…#22780)

Problem:
Wrong buffer size argument passed to snprintf() in set_cmdarg():
	Thread no. 1 (24 frames)
	 #8 snprintf at /usr/include/bits/stdio2.h:54
	 #9 set_cmdarg at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/eval.c:7044
	 #10 apply_autocmds_group at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/autocmd.c:1843
	 #11 apply_autocmds_exarg at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/autocmd.c:1549
	 #12 readfile at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/fileio.c:617
	 #13 buf_reload at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/fileio.c:5038
	 #14 buf_check_timestamp at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/fileio.c:4952
	 #15 check_timestamps at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/fileio.c:4678
	 #16 ex_checktime at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_cmds2.c:765
	 #17 execute_cmd0 at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:1620
	 neovim#18 do_one_cmd at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:2275
	 neovim#19 do_cmdline at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:584
	 neovim#20 ex_execute at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/eval.c:7727
	 neovim#21 execute_cmd0 at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:1620
	 neovim#22 do_one_cmd at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:2275
	 neovim#23 do_cmdline at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:584
	 neovim#24 do_ucmd at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/usercmd.c:1661
	 neovim#25 execute_cmd0 at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:1612
	 neovim#26 do_one_cmd at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:2275
	 neovim#27 do_cmdline at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/ex_docmd.c:584
	 neovim#28 nv_colon at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/normal.c:4058
	 neovim#29 normal_execute at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/normal.c:1172
	 neovim#30 state_enter at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/state.c:88
	 neovim#31 normal_enter at /usr/src/debug/neovim-0.8.2-2.fc38.x86_64/src/nvim/normal.c:471

Solution:
Subtract the offset from the buffer size.

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

fix(usercmd): fix buffer overflow in uc_list()

Build with: -Wp,-D_FORTIFY_SOURCE=3 -O1 and gcc 13.

*** buffer overflow detected ***: terminated

(gdb) bt
  #0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
  #1  0x00007f3eb8b93c03 in __pthread_kill_internal (signo=6, threadid=<optimized out>) at pthread_kill.c:78
  #2  0x00007f3eb8b42aee in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
  #3  0x00007f3eb8b2b87f in __GI_abort () at abort.c:79
  #4  0x00007f3eb8b2c60f in __libc_message (fmt=fmt@entry=0x7f3eb8ca72e6 "*** %s ***: terminated\n") at ../sysdeps/posix/libc_fatal.c:150
  #5  0x00007f3eb8c27b29 in __GI___fortify_fail (msg=msg@entry=0x7f3eb8ca728c "buffer overflow detected") at fortify_fail.c:24
  #6  0x00007f3eb8c26364 in __GI___chk_fail () at chk_fail.c:28
  #7  0x00007f3eb8c25f45 in ___snprintf_chk (s=s@entry=0x55b8c7c096a5 <IObuff+5> "t' item", maxlen=maxlen@entry=1025, flag=flag@entry=2, slen=slen@entry=1020, format=format@entry=0x55b8c7b872a6 "%ldc") at snprintf_chk.c:29
  #8  0x000055b8c7aea59f in snprintf (__fmt=0x55b8c7b872a6 "%ldc", __n=1025, __s=0x55b8c7c096a5 <IObuff+5> "t' item") at /usr/include/bits/stdio2.h:54
  #9  uc_list (name=name@entry=0x55b8c8351788 "Explore", name_len=name_len@entry=7) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/usercmd.c:534
  #10 0x000055b8c7aeb8a0 in ex_command (eap=0x7fffdc350e60) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/usercmd.c:1009
  #11 0x000055b8c7972537 in execute_cmd0 (retv=retv@entry=0x7fffdc350e54, eap=eap@entry=0x7fffdc350e60, errormsg=errormsg@entry=0x7fffdc350e58, preview=preview@entry=false) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:1620
  #12 0x000055b8c7975c55 in do_one_cmd (cmdlinep=cmdlinep@entry=0x7fffdc3510b8, flags=flags@entry=0, cstack=cstack@entry=0x7fffdc351140, fgetline=fgetline@entry=0x55b8c79882b8 <getexline>, cookie=cookie@entry=0x0) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:2279
  #13 0x000055b8c79767fe in do_cmdline (cmdline=<optimized out>, fgetline=0x55b8c79882b8 <getexline>, cookie=0x0, flags=0) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:578
  #14 0x000055b8c7a17463 in nv_colon (cap=0x7fffdc351780) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:3228
  #15 0x000055b8c7a11b35 in normal_execute (state=0x7fffdc351700, key=<optimized out>) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:1196
  #16 0x000055b8c7ab0994 in state_enter (s=0x7fffdc351700) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/state.c:99
  #17 0x000055b8c7a0ef68 in normal_enter (cmdwin=false, noexmode=false) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:497
  neovim#18 0x000055b8c78a0640 in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/main.c:641

