#21415: tor_bug_occurred_: Bug: src/or/entrynodes.c:1845:
select_entry_guard_for_circuit: Non-fatal assertion
!(!guard_has_descriptor(guard)) failed.
-----------------------------+------------------------------------
Reporter: cypherpunks | Owner: nickm
Type: defect | Status: needs_review
Priority: Medium | Milestone: Tor: 0.3.0.x-final
Component: Core Tor/Tor | Version: Tor: 0.3.0.3-alpha
Severity: Normal | Resolution:
Keywords: review-group-16 | Actual Points:
Parent ID: | Points:
Reviewer: asn | Sponsor:
-----------------------------+------------------------------------
Comment (by asn):
Replying to [comment:25 nickm]:
> The get_configured_bridge_by_exact_addr_port_digest() change looks safe.
>
> For the learned_router_identity change -- is there some way we might
have changed the addr:port arguments to that function before we call it,
and they might not be the same as the bridge line any more? I know there
are some weird cases with connection addresses in the code, but I'm not
sure if they apply to bridges.
>
Yes that's a good point and we should be careful.
I used the `make -k` trick and I audited the places that could be
rewriting the addrport of a connection but I didn't find anything relevant
for this case...
As an example, `connection_or_check_canonicity()` does a pretty sneaky
rewrite, but it only seems to happen for ORs and in our case we are a
client using bridges.
For an alternative confidence-inspiring obsevation, notice that in
`learned_router_identity()` (the function we modded), a bit after we call
`get_configured_bridge_by_exact_addr_port_digest()` we call
`find_transport_name_by_bridge_addrport()` which does a very similar
operation as the `_exact_` function; namely it walks through the bridges
and compares their addrport with the conn addrport. So if
`find_transport_name_by_bridge_addrport()` is trusting the connection
addrport and the code has been working for a while, it seems to be an
argument that our modification is also innocuous.
> General note -- this branch is based on master. When you're writing a
branch to go into 0.3.0, it's a little easier for me if you base the
branch on maint-0.3.0 instead of on master. "git worktree" can make this
really convenient, and let you have separate directories for each branch
you're working on.
Oops yes, sorry about that. I need to take some time and learn how to use
`git worktree`. Last time I spent 10 minutes but didn't manage to grasp it
completely. Will try to do this soon.
Let me know if you want me to rebase the branch to 0.3.0.
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21415#comment:26>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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