Opened 8 years ago

Closed 8 years ago

Last modified 7 years ago

#2749 closed enhancement (wontfix)

Persistent storage for HSDir descriptors

Reported by: special Owned by: rransom
Priority: Medium Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Keywords: tor-hs
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

Store descriptors on HSDir nodes on disk, rather than in memory, so they can persist between Tor restarts, and to avoid excessive memory usage if the directory becomes large.

This would also be a good opportunity to evaluate REND_CACHE_MAX_AGE and REND_CACHE_MAX_SKEW, which seem to currently keep descriptors for three days.

Child Tickets

Change History (5)

comment:1 in reply to:  description Changed 8 years ago by rransom

Replying to special:

Store descriptors on HSDir nodes on disk, rather than in memory, so they can persist between Tor restarts, and to avoid excessive memory usage if the directory becomes large.

One of the drawbacks of this (with the current v2 HS directory protocol) is that it makes enumeration of hidden service names much easier. Currently, an attacker can make a list of most, if not all, hidden service names in use by running one or more HSDir relays modified to log the hidden services' identity keys (contained in the descriptors) to disk; if we make Tor log the descriptors to disk ourselves, there is no longer any barrier to performing this 'attack'. Do we care about this issue?

comment:2 Changed 8 years ago by nickm

Milestone: Tor: unspecified

comment:3 Changed 8 years ago by rransom

Resolution: wontfix
Status: newclosed

I no longer believe that storing HS descriptors on disk would improve HS reachability. We might have relays store HS descriptors on disk someday if they start eating up a significant amount of memory, but it's not worth the trouble until that actually becomes a problem.

comment:4 Changed 7 years ago by nickm

Keywords: tor-hs added

comment:5 Changed 7 years ago by nickm

Component: Tor Hidden ServicesTor
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