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read -r -d should not ignore -r #17

Merged
merged 1 commit into from
Jun 16, 2020
Merged

read -r -d should not ignore -r #17

merged 1 commit into from
Jun 16, 2020

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JohnoKing
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This bug was previously reported in att#37. Ksh ignores -r when read -r -d is run because when the bit for D_FLAG is set, the bit for R_FLAG is unset as a side effect of setting D_FLAG. The following set of commands fails to print a backslash:

$ printf '\\\000' | read -r -d ''
$ echo $REPLY

The fix for this bug is to set the bit for D_FLAG with D_FLAG + 1, which prevents R_FLAG from being unset. This bugfix and its regression test have been backported from ksh93v- 2013-10-10-alpha.

@JohnoKing
read -r -d should not ignore -r
1c3958d 
This bug was previously reported in att#37.
Ksh ignores `-r` when `read -r -d` is run because when
the bit for `D_FLAG` is set, the bit for `R_FLAG` is unset
as a side effect of setting `D_FLAG`. The following set
of commands fails to print a backslash:

$ printf '\\\000' | read -r -d ''
$ echo $REPLY

The fix for this bug is to set `D_FLAG` with `D_FLAG + 1`,
which prevents `R_FLAG` from being unset. This bugfix
has been backported from ksh93v- 2013-10-10-alpha.

src/cmd/ksh93/bltins/read.c:
 - Set `D_FLAG` with `D_FLAG + 1` to prevent the bit for
   `R_FLAG` from being unset.

src/cmd/ksh93/tests/builtins.sh:
 - Add the regression test for `read -r -d` from ksh93v-.
@McDutchie McDutchie merged commit 764acef into ksh93:master Jun 16, 2020
@JohnoKing JohnoKing deleted the fix-read-d-r branch June 18, 2020 02:43
McDutchie added a commit that referenced this pull request Jun 13, 2022
@McDutchie
remove ( simple_command & ) optimisation (re: e3d7bf1)
3b8c14a 
I didn't trust this back in e3d7bf1 (which disabled it for
interactive shells) and I trust it less now. In af6a32d/6b380572,
this was also disabled for virtual subshells as it caused program
flow corruption there. Now, on macOS 10.14.6, a crash occurs when
repeatedly running a command with this optimisation:

$ ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
0 1 2 3 4 5 6 7 Illegal instruction

Oddly enough it seems that I can only reproduce this crash on macOS
-- not on Linux, OpenBSD, or Solaris. It could be a macOS bug,
particularly given the odd message in the stack trace below.

I've had enough, though. Out it comes. Things now work fine, the
reproducer is fixed on macOS, and it didn't optimise much anyway.

The double-fork issue discussed in e3d7bf1 remains.
________
For future reference, here's an lldb debugger session with a stack
trace. It crashes on calling calloc() (via sh_calloc(), via
sh_newof()) in jobsave_create(). This is not an invalid pointer
problem as we're allocating new memory, so it does look like an OS
bug. The "BUG IN CLIENT OF LIBPLATFORM" message is interesting.

$ lldb -- arch/*/bin/ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
(lldb) target create "arch/darwin.i386-64/bin/ksh"
Current executable set to 'arch/darwin.i386-64/bin/ksh' (x86_64).
(lldb) settings set -- target.run-args  "-c" "for((i=0;i<100;i++));do print -n \"$i \";(sleep 1&);done"
(lldb) run
error: shell expansion failed (reason: lldb-argdumper exited with error 2). consider launching with 'process launch'.
(lldb) process launch
Process 35038 launched: '/usr/local/src/ksh93/ksh/arch/darwin.i386-64/bin/ksh' (x86_64)
0 1 2 3 4 5 6 7 8 9 Process 35038 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
libsystem_platform.dylib`_os_unfair_lock_recursive_abort:
->  0x7fff70deb1c2 <+23>: ud2

