Out-of-bounds write in function vim_regsub_both in vim/vim
Valid
Reported on
Jun 16th 2022
Description
Out-of-bounds write in function vim_regsub_both at regexp.c:1973
vim version
git log
commit 83497f875881973df772cc4cc593766345df6c4a (HEAD -> master, tag: v8.2.5105, origin/master, origin/HEAD)
POC
root@fuzz-vm0-187:/home/fuzz/fuzz/vim/afl/src# ./vim -u NONE -i NONE -n -m -X -Z -e -s -S /mnt/share/max/fuzz/poc/vim/poc_obw7_s.dat -c :qa!
=================================================================
==25109==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x606000000f55 at pc 0x000000485338 bp 0x7fff61087290 sp 0x7fff61086a50
WRITE of size 2 at 0x606000000f55 thread T0
#0 0x485337 in strcpy (/home/fuzz/fuzz/vim/afl/src/vim+0x485337)
#1 0xcebc36 in vim_regsub_both /home/fuzz/fuzz/vim/afl/src/regexp.c:1973:3
#2 0xcf06eb in vim_regsub_multi /home/fuzz/fuzz/vim/afl/src/regexp.c:1915:14
#3 0x7b4328 in ex_substitute /home/fuzz/fuzz/vim/afl/src/ex_cmds.c:4531:9
#4 0x7dd249 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
#5 0x7ca105 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
#6 0xe58b5e in do_source_ext /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1674:5
#7 0xe555f6 in do_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1801:12
#8 0xe54f33 in cmd_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1174:14
#9 0xe5463e in ex_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1200:2
#10 0x7dd249 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
#11 0x7ca105 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
#12 0x7ced81 in do_cmdline_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:586:12
#13 0x1422702 in exe_commands /home/fuzz/fuzz/vim/afl/src/main.c:3133:2
#14 0x141e89b in vim_main2 /home/fuzz/fuzz/vim/afl/src/main.c:780:2
#15 0x1413dad in main /home/fuzz/fuzz/vim/afl/src/main.c:432:12
#16 0x7fc0b29a6082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
#17 0x41ea4d in _start (/home/fuzz/fuzz/vim/afl/src/vim+0x41ea4d)
0x606000000f55 is located 0 bytes to the right of 53-byte region [0x606000000f20,0x606000000f55)
allocated by thread T0 here:
#0 0x499cad in malloc (/home/fuzz/fuzz/vim/afl/src/vim+0x499cad)
#1 0x4cb382 in lalloc /home/fuzz/fuzz/vim/afl/src/alloc.c:246:11
#2 0x4cb26a in alloc /home/fuzz/fuzz/vim/afl/src/alloc.c:151:12
#3 0x7b3f23 in ex_substitute /home/fuzz/fuzz/vim/afl/src/ex_cmds.c:4493:24
#4 0x7dd249 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
#5 0x7ca105 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
#6 0xe58b5e in do_source_ext /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1674:5
#7 0xe555f6 in do_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1801:12
#8 0xe54f33 in cmd_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1174:14
#9 0xe5463e in ex_source /home/fuzz/fuzz/vim/afl/src/scriptfile.c:1200:2
#10 0x7dd249 in do_one_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:2570:2
#11 0x7ca105 in do_cmdline /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:992:17
#12 0x7ced81 in do_cmdline_cmd /home/fuzz/fuzz/vim/afl/src/ex_docmd.c:586:12
#13 0x1422702 in exe_commands /home/fuzz/fuzz/vim/afl/src/main.c:3133:2
#14 0x141e89b in vim_main2 /home/fuzz/fuzz/vim/afl/src/main.c:780:2
#15 0x1413dad in main /home/fuzz/fuzz/vim/afl/src/main.c:432:12
#16 0x7fc0b29a6082 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/afl/src/vim+0x485337) in strcpy
Shadow bytes around the buggy address:
0x0c0c7fff8190: fd fd fd fd fd fd fd fa fa fa fa fa 00 00 00 00
0x0c0c7fff81a0: 00 00 05 fa fa fa fa fa fd fd fd fd fd fd fd fa
0x0c0c7fff81b0: fa fa fa fa fd fd fd fd fd fd fd fd fa fa fa fa
0x0c0c7fff81c0: 00 00 00 00 00 00 00 fa fa fa fa fa 00 00 00 00
0x0c0c7fff81d0: 00 00 00 fa fa fa fa fa 00 00 00 00 00 00 00 fa
=>0x0c0c7fff81e0: fa fa fa fa 00 00 00 00 00 00[05]fa fa fa fa fa
0x0c0c7fff81f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c7fff8200: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c7fff8210: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c7fff8220: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0c7fff8230: 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
==25109==ABORTING
Impact
This may result in corruption of sensitive information, a crash, or code execution among other things.
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
I can reproduce the problem. Also with a further simplified POC.
Uinitech
has been awarded the disclosure bounty
The fix bounty is now up for grabs
The researcher's credibility has increased: +7
Fixed with patch 8.2.5126, which includes a regression test.
ren0216
commented
a year ago
Found that patch 8.2.4616 can not reproduce the problem, but patch 8.2.4617 can not , thus , dose this mean 4617 taking the vulnerability in ?
Not sure. Sometimes a patch does not fix an issue, but changes the way it is reproduced. Especially issues that rely on text being in a certain allocated area. I made patch 9.0.0013 specifically to make it simpler to reproduce issues.
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