8289697: buffer overflow in MTLVertexCache.m: MTLVertexCache_AddGlyphQuad

[VladimirKempik]

Please review this simple patch. When running idea on jdk17 with asan I have found this buffer overflow.
The code checks the cache for at least one free element, while placing 6 elements to the cache.
The fix checks the presence of 6 free elements.

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Issue

• JDK-8289697: buffer overflow in MTLVertexCache.m: MTLVertexCache_AddGlyphQuad

Reviewers

• Phil Race (@prrace - Reviewer) ⚠️ Review applies to 2676028f

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Webrevs

• 06: Full - Incremental (ecfbd563)
• 05: Full - Incremental (2676028f)
• 04: Full - Incremental (662a6bef)
• 03: Full - Incremental (0af4ec81)
• 02: Full - Incremental (23438f27)
• 01: Full - Incremental (88402dbe)
• 00: Full (35ed932e)

[avu]

Looks good for me

[VladimirKempik]

Linux test failure unrelated, this commit changes only macos's code

[aghaisas]

This is a good catch and fix.

There is another place in this file where MTLVC_ADD_TRIANGLES is used.
Although it is a corner case, it is worth adding the check for additional 6 vertices at that place as well.
Adding a separate check at the beginning of the MTLVertexCache_AddMaskQuad method where there is a check for maskCacheIndex seems logical to me. What do you think?

[VladimirKempik]

Added one more check into MTLVertexCache_AddMaskQuad, to the first if condition.

[prrace]

Are there any other cases like this ? We should look around. (PS I see Ajit asked the same question and perhaps even answered it !)
Did you find this by inspection or did you hit it ?
Can we use a defined constant instead of "6" ?

[VladimirKempik]

Are there any other cases like this ? We should look around. (PS I see Ajit asked the same question and perhaps even answered it !) Did you find this by inspection or did you hit it ?

I hit this bug when running IDEA on asan-enabled build of ojdk

ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6210011b94a8 at pc 0x0001707b9c0e bp 0x70001358e8f0 sp 0x70001358e8e8
WRITE of size 4 at 0x6210011b94a8 thread T56
#0 0x1707b9c0d in MTLVertexCache_AddGlyphQuad+0x5ed (libawt_lwawt.dylib:x86_64+0x1cbc0d)
....
0x6210011b94a8 is located 8 bytes to the right of 4000-byte region [0x6210011b8500,0x6210011b94a0)
allocated by thread T56 here:
#0 0x106857400 in wrap_malloc+0xa0 (libclang_rt.asan_osx_dynamic.dylib:x86_64h+0x44400)
#1 0x1707b8277 in MTLVertexCache_InitVertexCache+0x17 (libawt_lwawt.dylib:x86_64+0x1ca277)

Can we use a defined constant instead of "6" ?

#define TRI_IN_VERT 6 ?

[aghaisas]

I will submit a full test run with this patch and then approve on it's successful completion.

[aghaisas]

The full test run is good with this change.
2 comments in the code still use MTL_TRIS_IN_VERTEX. These need to be corrected.

[VladimirKempik]

Yeah, missed that, thanks for noticing

[aghaisas]

Yeah, missed that, thanks for noticing

There is one instance of MTL_TRIS_IN_VERTEX still remaining in a comment!

[prrace]

LGTM although I'd really (really!) like you to break up those long lines before pushing.

[openjdk]

@VladimirKempik This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8289697: buffer overflow in MTLVertexCache.m: MTLVertexCache_AddGlyphQuad

Reviewed-by: prr

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 482 new commits pushed to the master branch:

• 1b8f466: 8289740: Add verification testing during all concurrent phases in G1
• ac399e9: 8286957: Held monitor count
• 1fec62f: 8289710: Move Suspend/Resume classes out of os.hpp
• 01b9f95: Merge
• 3212dc9: 8289486: Improve XSLT XPath operators count efficiency
• a8eb728: 8289779: Map::replaceAll javadoc has redundant @throws clauses
• 889150b: 8289558: Need spec clarification of j.l.foreign.*Layout
• 8dd94a2: 8289196: Pattern domination not working properly for record patterns
• 8f24d25: 6509045: {@inheritdoc} only copies one instance of the specified exception
• 9a0fa82: 8288949: serviceability/jvmti/vthread/ContStackDepthTest/ContStackDepthTest.java failing
• ... and 472 more: https://git.openjdk.org/jdk/compare/407abf5d65af918e6d9bfed1f4cc7d4cfd74ce24...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[VladimirKempik]

/reviewer credit aghaisas

[openjdk]

@VladimirKempik Reviewer aghaisas has already made an authenticated review of this PR, and does not need to be credited manually.

[VladimirKempik]

/integrate

[openjdk]

Going to push as commit d852e99.
Since your change was applied there have been 484 commits pushed to the master branch:

• a13af65: 8282322: AArch64: Provide a means to eliminate all STREX family of instructions
• f1967cf: 8289997: gc/g1/TestVerificationInConcurrentCycle.java fails due to use of debug-only option
• 1b8f466: 8289740: Add verification testing during all concurrent phases in G1
• ac399e9: 8286957: Held monitor count
• 1fec62f: 8289710: Move Suspend/Resume classes out of os.hpp
• 01b9f95: Merge
• 3212dc9: 8289486: Improve XSLT XPath operators count efficiency
• a8eb728: 8289779: Map::replaceAll javadoc has redundant @throws clauses
• 889150b: 8289558: Need spec clarification of j.l.foreign.*Layout
• 8dd94a2: 8289196: Pattern domination not working properly for record patterns
• ... and 474 more: https://git.openjdk.org/jdk/compare/407abf5d65af918e6d9bfed1f4cc7d4cfd74ce24...master

Your commit was automatically rebased without conflicts.

[openjdk]

@VladimirKempik Pushed as commit d852e99.

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