* [PATCH v2 01/10] SecurityPkg/DxeImageVerificationLib: Fix memory leaks(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 02/10] SecurityPkg/DxeImageVerificationLib: reject CertStack.CertNumber==0 per DBX(CVE-2019-14575) Wang, Jian J
` (9 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
Pointer HashCtx used in IsCertHashFoundInDatabase() is not freed inside
the while-loop, if it will run more than once.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index dbfbfcb4fb..74dbffa122 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -908,6 +908,9 @@ IsCertHashFoundInDatabase (
goto Done;
}
+ FreePool (HashCtx);
+ HashCtx = NULL;
+
SiglistHeaderSize = sizeof (EFI_SIGNATURE_LIST) + DbxList->SignatureHeaderSize;
CertHash = (EFI_SIGNATURE_DATA *) ((UINT8 *) DbxList + SiglistHeaderSize);
CertHashCount = (DbxList->SignatureListSize - SiglistHeaderSize) / DbxList->SignatureSize;
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 02/10] SecurityPkg/DxeImageVerificationLib: reject CertStack.CertNumber==0 per DBX(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 01/10] SecurityPkg/DxeImageVerificationLib: Fix memory leaks(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 03/10] SecurityPkg/DxeImageVerificationLib: fix wrong fetch dbx in IsAllowedByDb(CVE-2019-14575) Wang, Jian J
` (8 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang, Laszlo Ersek
In case the signers' certificate stack, retrieved from the PE/COFF image's
Authenticode blob, has zero elements (=there are zero signer certificates),
then we should consider the image forbidden by DBX, not accepted by DBX.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 74dbffa122..5dcd6efed5 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1326,7 +1326,7 @@ IsForbiddenByDbx (
// UINT8 Certn[];
//
Pkcs7GetSigners (AuthData, AuthDataSize, &CertBuffer, &BufferLength, &TrustedCert, &TrustedCertLength);
- if ((BufferLength == 0) || (CertBuffer == NULL)) {
+ if ((BufferLength == 0) || (CertBuffer == NULL) || (*CertBuffer) == 0) {
IsForbidden = TRUE;
goto Done;
}
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 03/10] SecurityPkg/DxeImageVerificationLib: fix wrong fetch dbx in IsAllowedByDb(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 01/10] SecurityPkg/DxeImageVerificationLib: Fix memory leaks(CVE-2019-14575) Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 02/10] SecurityPkg/DxeImageVerificationLib: reject CertStack.CertNumber==0 per DBX(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 04/10] SecurityPkg/DxeImageVerificationLib: avoid bypass in fetching dbx(CVE-2019-14575) Wang, Jian J
` (7 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
Normally two times of calling gRT->GetVariable() are needed to get
the data of a variable: get the variable size by passing zero variable
size, and then allocate enough memory and pass the correct variable size
and buffer.
But in the inner loop in IsAllowedByDb(), the DbxDataSize was not
initialized to zero before calling gRT->GetVariable(). It won't cause
problem if dbx does not exist. But it will give wrong result if dbx
exists and the DbxDataSize happens to be a small enough value. In this
situation, EFI_BUFFER_TOO_SMALL will be returned. Then the result check
code followed will jump to 'Done', which is not correct because it's
actually the value expected.
if (Status == EFI_BUFFER_TOO_SMALL) {
goto Done;
}
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 5dcd6efed5..1efb2f96cd 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1456,8 +1456,9 @@ IsAllowedByDb (
//
// Here We still need to check if this RootCert's Hash is revoked
//
+ DbxDataSize = 0;
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
- if (Status == EFI_BUFFER_TOO_SMALL) {
+ if (Status != EFI_BUFFER_TOO_SMALL) {
goto Done;
}
DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 04/10] SecurityPkg/DxeImageVerificationLib: avoid bypass in fetching dbx(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (2 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 03/10] SecurityPkg/DxeImageVerificationLib: fix wrong fetch dbx in IsAllowedByDb(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 05/10] SecurityPkg/DxeImageVerificationLib: refactor db/dbx fetching code(CVE-2019-14575) Wang, Jian J
` (6 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
In timestamp check after the cert is found in db, the original code jumps
to 'Done' if any error happens in fetching dbx variable. At any of the
jump, VerifyStatus equals to TRUE, which means allowed-by-db. This should
not be allowed except to EFI_NOT_FOUND case (meaning dbx doesn't exist),
because it could be used to bypass timestamp check.
