16 0x7ca915 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
    #17 0xe5c8fe in do_source_ext /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1674:5
    #18 0xe59396 in do_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1801:12
    #19 0xe58cd3 in cmd_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1174:14
    #20 0xe583de in ex_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1200:2
    #21 0x7dda59 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
    #22 0x7ca915 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
    #23 0x7cf591 in do_cmdline_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:586:12
    #24 0x1427482 in exe_commands /home/fuzz/fuzz/vim/afl/src/main.c:3133:2
    #25 0x142361b in vim_main2 /home/fuzz/fuzz/vim/afl/src/main.c:780:2
    #26 0x1418b2d in main /home/fuzz/fuzz/vim/afl/src/main.c:432:12
    #27 0x7fd83cb66082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
    #28 0x41ea5d in _start (/home/fuzz/fuzz/vim/afl/src/vim+0x41ea5d)

0x61e0000827cb is located 125 bytes to the right of 2766-byte region [0x61e000081c80,0x61e00008274e)
allocated by thread T0 here:
    #0 0x499cbd in malloc (/home/fuzz/fuzz/vim/afl/src/vim+0x499cbd)
    #1 0x4cb392 in lalloc /home/fuzz/fuzz/vim/afl/src/alloc.c:246:11
    #2 0x4cb27a in alloc /home/fuzz/fuzz/vim/afl/src/alloc.c:151:12
    #3 0xf90f0d in vim_strnsave /home/fuzz/fuzz/vim/afl/src/strings.c:44:9
    #4 0x9b349a in ins_compl_add /home/fuzz/fuzz/vim/afl/src/insexpand.c:768:26
    #5 0x9b1294 in ins_compl_add_infercase /home/fuzz/fuzz/vim/afl/src/insexpand.c:697:12
    #6 0x9d137b in get_next_default_completion /home/fuzz/fuzz/vim/afl/src/insexpand.c:3629:6
    #7 0x9cc7f7 in get_next_completion_match /home/fuzz/fuzz/vim/afl/src/insexpand.c:3694:24
    #8 0x9c9a7e in ins_compl_get_exp /home/fuzz/fuzz/vim/afl/src/insexpand.c:3767:20
    #9 0x9c8438 in find_next_completion_match /home/fuzz/fuzz/vim/afl/src/insexpand.c:4002:21
    #10 0x9c0f04 in ins_compl_next /home/fuzz/fuzz/vim/afl/src/insexpand.c:4103:9
    #11 0x9c197c in ins_complete /home/fuzz/fuzz/vim/afl/src/insexpand.c:4954:9
    #12 0x674939 in edit /home/fuzz/fuzz/vim/afl/src/edit.c:1281:10
    #13 0xb989c7 in op_change /home/fuzz/fuzz/vim/afl/src/ops.c:1758:14
    #14 0xbb25f7 in do_pending_operator /home/fuzz/fuzz/vim/afl/src/ops.c:4041:7
    #15 0xb21ac3 in normal_cmd /home/fuzz/fuzz/vim/afl/src/normal.c:961:2
    #16 0x8156fe in exec_normal /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8814:6
    #17 0x814f28 in exec_normal_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8777:5
    #18 0x814ad9 in ex_normal /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:8695:6
    #19 0x7dda59 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
    #20 0x7ca915 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
    #21 0xe5c8fe in do_source_ext /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1674:5
    #22 0xe59396 in do_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1801:12
    #23 0xe58cd3 in cmd_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1174:14
    #24 0xe583de in ex_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1200:2
    #25 0x7dda59 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
    #26 0x7ca915 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
    #27 0x7cf591 in do_cmdline_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:586:12
    #28 0x1427482 in exe_commands /home/fuzz/fuzz/vim/afl/src/main.c:3133:2
    #29 0x142361b in vim_main2 /home/fuzz/fuzz/vim/afl/src/main.c:780:2

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/fuzz/fuzz/vim/afl/src/insexpand.c:751:10 in ins_compl_add
Shadow bytes around the buggy address:
  0x0c3c800084a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3c800084b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3c800084c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3c800084d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c3c800084e0: 00 00 00 00 00 00 00 00 00 06 fa fa fa fa fa fa
=>0x0c3c800084f0: fa fa fa fa fa fa fa fa fa[fa]fa fa fa fa fa fa
  0x0c3c80008500: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3c80008510: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3c80008520: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3c80008530: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c3c80008540: 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
  Shadow gap:              cc
==3114==ABORTING

poc_hbor4_s.dat

Impact

This vulnerability is capable of crashing software, modify memory, and possible remote execution.

We are processing your report and will contact the vim team within 24 hours. a year ago
We have contacted a member of the vim team and are waiting to hear back a year ago
Bram Moolenaar validated this vulnerability a year ago

I can reproduce it. There must be a much simpler way to reproduc this: using a line more than 1030 bytes long.

