[lwip-devel] [patch #10163] Fix failing fuzzer if compiling with ubsan

[Wouter van Gulik]

URL:
  <https://savannah.nongnu.org/patch/?10163>

                 Summary: Fix failing fuzzer if compiling with ubsan
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: wouter
            Submitted on: Wed 22 Dec 2021 11:41:00 AM UTC
                Category: Contrib
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

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Details:

The "random" generator uses a 32 bit multiply that overflows.
When building with "undefined behavior sanitizer" enabled the fuzzer stops
before even parsing the packet.
This make it impossible to use AFLPlusPlus (the 'successor' of AFL).
The fix is trivial; make the intermediate variable 'val' 64bit and use it
instead of state[0] in the multiplication. See attached patch.




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File Attachments:


-------------------------------------------------------
Date: Wed 22 Dec 2021 11:41:00 AM UTC  Name: fuzz_common.patch  Size: 577B  
By: wouter

<http://savannah.nongnu.org/patch/download.php?file_id=52554>

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