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ZIO: Add overflow checks for linear buffers #15553

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merged 1 commit into from Dec 1, 2023
Merged

ZIO: Add overflow checks for linear buffers #15553

merged 1 commit into from Dec 1, 2023

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amotin
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@amotin amotin commented Nov 22, 2023

Since we use a limited set of kmem caches, quite often we have unused memory after the end of the buffer. Put there up to a 512-byte canary when built with debug to detect buffer overflows at the free time.

How Has This Been Tested?

Hacked ZIL code to allocate insufficient ITX buffer. Observed the panic when ITX was freed.

Types of changes

  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Performance enhancement (non-breaking change which improves efficiency)
  • Code cleanup (non-breaking change which makes code smaller or more readable)
  • Breaking change (fix or feature that would cause existing functionality to change)
  • Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
  • Documentation (a change to man pages or other documentation)

Checklist:

@amotin amotin force-pushed the zio_overflow branch 3 times, most recently from 28d8e87 to e98305f Compare November 22, 2023 16:45
@amotin amotin added the Status: Code Review Needed Ready for review and testing label Nov 22, 2023
behlendorf
behlendorf approved these changes Dec 1, 2023
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I'm all for this kind of additional verification. Can you just enhance your comment above zio_buf_put_canary() to clarify why it's commit for there to be allocated but unused space at the end of the buffer.

@amotin
ZIO: Add overflow checks for linear buffers
1a6b7b1 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
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amotin commented Dec 1, 2023

@behlendorf Extended the comment.

@behlendorf behlendorf added Status: Accepted Ready to integrate (reviewed, tested) and removed Status: Code Review Needed Ready for review and testing labels Dec 1, 2023
@behlendorf behlendorf merged commit adcea23 into openzfs:master Dec 1, 2023
22 of 26 checks passed
lundman pushed a commit to openzfsonwindows/openzfs that referenced this pull request Dec 12, 2023
@amotin @lundman
ZIO: Add overflow checks for linear buffers
8849fa5 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#15553
mmatuska pushed a commit to mmatuska/zfs that referenced this pull request Dec 26, 2023
@amotin @mmatuska
ZIO: Add overflow checks for linear buffers
d9e110a 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#15553
@mmatuska mmatuska mentioned this pull request Dec 26, 2023
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mmatuska pushed a commit to mmatuska/zfs that referenced this pull request Dec 27, 2023
@amotin @mmatuska
ZIO: Add overflow checks for linear buffers
c88f0b0 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#15553
@amotin amotin deleted the zio_overflow branch December 27, 2023 15:03
mmatuska pushed a commit to mmatuska/zfs that referenced this pull request Dec 27, 2023
@amotin @mmatuska
ZIO: Add overflow checks for linear buffers
650c4b0 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes openzfs#15553
behlendorf pushed a commit that referenced this pull request Jan 9, 2024
@amotin @behlendorf
ZIO: Add overflow checks for linear buffers
e48195c 
Since we use a limited set of kmem caches, quite often we have unused
memory after the end of the buffer.  Put there up to a 512-byte canary
when built with debug to detect buffer overflows at the free time.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15553
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