net: properly handle PF_NOBAN in CConnman::Bind() #21668

1. 
   vasild commented at 5:01 pm on April 13, 2021: member

   0PF_DOWNLOAD is 0b1000000 and
   1PF_NOBAN    is 0b1010000.
   

   This makes a check like flags & PF_NOBAN return true even if flags is equal to PF_DOWNLOAD.

   If -whitebind=download@1.1.1.1:8765 is specified, then 1.1.1.1:8765 should be added to the list of local addresses. We only want to avoid adding to local addresses (that are advertised) a whitebind that has noban@ flag.

   As a result of a mis-check in CConnman::Bind() we would not have added 1.1.1.1:8765 to the local addresses in the example above.

2. net: properly handle PF_NOBAN in CConnman::Bind()

   `PF_DOWNLOAD` is `0b1000000` and
   `PF_NOBAN`    is `0b1010000`.
   
   This makes a check like `flags & PF_NOBAN` return `true` even if `flags`
   is equal to `PF_DOWNLOAD`.
   
   If `-whitebind=download@1.1.1.1:8765` is specified, then `1.1.1.1:8765`
   should be added to the list of local addresses. We only want to avoid
   adding to local addresses (that are advertised) a whitebind that has
   `noban@` flag.
   
   As a result of a mis-check in `CConnman::Bind()` we would not have added
   `1.1.1.1:8765` to the local addresses in the example above.

   d059b3a4c7
3. 
   vasild commented at 5:03 pm on April 13, 2021: member

   Similar issue spotted in #20196 (review) by @jonatack. I checked that what’s fixed in this PR is the only other case.

   cc @hebasto, @NicolasDorier

4. 
   jonatack commented at 5:39 pm on April 13, 2021: member

   Proposed in #21644.
5. 
   jonatack commented at 5:41 pm on April 13, 2021: member

   (#21506 would eliminate this class of NetPermissionFlags bug as well, as only defined operations would compile.)
6. DrahtBot added the label P2P on Apr 13, 2021
7. 
   DrahtBot commented at 11:54 pm on April 13, 2021: member

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #21644 (p2p, bugfix: use NetPermissions::HasFlag() in CConnman::Bind() by jonatack)
   • #21506 (p2p, refactor: make NetPermissionFlags an enum class by jonatack)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

8. 
   vasild commented at 7:41 am on April 14, 2021: member

   Closing in favor of #21644.
9. vasild closed this on Apr 14, 2021

   ---

10. vasild deleted the branch on Apr 14, 2021
11. in src/net.cpp:2421 in d059b3a4c7

    2417@@ -2418,7 +2418,9 @@ bool CConnman::Bind(const CService &addr, unsigned int flags, NetPermissionFlags
    2418         return false;
    2419     }
    2420 
    2421-    if (addr.IsRoutable() && fDiscover && !(flags & BF_DONT_ADVERTISE) && !(permissions & PF_NOBAN)) {
    2422+    const bool noban{NetPermissions::HasFlag(static_cast<NetPermissionFlags>(flags), PF_NOBAN)};
    

    ---

    ---

    

    jonatack commented at 4:30 pm on April 14, 2021:

    I stared at this for a minute to figure out why the cast added. Then I realized it’s because this line uses flags instead of permissions. The names are certainly similar enough to be confusing.

    ---

    

    vasild commented at 4:48 pm on April 14, 2021:

    Right, it is using the wrong variable :facepalm:

    ---

    

    MarcoFalke commented at 6:57 am on May 12, 2021:

    Would be nice if there was a test that failed with this diff
12. DrahtBot locked this on Aug 18, 2022

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