Uinitech has been awarded the disclosure bounty
The fix bounty is now up for grabs
The researcher's credibility has increased: +7
Bram Moolenaar marked this as fixed in 9.0.0044 with commit caea66 a year ago
Bram Moolenaar has been awarded the fix bounty
This vulnerability will not receive a CVE
xiaoge1001
a year ago

After fixing the vulnerability, there are new problems, and the corresponding information is as follows:

=================================================================
==33751==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x619000000981 at pc 0x7fa2ab4b7fe4 bp 0x7ffe8d066220 sp 0x7ffe8d0659c8
READ of size 1026 at 0x619000000981 thread T0
    #0 0x7fa2ab4b7fe3  (/usr/lib64/libasan.so.6+0x52fe3)
    #1 0x66cbdb in ins_compl_infercase_gettext /root/github_vim/src/insexpand.c:645
    #2 0x66d350 in ins_compl_add_infercase /root/github_vim/src/insexpand.c:725
    #3 0x6796d9 in get_next_default_completion /root/github_vim/src/insexpand.c:3668
    #4 0x6799db in get_next_completion_match /root/github_vim/src/insexpand.c:3733
    #5 0x679e91 in ins_compl_get_exp /root/github_vim/src/insexpand.c:3806
    #6 0x67aafa in find_next_completion_match /root/github_vim/src/insexpand.c:4041
    #7 0x67ae9e in ins_compl_next /root/github_vim/src/insexpand.c:4142
    #8 0x67e01c in ins_complete /root/github_vim/src/insexpand.c:4993
    #9 0x4d8fb4 in edit /root/github_vim/src/edit.c:1281
    #10 0x75c69a in op_change /root/github_vim/src/ops.c:1758
    #11 0x76e7ed in do_pending_operator /root/github_vim/src/ops.c:4041
    #12 0x724e12 in normal_cmd /root/github_vim/src/normal.c:961
    #13 0x5a98ab in exec_normal /root/github_vim/src/ex_docmd.c:8814
    #14 0x5a9674 in exec_normal_cmd /root/github_vim/src/ex_docmd.c:8777
    #15 0x5a8f0b in ex_normal /root/github_vim/src/ex_docmd.c:8695
    #16 0x5857c0 in do_one_cmd /root/github_vim/src/ex_docmd.c:2570
    #17 0x57c853 in do_cmdline /root/github_vim/src/ex_docmd.c:992
    #18 0x89e715 in do_source_ext /root/github_vim/src/scriptfile.c:1674
    #19 0x89f8aa in do_source /root/github_vim/src/scriptfile.c:1801
    #20 0x89c32d in cmd_source /root/github_vim/src/scriptfile.c:1174
    #21 0x89c3a0 in ex_source /root/github_vim/src/scriptfile.c:1200
    #22 0x5857c0 in do_one_cmd /root/github_vim/src/ex_docmd.c:2570
    #23 0x57c853 in do_cmdline /root/github_vim/src/ex_docmd.c:992
    #24 0x57ab0e in do_cmdline_cmd /root/github_vim/src/ex_docmd.c:586
    #25 0xb6de7a in exe_commands /root/github_vim/src/main.c:3133
    #26 0xb66d6a in vim_main2 /root/github_vim/src/main.c:780
    #27 0xb66570 in main /root/github_vim/src/main.c:432
    #28 0x7fa2ab18220f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
    #29 0x7fa2ab1822bb in __libc_start_main_impl ../csu/libc-start.c:409
    #30 0x404f24 in _start (/root/github_vim/src/vim+0x404f24)

0x619000000981 is located 0 bytes to the right of 1025-byte region [0x619000000580,0x619000000981)
allocated by thread T0 here:
    #0 0x7fa2ab5141c7 in __interceptor_malloc (/usr/lib64/libasan.so.6+0xaf1c7)
    #1 0x405370 in lalloc /root/github_vim/src/alloc.c:246
    #2 0x405161 in alloc /root/github_vim/src/alloc.c:151
    #3 0xb66fc1 in common_init /root/github_vim/src/main.c:914
    #4 0xb66220 in main /root/github_vim/src/main.c:185
    #5 0x7fa2ab18220f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

SUMMARY: AddressSanitizer: heap-buffer-overflow (/usr/lib64/libasan.so.6+0x52fe3) 
Shadow bytes around the buggy address:
  0x0c327fff80e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff80f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c327fff8120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c327fff8130:[01]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fff8140: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c327fff8150: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8160: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8170: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c327fff8180: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
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
  Shadow gap:              cc
==33751==ABORTING

Occurrences

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