[MacPorts] #74183: outguess @0.4: -e (error correction) crashes with SIGABRT / stack smashing detected in steg_adjust_errors (was: outguess 0.4: -e (error correction) crashes with SIGABRT / stack smashing detected in steg_adjust_errors)
MacPorts
noreply at macports.org
Sat Jul 4 14:48:22 UTC 2026
#74183: outguess @0.4: -e (error correction) crashes with SIGABRT / stack smashing
detected in steg_adjust_errors
-------------------------+--------------------
Reporter: HybridBits | Owner: (none)
Type: defect | Status: new
Priority: Normal | Milestone:
Component: ports | Version:
Resolution: | Keywords:
Port: outguess |
-------------------------+--------------------
Old description:
> '''Port:''' outguess
> '''Port version:''' 0.4
> '''macOS version:''' macOS Sequoia 15.7.7
> '''Xcode version:''' 16.2
> '''Architecture:''' arm64 (Apple Silicon)
>
> == Summary ==
>
> outguess reliably crashes with SIGABRT (stack smashing /
> __stack_chk_fail) whenever the -e (error-correcting encoding) flag is
> used during embedding. The crash occurs inside steg_adjust_errors, part
> of the Golay error-correction code path. Output is left as a 0-byte file.
>
> I compared this against a separately-built outguess 0.2 binary (bundled
> with a third-party macOS app, built from what appears to be the original
> 2001 Niels Provos source) run against the identical image and message on
> the same machine — that build completes successfully with -e. Only the
> MacPorts-packaged 0.4 build crashes, which points to something in the
> 0.3/0.4 codebase (or how this port builds it) rather than an environment
> or usage issue.
>
> == Steps to reproduce ==
>
> {{{
> outguess -k testkey -e -p 85 -x 10 -s 1 -i 1000 -F- -d dataset.txt
> check.jpg out.jpg
> }}}
>
> (dataset.txt is any small text file, a few dozen bytes is enough to
> reproduce; check.jpg is any ordinary JPEG.)
>
> == Expected behavior ==
>
> Embedding completes normally, e.g.:
>
> {{{
> Initialize encoding/decoding tables
> Reading check.jpg....
> JPEG compression quality set to 85
> Extracting usable bits: 49398 bits
> Encoded 'dataset.txt' with ECC: 184 bits, 23 bytes
> Finding best embedding...
> 0: 7467(50.6%)[50.8%], bias 8137(1.09), saved: -13, total: 18.64%
> ...
> Bits embedded: ...
> Storing bitmap into data...
> Writing out.jpg....
> }}}
>
> == Actual behavior ==
>
> Process aborts immediately after "Finding best embedding...", before any
> embedding-progress lines print. out.jpg is created but is 0 bytes.
>
> {{{
> Initialize encoding/decoding tables
> Reading check.jpg....
> JPEG compression quality set to 85
> Extracting usable bits: 49398 bits
> Encoded 'dataset.txt' with ECC: 184 bits, 23 bytes
> Finding best embedding...
> Process ... stopped
>
> thread #1, stop reason = signal SIGABRT
> }}}
>
> Exit status observed via NSTask/shell: 6 (SIGABRT).
>
> == Backtrace (lldb) ==
>
> {{{
>
> thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
>
> frame #0: libsystem_kernel.dylib__pthread_kill + 8 frame #1:
> libsystem_pthread.dylibpthread_kill + 296
> frame #2: libsystem_c.dylib__abort + 132 frame #3:
> libsystem_c.dylib__stack_chk_fail + 96
> frame #4: outguesssteg_adjust_errors + 740 frame #5:
> outguesssteg_embedchunk + 128
> frame #6: outguesssteg_embed + 248 frame #7: outguesssteg_find + 320
> frame #8: outguessdo_embed + 332 frame #9: outguessmain + 1580
> frame #10: dyld`start + 6076
> }}}
>
>
>
> __stack_chk_fail indicates the stack protector detected a corrupted stack
> canary — i.e. a stack buffer overflow — inside steg_adjust_errors. This
> is a real memory-safety bug, not a false positive.