libsystem_platform.dylib`_os_unfair_lock_unowned_abort:
    0x7fff70deb1c4 <+0>:  movl   %edi, %eax
    0x7fff70deb1c6 <+2>:  leaq   0x1a8a(%rip), %rcx        ; "BUG IN CLIENT OF LIBPLATFORM: Unlock of an os_unfair_lock not owned by current thread"
    0x7fff70deb1cd <+9>:  movq   %rcx, 0x361cb16c(%rip)    ; gCRAnnotations + 8
Target 0: (ksh) stopped.
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
    frame #1: 0x00007fff70de7c9a libsystem_platform.dylib`_os_unfair_lock_lock_slow + 239
    frame #2: 0x00007fff70daa3bd libsystem_malloc.dylib`tiny_malloc_should_clear + 188
    frame #3: 0x00007fff70daa20f libsystem_malloc.dylib`szone_malloc_should_clear + 66
    frame #4: 0x00007fff70dab444 libsystem_malloc.dylib`malloc_zone_calloc + 99
    frame #5: 0x00007fff70dab3c4 libsystem_malloc.dylib`calloc + 30
    frame #6: 0x000000010003fa5d ksh`sh_calloc(nmemb=1, size=16) at init.c:264:13
    frame #7: 0x000000010004f8a6 ksh`jobsave_create(pid=35055) at jobs.c:272:8
    frame #8: 0x000000010004ed42 ksh`job_reap(sig=20) at jobs.c:363:9
    frame #9: 0x000000010004ff6f ksh`job_waitsafe(sig=20) at jobs.c:511:3
    frame #10: 0x00007fff70de9b5d libsystem_platform.dylib`_sigtramp + 29
    frame #11: 0x00007fff70d39ac4 libsystem_kernel.dylib`__fork + 12
    frame #12: 0x00007fff70c57d80 libsystem_c.dylib`fork + 17
    frame #13: 0x000000010009590d ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:1883:16
    frame #14: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:2019:4
    frame #15: 0x0000000100096c4f ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2213:9
    frame #16: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2019:4
    frame #17: 0x000000010001c23f ksh`exfile(iop=0x0000000100405750, fno=-1) at main.c:603:4
    frame #18: 0x000000010001b23c ksh`sh_main(ac=3, av=0x00007ffeefbff4f0, userinit=0x0000000000000000) at main.c:365:2
    frame #19: 0x0000000100000776 ksh`main(argc=3, argv=0x00007ffeefbff4f0) at pmain.c:45:9
    frame #20: 0x00007fff70bfe3d5 libdyld.dylib`start + 1
McDutchie added a commit that referenced this pull request Jun 13, 2022
@McDutchie
remove ( simple_command & ) optimisation (re: e3d7bf1)
5a9d13f 
I didn't trust this back in e3d7bf1 (which disabled it for
interactive shells) and I trust it less now. In af6a32d/6b380572,
this was also disabled for virtual subshells as it caused program
flow corruption there. Now, on macOS 10.14.6, a crash occurs when
repeatedly running a command with this optimisation:

$ ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
0 1 2 3 4 5 6 7 Illegal instruction

Oddly enough it seems that I can only reproduce this crash on macOS
-- not on Linux, OpenBSD, or Solaris. It could be a macOS bug,
particularly given the odd message in the stack trace below.

I've had enough, though. Out it comes. Things now work fine, the
reproducer is fixed on macOS, and it didn't optimise much anyway.

The double-fork issue discussed in e3d7bf1 remains.
________
For future reference, here's an lldb debugger session with a stack
trace. It crashes on calling calloc() (via sh_calloc(), via
sh_newof()) in jobsave_create(). This is not an invalid pointer
problem as we're allocating new memory, so it does look like an OS
bug. The "BUG IN CLIENT OF LIBPLATFORM" message is interesting.

$ lldb -- arch/*/bin/ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
(lldb) target create "arch/darwin.i386-64/bin/ksh"
Current executable set to 'arch/darwin.i386-64/bin/ksh' (x86_64).
(lldb) settings set -- target.run-args  "-c" "for((i=0;i<100;i++));do print -n \"$i \";(sleep 1&);done"
(lldb) run
error: shell expansion failed (reason: lldb-argdumper exited with error 2). consider launching with 'process launch'.
(lldb) process launch
Process 35038 launched: '/usr/local/src/ksh93/ksh/arch/darwin.i386-64/bin/ksh' (x86_64)
0 1 2 3 4 5 6 7 8 9 Process 35038 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
libsystem_platform.dylib`_os_unfair_lock_recursive_abort:
->  0x7fff70deb1c2 <+23>: ud2

