initrd: add TPM DA lockout gating, counter auth fix, bad_auth tooling and documentation by tlaurion · Pull Request #2117 · linuxboot/heads

tlaurion · 2026-05-14T19:09:04Z

Summary

Fixes a TPM1 counter auth regression (PR #2068) where increment_tpm_counter was changed from hardcoded -pwdc '' (empty counter auth) to -pwdc "${tpm_passphrase:-}" (owner passphrase), while counters continued to be created with -pwdc "". This caused every increment to compute SHA1(owner_pass) against a counter created with SHA1(""), producing persistent TPM_AUTHFAIL.

Per TCG TPM Main Spec Part 3, TPM_CreateCounter uses owner auth (-pwdo) but TPM_IncrementCounter uses the counter's own authData, not the owner password. The correct design for Heads' rollback counter is empty auth.

The repeated auth failures (3 per boot) triggered TPM 1.2 dictionary-attack lockout (TPM_DEFEND_LOCK_RUNNING), which persisted through forceclear on some implementations.

Adds DA state diagnostics, preflight guard and testing tooling.

Changes

`initrd/bin/tpmr.sh` — auth fix + DA state + bad_auth

tpm1_counter_increment(): detect -pwdc '', call tpm directly (bypass _tpm_auth_retry)
tpm1_reset(): detect defend lock, cycle physical presence, retry takeown
tpm1_da_state(): TPM1 DA via TPM_CAP_DA_LOGIC, output DA: line
tpm2_da_state(): TPM2 DA via getcap properties-variable, unlock estimate
tpm1_bad_auth() / tpm2_bad_auth(): deliberate wrong-auth for testing
Add 'defend' and '0x98e|0x149' to auth detection patterns

`initrd/etc/functions.sh` — counter auth + DA preflight

check_tpm_counter(): -pwdc '' per TCG spec
increment_tpm_counter(): empty auth first, migration fallback with owner passphrase
DA preflight guard: DIE on lockout, WARN near threshold, DEBUG at each decision
Remove TPM1 owner-passphrase prompt from PR UX improvements: TPM reseal (HOTP/TOTP/DUK) adds integrity report; detects disk/tpm swap and guide user into action, add terminal colors and guidance! Reduced quiet noise #2068

Other

initrd/bin/tpm-reset.sh: TPM reset frontend
initrd/bin/oem-factory-reset.sh: -pwdc '' for consistency
doc/tpm.md: DA diagnosis, testing, escalation, physical presence

Copilot

Pull request overview

This PR improves Heads’ TPM error handling for TPM1 by correctly classifying tpmtotp “Defend lock running” output as an authorization-related failure (so it doesn’t immediately hard-fail), and adds a recovery path in tpm1_reset() to attempt clearing TPM1 defend-lock after forceclear by cycling physical presence.

Changes:

Extend auth-failure grep patterns to include defend (and unify inclusion of TPM2 auth hex codes in the shared retry helper).
Enhance tpm1_reset() to detect “defend lock” after takeown and retry after cycling physical presence.
Expand TPM documentation to describe tool selection, auth retry detection, and TPM1 defend-lock behavior.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 3 comments.

File	Description
initrd/bin/tpmr.sh	Treat “defend lock” as auth-related and add TPM1 defend-lock recovery logic during reset.
doc/tpm.md	Document TPM toolchain selection and the updated auth retry / defend-lock behavior.

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Copilot

Pull request overview

Copilot reviewed 1 out of 2 changed files in this pull request and generated 2 comments.

Copilot

Pull request overview

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

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notgivenby · 2026-05-15T05:50:02Z

The fix did not work…will copy logs.

tlaurion · 2026-05-16T01:04:25Z

The fix did not work…will copy logs.

Found the bug and where the regression comes from. Damn that one was not easy. Pushing fix and updating the other pr

Copilot

Pull request overview

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

Copilot

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Copilot reviewed 2 out of 3 changed files in this pull request and generated no new comments.

Copilot

Pull request overview

Copilot reviewed 2 out of 4 changed files in this pull request and generated no new comments.