>
> == Notes on where else this has been reported ==
>
> Upstream (resurrecting-open-source-projects/outguess on GitHub) was
> archived by its owner on 2025-09-20 and is now read-only; no new issues
> can be filed there. Filing here instead since this affects the MacPorts-
> distributed build specifically and upstream is no longer reachable.
New description:
'''Port:''' outguess \\
'''Port version:''' 0.4 \\
'''macOS version:''' macOS Sequoia 15.7.7 \\
'''Xcode version:''' 16.2 \\
'''Architecture:''' arm64 (Apple Silicon)
== Summary ==
outguess reliably crashes with SIGABRT (stack smashing /
`__stack_chk_fail`) whenever the `-e` (error-correcting encoding) flag is
used during embedding. The crash occurs inside steg_adjust_errors, part of
the Golay error-correction code path. Output is left as a 0-byte file.
I compared this against a separately-built outguess 0.2 binary (bundled
with a third-party macOS app, built from what appears to be the original
2001 Niels Provos source) run against the identical image and message on
the same machine — that build completes successfully with `-e`. Only the
MacPorts-packaged 0.4 build crashes, which points to something in the
0.3/0.4 codebase (or how this port builds it) rather than an environment
or usage issue.
== Steps to reproduce ==
{{{
outguess -k testkey -e -p 85 -x 10 -s 1 -i 1000 -F- -d dataset.txt
check.jpg out.jpg
}}}
(dataset.txt is any small text file, a few dozen bytes is enough to
reproduce; check.jpg is any ordinary JPEG.)
== Expected behavior ==
Embedding completes normally, e.g.:
{{{
Initialize encoding/decoding tables
Reading check.jpg....
JPEG compression quality set to 85
Extracting usable bits: 49398 bits
Encoded 'dataset.txt' with ECC: 184 bits, 23 bytes
Finding best embedding...
0: 7467(50.6%)[50.8%], bias 8137(1.09), saved: -13, total: 18.64%
...
Bits embedded: ...
Storing bitmap into data...
Writing out.jpg....
}}}
== Actual behavior ==
Process aborts immediately after "Finding best embedding...", before any
embedding-progress lines print. out.jpg is created but is 0 bytes.
{{{
Initialize encoding/decoding tables
Reading check.jpg....
JPEG compression quality set to 85
Extracting usable bits: 49398 bits
Encoded 'dataset.txt' with ECC: 184 bits, 23 bytes
Finding best embedding...
Process ... stopped
thread #1, stop reason = signal SIGABRT
}}}
Exit status observed via NSTask/shell: 6 (SIGABRT).
== Backtrace (lldb) ==
{{{
thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGABRT
frame #0: libsystem_kernel.dylib__pthread_kill + 8 frame #1:
libsystem_pthread.dylibpthread_kill + 296
frame #2: libsystem_c.dylib__abort + 132 frame #3:
libsystem_c.dylib__stack_chk_fail + 96
frame #4: outguesssteg_adjust_errors + 740 frame #5:
outguesssteg_embedchunk + 128
frame #6: outguesssteg_embed + 248 frame #7: outguesssteg_find + 320
frame #8: outguessdo_embed + 332 frame #9: outguessmain + 1580
frame #10: dyld`start + 6076
}}}
`__stack_chk_fail` indicates the stack protector detected a corrupted
stack canary — i.e. a stack buffer overflow — inside `steg_adjust_errors`.
This is a real memory-safety bug, not a false positive.
== Notes on where else this has been reported ==
Upstream (resurrecting-open-source-projects/outguess on GitHub) was
archived by its owner on 2025-09-20 and is now read-only; no new issues
can be filed there. Filing here instead since this affects the MacPorts-
distributed build specifically and upstream is no longer reachable.
--
Comment (by ryandesign):
This port has no MacPorts maintainer, so if you know a fix, please submit
it!
--
Ticket URL: <https://trac.macports.org/ticket/74183#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS
More information about the macports-tickets
mailing list