Check the size of PROTMESSID_ACKN messages#302
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corrados merged 1 commit intojamulussoftware:masterfrom May 28, 2020
Merged
Check the size of PROTMESSID_ACKN messages#302corrados merged 1 commit intojamulussoftware:masterfrom
corrados merged 1 commit intojamulussoftware:masterfrom
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The Evaluate* functions that parse other types of messages all check the message size before starting to read data, but the special code for acknowledgements didn't do this, so an ACKN message on an existing connection that had a valid checksum but no data would result in an out-of-bounds read. Found by fuzzing with afl-fuzz.
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The Evaluate* functions that parse other types of messages all check the body size before starting to read data, but the special code for acknowledgements didn't do this, so an ACKN message on an existing connection that had a valid checksum but no body would result in an out-of-bounds read.
Found by fuzzing the protocol parser with afl-fuzz, using messages from CTestbench as an initial corpus and disabling the CRC check. This was the only problem it found in a 24h fuzzing run.