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Fix two problems with unset -f behavior #22

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merged 1 commit into from
Jun 17, 2020
Merged

Fix two problems with unset -f behavior #22

merged 1 commit into from
Jun 17, 2020

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JohnoKing
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@JohnoKing JohnoKing commented Jun 17, 2020 •
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This pull request backports two bug fixes from ksh93v- for the problems detailed in #21. These fixes do the following:

In src/cmd/ksh93/sh/name.c, the check for if a function is still running has been corrected to fix a segmentation fault that occurred when a POSIX function unset itself.

The missing functionality for when a KornShell style function unsets itself has been added to src/cmd/ksh93/sh/xec.c. This kind of function will now be properly unset after it has finished running, rather than silently cause unset -f to fail.

McDutchie
McDutchie requested changes Jun 17, 2020
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I was half expecting you to show up for this one. :) Couple of comments below…

NEWS Show resolved Hide resolved
src/cmd/ksh93/tests/functions.sh Outdated Show resolved Hide resolved
@JohnoKing
Fix two problems with unset -f behavior
38d9279 
src/cmd/ksh93/sh/name.c:
 - Correct the check for when a function is currently running
   to fix a segmentation fault that occurred when a POSIX
   function tries to unset itself while it is running.
   This bug fix was backported from ksh93v-.

src/cmd/ksh93/sh/xec.c:
 - If a function tries to unset itself, unset the function
   with `_nv_unset(np, NV_RDONLY)` to fix a silent failure.
   This fix was also backported from ksh93v-.

src/cmd/ksh93/tests/functions.sh:
 - Add four regression tests for when a function unsets itself.
@McDutchie McDutchie merged commit b7932e8 into ksh93:master Jun 17, 2020
@McDutchie McDutchie mentioned this pull request Jun 17, 2020
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McDutchie added a commit that referenced this pull request Jun 17, 2020
@McDutchie
Part revert #22 to undo memory fault (re: b7932e8)
9751174 
The fix in sh/xec.c, which was backported from the ksh 93v- beta to
delay the actual removal of a running function that unsets itself,
caused a segfault in the variables.sh regression tests (see #23).

src/cmd/ksh93/sh/xec.c:
- Comment out the backported code pending a correct fix for #21.
  Now both types of functions silently fail to unset themselves
  (unless they're discipline functions).

src/cmd/ksh93/tests/functions.sh:
- Disable regression tests checking that the function was actually
  unset, pending a correct fix for #21.

Resolves: #23
Reopens: #21
McDutchie added a commit that referenced this pull request Jun 18, 2020
@McDutchie
Restore #22 'unset -f' fix minus segfault (re: b7932e8, 9751174)
3e3f6b0 
Applying the fix for 'unset -f' exposed a crashing bug in lookup()
in sh/nvdisc.c, which is the function for looking up discipline
functions. This is what caused tests/variables.sh to crash.
Ref.: #23 (comment)

src/cmd/ksh93/sh/nvdisc.c: lookup():
- To avoid segfault, check that the function pointer nq->nvalue.rp
  is actually set before checking if nq->nvalue.rp->running==1.

src/cmd/ksh93/sh/xec.c,
src/cmd/ksh93/tests/functions.sh:
- Uncomment the 'unset -f' fix from b7932e8.

Resolves #21 (again).
@JohnoKing JohnoKing deleted the fix-unset-f branch June 18, 2020 02:45
JohnoKing added a commit to JohnoKing/ksh that referenced this pull request Sep 23, 2022
@JohnoKing
Fix buffer overflow in quoting2.sh under ASan
d97873a 
The isaname, isaletter, isadigit, isexp and ismeta macros don't check if
c is a negative value before accessing sh_lexstates. This can result in
ASan crashing because of a buffer overflow in quoting2.sh when running
in a multibyte locale:
  test quoting2(C.UTF-8) begins at 2022-09-23+14:03:12
  =================================================================
  ==262224==ERROR: AddressSanitizer: global-buffer-overflow on address 0x557b201a451f at pc 0x557b1fe5e6fc bp 0x7fffcf1ac700 sp 0x7fffcf1ac6f8
  READ of size 1 at 0x557b201a451f thread T0
      #0 0x557b1fe5e6fb in sh_fmtq /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/string.c:341:5
      ksh93#1 0x557b1fe6098c in sh_fmtqf /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/string.c:473:10
      ksh93#2 0x557b1ff08dc0 in extend /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/print.c:998:14
      ksh93#3 0x557b2008a56c in sfvprintf /home/johno/GitRepos/KornShell/ksh/src/lib/libast/sfio/sfvprintf.c:531:8
      ksh93#4 0x557b2005b7f7 in sfprintf /home/johno/GitRepos/KornShell/ksh/src/lib/libast/sfio/sfprintf.c:31:7
      ksh93#5 0x557b1ff04272 in b_print /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/print.c:343:4
      ksh93#6 0x557b1ff04ebf in b_printf /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/print.c:148:9
      ksh93#7 0x557b1fe8d9a7 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1261:21
      ksh93#8 0x557b1fe7a7cf in sh_subshell /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/subshell.c:652:4
      ksh93#9 0x557b1fdedc0d in comsubst /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/macro.c:2207:9
      ksh93#10 0x557b1fdefc79 in varsub /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/macro.c:1181:3
      ksh93#11 0x557b1fde3bef in copyto /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/macro.c:620:21
      ksh93#12 0x557b1fde0b07 in sh_mactrim /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/macro.c:169:2
      ksh93#13 0x557b1fe05ab6 in nv_setlist /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/name.c:280:9
      ksh93#14 0x557b1fe8a7e8 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1051:7
      ksh93#15 0x557b1fe95b85 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1940:5
      ksh93#16 0x557b1fe99ea6 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:2271:10
      ksh93#17 0x557b1fd23b04 in exfile /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:604:4
      ksh93#18 0x557b1fd1fe10 in sh_main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:369:2
      ksh93#19 0x557b1fd1d585 in main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/pmain.c:41:9
      ksh93#20 0x7f55d5b5028f  (/usr/lib/libc.so.6+0x2328f) (BuildId: 26c81e7e05ebaf40bac3523b7d76be0cd71fad82)
      ksh93#21 0x7f55d5b50349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) (BuildId: 26c81e7e05ebaf40bac3523b7d76be0cd71fad82)
      ksh93#22 0x557b1fc158d4 in _start /build/glibc/src/glibc/csu/../sysdeps/x86_64/start.S:115

src/cmd/ksh93/include/lexstates.h:
- Check if c is negative before accessing sh_lexstates. Backported from
  ksh2020: att@a7013320.
  I'll note that later in ksh2020 these macros became functions:
  att@adc589de. I didn't backport that
  commit because it requires the C99 bool type to avoid compiler
  warnings.
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@JohnoKing @McDutchie