usr.bin/sort: Avoid UBSan errors
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Authored by arichardson on Jul 3 2021, 3:10 PM.

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Reviewers

markj
jrtc27

Commits

rGe4c2ffe93205: usr.bin/sort: Avoid UBSan errors
rGd053fb22f6d3: usr.bin/sort: Avoid UBSan errors

Summary

UBSan complains about out-of-bounds accesses for zero-length arrays. To
avoid this we can use flexible array members. However, the C standard does
not allow for structures that only contain flexible array members, so we
move the length parameters into that structure too.

Split out from D28233.

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Build Status

Buildable 40251
Build 37140: arc lint + arc unit

Event Timeline

arichardson requested review of this revision.Jul 3 2021, 3:10 PM

arichardson created this revision.

Harbormaster completed remote builds in B40251: Diff 91699.Jul 3 2021, 3:10 PM

arichardson added a parent revision: D31043: Add build system support for ASAN+UBSAN instrumentation.Jul 5 2021, 12:17 PM

markj accepted this revision.Jul 5 2021, 12:24 PM

markj added inline comments.

usr.bin/sort/bwstring.c
170	Why is it `+ 2`?
usr.bin/sort/bwstring.h
78	Can't this be `mb_cur_max` instead? I guess it ought to be irrelevant since both branches do the same thing.

This revision is now accepted and ready to land.Jul 5 2021, 12:24 PM

arichardson added inline comments.Jul 5 2021, 12:26 PM

usr.bin/sort/bwstring.c
170	Why is it `+ 2`? I am not sure about this, I would assume + 1 is sufficient for the zero char, but I didn't want to change the existing code in case something depends on the + 2.
usr.bin/sort/bwstring.h
78	Ah good catch, I missed this one while rebasing.