From: Ivan Kruglov Date: Fri, 19 Jun 2026 10:18:15 +0000 (-0700) Subject: test-tpm2: add tests for tpm2_pcr_bank_from_efi_active() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F42538%2Fhead;p=thirdparty%2Fsystemd.git test-tpm2: add tests for tpm2_pcr_bank_from_efi_active() Cover the full preference order (SHA256 > SHA384 > SHA512 > SHA1), the single-bank cases and the -EOPNOTSUPP path. Also test the _legacy() variant: a set with SHA384/SHA512 active but no SHA256 must resolve to SHA1, not SHA384, pinning down the backwards-compatibility behavior that keeps legacy sealed secrets unsealable. Co-developed-by: Claude Opus 4.8 --- diff --git a/src/test/test-tpm2.c b/src/test/test-tpm2.c index 6e95499a8ac..2650319094a 100644 --- a/src/test/test-tpm2.c +++ b/src/test/test-tpm2.c @@ -46,6 +46,70 @@ TEST(tpm2_pcr_index_from_string) { assert_se(tpm2_pcr_index_from_string("24") == -EINVAL); } +TEST(tpm2_pcr_bank_from_efi_active) { + uint16_t bank; + + /* SHA256 is the top preference whenever it is active. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active((1u << TPM2_ALG_SHA1) | (1u << TPM2_ALG_SHA256) | (1u << TPM2_ALG_SHA384) | (1u << TPM2_ALG_SHA512), &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA256); + + /* Without SHA256, SHA384 is preferred over SHA512 (shorter digest, less TPM event log space), and + * both win over SHA1. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active((1u << TPM2_ALG_SHA1) | (1u << TPM2_ALG_SHA384) | (1u << TPM2_ALG_SHA512), &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA384); + ASSERT_OK(tpm2_pcr_bank_from_efi_active((1u << TPM2_ALG_SHA1) | (1u << TPM2_ALG_SHA512), &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA512); + + /* SHA384-only firmware must resolve, not fail. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active(1u << TPM2_ALG_SHA384, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA384); + + /* Single-bank cases pick the obvious bank. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active(1u << TPM2_ALG_SHA256, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA256); + ASSERT_OK(tpm2_pcr_bank_from_efi_active(1u << TPM2_ALG_SHA512, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA512); + ASSERT_OK(tpm2_pcr_bank_from_efi_active(1u << TPM2_ALG_SHA1, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA1); + + /* No bank we are willing to use -> -EOPNOTSUPP. Empty mask, or only a bank we cannot hash in + * software (SM3_256, TCG algorithm id 0x12). */ + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active(0, &bank), EOPNOTSUPP); + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active(1u << 0x12, &bank), EOPNOTSUPP); +} + +TEST(tpm2_pcr_bank_from_efi_active_legacy) { + uint16_t bank; + + /* The legacy variant re-derives the bank for old enrollments that did not record one. Such secrets + * could only ever have been sealed against SHA256 or SHA1, so the choice MUST stay restricted to + * those two banks regardless of which stronger banks the firmware reports as active — otherwise we'd + * re-derive a bank the secret was never bound to and silently fail to unseal. */ + + /* SHA256 stays the top preference. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active_legacy((1u << TPM2_ALG_SHA1) | (1u << TPM2_ALG_SHA256) | (1u << TPM2_ALG_SHA384) | (1u << TPM2_ALG_SHA512), &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA256); + + /* The crucial backwards-compatibility case: with SHA384/SHA512 active but no SHA256, the legacy + * variant must fall back to SHA1, NOT pick the stronger SHA384 the way the non-legacy variant does + * (compare the SHA384 result in the test above). */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active_legacy((1u << TPM2_ALG_SHA1) | (1u << TPM2_ALG_SHA384) | (1u << TPM2_ALG_SHA512), &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA1); + + /* Single-bank cases for the two banks we accept. */ + ASSERT_OK(tpm2_pcr_bank_from_efi_active_legacy(1u << TPM2_ALG_SHA256, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA256); + ASSERT_OK(tpm2_pcr_bank_from_efi_active_legacy(1u << TPM2_ALG_SHA1, &bank)); + ASSERT_EQ(bank, TPM2_ALG_SHA1); + + /* Banks the legacy variant never binds to -> -EOPNOTSUPP, even when active. A secret could not have + * been sealed against these by the old code, so there is nothing to re-derive. */ + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active_legacy(1u << TPM2_ALG_SHA384, &bank), EOPNOTSUPP); + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active_legacy(1u << TPM2_ALG_SHA512, &bank), EOPNOTSUPP); + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active_legacy((1u << TPM2_ALG_SHA384) | (1u << TPM2_ALG_SHA512), &bank), EOPNOTSUPP); + ASSERT_ERROR(tpm2_pcr_bank_from_efi_active_legacy(0, &bank), EOPNOTSUPP); +} + TEST(tpm2_util_pbkdf2_hmac_sha256) { /*