fix: enforce max_string_length on JSON escape/unicode appends - #24
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Escape and \uXXXX decode paths appended to the accumulating string without checking max_string_length, so escape-only payloads could bypass the 100MB DoS cap. Route all appends through a shared length check; add a small-limit decoder regression covering escapes, unicode, and names. Co-authored-by: Kaius Ruokonen <ruoka@users.noreply.github.com>
Escape and \uXXXX decode paths appended without checking max_string_length. Route all appends through a shared length check that rejects when the next append would exceed the remaining budget (no size_t underflow). Co-authored-by: Cursor <cursoragent@cursor.com>
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Summary
max_string_length(100MB DoS cap) was only checked on raw string/name characters. Escape sequences (\n,\", …) and\uXXXXUTF-8 writes appended unchecked, so escape-only payloads could grow the decoded string without bound.Bug and impact
\nor\u0041, past 100MB decoded length.Fix
decoderfor fast regressions.Validation
StringLengthLimitAppliesToEscapescovering short escapes, BMP unicode, multi-byte UTF-8, and object names../tools/CB.sh debug test --tags='\[xson\]'— 422/422 passed.