Validate PicoTCP DNS responses - #2416
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CUE and GDI descriptor parsing continued appending after a quoted filename reached end of input. A malformed descriptor could consume CPU and memory until Flycast stopped responding. Treat failed character extraction as an invalid descriptor while skipping whitespace and while scanning quoted filenames.
The ISO9660 reader constructed filenames using record lengths supplied by the disc without confirming that the record remained in the loaded directory buffer. A malformed image could read past that buffer. Reject incomplete records and filenames before accessing their fields.
RZIP savestate headers controlled allocation sizes without a limit or an allocation failure boundary. A malicious savestate could terminate Flycast by requesting an impractically large allocation. Reject oversized chunks and handle allocation failures when reading compressed chunk data.
The PicoTCP DNS resolver accepted the first UDP response and parsed DNS fields without checking the received length. A malformed response could read past the resolver buffer and terminate Flycast. Match replies to the queried endpoint and transaction ID, then validate DNS names, records, and data lengths before reading them.
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PicoTCP accepted the first UDP response received during startup DNS
resolution and parsed DNS names and record lengths without validating
the received length. A forged or malformed response could read past
Flycast's resolver buffer and terminate the process.
This matches replies to the queried endpoint and transaction ID, and
performs bounds checks for DNS questions, names, records, and record
data before reading them.