Buffer Over-read in function get_one_sourceline in vim/vim

Valid

Reported on

May 16th 2022

Description

Buffer Over-read in function get_one_sourceline at scriptfile.c:1976

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_h6_s.dat -c :qa!
=================================================================
==16909==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61100000603a at pc 0x000000430bd6 bp 0x7fffaeb57dd0 sp 0x7fffaeb57590
READ of size 1 at 0x61100000603a thread T0
    #0 0x430bd5 in strlen (/home/fuzz/fuzz/vim/vim/src/vim+0x430bd5)
    #1 0xe57851 in get_one_sourceline /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1976:25
    #2 0xe550dc in getsourceline /home/fuzz/fuzz/vim/vim/src/scriptfile.c:2097:9
    #3 0xe514f9 in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1657:17
    #4 0xe4d919 in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1157:6
    #5 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #6 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #7 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #8 0x11503df in call_user_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:2900:2
    #9 0x114c4bd in call_user_func_check /home/fuzz/fuzz/vim/vim/src/userfunc.c:3048:2
    #10 0x1146844 in call_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:3612:11
    #11 0x1143bef in get_func_tv /home/fuzz/fuzz/vim/vim/src/userfunc.c:1833:8
    #12 0x11764b6 in ex_call /home/fuzz/fuzz/vim/vim/src/userfunc.c:5513:6
    #13 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #14 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #15 0xe5191c in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1674:5
    #16 0xe4e376 in do_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1801:12
    #17 0xe4dcac in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1174:14
    #18 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #19 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #20 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #21 0x7c8f31 in do_cmdline_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:586:12
    #22 0x1419502 in exe_commands /home/fuzz/fuzz/vim/vim/src/main.c:3108:2
    #23 0x141569b in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:780:2
    #24 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #25 0x7f6a7372b082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
    #26 0x41ea6d in _start (/home/fuzz/fuzz/vim/vim/src/vim+0x41ea6d)

0x61100000603a is located 0 bytes to the right of 250-byte region [0x611000005f40,0x61100000603a)
allocated by thread T0 here:
    #0 0x499fe9 in realloc (/home/fuzz/fuzz/vim/vim/src/vim+0x499fe9)
    #1 0x4ccc44 in ga_grow_inner /home/fuzz/fuzz/vim/vim/src/alloc.c:753:10
    #2 0x4cc8a5 in ga_grow /home/fuzz/fuzz/vim/vim/src/alloc.c:718:9
    #3 0xe570fa in get_one_sourceline /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1956:6
    #4 0xe550dc in getsourceline /home/fuzz/fuzz/vim/vim/src/scriptfile.c:2097:9
    #5 0xe514f9 in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1657:17
    #6 0xe4d919 in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1157:6
    #7 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #8 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #9 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #10 0x11503df in call_user_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:2900:2
    #11 0x114c4bd in call_user_func_check /home/fuzz/fuzz/vim/vim/src/userfunc.c:3048:2
    #12 0x1146844 in call_func /home/fuzz/fuzz/vim/vim/src/userfunc.c:3612:11
    #13 0x1143bef in get_func_tv /home/fuzz/fuzz/vim/vim/src/userfunc.c:1833:8
    #14 0x11764b6 in ex_call /home/fuzz/fuzz/vim/vim/src/userfunc.c:5513:6
    #15 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #16 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #17 0xe5191c in do_source_ext /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1674:5
    #18 0xe4e376 in do_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1801:12
    #19 0xe4dcac in cmd_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1174:14
    #20 0xe4d38e in ex_source /home/fuzz/fuzz/vim/vim/src/scriptfile.c:1200:2
    #21 0x7d7529 in do_one_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:2567:2
    #22 0x7c42e5 in do_cmdline /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:992:17
    #23 0x7c8f31 in do_cmdline_cmd /home/fuzz/fuzz/vim/vim/src/ex_docmd.c:586:12
    #24 0x1419502 in exe_commands /home/fuzz/fuzz/vim/vim/src/main.c:3108:2
    #25 0x141569b in vim_main2 /home/fuzz/fuzz/vim/vim/src/main.c:780:2
    #26 0x140ad95 in main /home/fuzz/fuzz/vim/vim/src/main.c:432:12
    #27 0x7f6a7372b082 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/vim+0x430bd5) in strlen
Shadow bytes around the buggy address:
  0x0c227fff8bb0: 00 00 00 00 00 00 00 02 fa fa fa fa fa fa fa fa
  0x0c227fff8bc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c227fff8bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02
  0x0c227fff8be0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  0x0c227fff8bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c227fff8c00: 00 00 00 00 00 00 00[02]fa fa fa fa fa fa fa fa
  0x0c227fff8c10: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8c20: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8c30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8c40: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c227fff8c50: 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
==16909==ABORTING

poc_h6_s.dat

Impact

This vulnerabilities are 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

commented a year ago

Maintainer

I managed to reproduce the problem. I could simplify the POC a bit more, which can be used for a test.

Bram Moolenaar validated this vulnerability a year ago

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 8.2 with commit 4748c4 a year ago

Bram Moolenaar has been awarded the fix bounty

This vulnerability will not receive a CVE

to join this conversation