Heap-based Buffer Overflow in function ins_compl_infercase_gettext() in vim/vim
Reported on
Jul 15th 2022
Description
Heap-based Buffer Overflow in function ins_compl_infercase_gettext at src/insexpand.c:645
vim version
commit 3a393790a4fd7a5edcafbb55cd79438b6e641714
Author: Dominique Pelle <dominique.pelle@gmail.com>
Date: Thu Jul 14 17:40:49 2022 +0100
patch 9.0.0053: E1281 not tested with the old regexp engine
Problem: E1281 not tested with the old regexp engine.
Solution: Loop over the values of 'regexp'. (Dominique Pellé, closes #10695)
To reproduce
export CFLAGS="-g3 -fsanitize=address -fno-common -fno-omit-frame-pointer -fPIC"
export LDFLAGS="-g3 -fsanitize=address -fno-common -fno-omit-frame-pointer -fPIC"
./configure
make -j4
./src/vim -u NONE -i NONE -n -m -X -Z -e -s -S ./poc_hbor4_s.dat -c :qa!
Stack information
=================================================================
==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
POC
https://raw.githubusercontent.com/JieyongMa/poc/main/vim/poc_hbor4_s.dat
Impact
This vulnerability is capable of crashing software, modify memory, and possible remote execution.
There was no response for a long time, so I decided to try to fix it.
I have verified that the patch is valid and the problem will not reproduce.
The POC is rather complicated, Ken Takata found a much simpler one.
I would like to mark this as fixed by patch 9.0.0060, but I can't select myself as fixer. The patch suggested above is not a good fix. @admin
Hi Bram, just responded to your e-mail. But in short, you need to ensure that you are not auth'ed as a magic maintainer, but instead are signed in with your GitHub account.
Please clear any tokens from your URL, and sign out / sign in again. Should work 👍
@brammool There is a problem with the associated patch. It should be patch 9.0.0060 not patch 9.0.0061, but the link given above is the link of patch 9.0.0061(https://www.github.com/vim/vim/commit/5fa9f2). The patch given by NVD is also patch 9.0.0061, which should be problematic.
@Bram - let me know if you need any support on the above, i.e. adjusting the CVE 👍
I guess the right commit is b9e717367c395490149495cf375911b5d9de889e
Note that I never use those hex numbers, we use human-readable patch numbers.
Whatever. I only care about fixing problems, I don't care much about the bookkeeping.