libsystem_platform.dylib`_os_unfair_lock_unowned_abort:
    0x7fff70deb1c4 <+0>:  movl   %edi, %eax
    0x7fff70deb1c6 <+2>:  leaq   0x1a8a(%rip), %rcx        ; "BUG IN CLIENT OF LIBPLATFORM: Unlock of an os_unfair_lock not owned by current thread"
    0x7fff70deb1cd <+9>:  movq   %rcx, 0x361cb16c(%rip)    ; gCRAnnotations + 8
Target 0: (ksh) stopped.
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
    frame #1: 0x00007fff70de7c9a libsystem_platform.dylib`_os_unfair_lock_lock_slow + 239
    frame #2: 0x00007fff70daa3bd libsystem_malloc.dylib`tiny_malloc_should_clear + 188
    frame #3: 0x00007fff70daa20f libsystem_malloc.dylib`szone_malloc_should_clear + 66
    frame #4: 0x00007fff70dab444 libsystem_malloc.dylib`malloc_zone_calloc + 99
    frame #5: 0x00007fff70dab3c4 libsystem_malloc.dylib`calloc + 30
    frame #6: 0x000000010003fa5d ksh`sh_calloc(nmemb=1, size=16) at init.c:264:13
    frame #7: 0x000000010004f8a6 ksh`jobsave_create(pid=35055) at jobs.c:272:8
    frame #8: 0x000000010004ed42 ksh`job_reap(sig=20) at jobs.c:363:9
    frame #9: 0x000000010004ff6f ksh`job_waitsafe(sig=20) at jobs.c:511:3
    frame #10: 0x00007fff70de9b5d libsystem_platform.dylib`_sigtramp + 29
    frame #11: 0x00007fff70d39ac4 libsystem_kernel.dylib`__fork + 12
    frame #12: 0x00007fff70c57d80 libsystem_c.dylib`fork + 17
    frame #13: 0x000000010009590d ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:1883:16
    frame #14: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:2019:4
    frame #15: 0x0000000100096c4f ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2213:9
    frame #16: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2019:4
    frame #17: 0x000000010001c23f ksh`exfile(iop=0x0000000100405750, fno=-1) at main.c:603:4
    frame #18: 0x000000010001b23c ksh`sh_main(ac=3, av=0x00007ffeefbff4f0, userinit=0x0000000000000000) at main.c:365:2
    frame #19: 0x0000000100000776 ksh`main(argc=3, argv=0x00007ffeefbff4f0) at pmain.c:45:9
    frame #20: 0x00007fff70bfe3d5 libdyld.dylib`start + 1
McDutchie added a commit that referenced this pull request Jun 14, 2022
@McDutchie
remove ( simple_command & ) optimisation (re: e3d7bf1)
ed9053e 
I didn't trust this back in e3d7bf1 (which disabled it for
interactive shells) and I trust it less now. In af6a32d/6b380572,
this was also disabled for virtual subshells as it caused program
flow corruption there. Now, on macOS 10.14.6, a crash occurs when
repeatedly running a command with this optimisation:

$ ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
0 1 2 3 4 5 6 7 Illegal instruction

Oddly enough it seems that I can only reproduce this crash on macOS
-- not on Linux, OpenBSD, or Solaris. It could be a macOS bug,
particularly given the odd message in the stack trace below.

I've had enough, though. Out it comes. Things now work fine, the
reproducer is fixed on macOS, and it didn't optimise much anyway.

The double-fork issue discussed in e3d7bf1 remains.
________
For future reference, here's an lldb debugger session with a stack
trace. It crashes on calling calloc() (via sh_calloc(), via
sh_newof()) in jobsave_create(). This is not an invalid pointer
problem as we're allocating new memory, so it does look like an OS
bug. The "BUG IN CLIENT OF LIBPLATFORM" message is interesting.

$ lldb -- arch/*/bin/ksh -c 'for((i=0;i<100;i++));do print -n "$i ";(sleep 1&);done'
(lldb) target create "arch/darwin.i386-64/bin/ksh"
Current executable set to 'arch/darwin.i386-64/bin/ksh' (x86_64).
(lldb) settings set -- target.run-args  "-c" "for((i=0;i<100;i++));do print -n \"$i \";(sleep 1&);done"
(lldb) run
error: shell expansion failed (reason: lldb-argdumper exited with error 2). consider launching with 'process launch'.
(lldb) process launch
Process 35038 launched: '/usr/local/src/ksh93/ksh/arch/darwin.i386-64/bin/ksh' (x86_64)
0 1 2 3 4 5 6 7 8 9 Process 35038 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
libsystem_platform.dylib`_os_unfair_lock_recursive_abort:
->  0x7fff70deb1c2 <+23>: ud2

