Description

Heap-based Buffer Overflow in function ml_append_int at memline.c:2951

vim version

git log
commit 043d7b2c84cda275354aa023b5769660ea70a168 (HEAD -> master, tag: v9.0.1182, origin/master, origin/HEAD)

POC

./vim -u NONE -i NONE -n -m -X -Z -e -s -S ./poc_hbo02_s.dat -c :qa!
=================================================================
==11458==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x621000009d00 at pc 0x00000049950f bp 0x7ffcbaff3ef0 sp 0x7ffcbaff36b8
READ of size 2147479553 at 0x621000009d00 thread T0
    #0 0x49950e in __asan_memmove (/home/fuzz/vim/src/vim+0x49950e)
    #1 0xabc5d7 in ml_append_int /home/fuzz/vim/src/memline.c:2951:6
    #2 0xa9b51f in ml_flush_line /home/fuzz/vim/src/memline.c:4109:9
    #3 0xab24bc in ml_append_flush /home/fuzz/vim/src/memline.c:3370:2
    #4 0xab2342 in ml_append_flags /home/fuzz/vim/src/memline.c:3415:12
    #5 0x117b44a in u_undoredo /home/fuzz/vim/src/undo.c:2821:7
    #6 0x117535b in u_doit /home/fuzz/vim/src/undo.c:2273:6
    #7 0x1174c1a in u_undo /home/fuzz/vim/src/undo.c:2214:5
    #8 0xbaad92 in nv_kundo /home/fuzz/vim/src/normal.c:4737:2
    #9 0xba3d19 in nv_undo /home/fuzz/vim/src/normal.c:4719:2
    #10 0xb6448b in normal_cmd /home/fuzz/vim/src/normal.c:939:5
    #11 0x83ea0e in exec_normal /home/fuzz/vim/src/ex_docmd.c:8887:6
    #12 0x83e238 in exec_normal_cmd /home/fuzz/vim/src/ex_docmd.c:8850:5
    #13 0x83dde9 in ex_normal /home/fuzz/vim/src/ex_docmd.c:8768:6
    #14 0x8060c1 in do_one_cmd /home/fuzz/vim/src/ex_docmd.c:2580:2
    #15 0x7f2ae5 in do_cmdline /home/fuzz/vim/src/ex_docmd.c:993:17
    #16 0xea1d75 in do_source_ext /home/fuzz/vim/src/scriptfile.c:1672:5
    #17 0xe9e7d6 in do_source /home/fuzz/vim/src/scriptfile.c:1818:12
    #18 0xe9e10c in cmd_source /home/fuzz/vim/src/scriptfile.c:1163:14
    #19 0xe9d7ee in ex_source /home/fuzz/vim/src/scriptfile.c:1189:2
    #20 0x8060c1 in do_one_cmd /home/fuzz/vim/src/ex_docmd.c:2580:2
    #21 0x7f2ae5 in do_cmdline /home/fuzz/vim/src/ex_docmd.c:993:17
    #22 0x7f7831 in do_cmdline_cmd /home/fuzz/vim/src/ex_docmd.c:587:12
    #23 0x14c4e12 in exe_commands /home/fuzz/vim/src/main.c:3146:2
    #24 0x14c0fae in vim_main2 /home/fuzz/vim/src/main.c:782:2
    #25 0x14b6449 in main /home/fuzz/vim/src/main.c:433:12
    #26 0x7f8319ce2082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
    #27 0x41eaad in _start (/home/fuzz/vim/src/vim+0x41eaad)

0x621000009d00 is located 0 bytes to the right of 4096-byte region [0x621000008d00,0x621000009d00)
allocated by thread T0 here:
    #0 0x499d0d in malloc (/home/fuzz/vim/src/vim+0x499d0d)
    #1 0x4cb3ea in lalloc /home/fuzz/vim/src/alloc.c:246:11
    #2 0x4cb2ca in alloc /home/fuzz/vim/src/alloc.c:151:12
    #3 0x14ce9f5 in mf_alloc_bhdr /home/fuzz/vim/src/memfile.c:884:21
    #4 0x14cd807 in mf_new /home/fuzz/vim/src/memfile.c:375:26
    #5 0xa98308 in ml_new_data /home/fuzz/vim/src/memline.c:4138:15
    #6 0xa96ca7 in ml_open /home/fuzz/vim/src/memline.c:391:15
    #7 0x503cd6 in open_buffer /home/fuzz/vim/src/buffer.c:192:9
    #8 0x14c265c in create_windows /home/fuzz/vim/src/main.c:2915:9
    #9 0x14c092d in vim_main2 /home/fuzz/vim/src/main.c:713:5
    #10 0x14b6449 in main /home/fuzz/vim/src/main.c:433:12
    #11 0x7f8319ce2082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/fuzz/vim/src/vim+0x49950e) in __asan_memmove
Shadow bytes around the buggy address:
  0x0c427fff9350: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff9360: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff9370: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff9380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c427fff9390: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c427fff93a0:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff93b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff93c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff93d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff93e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c427fff93f0: 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
==11458==ABORTING

poc_hbo02_s.dat

Impact

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