Reviewed-by: Long Qin <qin.l...@intel.com>
Best Regards & Thanks,
LONG, Qin
-----Original Message-----
From: Zhang, Chao B
Sent: Thursday, October 12, 2017 5:14 PM
To: edk2-devel@lists.01.org
Cc: Long, Qin <qin.l...@intel.com>; Chen, Chen A <chen.a.c...@intel.com>;
Zhang, Chao B <chao.b.zh...@intel.com>
Subject: [PATCH] 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 <qin.l...@intel.com>
Cc: Chen Chen <chen.a.c...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chao Zhang <chao.b.zh...@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); 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
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