Limit remarkup URI protocol length to 32 characters to avoid expensive regex behavior
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Authored by epriestley on Feb 17 2021, 9:12 PM.

Details

Reviewers: None
Maniphest Tasks: T13608: Remarkup hyperlink pattern may backtrack explosively
Commits: rPbd4d9d88f2df: Limit remarkup URI protocol length to 32 characters to avoid expensive regex…

Summary

Ref T13608. When searching for bare URIs in remarkup text, don't look for URIs with a protocol string longer than 32 characters.

This avoids a case where the regexp engine may be tricked into executing at O(N^2) or some similar complexity.

Test Plan

Applied remarkup to "AAAA..." (512KB).
Before: 64 seconds to process.
After: <10ms to process.
Ran unit tests.

Diff Detail

Repository

rP Phabricator

Branch

remarkup1

Lint

Lint Passed

Unit

Tests Passed

Build Status

Buildable 25141
Build 34696: Run Core Tests
Build 34695: arc lint + arc unit

Event Timeline

epriestley created this revision.Feb 17 2021, 9:12 PM

Harbormaster completed remote builds in B25141: Diff 51331.Feb 17 2021, 9:13 PM

epriestley requested review of this revision.Feb 17 2021, 9:13 PM

This revision was not accepted when it landed; it landed in state Needs Review.Feb 17 2021, 9:21 PM

Closed by commit rPbd4d9d88f2df: Limit remarkup URI protocol length to 32 characters to avoid expensive regex… (authored by epriestley). · Explain Why

This revision was automatically updated to reflect the committed changes.

epriestley added a commit: rPbd4d9d88f2df: Limit remarkup URI protocol length to 32 characters to avoid expensive regex….

epriestley mentioned this in T13608: Remarkup hyperlink pattern may backtrack explosively.Feb 17 2021, 9:23 PM

epriestley mentioned this in D21568: Add a negative lookbehind to the Remarkup "bare URI" regular expression pattern.Feb 18 2021, 7:56 PM

epriestley mentioned this in rP8cfd22c5fe88: Add a negative lookbehind to the Remarkup "bare URI" regular expression pattern.Feb 18 2021, 7:59 PM

Revision Contents
Changeset List

Path

Size

src/

infrastructure/

markup/

markuprule/

PhutilRemarkupHyperlinkRule.php

40 lines

Diff 51331

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src/infrastructure/markup/markuprule/PhutilRemarkupHyperlinkRule.php

Limit remarkup URI protocol length to 32 characters to avoid expensive regex behaviorClosedPublicActions