This patch add code to change VerifyStatus to FALSE in the case of memory
allocation failure and dbx fetching failure to avoid potential bypass
issue.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../DxeImageVerificationLib/DxeImageVerificationLib.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 1efb2f96cd..ed5dbf26b0 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1459,15 +1459,26 @@ IsAllowedByDb (
DbxDataSize = 0;
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
if (Status != EFI_BUFFER_TOO_SMALL) {
+ if (Status != EFI_NOT_FOUND) {
+ VerifyStatus = FALSE;
+ }
goto Done;
}
DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
if (DbxData == NULL) {
+ //
+ // Force not-allowed-by-db to avoid bypass
+ //
+ VerifyStatus = FALSE;
goto Done;
}
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
if (EFI_ERROR (Status)) {
+ //
+ // Force not-allowed-by-db to avoid bypass
+ //
+ VerifyStatus = FALSE;
goto Done;
}
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 05/10] SecurityPkg/DxeImageVerificationLib: refactor db/dbx fetching code(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (3 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 04/10] SecurityPkg/DxeImageVerificationLib: avoid bypass in fetching dbx(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (1)(CVE-2019-14575) Wang, Jian J
` (5 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
The dbx fetching code inside the while/for-loop causes code hard to
understand. Since there's no need to get dbx more than once, this patch
simplify the code logic by moving related code to be outside the while-
loop. db fetching code is also refined accordingly to reduce the indent
level of code.
More comments are also added or refined to explain more details.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../DxeImageVerificationLib.c | 144 ++++++++++--------
1 file changed, 83 insertions(+), 61 deletions(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index ed5dbf26b0..8739d1fa29 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1412,76 +1412,92 @@ IsAllowedByDb (
RootCertSize = 0;
VerifyStatus = FALSE;
+ //
+ // Fetch 'db' content. If 'db' doesn't exist or encounters problem to get the
+ // data, return not-allowed-by-db (FALSE).
+ //
DataSize = 0;
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
- if (Status == EFI_BUFFER_TOO_SMALL) {
- Data = (UINT8 *) AllocateZeroPool (DataSize);
- if (Data == NULL) {
- return VerifyStatus;
+ ASSERT (EFI_ERROR (Status));
+ if (Status != EFI_BUFFER_TOO_SMALL) {
+ return VerifyStatus;
+ }
+
+ Data = (UINT8 *) AllocateZeroPool (DataSize);
+ if (Data == NULL) {
+ return VerifyStatus;
+ }
+
+ Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
+ if (EFI_ERROR (Status)) {
+ goto Done;
+ }
+
+ //
+ // Fetch 'dbx' content. If 'dbx' doesn't exist, continue to check 'db'.
+ // If any other errors occured, no need to check 'db' but just return
+ // not-allowed-by-db (FALSE) to avoid bypass.
+ //
+ DbxDataSize = 0;
+ Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
+ ASSERT (EFI_ERROR (Status));
+ if (Status != EFI_BUFFER_TOO_SMALL) {
+ if (Status != EFI_NOT_FOUND) {
+ goto Done;
+ }
+ //
+ // 'dbx' does not exist. Continue to check 'db'.
+ //
+ } else {
+ //
+ // 'dbx' exists. Get its content.
+ //
+ DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
+ if (DbxData == NULL) {
+ goto Done;
}
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
+ Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
if (EFI_ERROR (Status)) {
goto Done;
}
+ }
- //
- // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
- //
- CertList = (EFI_SIGNATURE_LIST *) Data;
- while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
- if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
- CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
+ //
+ // Find X509 certificate in Signature List to verify the signature in pkcs7 signed data.
+ //
+ CertList = (EFI_SIGNATURE_LIST *) Data;
+ while ((DataSize > 0) && (DataSize >= CertList->SignatureListSize)) {
+ if (CompareGuid (&CertList->SignatureType, &gEfiCertX509Guid)) {
+ CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertList + sizeof (EFI_SIGNATURE_LIST) + CertList->SignatureHeaderSize);
+ CertCount = (CertList->SignatureListSize - sizeof (EFI_SIGNATURE_LIST) - CertList->SignatureHeaderSize) / CertList->SignatureSize;
- for (Index = 0; Index < CertCount; Index++) {
- //
- // Iterate each Signature Data Node within this CertList for verify.
- //
- RootCert = CertData->SignatureData;
- RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
+ for (Index = 0; Index < CertCount; Index++) {
+ //
+ // Iterate each Signature Data Node within this CertList for verify.
+ //
+ RootCert = CertData->SignatureData;
+ RootCertSize = CertList->SignatureSize - sizeof (EFI_GUID);
+ //
+ // Call AuthenticodeVerify library to Verify Authenticode struct.
+ //
+ VerifyStatus = AuthenticodeVerify (
+ AuthData,
+ AuthDataSize,
+ RootCert,
+ RootCertSize,
+ mImageDigest,
+ mImageDigestSize
+ );
+ if (VerifyStatus) {
//
- // Call AuthenticodeVerify library to Verify Authenticode struct.
