From: Zhang, Chao B Date: Tue, 12 Sep 2017 07:41:12 +0000 (+0800) Subject: SecurityPkg:AuthVariableLib:Implement ECR1707 for Private Auth Variable X-Git-Tag: edk2-stable201903~3223 X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=53c6ff18032737fabb644a9e0c781d91a6830248;hp=120fd64781d2c0810ce41c0d4a6ecd348ff7bc49 SecurityPkg:AuthVariableLib:Implement ECR1707 for Private Auth Variable ECR1707 for UEFI2.7 clarified certificate management rule for private time-based AuthVariable.Trusted cert rule changed from whole signer's certificate stack to top-level issuer cert tbscertificate + SignerCert CN for better management compatibility. Hash is used to reduce storage overhead. Cc: Long Qin Cc: Chen Chen Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Chao Zhang ' Reviewed-by: Long Qin Reviewed-by: Chen Chen --- diff --git a/SecurityPkg/Library/AuthVariableLib/AuthService.c b/SecurityPkg/Library/AuthVariableLib/AuthService.c index a37ec0bd0f..7188ff6008 100644 --- a/SecurityPkg/Library/AuthVariableLib/AuthService.c +++ b/SecurityPkg/Library/AuthVariableLib/AuthService.c @@ -1529,6 +1529,85 @@ AuthServiceInternalCompareTimeStamp ( return (BOOLEAN) (FirstTime->Second <= SecondTime->Second); } +/** + Calculate SHA256 digest of SignerCert CommonName + ToplevelCert tbsCertificate + SignerCert and ToplevelCert are inside the signer certificate chain. + + @param[in] SignerCert A pointer to SignerCert data. + @param[in] SignerCertSize Length of SignerCert data. + @param[in] TopLevelCert A pointer to TopLevelCert data. + @param[in] TopLevelCertSize Length of TopLevelCert data. + @param[out] Sha256Digest Sha256 digest calculated. + + @return EFI_ABORTED Digest process failed. + @return EFI_SUCCESS SHA256 Digest is succesfully calculated. + +**/ +EFI_STATUS +CalculatePrivAuthVarSignChainSHA256Digest( + IN UINT8 *SignerCert, + IN UINTN SignerCertSize, + IN UINT8 *TopLevelCert, + IN UINTN TopLevelCertSize, + OUT UINT8 *Sha256Digest + ) +{ + UINT8 *TbsCert; + UINTN TbsCertSize; + UINT8 CertCommonName[128]; + UINTN CertCommonNameSize; + BOOLEAN CryptoStatus; + EFI_STATUS Status; + + CertCommonNameSize = sizeof(CertCommonName); + + // + // Get SignerCert CommonName + // + Status = X509GetCommonName(SignerCert, SignerCertSize, CertCommonName, &CertCommonNameSize); + if (EFI_ERROR(Status)) { + DEBUG((DEBUG_INFO, "%a Get SignerCert CommonName failed with status %x\n", __FUNCTION__, Status)); + return EFI_ABORTED; + } + + // + // Get TopLevelCert tbsCertificate + // + if (!X509GetTBSCert(TopLevelCert, TopLevelCertSize, &TbsCert, &TbsCertSize)) { + DEBUG((DEBUG_INFO, "%a Get Top-level Cert tbsCertificate failed!\n", __FUNCTION__)); + return EFI_ABORTED; + } + + // + // Digest SignerCert CN + TopLevelCert tbsCertificate + // + ZeroMem (Sha256Digest, SHA256_DIGEST_SIZE); + CryptoStatus = Sha256Init (mHashCtx); + if (!CryptoStatus) { + return EFI_ABORTED; + } + + // + // '\0' is forced in CertCommonName. No overflow issue + // + CryptoStatus = Sha256Update (mHashCtx, CertCommonName, AsciiStrLen((CHAR8 *)CertCommonName)); + if (!CryptoStatus) { + return EFI_ABORTED; + } + + CryptoStatus = Sha256Update (mHashCtx, TbsCert, TbsCertSize); + if (!CryptoStatus) { + return EFI_ABORTED; + } + + CryptoStatus = Sha256Final (mHashCtx, Sha256Digest); + if (!CryptoStatus) { + return EFI_ABORTED; + } + + return EFI_SUCCESS; +} + /** Find matching signer's certificates for common authenticated variable by corresponding VariableName and VendorGuid from "certdb" or "certdbv". @@ -1872,13 +1951,16 @@ DeleteCertsFromDb ( /** Insert signer's certificates for common authenticated variable with VariableName and VendorGuid in AUTH_CERT_DB_DATA to "certdb" or "certdbv" according to - time based authenticated variable