libsystem_platform.dylib`_os_unfair_lock_unowned_abort:
    0x7fff70deb1c4 <+0>:  movl   %edi, %eax
    0x7fff70deb1c6 <+2>:  leaq   0x1a8a(%rip), %rcx        ; "BUG IN CLIENT OF LIBPLATFORM: Unlock of an os_unfair_lock not owned by current thread"
    0x7fff70deb1cd <+9>:  movq   %rcx, 0x361cb16c(%rip)    ; gCRAnnotations + 8
Target 0: (ksh) stopped.
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x00007fff70deb1c2 libsystem_platform.dylib`_os_unfair_lock_recursive_abort + 23
    frame #1: 0x00007fff70de7c9a libsystem_platform.dylib`_os_unfair_lock_lock_slow + 239
    frame #2: 0x00007fff70daa3bd libsystem_malloc.dylib`tiny_malloc_should_clear + 188
    frame #3: 0x00007fff70daa20f libsystem_malloc.dylib`szone_malloc_should_clear + 66
    frame #4: 0x00007fff70dab444 libsystem_malloc.dylib`malloc_zone_calloc + 99
    frame #5: 0x00007fff70dab3c4 libsystem_malloc.dylib`calloc + 30
    frame #6: 0x000000010003fa5d ksh`sh_calloc(nmemb=1, size=16) at init.c:264:13
    frame #7: 0x000000010004f8a6 ksh`jobsave_create(pid=35055) at jobs.c:272:8
    frame #8: 0x000000010004ed42 ksh`job_reap(sig=20) at jobs.c:363:9
    frame #9: 0x000000010004ff6f ksh`job_waitsafe(sig=20) at jobs.c:511:3
    frame #10: 0x00007fff70de9b5d libsystem_platform.dylib`_sigtramp + 29
    frame #11: 0x00007fff70d39ac4 libsystem_kernel.dylib`__fork + 12
    frame #12: 0x00007fff70c57d80 libsystem_c.dylib`fork + 17
    frame #13: 0x000000010009590d ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:1883:16
    frame #14: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005d30, flags=4) at xec.c:2019:4
    frame #15: 0x0000000100096c4f ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2213:9
    frame #16: 0x0000000100096013 ksh`sh_exec(t=0x0000000101005a40, flags=5) at xec.c:2019:4
    frame #17: 0x000000010001c23f ksh`exfile(iop=0x0000000100405750, fno=-1) at main.c:603:4
    frame #18: 0x000000010001b23c ksh`sh_main(ac=3, av=0x00007ffeefbff4f0, userinit=0x0000000000000000) at main.c:365:2
    frame #19: 0x0000000100000776 ksh`main(argc=3, argv=0x00007ffeefbff4f0) at pmain.c:45:9
    frame #20: 0x00007fff70bfe3d5 libdyld.dylib`start + 1
JohnoKing added a commit to JohnoKing/ksh that referenced this pull request Aug 19, 2022
@JohnoKing
funct(): Fix another use after free bug (re: 59a5672, 7e317c5)
8d3c769 
The ASan crash in basic.sh when sourcing multiple files is caused by
a bug that is similar to the crash fixed in 59a5672. This is the
trace for the regression test crash (note that in order to see the
trace, the 2>/dev/null redirect must be disabled):

==1899388==ERROR: AddressSanitizer: heap-use-after-free on address 0x6150000005b0 at pc 0x55a5e3f9432a bp 0x7ffeb91ea110 sp 0x7ffeb91ea100
WRITE of size 8 at 0x6150000005b0 thread T0
    #0 0x55a5e3f94329 in funct /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:967
    ksh93#1 0x55a5e3f96f77 in item /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:1349
    ksh93#2 0x55a5e3f90c9f in term /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:642
    ksh93#3 0x55a5e3f90ac1 in list /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:613
    ksh93#4 0x55a5e3f90845 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:561
    ksh93#5 0x55a5e3f909e0 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:586
    ksh93#6 0x55a5e3f8fd5e in sh_parse /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:438
    ksh93#7 0x55a5e3fc43c1 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:635
    ksh93#8 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    ksh93#9 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    ksh93#10 0x55a5e3fd01d4 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1932
    ksh93#11 0x55a5e3fc4544 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:651
    ksh93#12 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    ksh93#13 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    ksh93#14 0x55a5e3ecc1cd in exfile /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:604
    ksh93#15 0x55a5e3ec9e7f in sh_main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:369
    ksh93#16 0x55a5e3ec801d in main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/pmain.c:41
    ksh93#17 0x7f637b4db2cf  (/usr/lib/libc.so.6+0x232cf)
    ksh93#18 0x7f637b4db389 in __libc_start_main (/usr/lib/libc.so.6+0x23389)
    ksh93#19 0x55a5e3ec7f24 in _start ../sysdeps/x86_64/start.S:115

Code in question:
https://github.com/ksh93/ksh/blob/8d57369b0cb39074437dd82924b604155e30e1e0/src/cmd/ksh93/sh/parse.c#L963-L968