+ // The image is signed and its signature is found in 'db'.
//
- VerifyStatus = AuthenticodeVerify (
- AuthData,
- AuthDataSize,
- RootCert,
- RootCertSize,
- mImageDigest,
- mImageDigestSize
- );
- if (VerifyStatus) {
+ if (DbxData != NULL) {
//
// Here We still need to check if this RootCert's Hash is revoked
//
- DbxDataSize = 0;
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, NULL);
- if (Status != EFI_BUFFER_TOO_SMALL) {
- if (Status != EFI_NOT_FOUND) {
- VerifyStatus = FALSE;
- }
- goto Done;
- }
- DbxData = (UINT8 *) AllocateZeroPool (DbxDataSize);
- if (DbxData == NULL) {
- //
- // Force not-allowed-by-db to avoid bypass
- //
- VerifyStatus = FALSE;
- goto Done;
- }
-
- Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DbxDataSize, (VOID *) DbxData);
- if (EFI_ERROR (Status)) {
- //
- // Force not-allowed-by-db to avoid bypass
- //
- VerifyStatus = FALSE;
- goto Done;
- }
-
if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
//
// Check the timestamp signature and signing time to determine if the RootCert can be trusted.
@@ -1491,17 +1507,23 @@ IsAllowedByDb (
DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed and signature is accepted by DB, but its root cert failed the timestamp check.\n"));
}
}
-
- goto Done;
}
- CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
+ //
+ // There's no 'dbx' to check revocation time against (must-be pass),
+ // or, there's revocation time found in 'dbx' and checked againt 'dbt'
+ // (maybe pass or fail, depending on timestamp compare result). Either
+ // way the verification job has been completed at this point.
+ //
+ goto Done;
}
- }
- DataSize -= CertList->SignatureListSize;
- CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
+ CertData = (EFI_SIGNATURE_DATA *) ((UINT8 *) CertData + CertList->SignatureSize);
+ }
}
+
+ DataSize -= CertList->SignatureListSize;
+ CertList = (EFI_SIGNATURE_LIST *) ((UINT8 *) CertList + CertList->SignatureListSize);
}
Done:
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (1)(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (4 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 05/10] SecurityPkg/DxeImageVerificationLib: refactor db/dbx fetching code(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:47 ` Yao, Jiewen
2020-02-14 7:27 ` [PATCH v2 07/10] SecurityPkg/DxeImageVerificationLib: tighten default result(CVE-2019-14575) Wang, Jian J
` (4 subsequent siblings)
10 siblings, 1 reply; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang, Laszlo Ersek
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
To avoid false-negative issue in check hash against dbx, both error
condition (as return value) and check result (as out parameter) of
IsCertHashFoundInDatabase() are added. So the caller of this function
will know exactly if a failure is caused by a black list hit or
other error happening, and enforce a more secure operation to prevent
secure boot from being bypassed. For a white list check (db), there's
no such necessity.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
.../DxeImageVerificationLib.c | 64 ++++++++++++-------
1 file changed, 42 insertions(+), 22 deletions(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 8739d1fa29..85261ba7f2 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -822,22 +822,23 @@ AddImageExeInfo (
@param[in] SignatureList Pointer to the Signature List in forbidden database.
@param[in] SignatureListSize Size of Signature List.
@param[out] RevocationTime Return the time that the certificate was revoked.
+ @param[out] IsFound Search result. Only valid if EFI_SUCCESS returned.
- @return TRUE The certificate hash is found in the forbidden database.
- @return FALSE The certificate hash is not found in the forbidden database.
+ @retval EFI_SUCCESS Finished the search without any error.
+ @retval Others Error occurred in the search of database.
**/
-BOOLEAN
+EFI_STATUS
IsCertHashFoundInDatabase (
IN UINT8 *Certificate,
IN UINTN CertSize,
IN EFI_SIGNATURE_LIST *SignatureList,
IN UINTN SignatureListSize,
- OUT EFI_TIME *RevocationTime
+ OUT EFI_TIME *RevocationTime,
+ OUT BOOLEAN *IsFound
)
{
- BOOLEAN IsFound;
- BOOLEAN Status;
+ EFI_STATUS Status;
EFI_SIGNATURE_LIST *DbxList;
UINTN DbxSize;
EFI_SIGNATURE_DATA *CertHash;
@@ -851,21 +852,22 @@ IsCertHashFoundInDatabase (
UINT8 *TBSCert;
UINTN TBSCertSize;
- IsFound = FALSE;
+ Status = EFI_ABORTED;
+ *IsFound = FALSE;
DbxList = SignatureList;
DbxSize = SignatureListSize;
HashCtx = NULL;
HashAlg = HASHALG_MAX;
if ((RevocationTime == NULL) || (DbxList == NULL)) {
- return FALSE;
+ return EFI_INVALID_PARAMETER;
}
//
// Retrieve the TBSCertificate from the X.509 Certificate.
