harden: ZstdException on oversized declared size + decompression-bomb tests#35
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…ling Zstd.decompress(byte[]) reads the (untrusted) content size from the frame header to size its output. A header declaring more than Integer.MAX_VALUE bytes previously let a raw ArithmeticException escape from Math.toIntExact; it now fails with a ZstdException naming the limit and pointing to decompress(byte[], int) for bounded, untrusted-safe decoding. Adds ZstdTest.UntrustedInput documenting decompression-bomb behaviour: - decompress(byte[], maxSize) refuses a tiny frame that expands to 8 MiB, - decompress(byte[]) trusts the declared size and expands fully (so untrusted callers must pass a bound), - a hand-built frame header declaring > 2 GiB throws ZstdException, not ArithmeticException. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adds a Security note to Zstd.decompress(byte[]) that it trusts the frame's declared content size and can be a decompression-bomb vector, steering untrusted callers to decompress(byte[], int); and notes on the bounded overload that it is the safe entry point for untrusted input. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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What
Hardening for untrusted compressed input, from the security review.
(c) Oversized declared size →
ZstdExceptionZstd.decompress(byte[])sizes its output from the frame's attacker-controlled declared content size. A header claiming >Integer.MAX_VALUEbytes previously leaked a rawArithmeticExceptionfromMath.toIntExact. It now throws aZstdExceptionnaming the limit and pointing todecompress(byte[], int).(a) Decompression-bomb tests
New
ZstdTest.UntrustedInputpins the behaviour:decompress(byte[], maxSize)refuses a tiny frame that expands to 8 MiB (the safe path).decompress(byte[])trusts the declared size and expands fully — documenting that untrusted callers must pass a bound.ZstdException, notArithmeticException.Not in scope (deferred)
(b) the Javadoc security note steering untrusted callers to
maxSize— say the word and I'll add it.Verify
235 tests green, checkstyle + javadoc clean.
🤖 Generated with Claude Code