fix: Fix OOM crash in SettingsSerializer readStream() VInt decoder.#707
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lggcs wants to merge 2 commits into
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fix: Fix OOM crash in SettingsSerializer readStream() VInt decoder.#707lggcs wants to merge 2 commits into
lggcs wants to merge 2 commits into
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readStream() had no bounds check on the VInt shift count or the accumulated size value before calling QByteArray::resize(), allowing a crafted settings file to trigger an unbounded allocation (up to 2GB) and immediate OOM crash. The signed left-shift also produced undefined behavior when the shift exceeded 28 bits. Add the same overflow guard used by dataToVInt() (num2 > sizeof(int) * CHAR_BIT), stream error status checks, and a post-loop validity check on the decoded size before allocation.
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Apr 19, 2026
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If there's an easy way to unit test this, please add a test. If not, file an issue and I'll follow up.
…tion Covers the three guards added to readStream(): - OOM payload: VInt encoding 0x7FFFFFFF triggers the shift-count guard (num2 > sizeof(int)*CHAR_BIT), preventing QByteArray::resize(INT_MAX) - Shift overflow: 5 continuation bytes push shifts past 32 bits, exercising the same guard for the UB case - Truncated stream: premature EOF is caught by the QDataStream status check before each readRawData - Zero-size VInt: the post-loop num <= 0 guard rejects empty values - Valid settings: round-trips a key/value pair through the serializer - isSerializedFormat: verifies QTOX magic detection
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@lggcs we require signed commit, to denote authorship and origin. Other than that, it looks good now (: |
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readStream() had no bounds check on the VInt shift count or the accumulated size value before calling QByteArray::resize(), allowing a crafted settings file to trigger an unbounded allocation (up to 2GB) and immediate OOM crash. The signed left-shift also produced undefined behavior when the shift exceeded 28 bits. Add the same overflow guard used by dataToVInt() (num2 > sizeof(int) * CHAR_BIT), stream error status checks, and a post-loop validity check on the decoded size before allocation.
Resolves #706
This change is