Description

Buffer Over-read in function utfc_ptr2len at mbyte.c:2113

vim version

git log
commit 5a8fad32ea9c075f045b37d6c7739891d458f82b (HEAD -> master, tag: v8.2.4962, origin/master, origin/HEAD)

POC

./vim -u NONE -i NONE -n -m -X -Z -e -s -S /mnt/share/max/fuzz/poc/vim/poc_h8_s.dat -c :qa!
=================================================================
==18557==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000077b2 at pc 0x000000a3df46 bp 0x7ffe920fd0e0 sp 0x7ffe920fd0d8
READ of size 1 at 0x6020000077b2 thread T0
    #0 0xa3df45 in utfc_ptr2len /home/fuzz/fuzz/vim/vim/src/mbyte.c:2113:15
    #1 0xb34578 in get_visual_text /home/fuzz/fuzz/vim/vim/src/normal.c:3679:12
    #2 0xb31086 in nv_ident /home/fuzz/fuzz/vim/vim/src/normal.c:3469:23
    #3 0xb1a341 in normal_cmd /home/fuzz/fuzz/vim/vim/src/normal.c:930:5
    #4 0x80ebde in exec_normal /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8757:6
    #5 0x80e408 in exec_normal_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8720:5
    #6 0x80dfb9 in ex_normal /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:8638:6
    #7 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #8 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #9 0x11503df in call_user_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:2900:2
    #10 0x114c4bd in call_user_func_check /home/fuzz/fuzz/vim/vim/src/userfunc.c:3048:2
    #11 0x1146844 in call_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:3612:11
    #12 0x1143bef in get_func_tv /home/fuzz/fuzz/vim/vim/src/userfunc.c:1833:8
    #13 0x11764b6 in ex_call /home/fuzz/fuzz/vim/vim/src/userfunc.c:5513:6
    #14 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #15 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #16 0xe5191c in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1674:5
    #17 0xe4e376 in do_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1801:12
    #18 0xe4dcac in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1174:14
    #19 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #20 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #21 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #22 0x7c8f31 in do_cmdline_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:586:12
    #23 0x1419502 in exe_commands /home/fuzz/fuzz/vim/vim/src/main.c:3108:2
    #24 0x141569b in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:780:2
    #25 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #26 0x7fcb54965082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
    #27 0x41ea6d in _start (/home/fuzz/fuzz/vim/vim/src/vim+0x41ea6d)

0x6020000077b2 is located 0 bytes to the right of 2-byte region [0x6020000077b0,0x6020000077b2)
allocated by thread T0 here:
    #0 0x499ccd in malloc (/home/fuzz/fuzz/vim/vim/src/vim+0x499ccd)
    #1 0x4cb3aa in lalloc /home/fuzz/fuzz/vim/vim/src/alloc.c:246:11
    #2 0x4cb28a in alloc /home/fuzz/fuzz/vim/vim/src/alloc.c:151:12
    #3 0xf85f7d in vim_strnsave /home/fuzz/fuzz/vim/vim/src/strings.c:44:9
    #4 0xa75d55 in ml_replace_len /home/fuzz/fuzz/vim/vim/src/memline.c:3441:13
    #5 0xa75a22 in ml_replace /home/fuzz/fuzz/vim/vim/src/memline.c:3404:12
    #6 0x7af7f1 in ex_substitute /home/fuzz/fuzz/vim/vim/src/ex_cmds.c:4670:4
    #7 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #8 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #9 0x11503df in call_user_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:2900:2
    #10 0x114c4bd in call_user_func_check /home/fuzz/fuzz/vim/vim/src/userfunc.c:3048:2
    #11 0x1146844 in call_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:3612:11
    #12 0x1143bef in get_func_tv /home/fuzz/fuzz/vim/vim/src/userfunc.c:1833:8
    #13 0x11764b6 in ex_call /home/fuzz/fuzz/vim/vim/src/userfunc.c:5513:6
    #14 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #15 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #16 0xe5191c in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1674:5
    #17 0xe4e376 in do_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1801:12
    #18 0xe4dcac in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1174:14
    #19 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #20 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #21 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #22 0x7c8f31 in do_cmdline_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:586:12
    #23 0x1419502 in exe_commands /home/fuzz/fuzz/vim/vim/src/main.c:3108:2
    #24 0x141569b in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:780:2
    #25 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #26 0x7fcb54965082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/fuzz/fuzz/vim/vim/src/mbyte.c:2113:15 in utfc_ptr2len
Shadow bytes around the buggy address:
  0x0c047fff8ea0: fa fa 02 fa fa fa 02 fa fa fa fd fa fa fa fd fa
  0x0c047fff8eb0: fa fa 05 fa fa fa fd fd fa fa fd fa fa fa fd fa
  0x0c047fff8ec0: fa fa fd fa fa fa 02 fa fa fa 02 fa fa fa 02 fa
  0x0c047fff8ed0: fa fa fd fa fa fa fd fa fa fa 01 fa fa fa 02 fa
  0x0c047fff8ee0: fa fa 02 fa fa fa fd fa fa fa fd fa fa fa 01 fa
=>0x0c047fff8ef0: fa fa fd fa fa fa[02]fa fa fa 00 04 fa fa 01 fa
  0x0c047fff8f00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8f10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8f20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8f30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8f40: 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
==18557==ABORTING

poc_h8_s.dat