fix(oauth): Reject device code requests from unauthorised clients #2110

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nex merged 2 commits from mmaudet/continuwuity:fix/oauth-device-grant-type into main 2026-08-07 08:52:21 +00:00

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mmaudet commented 2026-08-06 17:55:46 +00:00

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This pull request fixes OAuth2 clients incorrectly being allowed to initiate the device authorization flow without registering the appropriate grant type.

Fixes: #2109

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mmaudet added 2 commits 2026-08-06 17:55:47 +00:00

fix(oauth): Reject device code requests from unauthorised clients ... d0a2c19955

The device authorization endpoint issued a device code to any registered
client, without checking that the client had registered the
`urn:ietf:params:oauth:grant-type:device_code` grant type. Such a client
could therefore start a device authorization flow and have the server
show an approval prompt to a user, even though the subsequent token
request was always going to be refused.

RFC 8628 section 3.2 states that, in the event of an error such as an
invalidly configured client, the device authorization endpoint responds
in the same way as the token endpoint specified in RFC 6749 section 5.2,
which defines `unauthorized_client` as "the authenticated client is not
authorized to use this authorization grant type".

Apply the same grant type check the token endpoint already performs, and
add the `unauthorized_client` error code it requires.

fix(oauth): Use unauthorized_client for unregistered grant types ... 474e37b03d

The token endpoint already refused grant types the client had not
registered, but reported it as `invalid_grant`. RFC 6749 section 5.2
reserves `invalid_grant` for an authorization grant which is "invalid,
expired, revoked, does not match the redirection URI used in the
authorization request, or was issued to another client", and defines
`unauthorized_client` for a client which "is not authorized to use this
authorization grant type".

Report the condition with the error code the specification assigns to it,
matching the device authorization endpoint.

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label 2026-08-06 17:55:53 +00:00

nex requested changes 2026-08-06 18:00:09 +00:00

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This doesn't need two changelogs, otherwise looks fine to me. Also please use the PR template next time

This doesn't need two changelogs, otherwise looks fine to me. Also please use the PR template next time

nex added the

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labels 2026-08-06 18:03:01 +00:00

nex commented 2026-08-06 18:04:08 +00:00

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I have updated your pull request description to follow the template. Please check off the checkboxes at your earliest convenience so that this PR is eligible for merge.

I have updated your pull request description to follow the template. Please check off the checkboxes at your earliest convenience so that this PR is eligible for merge.

mmaudet force-pushed fix/oauth-device-grant-type from 474e37b03d to b23059734e 2026-08-06 18:24:31 +00:00 Compare

mmaudet commented 2026-08-06 18:39:04 +00:00

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Done : the two changelog fragments are now a single changelog.d/2110.bugfix.md, renamed to the {pull_request_number}.{type} format documented in CONTRIBUTING and with the usual attribution line. Checklist is filled in.

And I Ran prek --all-files, cargo check --workspace --features full, cargo clippy --workspace --features full -- -D warnings and cargo test --workspace --features full locally — all clean. CI is green on b2305973.

Thank you for your hospitality and understanding!

Done : the two changelog fragments are now a single changelog.d/2110.bugfix.md, renamed to the {pull_request_number}.{type} format documented in CONTRIBUTING and with the usual attribution line. Checklist is filled in. And I Ran prek --all-files, cargo check --workspace --features full, cargo clippy --workspace --features full -- -D warnings and cargo test --workspace --features full locally — all clean. CI is green on b2305973. Thank you for your hospitality and understanding!

nex approved these changes 2026-08-06 18:39:51 +00:00

Jade approved these changes 2026-08-06 22:50:33 +00:00

Aranjedeath requested review from ginger 2026-08-06 22:58:08 +00:00

nex merged commit f0493a7ba8 into main 2026-08-07 08:52:21 +00:00

nex deleted branch fix/oauth-device-grant-type 2026-08-07 08:52:21 +00:00

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