From: Gary Lin <glin@suse.com>
To: "Zhang, Chao B" <chao.b.zhang@intel.com>
Cc: edk2-devel@lists.01.org, qin.long@intel.com
Subject: Re: [PATCH] SecurityPkg:AuthVariableLib:Implement ECR1707 for Private Auth Variable
Date: Mon, 16 Oct 2017 10:15:29 +0800 [thread overview]
Message-ID: <20171016021529.sz6sqnud5twdxj6w@GaryWorkstation> (raw)
In-Reply-To: <20171012091425.29420-1-chao.b.zhang@intel.com>
On Thu, Oct 12, 2017 at 05:14:25PM +0800, Zhang, Chao B wrote:
> 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 <qin.long@intel.com>
> Cc: Chen Chen <chen.a.chen@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
> ---
> SecurityPkg/Library/AuthVariableLib/AuthService.c | 208 ++++++++++++++++++----
> 1 file changed, 171 insertions(+), 37 deletions(-)
>
> diff --git a/SecurityPkg/Library/AuthVariableLib/AuthService.c b/SecurityPkg/Library/AuthVariableLib/AuthService.c
> index a37ec0b..7188ff6 100644
> --- a/SecurityPkg/Library/AuthVariableLib/AuthService.c
> +++ b/SecurityPkg/Library/AuthVariableLib/AuthService.c
> @@ -1530,6 +1530,85 @@ AuthServiceInternalCompareTimeStamp (
> }
>
> /**
> + 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);
An error showed while building ovmf with gcc 7.2.1:
SecurityPkg/Library/AuthVariableLib/AuthService.c: In function ‘CalculatePrivAuthVarSignChainSHA256Digest’:
SecurityPkg/Library/AuthVariableLib/AuthService.c:1567:58: error: pointer targets in passing argument 3 of ‘X509GetCommonName’ differ in signedness [-Werror=pointer-sign]
Status = X509GetCommonName(SignerCert, SignerCertSize, CertCommonName, &CertCommonNameSize);
^~~~~~~~~~~~~~
In file included from SecurityPkg/Library/AuthVariableLib/AuthServiceInternal.h:34:0,
from SecurityPkg/Library/AuthVariableLib/AuthService.c:32:
CryptoPkg/Include/Library/BaseCryptLib.h:2202:1: note: expected ‘CHAR8 * {aka char *}’ but argument is of type ‘UINT8 * {aka unsigned char *}’
X509GetCommonName (
^~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Changing the type of CertCommonName from UINT8 to CHAR8 fixes the
warning.
Cheers,
Gary Lin
> + 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);
> }
>
> --
> 1.9.5.msysgit.1
>
> _______________________________________________
> edk2-devel mailing list
> edk2-devel@lists.01.org
> https://lists.01.org/mailman/listinfo/edk2-devel
>
next prev parent reply other threads:[~2017-10-16 2:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-12 9:14 [PATCH] SecurityPkg:AuthVariableLib:Implement ECR1707 for Private Auth Variable Zhang, Chao B
2017-10-13 6:50 ` Chen, Chen A
2017-10-13 8:43 ` Long, Qin
2017-10-16 2:15 ` Gary Lin [this message]
2017-10-16 14:09 ` Zhang, Chao B
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