//
if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
- return FALSE;
+ return Status;
}
while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
@@ -895,16 +897,13 @@ IsCertHashFoundInDatabase (
if (HashCtx == NULL) {
goto Done;
}
- Status = mHash[HashAlg].HashInit (HashCtx);
- if (!Status) {
+ if (!mHash[HashAlg].HashInit (HashCtx)) {
goto Done;
}
- Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize);
- if (!Status) {
+ if (!mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize)) {
goto Done;
}
- Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest);
- if (!Status) {
+ if (!mHash[HashAlg].HashFinal (HashCtx, CertDigest)) {
goto Done;
}
@@ -923,7 +922,8 @@ IsCertHashFoundInDatabase (
//
// Hash of Certificate is found in forbidden database.
//
- IsFound = TRUE;
+ Status = EFI_SUCCESS;
+ *IsFound = TRUE;
//
// Return the revocation time.
@@ -938,12 +938,14 @@ IsCertHashFoundInDatabase (
DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList->SignatureListSize);
}
+ Status = EFI_SUCCESS;
+
Done:
if (HashCtx != NULL) {
FreePool (HashCtx);
}
- return IsFound;
+ return Status;
}
/**
@@ -1216,6 +1218,7 @@ IsForbiddenByDbx (
{
EFI_STATUS Status;
BOOLEAN IsForbidden;
+ BOOLEAN IsFound;
UINT8 *Data;
UINTN DataSize;
EFI_SIGNATURE_LIST *CertList;
@@ -1344,20 +1347,29 @@ IsForbiddenByDbx (
//
CertPtr = CertPtr + sizeof (UINT32) + CertSize;
- if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
+ Status = IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime, &IsFound);
+ if (EFI_ERROR (Status)) {
//
- // Check the timestamp signature and signing time to determine if the image can be trusted.
+ // Error in searching dbx. Consider it as 'found'. RevocationTime might
+ // not be valid in such situation.
//
IsForbidden = TRUE;
+ } else if (IsFound) {
+ //
+ // Found Cert in dbx successfully. Check the timestamp signature and
+ // signing time to determine if the image can be trusted.
+ //
if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
IsForbidden = FALSE;
//
// Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
//
continue;
+ } else {
+ IsForbidden = TRUE;
+ DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
+ goto Done;
}
- DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature failed the timestamp check.\n"));
- goto Done;
}
}
@@ -1392,6 +1404,7 @@ IsAllowedByDb (
{
EFI_STATUS Status;
BOOLEAN VerifyStatus;
+ BOOLEAN IsFound;
EFI_SIGNATURE_LIST *CertList;
EFI_SIGNATURE_DATA *CertData;
UINTN DataSize;
@@ -1498,7 +1511,14 @@ IsAllowedByDb (
//
// Here We still need to check if this RootCert's Hash is revoked
//
- if (IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
+ Status = IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
+ if (EFI_ERROR (Status)) {
+ //
+ // Error in searching dbx. Consider it as 'found'. RevocationTime might
+ // not be valid in such situation.
+ //
+ VerifyStatus = FALSE;
+ } else if (IsFound) {
//
// Check the timestamp signature and signing time to determine if the RootCert can be trusted.
//
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (1)(CVE-2019-14575)
2020-02-14 7:27 ` [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (1)(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:47 ` Yao, Jiewen
0 siblings, 0 replies; 15+ messages in thread
From: Yao, Jiewen @ 2020-02-14 7:47 UTC (permalink / raw)
To: Wang, Jian J, devel@edk2.groups.io; +Cc: Zhang, Chao B, Laszlo Ersek
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
> -----Original Message-----
> From: Wang, Jian J <jian.j.wang@intel.com>
> Sent: Friday, February 14, 2020 3:28 PM
> To: devel@edk2.groups.io
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Zhang, Chao B
> <chao.b.zhang@intel.com>; Laszlo Ersek <lersek@redhat.com>
> Subject: [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate
> error/search result (1)(CVE-2019-14575)
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
>
> To avoid false-negative issue in check hash against dbx, both error
> condition (as return value) and check result (as out parameter) of
> IsCertHashFoundInDatabase() are added. So the caller of this function
> will know exactly if a failure is caused by a black list hit or
> other error happening, and enforce a more secure operation to prevent
> secure boot from being bypassed. For a white list check (db), there's
> no such necessity.
