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Correct PolicyAuthorize response codes for keySign name ticket and approvedPolicy #572

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Merged
dgarske merged 3 commits into from
Aug 13, 2026
Merged

Correct PolicyAuthorize response codes for keySign name ticket and approvedPolicy #572

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897f5e4
F-9200 - Validate PolicyAuthorize keySign name hash and length
aidangarske Aug 12, 2026
4d543ad
F-9201 - Return TPM_RC_VALUE for an invalid PolicyAuthorize ticket
aidangarske Aug 12, 2026
f55b0a6
F-9202 - Return TPM_RC_VALUE for a PolicyAuthorize approvedPolicy mis…
aidangarske Aug 12, 2026
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21 changes: 18 additions & 3 deletions src/fwtpm/fwtpm_command.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9726,6 +9726,7 @@ static TPM_RC FwCmd_PolicyAuthorize(FWTPM_CTX* ctx, TPM2_Packet* cmd,
byte ccBuf[4];
UINT32 cc = TPM_CC_PolicyAuthorize;
TPMI_ALG_HASH keyNameAlg = TPM_ALG_SHA256; /* from keySignName */
int keyNameDigestSz = 0;
(void)cmdSize;

FWTPM_ALLOC_VAR(hashCtx, wc_HashAlg);
Expand Down Expand Up @@ -9760,11 +9761,25 @@ static TPM_RC FwCmd_PolicyAuthorize(FWTPM_CTX* ctx, TPM2_Packet* cmd,
TPM2_Packet_ParseBytes(cmd, keySignName, keySignNameSz);

/* Extract nameAlg from keySignName (first 2 bytes, big-endian).
* This determines the hash algorithm for aHash and ticket HMAC. */
* This determines the hash algorithm for aHash and ticket HMAC. A
* valid Name is a supported hash selector followed by exactly that
* algorithm's digest. */
if (keySignNameSz >= 2) {
keyNameAlg = (TPMI_ALG_HASH)(
((UINT16)keySignName[0] << 8) | keySignName[1]);
keyNameDigestSz = TPM2_GetHashDigestSize(keyNameAlg);
if (keyNameDigestSz <= 0) {
rc = TPM_RC_HASH;
}
else if (keySignNameSz != (UINT16)(2 + keyNameDigestSz)) {
rc = TPM_RC_SIZE;
}
}
else {
rc = TPM_RC_SIZE;
}
}
if (rc == 0) {

/* checkTicket: TPMT_TK_VERIFIED: tag(2) + hierarchy(4) + digest(TPM2B)
* Per TPM 2.0 Part 3 Section 23.16: verify ticket was produced by
Expand Down Expand Up @@ -9875,7 +9890,7 @@ static TPM_RC FwCmd_PolicyAuthorize(FWTPM_CTX* ctx, TPM2_Packet* cmd,
"(tag=0x%x, hier=0x%x, ticketSz=%d, expectedSz=%d)\n",
ticketTag, ticketHier, ticketDigestSz, expectedSz);
#endif
rc = TPM_RC_POLICY_FAIL;
rc = TPM_RC_VALUE;
}
}
TPM2_ForceZero(aHash, sizeof(aHash));
Expand Down Expand Up @@ -9918,7 +9933,7 @@ static TPM_RC FwCmd_PolicyAuthorize(FWTPM_CTX* ctx, TPM2_Packet* cmd,
printf("fwTPM: PolicyAuthorize: "
"approvedPolicy != policyDigest\n");
#endif
rc = TPM_RC_POLICY_FAIL;
rc = TPM_RC_VALUE;
}
}
}
Expand Down
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