To avoid any more similar crashes, all of the fixes introduced
in 7e317c5 that set slp->slptr to null have been improved with the
fix in 59a5672.
McDutchie pushed a commit that referenced this pull request Aug 19, 2022
@JohnoKing
funct(): Fix another use after free bug (re: 59a5672, 7e317c5) (#519)
645f8db 
The ASan crash in basic.sh when sourcing multiple files is caused by
a bug that is similar to the crash fixed in 59a5672. This is the
trace for the regression test crash (note that in order to see the
trace, the 2>/dev/null redirect must be disabled):

==1899388==ERROR: AddressSanitizer: heap-use-after-free on address 0x6150000005b0 at pc 0x55a5e3f9432a bp 0x7ffeb91ea110 sp 0x7ffeb91ea100
WRITE of size 8 at 0x6150000005b0 thread T0
    #0 0x55a5e3f94329 in funct /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:967
    #1 0x55a5e3f96f77 in item /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:1349
    #2 0x55a5e3f90c9f in term /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:642
    #3 0x55a5e3f90ac1 in list /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:613
    #4 0x55a5e3f90845 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:561
    #5 0x55a5e3f909e0 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:586
    #6 0x55a5e3f8fd5e in sh_parse /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:438
    #7 0x55a5e3fc43c1 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:635
    #8 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    #9 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    #10 0x55a5e3fd01d4 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1932
    #11 0x55a5e3fc4544 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:651
    #12 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    #13 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    #14 0x55a5e3ecc1cd in exfile /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:604
    #15 0x55a5e3ec9e7f in sh_main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:369
    #16 0x55a5e3ec801d in main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/pmain.c:41
    #17 0x7f637b4db2cf  (/usr/lib/libc.so.6+0x232cf)
    #18 0x7f637b4db389 in __libc_start_main (/usr/lib/libc.so.6+0x23389)
    #19 0x55a5e3ec7f24 in _start ../sysdeps/x86_64/start.S:115

Code in question:
https://github.com/ksh93/ksh/blob/8d57369b0cb39074437dd82924b604155e30e1e0/src/cmd/ksh93/sh/parse.c#L963-L968

To avoid any more similar crashes, all of the fixes introduced
in 7e317c5 that set slp->slptr to null have been improved with the
fix in 59a5672.
McDutchie pushed a commit that referenced this pull request Aug 19, 2022
@JohnoKing @McDutchie
funct(): Fix another use after free bug (re: f24040e, 69d37d5) (#519)
bee2e1c 
The ASan crash in basic.sh when sourcing multiple files is caused by
a bug that is similar to the crash fixed in f24040e. This is the
trace for the regression test crash (note that in order to see the
trace, the 2>/dev/null redirect must be disabled):

==1899388==ERROR: AddressSanitizer: heap-use-after-free on address 0x6150000005b0 at pc 0x55a5e3f9432a bp 0x7ffeb91ea110 sp 0x7ffeb91ea100
WRITE of size 8 at 0x6150000005b0 thread T0
    #0 0x55a5e3f94329 in funct /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:967
    #1 0x55a5e3f96f77 in item /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:1349
    #2 0x55a5e3f90c9f in term /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:642
    #3 0x55a5e3f90ac1 in list /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:613
    #4 0x55a5e3f90845 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:561
    #5 0x55a5e3f909e0 in sh_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:586
    #6 0x55a5e3f8fd5e in sh_parse /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/parse.c:438
    #7 0x55a5e3fc43c1 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:635
    #8 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    #9 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    #10 0x55a5e3fd01d4 in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1932
    #11 0x55a5e3fc4544 in sh_eval /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:651
    #12 0x55a5e4012172 in b_dot_cmd /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/bltins/misc.c:318
    #13 0x55a5e3fca3cb in sh_exec /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/xec.c:1254
    #14 0x55a5e3ecc1cd in exfile /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:604
    #15 0x55a5e3ec9e7f in sh_main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/main.c:369
    #16 0x55a5e3ec801d in main /home/johno/GitRepos/KornShell/ksh/src/cmd/ksh93/sh/pmain.c:41
    #17 0x7f637b4db2cf  (/usr/lib/libc.so.6+0x232cf)
    #18 0x7f637b4db389 in __libc_start_main (/usr/lib/libc.so.6+0x23389)
    #19 0x55a5e3ec7f24 in _start ../sysdeps/x86_64/start.S:115

Code in question:
https://github.com/ksh93/ksh/blob/8d57369b0cb39074437dd82924b604155e30e1e0/src/cmd/ksh93/sh/parse.c#L963-L968

To avoid any more similar crashes, all of the fixes introduced
in 69d37d5 that set slp->slptr to null have been improved with the
fix in f24040e.
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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2 participants
@JohnoKing @McDutchie