Differential D28997

Allow ssp_test:read to pass more reliably
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Authored by arichardson on Mar 1 2021, 2:55 PM.

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Details

Reviewers

brooks
lwhsu
kevans
ngie
emaste

Commits

rGc8f8369856b5: Allow ssp_test:read to pass more reliably
rGc88c1f23a898: Allow ssp_test:read to pass more reliably

Summary

It appears that the stackframe layout can be slightly different depending on
compiler and target architecture. For example, when using CHERI LLVM for RISC-V
we can actually overflow the buffer by up to 8 bytes without SSP detecting it.
Fix this by increasing the overflow to 15 bytes.

Diff Detail

Repository

rS FreeBSD src repository - subversion

Lint

No Lint Coverage

Unit

No Test Coverage

Build Status

Buildable 37477
Build 34366: arc lint + arc unit

Event Timeline

arichardson created this revision.Mar 1 2021, 2:55 PM

Herald added a reviewer: ngie. · View Herald TranscriptMar 1 2021, 2:55 PM

Herald added a subscriber: imp. · View Herald Transcript

arichardson requested review of this revision.Mar 1 2021, 2:55 PM

Harbormaster completed remote builds in B37477: Diff 84904.Mar 1 2021, 2:55 PM

arichardson added a reviewer: emaste.Mar 1 2021, 3:29 PM

I think this is reasonable. I don't think we care whether SSP detects a stack overflow that overwrites only padding.

This revision is now accepted and ready to land.Mar 1 2021, 3:36 PM

emaste added inline comments.Mar 1 2021, 3:40 PM

contrib/netbsd-tests/lib/libc/ssp/t_ssp.sh
397	I wonder if this consistently works on NetBSD?

arichardson added inline comments.Mar 1 2021, 3:48 PM

contrib/netbsd-tests/lib/libc/ssp/t_ssp.sh
397	Unlikely.

LGTM!

Closed by commit rGc88c1f23a898: Allow ssp_test:read to pass more reliably (authored by arichardson). · Explain WhyMar 1 2021, 7:57 PM

This revision was automatically updated to reflect the committed changes.

arichardson added a commit: rGc88c1f23a898: Allow ssp_test:read to pass more reliably.

arichardson added a commit: rGc8f8369856b5: Allow ssp_test:read to pass more reliably.Apr 22 2021, 11:09 AM

Revision Contents
Changeset List

Path

Size

contrib/

netbsd-tests/

lib/

libc/

ssp/

2 lines

Diff 84904

contrib/netbsd-tests/lib/libc/ssp/t_ssp.sh

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