PR #2068 (tpm_reseal_ux-integrity_report-detect_disk_and_tpm_swap, merged at d3d8053) changed increment_tpm_counter from hardcoded -pwdc '' (empty counter auth) to -pwdc "${tpm_passphrase:-}" (owner passphrase from cache/prompt), but left check_tpm_counter using empty -pwdc when called from kexec-sign-config.sh without a $3 passphrase argument. This caused every counter increment to compute SHA1(owner_pass) while the counter was created with SHA1("") - persistent TPM_AUTH_FAIL. Per TCG TPM Main Spec Part 3, TPM_CreateCounter uses owner auth (-pwdo) but TPM_IncrementCounter uses the counter's own authData, not the owner password. The correct design for Heads' rollback counter is empty auth: rollback security comes from the signed /boot/kexec_rollback.txt and TPM sealing, not counter access control. The repeated auth failures (3 per boot x ~5 boots via the _tpm_auth_retry loop) triggered TPM 1.2 dictionary-attack lockout (TPM_DEFEND_LOCK_RUNNING), which persisted through forceclear on some implementations, causing tpm takeown to fail and TPM reset to abort - a cascade failure from the counter auth mismatch. Changes: - initrd/bin/tpmr.sh (_tpm_auth_retry, tpm2_counter_inc, tpm2_seal, tpm1_seal): add 'defend' and '0x98e|0x149' to auth detection grep patterns so defend lock and TPM2 RC codes are treated as retryable auth failures rather than fatal errors - initrd/bin/tpmr.sh (tpm1_reset): detect defend lock after takeown failure and cycle physical presence to clear the lock state before retrying; full AC power cycle remains the fallback if software presence is insufficient - initrd/bin/tpmr.sh (tpm1_counter_increment): detect -pwdc '' and call tpm directly, bypassing _tpm_auth_retry which injected the owner passphrase. Use || return to survive set -e on expected auth failure. - initrd/etc/functions.sh (check_tpm_counter): pass -pwdc '' instead of -pwdc "${tpm_passphrase:-}" so counters use SHA1("") per TCG spec. Document that $3 is intentionally ignored. - initrd/etc/functions.sh (increment_tpm_counter): try -pwdc '' first for TPM1. If that fails on a readable counter (created by PR #2068 era code), prompt for owner passphrase and retry as migration fallback with clear WARN explaining the one-time migration and TPM reset option. - initrd/etc/functions.sh (increment_tpm_counter): remove the TPM1-specific owner-passphrase prompt block added by PR #2068 - initrd/etc/functions.sh (increment_tpm_counter): DIE-path fallback counter_create: -pwdc '' for consistency - initrd/bin/oem-factory-reset.sh: counter_create -pwdc '' for consistency with the empty-auth design - doc/tpm.md: document TPM1 boot chain, tpmtotp tool selection, auth retry patterns, defend lock recovery, and physical presence Signed-off-by: Thierry Laurion <insurgo@riseup.net>

…iew fixes Add preflight dictionary attack (DA) lockout guard to increment_tpm_counter, querying da_state before every counter increment. DIE on active lockout, WARN when count nears threshold. Add tpm1_da_state and tpm2_da_state for unified DA state query: - TPM1: reads TPM_CAP_DA_LOGIC (0x19); actionDependValue>0 + state=1 = locked; DA: line timer=field maps to actionDependValue - TPM2: reads getcap properties-variable (no single DA query); count >= max_auth = locked; estimate = (counter - max_auth + 1) * interval; DA: line timer=present when locked, absent when clean - Both output machine-parsable DA: line for the preflight guard Fix da_timer sed pattern: use sed -n with /p so da_timer stays empty when DA: line has no timer= field (TPM2 count < threshold). Without -n, non-matching lines echoed the full line as da_timer. Add tpm1_bad_auth and tpm2_bad_auth for testing: - Uses NV index auth (-P) not owner auth (-C o -P) for TPM2 because NV auth failure produces TPM2_RC_AUTH_FAIL (0x98e) and increments LOCKOUT_COUNTER; owner auth may not increment on some TPM2 implementations - Intentionally wrong password TPM_DEFEND_LOCK_TEST_WRONG_PASSWORD - Shows DA state before and after; uses || true to survive set -e Add tpm-reset.sh as a TPM reset frontend via tpmr.sh wrapper. Add DA documentation in doc/tpm.md covering diagnosis, testing, escalation, TPM1 vs TPM2 DA parameter configurability. Review fixes: - Fix TPM2 property names: TPM_PT_ -> TPM2_PT_ prefix in doc/tpm.md - Remove misplaced design decision comment from tpm2_da_state (belongs in tpm2_bad_auth where it already exists) - Add DEBUG logging at every decision point across preflight guard and all DA state functions for runtime traceability - Document design decisions inline: timer logic, estimate formula, empty auth retry bypass, NV vs owner auth Signed-off-by: Thierry Laurion <insurgo@riseup.net>