Build with: -Wp,-D_FORTIFY_SOURCE=3 -O1 and gcc 13.

*** buffer overflow detected ***: terminated

(gdb) bt
  #0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
  #1  0x00007f3eb8b93c03 in __pthread_kill_internal (signo=6, threadid=<optimized out>) at pthread_kill.c:78
  #2  0x00007f3eb8b42aee in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
  #3  0x00007f3eb8b2b87f in __GI_abort () at abort.c:79
  #4  0x00007f3eb8b2c60f in __libc_message (fmt=fmt@entry=0x7f3eb8ca72e6 "*** %s ***: terminated\n") at ../sysdeps/posix/libc_fatal.c:150
  #5  0x00007f3eb8c27b29 in __GI___fortify_fail (msg=msg@entry=0x7f3eb8ca728c "buffer overflow detected") at fortify_fail.c:24
  #6  0x00007f3eb8c26364 in __GI___chk_fail () at chk_fail.c:28
  #7  0x00007f3eb8c25f45 in ___snprintf_chk (s=s@entry=0x55b8c7c096a5 <IObuff+5> "t' item", maxlen=maxlen@entry=1025, flag=flag@entry=2, slen=slen@entry=1020, format=format@entry=0x55b8c7b872a6 "%ldc") at snprintf_chk.c:29
  #8  0x000055b8c7aea59f in snprintf (__fmt=0x55b8c7b872a6 "%ldc", __n=1025, __s=0x55b8c7c096a5 <IObuff+5> "t' item") at /usr/include/bits/stdio2.h:54
  #9  uc_list (name=name@entry=0x55b8c8351788 "Explore", name_len=name_len@entry=7) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/usercmd.c:534
  #10 0x000055b8c7aeb8a0 in ex_command (eap=0x7fffdc350e60) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/usercmd.c:1009
  #11 0x000055b8c7972537 in execute_cmd0 (retv=retv@entry=0x7fffdc350e54, eap=eap@entry=0x7fffdc350e60, errormsg=errormsg@entry=0x7fffdc350e58, preview=preview@entry=false) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:1620
  #12 0x000055b8c7975c55 in do_one_cmd (cmdlinep=cmdlinep@entry=0x7fffdc3510b8, flags=flags@entry=0, cstack=cstack@entry=0x7fffdc351140, fgetline=fgetline@entry=0x55b8c79882b8 <getexline>, cookie=cookie@entry=0x0) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:2279
  #13 0x000055b8c79767fe in do_cmdline (cmdline=<optimized out>, fgetline=0x55b8c79882b8 <getexline>, cookie=0x0, flags=0) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/ex_docmd.c:578
  #14 0x000055b8c7a17463 in nv_colon (cap=0x7fffdc351780) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:3228
  #15 0x000055b8c7a11b35 in normal_execute (state=0x7fffdc351700, key=<optimized out>) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:1196
  #16 0x000055b8c7ab0994 in state_enter (s=0x7fffdc351700) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/state.c:99
  #17 0x000055b8c7a0ef68 in normal_enter (cmdwin=false, noexmode=false) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/normal.c:497
  neovim#18 0x000055b8c78a0640 in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/neovim-0.9.0-1.fc38.x86_64/src/nvim/main.c:641