[3.11] gh-98433: Fix quadratic time idna decoding. (GH-99092) by miss-islington · Pull Request #99222

[3.11] gh-98433: Fix quadratic time idna decoding. (GH-99092) by miss-islington · Pull Request #99222 · python/cpython

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

This also adds an early length check in IDNA decoding to outright reject
huge inputs early on given the ultimate result is defined to be 63 or fewer
characters.
(cherry picked from commit d315722)

Co-authored-by: Gregory P. Smith <greg@krypto.org>

mentioned this pull request

Nov 8, 2022

While I don't think anyone should have reasonable code depending on
unbounded strings full of Nothing characters to silently be removed
during idna decoding... this is the conservative choice for a bugfix
backport.

miss-islington added a commit to miss-islington/cpython that referenced this pull request

Nov 8, 2022

) (pythonGH-99222)

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)

(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

miss-islington added a commit to miss-islington/cpython that referenced this pull request

Nov 8, 2022

) (pythonGH-99222)

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)

(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

miss-islington added a commit to miss-islington/cpython that referenced this pull request

Nov 8, 2022

) (pythonGH-99222)

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)

(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

miss-islington added a commit that referenced this pull request

Nov 8, 2022

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)

(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

ambv pushed a commit that referenced this pull request

Nov 10, 2022

… (GH-99231)

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)
(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>

ambv pushed a commit that referenced this pull request

Nov 10, 2022

… (#99230)

There was an unnecessary quadratic loop in idna decoding. This restores
the behavior to linear.

(cherry picked from commit d315722)
(cherry picked from commit a6f6c3a)

Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Co-authored-by: Gregory P. Smith <greg@krypto.org>