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gh-127182: Fix io.StringIO.__setstate__ crash when None is the first value #127219

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merged 3 commits into from
Nov 25, 2024
Merged

gh-127182: Fix io.StringIO.__setstate__ crash when None is the first value #127219

merged 3 commits into from
Nov 25, 2024

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sobolevn
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@sobolevn sobolevn commented Nov 24, 2024 •
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Change:

  • We now check for explicit None value in __setstate__, it cannot be recieved normally, because __getstate__ never returns None, but we should not let a simple direct call to crash, when the fix is rather simple
  • Why does it happen in the first place? Because we do the input validation with __init__ method:

    cpython/Modules/_io/stringio.c

    Line 898 in f7bb658

    if (_io_StringIO___init__((PyObject *)self, initarg, NULL) < 0) {
  • But, None is an allowed input value, see

    cpython/Modules/_io/stringio.c

    Line 693 in f7bb658

    if (value && value != Py_None && !PyUnicode_Check(value)) {
  • We did not check for None in __setstate__
  • NULL cannot be passed to __setstate__, because it requires a tuple input

@sobolevn sobolevn added needs backport to 3.12 bug and security fixes needs backport to 3.13 bugs and security fixes labels Nov 24, 2024
@bedevere-app bedevere-app bot mentioned this pull request Nov 24, 2024
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vstinner
vstinner reviewed Nov 25, 2024
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Modules/_io/stringio.c
self->string_size = bufsize;
}
else {
assert(item == Py_None);
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It may be worth it to check item value at runtime, and fail with an assertion if it's not None.

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I don't think that it is, because __init__ call above checks that. I don't think that it would be possible to trigger this error here.

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Oh right, it makes sense. I didn't see the _io_StringIO___init__() call.

Lib/test/test_io.py Outdated Show resolved Hide resolved
@sobolevn @vstinner
Update Lib/test/test_io.py
3ffff8e 
Co-authored-by: Victor Stinner <vstinner@python.org>
vstinner
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LGTM

Modules/_io/stringio.c
self->string_size = bufsize;
}
else {
assert(item == Py_None);
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Oh right, it makes sense. I didn't see the _io_StringIO___init__() call.

ZeroIntensity
ZeroIntensity approved these changes Nov 25, 2024
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LGTM

Modules/_io/stringio.c
self->string_size = bufsize;
}
else {
assert(item == Py_None);
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As a side note, should we encourage using Py_Is instead of ==?

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In this case, Py_IsNone() can be used ;-)

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I would prefer to keep it as == Py_None, because other related parts do the same thing: if (value && value != Py_None && !PyUnicode_Check(value)) in __init__, for example.

@sobolevn sobolevn merged commit a2ee899 into python:main Nov 25, 2024
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Thanks @sobolevn for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Nov 25, 2024
@sobolevn @vstinner @miss-islington
pythongh-127182: Fix io.StringIO.__setstate__ crash when None is …
5694d24 
…the first value (pythonGH-127219)

(cherry picked from commit a2ee899)

Co-authored-by: sobolevn <mail@sobolevn.me>
Co-authored-by: Victor Stinner <vstinner@python.org>
miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Nov 25, 2024
@sobolevn @vstinner @miss-islington
pythongh-127182: Fix io.StringIO.__setstate__ crash when None is …
b4c48aa 
…the first value (pythonGH-127219)

(cherry picked from commit a2ee899)

Co-authored-by: sobolevn <mail@sobolevn.me>
Co-authored-by: Victor Stinner <vstinner@python.org>
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bedevere-app bot commented Nov 25, 2024

GH-127262 is a backport of this pull request to the 3.13 branch.

@bedevere-app bedevere-app bot removed the needs backport to 3.13 bugs and security fixes label Nov 25, 2024
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bedevere-app bot commented Nov 25, 2024

GH-127263 is a backport of this pull request to the 3.12 branch.

@bedevere-app bedevere-app bot removed the needs backport to 3.12 bug and security fixes label Nov 25, 2024
sobolevn added a commit that referenced this pull request Nov 25, 2024
@miss-islington @sobolevn @vstinner
[3.12] gh-127182: Fix io.StringIO.__setstate__ crash when None is…
a4d6b90 
… the first value (GH-127219) (#127263)

gh-127182: Fix `io.StringIO.__setstate__` crash when `None` is the first value (GH-127219)
(cherry picked from commit a2ee899)

Co-authored-by: sobolevn <mail@sobolevn.me>
Co-authored-by: Victor Stinner <vstinner@python.org>
sobolevn added a commit that referenced this pull request Nov 25, 2024
@miss-islington @sobolevn @vstinner
[3.13] gh-127182: Fix io.StringIO.__setstate__ crash when None is…
a1b9663 
… the first value (GH-127219) (#127262)

gh-127182: Fix `io.StringIO.__setstate__` crash when `None` is the first value (GH-127219)
(cherry picked from commit a2ee899)

Co-authored-by: sobolevn <mail@sobolevn.me>
Co-authored-by: Victor Stinner <vstinner@python.org>
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@vstinner vstinner vstinner approved these changes

@ZeroIntensity ZeroIntensity ZeroIntensity approved these changes

@serhiy-storchaka serhiy-storchaka serhiy-storchaka approved these changes

@picnixz picnixz Awaiting requested review from picnixz

@erlend-aasland erlend-aasland Awaiting requested review from erlend-aasland

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