>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Chao Zhang <chao.b.zhang@intel.com>
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> .../DxeImageVerificationLib.c | 64 ++++++++++++-------
> 1 file changed, 42 insertions(+), 22 deletions(-)
>
> diff --git
> a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> index 8739d1fa29..85261ba7f2 100644
> --- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> +++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> @@ -822,22 +822,23 @@ AddImageExeInfo (
> @param[in] SignatureList Pointer to the Signature List in forbidden database.
>
> @param[in] SignatureListSize Size of Signature List.
>
> @param[out] RevocationTime Return the time that the certificate was
> revoked.
>
> + @param[out] IsFound Search result. Only valid if EFI_SUCCESS returned.
>
>
>
> - @return TRUE The certificate hash is found in the forbidden database.
>
> - @return FALSE The certificate hash is not found in the forbidden database.
>
> + @retval EFI_SUCCESS Finished the search without any error.
>
> + @retval Others Error occurred in the search of database.
>
>
>
> **/
>
> -BOOLEAN
>
> +EFI_STATUS
>
> IsCertHashFoundInDatabase (
>
> IN UINT8 *Certificate,
>
> IN UINTN CertSize,
>
> IN EFI_SIGNATURE_LIST *SignatureList,
>
> IN UINTN SignatureListSize,
>
> - OUT EFI_TIME *RevocationTime
>
> + OUT EFI_TIME *RevocationTime,
>
> + OUT BOOLEAN *IsFound
>
> )
>
> {
>
> - BOOLEAN IsFound;
>
> - BOOLEAN Status;
>
> + EFI_STATUS Status;
>
> EFI_SIGNATURE_LIST *DbxList;
>
> UINTN DbxSize;
>
> EFI_SIGNATURE_DATA *CertHash;
>
> @@ -851,21 +852,22 @@ IsCertHashFoundInDatabase (
> UINT8 *TBSCert;
>
> UINTN TBSCertSize;
>
>
>
> - IsFound = FALSE;
>
> + Status = EFI_ABORTED;
>
> + *IsFound = FALSE;
>
> DbxList = SignatureList;
>
> DbxSize = SignatureListSize;
>
> HashCtx = NULL;
>
> HashAlg = HASHALG_MAX;
>
>
>
> if ((RevocationTime == NULL) || (DbxList == NULL)) {
>
> - return FALSE;
>
> + return EFI_INVALID_PARAMETER;
>
> }
>
>
>
> //
>
> // Retrieve the TBSCertificate from the X.509 Certificate.
>
> //
>
> if (!X509GetTBSCert (Certificate, CertSize, &TBSCert, &TBSCertSize)) {
>
> - return FALSE;
>
> + return Status;
>
> }
>
>
>
> while ((DbxSize > 0) && (SignatureListSize >= DbxList->SignatureListSize)) {
>
> @@ -895,16 +897,13 @@ IsCertHashFoundInDatabase (
> if (HashCtx == NULL) {
>
> goto Done;
>
> }
>
> - Status = mHash[HashAlg].HashInit (HashCtx);
>
> - if (!Status) {
>
> + if (!mHash[HashAlg].HashInit (HashCtx)) {
>
> goto Done;
>
> }
>
> - Status = mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize);
>
> - if (!Status) {
>
> + if (!mHash[HashAlg].HashUpdate (HashCtx, TBSCert, TBSCertSize)) {
>
> goto Done;
>
> }
>
> - Status = mHash[HashAlg].HashFinal (HashCtx, CertDigest);
>
> - if (!Status) {
>
> + if (!mHash[HashAlg].HashFinal (HashCtx, CertDigest)) {
>
> goto Done;
>
> }
>
>
>
> @@ -923,7 +922,8 @@ IsCertHashFoundInDatabase (
> //
>
> // Hash of Certificate is found in forbidden database.
>
> //
>
> - IsFound = TRUE;
>
> + Status = EFI_SUCCESS;
>
> + *IsFound = TRUE;
>
>
>
> //
>
> // Return the revocation time.
>
> @@ -938,12 +938,14 @@ IsCertHashFoundInDatabase (
> DbxList = (EFI_SIGNATURE_LIST *) ((UINT8 *) DbxList + DbxList-
> >SignatureListSize);
>
> }
>
>
>
> + Status = EFI_SUCCESS;
>
> +
>
> Done:
>
> if (HashCtx != NULL) {
>
> FreePool (HashCtx);
>
> }
>
>
>
> - return IsFound;
>
> + return Status;
>
> }
>
>
>
> /**
>
> @@ -1216,6 +1218,7 @@ IsForbiddenByDbx (
> {
>
> EFI_STATUS Status;
>
> BOOLEAN IsForbidden;
>
> + BOOLEAN IsFound;
>
> UINT8 *Data;
>
> UINTN DataSize;
>
> EFI_SIGNATURE_LIST *CertList;
>
> @@ -1344,20 +1347,29 @@ IsForbiddenByDbx (
> //
>
> CertPtr = CertPtr + sizeof (UINT32) + CertSize;
>
>
>
> - if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data,
> DataSize, &RevocationTime)) {
>
> + Status = IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST
> *)Data, DataSize, &RevocationTime, &IsFound);
>
> + if (EFI_ERROR (Status)) {
>
> //
>
> - // Check the timestamp signature and signing time to determine if the image
> can be trusted.
