src: fix crash on empty, foreign or truncated --snapshot-blob files - #65955
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src: fix crash on empty, foreign or truncated --snapshot-blob files#65955codebytere wants to merge 1 commit into
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`node --snapshot-blob <file> main.js` aborted with an assertion when the file was empty (`ReadFileSync()` insists on reading one item), was not a Node.js snapshot (`CHECK_EQ(magic, kMagic)`) or had a zero-length startup blob, and read past the end of the buffer when a snapshot was truncated, because `BlobDeserializer` trusted every length field in the blob. `EmbedderSnapshotData::FromFile()` is documented to return an empty pointer for an invalid snapshot and crashed the same way. Bounds-check each read in `BlobDeserializer` and record the failure, have `SnapshotData::FromBlob()` print why and return false, and let `ReadFileSync()` return an empty vector for an empty file. Also add the missing space in the "built with Node.js version" messages. Refs: nodejs#38905 Refs: nodejs#47933 Signed-off-by: Shelley Vohr <shelley.vohr@gmail.com>
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Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #65955 +/- ##
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Coverage 90.17% 90.17%
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Files 771 771
Lines 265489 265510 +21
Branches 50471 50477 +6
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+ Hits 239405 239432 +27
+ Misses 17042 17010 -32
- Partials 9042 9068 +26
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node --snapshot-blob <file> main.jsaborts with an assertion when the file is empty, is not a Node.js snapshot, or has a zero-length startup blob, and reads past the end of the buffer when a snapshot is truncated, becauseBlobDeserializertrusted every length field in the blob;EmbedderSnapshotData::FromFile(), documented to return an empty pointer for an invalid snapshot, crashed the same way.BlobDeserializernow bounds-checks each read and records the failure,SnapshotData::FromBlob()prints "not a Node.js snapshot blob" or "truncated" and returns false so the CLI exits with the usual snapshot error code, andReadFileSync()accepts an empty file. Also adds the missing space in the "built with Node.js version" messages.Tests:
test/parallel/test-snapshot-invalid-blob.jscovers empty, garbage, zero-length-blob and truncated files (all aborted or overread before); the snapshot suites pass.Refs: #38905
Refs: #47933
Disclosure: the code, test and this description were written by Claude Code, directed and reviewed by @codebytere.