fix(issue-732): Add bounds check before native compress

[m-rola]

Security Fix

Fixes #732 - Out-of-bounds write vulnerability in Snappy.compress()

Vulnerability Details

Type: Out-of-Bounds Write (CWE-787)
CVSS 3.1: 5.9 (Medium)
Affected versions: 1.1.10.8 and earlier

Root Cause

The compress(ByteBuffer, ByteBuffer) method never validates that the
destination ByteBuffer has sufficient capacity before calling the native
rawCompress function, allowing off-heap out-of-bounds writes.

Fix

Added capacity check before native call:

• Calculate required capacity using maxCompressedLength()
• Throw IllegalArgumentException if insufficient space
• Clear error message shows bytes needed vs available

Testing

• New test case: testCompressWithInsufficientBuffer()
• Test reproduces issue from snappy-java through 1.1.10.8 Out-of-Bounds Write via compress #732
• All existing tests pass
• Verified with 1MB incompressible data

Impact

• Breaking change: No (only throws exception in error case)
• Performance impact: Negligible (O(1) check)

[beholders-eye]

Are there any plans to merge this?

[tourl]

Hope someone can review this soon...

[marcelstoer]

Fixes #732 - Out-of-bounds write vulnerability in Snappy.compress()

This is very much related to #728.

[beholders-eye]

Thanks @m-rola for stepping up and writing this patch.

[m-rola]

@xerial can we proceed with merge or I'm missing something?