attributes. + time based authenticated variable attributes. CertData is the SHA256 digest of + SignerCert CommonName + TopLevelCert tbsCertificate. - @param[in] VariableName Name of authenticated Variable. - @param[in] VendorGuid Vendor GUID of authenticated Variable. - @param[in] Attributes Attributes of authenticated variable. - @param[in] CertData Pointer to signer's certificates. - @param[in] CertDataSize Length of CertData in bytes. + @param[in] VariableName Name of authenticated Variable. + @param[in] VendorGuid Vendor GUID of authenticated Variable. + @param[in] Attributes Attributes of authenticated variable. + @param[in] SignerCert Signer certificate data. + @param[in] SignerCertSize Length of signer certificate. + @param[in] TopLevelCert Top-level certificate data. + @param[in] TopLevelCertSize Length of top-level certificate. @retval EFI_INVALID_PARAMETER Any input parameter is invalid. @retval EFI_ACCESS_DENIED An AUTH_CERT_DB_DATA entry with same VariableName @@ -1892,8 +1974,10 @@ InsertCertsToDb ( IN CHAR16 *VariableName, IN EFI_GUID *VendorGuid, IN UINT32 Attributes, - IN UINT8 *CertData, - IN UINTN CertDataSize + IN UINT8 *SignerCert, + IN UINTN SignerCertSize, + IN UINT8 *TopLevelCert, + IN UINTN TopLevelCertSize ) { EFI_STATUS Status; @@ -1904,10 +1988,12 @@ InsertCertsToDb ( UINT32 NewCertDbSize; UINT32 CertNodeSize; UINT32 NameSize; + UINT32 CertDataSize; AUTH_CERT_DB_DATA *Ptr; CHAR16 *DbName; + UINT8 Sha256Digest[SHA256_DIGEST_SIZE]; - if ((VariableName == NULL) || (VendorGuid == NULL) || (CertData == NULL)) { + if ((VariableName == NULL) || (VendorGuid == NULL) || (SignerCert == NULL) ||(TopLevelCert == NULL)) { return EFI_INVALID_PARAMETER; } @@ -1967,11 +2053,24 @@ InsertCertsToDb ( // Construct new data content of variable "certdb" or "certdbv". // NameSize = (UINT32) StrLen (VariableName); + CertDataSize = sizeof(Sha256Digest); CertNodeSize = sizeof (AUTH_CERT_DB_DATA) + (UINT32) CertDataSize + NameSize * sizeof (CHAR16); NewCertDbSize = (UINT32) DataSize + CertNodeSize; if (NewCertDbSize > mMaxCertDbSize) { return EFI_OUT_OF_RESOURCES; } + + Status = CalculatePrivAuthVarSignChainSHA256Digest( + SignerCert, + SignerCertSize, + TopLevelCert, + TopLevelCertSize, + Sha256Digest + ); + if (EFI_ERROR (Status)) { + return Status; + } + NewCertDb = (UINT8*) mCertDbStore; // @@ -1999,7 +2098,7 @@ InsertCertsToDb ( CopyMem ( (UINT8 *) Ptr + sizeof (AUTH_CERT_DB_DATA) + NameSize * sizeof (CHAR16), - CertData, + Sha256Digest, CertDataSize ); @@ -2181,19 +2280,27 @@ VerifyTimeBasedPayload ( UINTN NewDataSize; UINT8 *Buffer; UINTN Length; - UINT8 *RootCert; - UINTN RootCertSize; + UINT8 *TopLevelCert; + UINTN TopLevelCertSize; + UINT8 *TrustedCert; + UINTN TrustedCertSize; UINT8 *SignerCerts; UINTN CertStackSize; UINT8 *CertsInCertDb; UINT32 CertsSizeinDb; + UINT8 Sha256Digest[SHA256_DIGEST_SIZE]; + // + // 1. TopLevelCert is the top-level issuer certificate in signature Signer Cert Chain + // 2. TrustedCert is the certificate which firmware trusts. It could be saved in protected + // storage or PK payload on PK init + // VerifyStatus = FALSE; CertData = NULL; NewData = NULL; Attr = Attributes; SignerCerts = NULL; - RootCert = NULL; + TopLevelCert = NULL; CertsInCertDb = NULL; // @@ -2325,8 +2432,8 @@ VerifyTimeBasedPayload ( SigDataSize, &SignerCerts, &CertStackSize, - &RootCert, - &RootCertSize + &TopLevelCert, + &TopLevelCertSize ); if (!VerifyStatus) { goto Exit; @@ -2348,8 +2455,8 @@ VerifyTimeBasedPayload ( } CertList = (EFI_SIGNATURE_LIST *) Data; Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); - if ((RootCertSize != (CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1))) || - (CompareMem (Cert->SignatureData, RootCert, RootCertSize) != 