A regression would still absolutely fail and even a flaky pass isn't
harmful as it'd fail most of the time across our N system test runs.
Windows has a low resolution timer and CI systems are prone to odd
timing so this just gives more leeway to avoid flakiness.
This makes tokenizer.c:valid_utf8 match stringlib/codecs.h:decode_utf8.
It also fixes an off-by-one error introduced in 3.10 for the line number when the tokenizer reports bad UTF8.
This doesn't happen naturally, but is allowed by the ASDL and compiler.
We don't want to change ASDL for backward compatibility reasons
(#57645, #92987)
Converting a large enough `int` to a decimal string raises `ValueError` as expected. However, the raise comes _after_ the quadratic-time base-conversion algorithm has run to completion. For effective DOS prevention, we need some kind of check before entering the quadratic-time loop. Oops! =)
The quick fix: essentially we catch _most_ values that exceed the threshold up front. Those that slip through will still be on the small side (read: sufficiently fast), and will get caught by the existing check so that the limit remains exact.
The justification for the current check. The C code check is:
```c
max_str_digits / (3 * PyLong_SHIFT) <= (size_a - 11) / 10
```
In GitHub markdown math-speak, writing $M$ for `max_str_digits`, $L$ for `PyLong_SHIFT` and $s$ for `size_a`, that check is:
$$\left\lfloor\frac{M}{3L}\right\rfloor \le \left\lfloor\frac{s - 11}{10}\right\rfloor$$
From this it follows that
$$\frac{M}{3L} < \frac{s-1}{10}$$
hence that
$$\frac{L(s-1)}{M} > \frac{10}{3} > \log_2(10).$$
So
$$2^{L(s-1)} > 10^M.$$
But our input integer $a$ satisfies $|a| \ge 2^{L(s-1)}$, so $|a|$ is larger than $10^M$. This shows that we don't accidentally capture anything _below_ the intended limit in the check.
<!-- gh-issue-number: gh-95778 -->
* Issue: gh-95778
<!-- /gh-issue-number -->
Co-authored-by: Gregory P. Smith [Google LLC] <greg@krypto.org>
* gh-68163: Correct conversion of Rational instances to float
Also document that numerator/denominator properties are instances of Integral.
Co-authored-by: Mark Dickinson <dickinsm@gmail.com>
Link to #93884
* Test with some large negative and positive values(out of range of a longlong,i.e.[-2\*\*63, 2\*\*63-1])
* Test with objects of non-int type
Automerge-Triggered-By: GH:mdickinson
Integer to and from text conversions via CPython's bignum `int` type is not safe against denial of service attacks due to malicious input. Very large input strings with hundred thousands of digits can consume several CPU seconds.
This PR comes fresh from a pile of work done in our private PSRT security response team repo.
Signed-off-by: Christian Heimes [Red Hat] <christian@python.org>
Tons-of-polishing-up-by: Gregory P. Smith [Google] <greg@krypto.org>
Reviews via the private PSRT repo via many others (see the NEWS entry in the PR).
<!-- gh-issue-number: gh-95778 -->
* Issue: gh-95778
<!-- /gh-issue-number -->
I wrote up [a one pager for the release managers](https://docs.google.com/document/d/1KjuF_aXlzPUxTK4BMgezGJ2Pn7uevfX7g0_mvgHlL7Y/edit#). Much of that text wound up in the Issue. Backports PRs already exist. See the issue for links.
* gh-96132: Add some comments and minor fixes missed in the original PR
* Update Doc/using/cmdline.rst
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
⚠️⚠️ Note for reviewers, hackers and fellow systems/low-level/compiler engineers ⚠️⚠️
If you have a lot of experience with this kind of shenanigans and want to improve the **first** version, **please make a PR against my branch** or **reach out by email** or **suggest code changes directly on GitHub**.
If you have any **refinements or optimizations** please, wait until the first version is merged before starting hacking or proposing those so we can keep this PR productive.
datetime.isoformat generates the tzoffset with colons, but there
was no format code to make strftime output the same format.
for simplicity and consistency the %:z formatting behaves mostly
as %z, with the exception of adding colons. this includes the
dynamic behaviour of adding seconds and microseconds only when
needed (when not 0).
this fixes the still open "generate" part of this issue:
https://github.com/python/cpython/issues/69142
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Nikita Sobolev
Benjamin Peterson
Dennis Sweeney
Irit Katriel
Christian Heimes
Dong-hee Na
Gregory P. Smith
Guido van Rossum
Steve Dower
Zachary Ware
finefoot
Mark Shannon
philg314
Michael Droettboom
Jelle Zijlstra
Jason R. Coombs
Shantanu
Pamela Fox
Mark Dickinson
Sergey B Kirpichev
Charlie Zhao
Vinay Sajip
Serhiy Storchaka
Gregory P. Smith
Raymond Hettinger
Anh71me
Filip Łajszczak
Pablo Galindo Salgado
Alexandru Mărășteanu
Kumar Aditya
TW