string: improve stpncpy() "bounds" unit test
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Authored by fuz on Dec 10 2025, 9:18 PM.

Details

Reviewers

mjg
ngie
markj
getz

Commits

rGe2f095779323: libc/tests/string: improve stpncpy() "bounds" unit test
rG54849107681d: libc/tests/string: improve stpncpy() "bounds" unit test
rG8be864282609: libc/test: fix typo
rG123c08620049: libc/tests/string: improve stpncpy() "bounds" unit test

Summary

The test is extended the same way I previously extended the memccpy()
test to fix what is probably the same kind of bug.

PR: 291359
Reported by: Collin Funk <collin.funk1@gmail.com>
Fixes: 6fa9e7d8737548ef93c573387ce62402c368d486 (D42519)
See also: 61ed5748e4e9c7397fcb2638b442f46ac5c9e7c5 (D46051)
MFC after: 1 week

Test Plan

now correctly diagnoses bug #291359, while other
implementations of stpncpy() still pass.

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Passed

Unit

No Test Coverage

Build Status

Buildable 69167
Build 66050: arc lint + arc unit

Event Timeline

fuz created this revision.Dec 10 2025, 9:18 PM

Herald added a subscriber: imp. · View Herald TranscriptDec 10 2025, 9:18 PM

fuz requested review of this revision.Dec 10 2025, 9:18 PM

Harbormaster completed remote builds in B69167: Diff 167834.Dec 10 2025, 9:18 PM

fuz added a parent revision: D42519: lib/libc/amd64/string: add stpncpy scalar, baseline implementation.Dec 10 2025, 9:19 PM

fuz mentioned this in D54170: libc/amd64: fix overread conditions in stpncpy().Dec 10 2025, 9:20 PM

fuz added a child revision: D54170: libc/amd64: fix overread conditions in stpncpy().Dec 10 2025, 9:21 PM

ngie accepted this revision.Dec 11 2025, 6:58 AM

ngie added inline comments.

lib/libc/tests/string/stpncpy_test.c
105

This revision is now accepted and ready to land.Dec 11 2025, 6:58 AM

Approved

Closed by commit rG123c08620049: libc/tests/string: improve stpncpy() "bounds" unit test (authored by fuz). · Explain WhyDec 14 2025, 4:08 PM

This revision was automatically updated to reflect the committed changes.

fuz mentioned this in rG66eb78377bf1: libc/amd64: fix overread conditions in stpncpy().

fuz added a commit: rG123c08620049: libc/tests/string: improve stpncpy() "bounds" unit test.

fuz added a commit: rG8be864282609: libc/test: fix typo.Dec 14 2025, 5:07 PM

fuz added a commit: rG54849107681d: libc/tests/string: improve stpncpy() "bounds" unit test.Jan 1 2026, 10:22 PM

fuz mentioned this in rGb49401c0bd4c: libc/amd64: fix overread conditions in stpncpy().Jan 4 2026, 1:24 PM

fuz added a commit: rGe2f095779323: libc/tests/string: improve stpncpy() "bounds" unit test.Jan 4 2026, 1:27 PM

fuz mentioned this in rGb0dc25c6d378: libc/amd64: fix overread conditions in stpncpy().

Revision Contents
Changeset List

Path

Size

lib/

libc/

tests/

string/

stpncpy_test.c

55 lines

Diff 167834

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lib/libc/tests/string/stpncpy_test.c

libc/tests/string: improve stpncpy() "bounds" unit testClosedPublicActions