>
> + // Error in searching dbx. Consider it as 'found'. RevocationTime might
>
> + // not be valid in such situation.
>
> //
>
> IsForbidden = TRUE;
>
> + } else if (IsFound) {
>
> + //
>
> + // Found Cert in dbx successfully. Check the timestamp signature and
>
> + // signing time to determine if the image can be trusted.
>
> + //
>
> if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
>
> IsForbidden = FALSE;
>
> //
>
> // Pass DBT check. Continue to check other certs in image signer's cert list
> against DBX, DBT
>
> //
>
> continue;
>
> + } else {
>
> + IsForbidden = TRUE;
>
> + DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but
> signature failed the timestamp check.\n"));
>
> + goto Done;
>
> }
>
> - DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but
> signature failed the timestamp check.\n"));
>
> - goto Done;
>
> }
>
>
>
> }
>
> @@ -1392,6 +1404,7 @@ IsAllowedByDb (
> {
>
> EFI_STATUS Status;
>
> BOOLEAN VerifyStatus;
>
> + BOOLEAN IsFound;
>
> EFI_SIGNATURE_LIST *CertList;
>
> EFI_SIGNATURE_DATA *CertData;
>
> UINTN DataSize;
>
> @@ -1498,7 +1511,14 @@ IsAllowedByDb (
> //
>
> // Here We still need to check if this RootCert's Hash is revoked
>
> //
>
> - if (IsCertHashFoundInDatabase (RootCert, RootCertSize,
> (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime)) {
>
> + Status = IsCertHashFoundInDatabase (RootCert, RootCertSize,
> (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
>
> + if (EFI_ERROR (Status)) {
>
> + //
>
> + // Error in searching dbx. Consider it as 'found'. RevocationTime might
>
> + // not be valid in such situation.
>
> + //
>
> + VerifyStatus = FALSE;
>
> + } else if (IsFound) {
>
> //
>
> // Check the timestamp signature and signing time to determine if the
> RootCert can be trusted.
>
> //
>
> --
> 2.24.0.windows.2
^ permalink raw reply [flat|nested] 15+ messages in thread
* [PATCH v2 07/10] SecurityPkg/DxeImageVerificationLib: tighten default result(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (5 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 06/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (1)(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 08/10] SecurityPkg/DxeImageVerificationLib: plug Data leak in IsForbiddenByDbx()(CVE-2019-14575) Wang, Jian J
` (3 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang, Laszlo Ersek
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
All intermediate results inside this function will be checked and
returned immediately upon any failure or error, like out-of-resource,
hash calculation error or certificate retrieval failure.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../DxeImageVerificationLib/DxeImageVerificationLib.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 85261ba7f2..470a0d20ef 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1240,7 +1240,7 @@ IsForbiddenByDbx (
//
// Variable Initialization
//
- IsForbidden = FALSE;
+ IsForbidden = TRUE;
Data = NULL;
CertList = NULL;
CertData = NULL;
@@ -1257,7 +1257,14 @@ IsForbiddenByDbx (
//
DataSize = 0;
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
+ ASSERT (EFI_ERROR (Status));
if (Status != EFI_BUFFER_TOO_SMALL) {
+ if (Status == EFI_NOT_FOUND) {
+ //
+ // Evidently not in dbx if the database doesn't exist.
