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Set CTAP1 Authenticate UP byte correctly - #798
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kaczmarczyck merged 1 commit intoOct 10, 2026
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In Ctap1Command::process_command, user presence is only checked and consumed when flags == Ctap1Flags::EnforceUpAndSign. However, process_authenticate unconditionally passed USER_PRESENCE_INDICATOR_BYTE (0x01) to generate_auth_data, both signing and returning a user presence byte of 0x01 even for DontEnforceUpAndSign requests. [1] This means that through CTAP1, touchless assertions could be hidden to the relying party. Resident keys are unaffected. [1] https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fido-u2f-raw-message-formats-v1.2-ps-20170411.html#authentication-request-message---u2f_authenticate
ia0
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Oct 10, 2026
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coverage: 97.219%. remained the same — kaczmarczyck:ctap1-authenticate-up-byte into google:develop |
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In Ctap1Command::process_command, user presence is only checked and consumed when flags == Ctap1Flags::EnforceUpAndSign. However, process_authenticate unconditionally passed
USER_PRESENCE_INDICATOR_BYTE (0x01) to generate_auth_data, both signing and returning a user presence byte of 0x01 even for DontEnforceUpAndSign requests. [1]
This means that through CTAP1, touchless assertions could be hidden to the relying party. Resident keys are unaffected.
[1] https://fidoalliance.org/specs/fido-u2f-v1.2-ps-20170411/fido-u2f-raw-message-formats-v1.2-ps-20170411.html#authentication-request-message---u2f_authenticate