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genup fails, log message "porthash: error: Hashfile and computed hashes DIFFER" #57

sakaki- opened this issue Aug 28, 2018 · 1 comment


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commented Aug 28, 2018


I have become aware of a bug in the app-portage/porthash-1.0.6 repository verification script, which will cause the automatic weekly update (genup) process to fail for users of the gentoo-on-rpi3-64bit

A manual upgrade of this package is required to address this issue, the (simple) process for which is presented below (I have also pushed a matching news article via the rpi3-overlay repo).

Apologies for any inconvenience caused ><


Look near the end of your /var/log/latest-genup-run.log file to see if the issue affects you; if it does, you'll see something similar to the below:

=== Sync completed for gentoo
q: Updating ebuild cache for /usr/portage ...
q: Finished xxx entries in yyy seconds
Checking master signature on gentoo repo...
porthash: Using public key 09F2FF455D90CAF4
porthash: Entering /usr/portage...
porthash: Verifying existing hashfile...
porthash: Hashfile signature and format valid
porthash: Computing master hash of /usr/portage, may take some time...
porthash: error: Hashfile and computed hashes DIFFER
Killing parent process... 

Fixing the Issue

To address the issue, open a terminal and issue the following commands, as the root user, on your rpi3:
(if running as demouser, prefix the following commands with sudo):

pi64 ~ # emaint sync --repo sakaki-tools
pi64 ~ # emerge --update --oneshot --verbose app-portage/porthash

This should upgrade porthash to >= 1.0.7. Once this is done, your automatic weekly genup run should start working again.

That's it!

Background to the Issue (Optional Reading)

The porthash utility creates, or by default checks, the validity of a repository master hash (repo.hash) and counterpart digital signature (repo.hash.asc), to allow verification of a Portage tree distributed over an unauthenticated channel such as rsync. There was no such 'official' facility in Gentoo when the tool was originally deployed.

However, when Gentoo started rolling out its official app-portage/gemato manifest verification tool, porthash was modified (at v1.0.6) to migrate the location of the repo.hash{,.asc} files, from the top level /usr/portage/ directory (where they would clash with gemato) to /usr/portage/local/, which gemato ignores.

Unfortunately, during an rsync process of the Portage tree with the binhost, this local directory is not synced by default, but since (due to faulty logic; my bad) porthash-1.0.6 checks this location first when looking for the repo.hash{,.asc} files, the next time the tree is synced after the files have been migrated, the old (stale) /usr/portage/local/repo.hash{,.asc} files will be checked (not the fresh /usr/portage/repo.hash{,.asc} versions), and accordingly the signature verification will fail, and genup will halt with an error.

This error is addressed in >=porthash-1.0.7, so upgrading this single package is sufficient to fix the problem.

Thanks to orion777 and ericbish for reporting. I'm going to leave this issue open on GitHub for a month or so (even though the resolution is posted above), so that all affected users get a chance to fix the issue.


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commented Mar 8, 2019

Closing this now, as all users should have migrated to gemato verification by this point.

@sakaki- sakaki- closed this Mar 8, 2019

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