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Pull request overview

Copilot reviewed 2 out of 5 changed files in this pull request and generated 3 comments.

- Fix TPM2 time remaining table entry: estimate is derived from LOCKOUT_COUNTER vs MAX_AUTH_FAIL times LOCKOUT_INTERVAL, not LOCKOUT_RECOVERY (which is the lockout-auth-blocked-after-failure timer, not the remaining-until-unlock) - Reword migration WARN: 'older Heads version' not 'older firmware' (the migration case is caused by previous Heads code, not platform firmware) - Remove fragile PR #2117 reference from preventing-future-lockouts section: describe the fix generically (restoring empty counter auth) so the doc is correct regardless of branch context Signed-off-by: Thierry Laurion <insurgo@riseup.net>

When TPM1 does not support TPM_CAP_DA_LOGIC (0x19), tpm getcapability may print raw TSS error text to stdout instead of returning empty. The empty-string check missed this because error text is non-empty. Fix: check that the output contains the 'State' field (expected for valid DA capability data) before echoing. If missing, return 'unavailable' and suppress the raw TSS garbage. Signed-off-by: Thierry Laurion <insurgo@riseup.net>

TPM_CAP_DA_LOGIC (0x19) was added late in TPM 1.2 spec rev 103. Older Infineon TPMs (X230-era SLB9635/9645) and some Atmel chips do not implement it and return TPM_BAD_MODE (exit 44). Document this limitation in: - tpm1_da_state function comment: specific TPM models affected - increment_tpm_counter preflight guard: note that da_state may return unavailable on older TPM1 - doc/tpm.md: explain why some TPM1 hardware shows 'unavailable' Signed-off-by: Thierry Laurion <insurgo@riseup.net>

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tlaurion force-pushed the tpm1_fixes branch 2 times, most recently from b20be90 to a5a2ebb Compare May 14, 2026 19:17

tlaurion mentioned this pull request May 14, 2026

m900 tower port (rebased on tpm1_fixes with DA lockout gating) #2118

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tlaurion force-pushed the tpm1_fixes branch from 8d95198 to 072c089 Compare May 14, 2026 20:08

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tlaurion changed the title ~~initrd/bin/tpmr.sh: fix TPM1 auth failure detection and defend lock recovery~~ initrd: fix TPM1 counter auth regression and defend lock cascade failure May 16, 2026

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tlaurion changed the title ~~initrd: fix TPM1 counter auth regression and defend lock cascade failure~~ initrd: add TPM DA lockout gating, counter auth fix, bad_auth tooling and documentation May 17, 2026

tlaurion marked this pull request as draft May 17, 2026 18:35

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tlaurion commented May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Changes

initrd/bin/tpmr.sh — auth fix + DA state + bad_auth

initrd/etc/functions.sh — counter auth + DA preflight

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notgivenby commented May 15, 2026

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tlaurion commented May 16, 2026

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tlaurion commented May 14, 2026 •

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`initrd/bin/tpmr.sh` — auth fix + DA state + bad_auth

`initrd/etc/functions.sh` — counter auth + DA preflight