+ //
+ IsForbidden = FALSE;
+ }
return IsForbidden;
}
Data = (UINT8 *) AllocateZeroPool (DataSize);
@@ -1374,6 +1381,8 @@ IsForbiddenByDbx (
}
+ IsForbidden = FALSE;
+
Done:
if (Data != NULL) {
FreePool (Data);
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 08/10] SecurityPkg/DxeImageVerificationLib: plug Data leak in IsForbiddenByDbx()(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (6 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 07/10] SecurityPkg/DxeImageVerificationLib: tighten default result(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 09/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (2)(CVE-2019-14575) Wang, Jian J
` (2 subsequent siblings)
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Laszlo Ersek, Jiewen Yao, Chao Zhang
From: Laszlo Ersek <lersek@redhat.com>
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
If the second GetVariable() call for "dbx" fails, in IsForbiddenByDbx(),
we have to free Data. Jump to "Done" for that.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../Library/DxeImageVerificationLib/DxeImageVerificationLib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 470a0d20ef..f20640af68 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1274,7 +1274,7 @@ IsForbiddenByDbx (
Status = gRT->GetVariable (EFI_IMAGE_SECURITY_DATABASE1, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, (VOID *) Data);
if (EFI_ERROR (Status)) {
- return IsForbidden;
+ goto Done;
}
//
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 09/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (2)(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (7 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 08/10] SecurityPkg/DxeImageVerificationLib: plug Data leak in IsForbiddenByDbx()(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:27 ` [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase name(CVE-2019-14575) Wang, Jian J
2020-02-17 7:48 ` [edk2-devel] [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Laszlo Ersek
10 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang, Laszlo Ersek
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
To avoid false-negative issue in check hash against dbx, both error
condition (as return value) and check result (as out parameter) of
IsSignatureFoundInDatabase() are added. So the caller of this function
will know exactly if a failure is caused by a black list hit or
other error happening, and enforce a more secure operation to prevent
secure boot from being bypassed. For a white list check (db), there's
no such necessity.
All intermediate results inside this function will be checked and
returned immediately upon any failure or error, like out-of-resource,
hash calculation error or certificate retrieval failure.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
---
.../DxeImageVerificationLib.c | 77 ++++++++++++++-----
1 file changed, 58 insertions(+), 19 deletions(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index f20640af68..0e1587bc3c 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -955,17 +955,19 @@ Done:
@param[in] Signature Pointer to signature that is searched for.
@param[in] CertType Pointer to hash algorithm.
@param[in] SignatureSize Size of Signature.
+ @param[out] IsFound Search result. Only valid if EFI_SUCCESS returned
- @return TRUE Found the signature in the variable database.
- @return FALSE Not found the signature in the variable database.
+ @retval EFI_SUCCESS Finished the search without any error.
+ @retval Others Error occurred in the search of database.
**/
-BOOLEAN
+EFI_STATUS
IsSignatureFoundInDatabase (
- IN CHAR16 *VariableName,
- IN UINT8 *Signature,
- IN EFI_GUID *CertType,
- IN UINTN SignatureSize
+ IN CHAR16 *VariableName,
+ IN UINT8 *Signature,
+ IN EFI_GUID *CertType,
+ IN UINTN SignatureSize,
+ OUT BOOLEAN *IsFound
)
{
EFI_STATUS Status;
@@ -975,22 +977,28 @@ IsSignatureFoundInDatabase (
UINT8 *Data;
UINTN Index;
UINTN CertCount;
- BOOLEAN IsFound;
//
// Read signature database variable.
//
- IsFound = FALSE;
+ *IsFound = FALSE;
Data = NULL;
DataSize = 0;
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, NULL);
if (Status != EFI_BUFFER_TOO_SMALL) {
- return FALSE;
+ if (Status == EFI_NOT_FOUND) {
+ //
+ // No database, no need to search.
+ //
+ Status = EFI_SUCCESS;
+ }
+
+ return Status;
}
Data = (UINT8 *) AllocateZeroPool (DataSize);
if (Data == NULL) {
- return FALSE;
+ return EFI_OUT_OF_RESOURCES;
}
Status = gRT->GetVariable (VariableName, &gEfiImageSecurityDatabaseGuid, NULL, &DataSize, Data);
@@ -1010,7 +1018,7 @@ IsSignatureFoundInDatabase (
//
// Find the signature in database.
//
- IsFound = TRUE;
+ *IsFound = TRUE;
//
// Entries in UEFI_IMAGE_SECURITY_DATABASE that are used to validate image should be measured
//
@@ -1023,7 +1031,7 @@ IsSignatureFoundInDatabase (
Cert = (EFI_SIGNATURE_DATA *) ((UINT8 *) Cert + CertList->SignatureSize);
}
- if (IsFound) {
+ if (*IsFound) {
break;
}
}
@@ -1037,7 +1045,7 @@ Done:
FreePool (Data);
}
- return IsFound;
+ return Status;
}
/**
@@ -1648,6 +1656,8 @@ DxeImageVerificationHandler (
CHAR16 *NameStr;
RETURN_STATUS PeCoffStatus;
EFI_STATUS HashStatus;
+ EFI_STATUS DbStatus;
+ BOOLEAN IsFound;
SignatureList = NULL;
SignatureListSize = 0;
@@ -1656,7 +1666,7 @@ DxeImageVerificationHandler (
PkcsCertData = NULL;
Action = EFI_IMAGE_EXECUTION_AUTH_UNTESTED;
IsVerified = FALSE;
-
+ IsFound = FALSE;
//
// Check the image type and get policy setting.