0)) { + if ((TopLevelCertSize != (CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1))) || + (CompareMem (Cert->SignatureData, TopLevelCert, TopLevelCertSize) != 0)) { VerifyStatus = FALSE; goto Exit; } @@ -2360,8 +2467,8 @@ VerifyTimeBasedPayload ( VerifyStatus = Pkcs7Verify ( SigData, SigDataSize, - RootCert, - RootCertSize, + TopLevelCert, + TopLevelCertSize, NewData, NewDataSize ); @@ -2394,8 +2501,8 @@ VerifyTimeBasedPayload ( // // Iterate each Signature Data Node within this CertList for a verify // - RootCert = Cert->SignatureData; - RootCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1); + TrustedCert = Cert->SignatureData; + TrustedCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1); // // Verify Pkcs7 SignedData via Pkcs7Verify library. @@ -2403,8 +2510,8 @@ VerifyTimeBasedPayload ( VerifyStatus = Pkcs7Verify ( SigData, SigDataSize, - RootCert, - RootCertSize, + TrustedCert, + TrustedCertSize, NewData, NewDataSize ); @@ -2428,8 +2535,8 @@ VerifyTimeBasedPayload ( SigDataSize, &SignerCerts, &CertStackSize, - &RootCert, - &RootCertSize + &TopLevelCert, + &TopLevelCertSize ); if (!VerifyStatus) { goto Exit; @@ -2448,17 +2555,36 @@ VerifyTimeBasedPayload ( goto Exit; } - if ((CertStackSize != CertsSizeinDb) || - (CompareMem (SignerCerts, CertsInCertDb, CertsSizeinDb) != 0)) { - goto Exit; + if (CertsSizeinDb == SHA256_DIGEST_SIZE) { + // + // Check hash of signer cert CommonName + Top-level issuer tbsCertificate against data in CertDb + // + Status = CalculatePrivAuthVarSignChainSHA256Digest( + SignerCerts + sizeof(UINT8) + sizeof(UINT32), + ReadUnaligned32 ((UINT32 *)(SignerCerts + sizeof(UINT8))), + TopLevelCert, + TopLevelCertSize, + Sha256Digest + ); + if (EFI_ERROR(Status) || CompareMem (Sha256Digest, CertsInCertDb, CertsSizeinDb) != 0){ + goto Exit; + } + } else { + // + // Keep backward compatible with previous solution which saves whole signer certs stack in CertDb + // + if ((CertStackSize != CertsSizeinDb) || + (CompareMem (SignerCerts, CertsInCertDb, CertsSizeinDb) != 0)) { + goto Exit; + } } } VerifyStatus = Pkcs7Verify ( SigData, SigDataSize, - RootCert, - RootCertSize, + TopLevelCert, + TopLevelCertSize, NewData, NewDataSize ); @@ -2468,9 +2594,17 @@ VerifyTimeBasedPayload ( if ((OrgTimeStamp == NULL) && (PayloadSize != 0)) { // - // Insert signer's certificates when adding a new common authenticated variable. + // When adding a new common authenticated variable, always save Hash of cn of signer cert + tbsCertificate of Top-level issuer // - Status = InsertCertsToDb (VariableName, VendorGuid, Attributes, SignerCerts, CertStackSize); + Status = InsertCertsToDb ( + VariableName, + VendorGuid, + Attributes, + SignerCerts + sizeof(UINT8) + sizeof(UINT32), + ReadUnaligned32 ((UINT32 *)(SignerCerts + sizeof(UINT8))), + TopLevelCert, + TopLevelCertSize + ); if (EFI_ERROR (Status)) { VerifyStatus = FALSE; goto Exit; @@ -2479,16 +2613,16 @@ VerifyTimeBasedPayload ( } else if (AuthVarType == AuthVarTypePayload) { CertList = (EFI_SIGNATURE_LIST *) PayloadPtr; Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize); - RootCert = Cert->SignatureData; - RootCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1); + TrustedCert = Cert->SignatureData; + TrustedCertSize = CertList->SignatureSize - (sizeof (EFI_SIGNATURE_DATA) - 1); // // Verify Pkcs7 SignedData via Pkcs7Verify library. // VerifyStatus = Pkcs7Verify ( SigData, SigDataSize, - RootCert, - RootCertSize, + TrustedCert, + TrustedCertSize, NewData, NewDataSize ); @@ -2499,7 +2633,7 @@ VerifyTimeBasedPayload ( Exit: if (AuthVarType == AuthVarTypePk || AuthVarType == AuthVarTypePriv) { - Pkcs7FreeSigners (RootCert); + Pkcs7FreeSigners (TopLevelCert); Pkcs7FreeSigners (SignerCerts); }