[fuzz] Avoid partial negative result #29462

1. 
   murchandamus commented at 8:53 PM on February 21, 2024: contributor

   May address the problem reported by maflcko in #27877#pullrequestreview-1890304914.

   For some values, MAX_MONEY - max_spendable - max_output_groups could result in a partial negative value. By putting the addition of group_pos.size() first, all partial results in this line will be strictly positive.

   I opened this as a draft, since I was unable to reproduce the issue, so I’m waiting for confirmation whether this in fact mitigates the problem.

2. [fuzz] Avoid partial negative result 9dae3b970a
3. 
   DrahtBot commented at 8:53 PM on February 21, 2024: contributor

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   ACK	maflcko, sipa, brunoerg, achow101

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4. 
   murchandamus commented at 9:40 PM on February 21, 2024: contributor

   Opening for review: After @achow101 pointed out that I needed to enable the "integer" fuzz sanitizer, I was able to reproduce the issue and verify that the proposed fix mitigates the problem.

5. murchandamus marked this as ready for review on Feb 21, 2024
6. 
   murchandamus commented at 9:41 PM on February 21, 2024: contributor

   Opening for review: After @achow101 pointed out that I needed to enable the "integer" fuzz sanitizer, I was able to reproduce the issue and verify that the proposed fix mitigates the problem.

7. achow101 added this to the milestone 27.0 on Feb 21, 2024
8. 
   maflcko commented at 8:29 AM on February 22, 2024: member

   Tested with:

   ./autogen.sh && CC=clang CXX=clang++ ./configure -q --enable-c++20 --enable-fuzz --with-sanitizers=fuzzer,undefined,integer,float-divide-by-zero && make clean && make
   

   and #27877 (review) to confirm the fix

   ACK 9dae3b970a7a82e8d9f3f755048d427da78c49da

9. 
   sipa commented at 9:37 AM on February 22, 2024: member

   utACK 9dae3b970a7a82e8d9f3f755048d427da78c49da

10. brunoerg approved
11. 
    brunoerg commented at 1:47 PM on February 22, 2024: contributor

    crACK 9dae3b970a7a82e8d9f3f755048d427da78c49da

12. 
    achow101 commented at 1:59 PM on February 22, 2024: member

    ACK 9dae3b970a7a82e8d9f3f755048d427da78c49da

13. achow101 merged this on Feb 22, 2024
14. achow101 closed this on Feb 22, 2024

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15. bitcoin locked this on Feb 21, 2025

Milestone
27.0