@@ -1798,7 +1808,14 @@ DxeImageVerificationHandler (
goto Failed;
}
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
+ DbStatus = IsSignatureFoundInDatabase (
+ EFI_IMAGE_SECURITY_DATABASE1,
+ mImageDigest,
+ &mCertType,
+ mImageDigestSize,
+ &IsFound
+ );
+ if (EFI_ERROR (DbStatus) || IsFound) {
//
// Image Hash is in forbidden database (DBX).
//
@@ -1806,7 +1823,14 @@ DxeImageVerificationHandler (
goto Failed;
}
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
+ DbStatus = IsSignatureFoundInDatabase (
+ EFI_IMAGE_SECURITY_DATABASE,
+ mImageDigest,
+ &mCertType,
+ mImageDigestSize,
+ &IsFound
+ );
+ if (!EFI_ERROR (DbStatus) && IsFound) {
//
// Image Hash is in allowed database (DB).
//
@@ -1894,14 +1918,29 @@ DxeImageVerificationHandler (
//
// Check the image's hash value.
//
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE1, mImageDigest, &mCertType, mImageDigestSize)) {
+ DbStatus = IsSignatureFoundInDatabase (
+ EFI_IMAGE_SECURITY_DATABASE1,
+ mImageDigest,
+ &mCertType,
+ mImageDigestSize,
+ &IsFound
+ );
+ if (EFI_ERROR (DbStatus) || IsFound) {
Action = EFI_IMAGE_EXECUTION_AUTH_SIG_FOUND;
DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but %s hash of image is found in DBX.\n", mHashTypeStr));
IsVerified = FALSE;
break;
}
+
if (!IsVerified) {
- if (IsSignatureFoundInDatabase (EFI_IMAGE_SECURITY_DATABASE, mImageDigest, &mCertType, mImageDigestSize)) {
+ DbStatus = IsSignatureFoundInDatabase (
+ EFI_IMAGE_SECURITY_DATABASE,
+ mImageDigest,
+ &mCertType,
+ mImageDigestSize,
+ &IsFound
+ );
+ if (!EFI_ERROR (DbStatus) && IsFound) {
IsVerified = TRUE;
} else {
DEBUG ((DEBUG_INFO, "DxeImageVerificationLib: Image is signed but signature is not allowed by DB and %s hash of image is not found in DB/DBX.\n", mHashTypeStr));
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase name(CVE-2019-14575)
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (8 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 09/10] SecurityPkg/DxeImageVerificationLib: Differentiate error/search result (2)(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:27 ` Wang, Jian J
2020-02-14 7:46 ` Yao, Jiewen
2020-02-17 7:48 ` [edk2-devel] [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Laszlo Ersek
10 siblings, 1 reply; 15+ messages in thread
From: Wang, Jian J @ 2020-02-14 7:27 UTC (permalink / raw)
To: devel; +Cc: Jiewen Yao, Chao Zhang
IsCertHashFoundInDatabase() is actually used only for searching dbx,
according to the function logic, its comments and its use cases. Changing
it to IsCertHashFoundInDbx to avoid confusion.
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
.../DxeImageVerificationLib/DxeImageVerificationLib.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 0e1587bc3c..b7fa8ea8c5 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -829,7 +829,7 @@ AddImageExeInfo (
**/
EFI_STATUS
-IsCertHashFoundInDatabase (
+IsCertHashFoundInDbx (
IN UINT8 *Certificate,
IN UINTN CertSize,
IN EFI_SIGNATURE_LIST *SignatureList,
@@ -1362,7 +1362,7 @@ IsForbiddenByDbx (
//
CertPtr = CertPtr + sizeof (UINT32) + CertSize;
- Status = IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime, &IsFound);
+ Status = IsCertHashFoundInDbx (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime, &IsFound);
if (EFI_ERROR (Status)) {
//
// Error in searching dbx. Consider it as 'found'. RevocationTime might
@@ -1528,7 +1528,7 @@ IsAllowedByDb (
//
// Here We still need to check if this RootCert's Hash is revoked
//
- Status = IsCertHashFoundInDatabase (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
+ Status = IsCertHashFoundInDbx (RootCert, RootCertSize, (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
if (EFI_ERROR (Status)) {
//
// Error in searching dbx. Consider it as 'found'. RevocationTime might
--
2.24.0.windows.2
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase name(CVE-2019-14575)
2020-02-14 7:27 ` [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase name(CVE-2019-14575) Wang, Jian J
@ 2020-02-14 7:46 ` Yao, Jiewen
0 siblings, 0 replies; 15+ messages in thread
From: Yao, Jiewen @ 2020-02-14 7:46 UTC (permalink / raw)
To: Wang, Jian J, devel@edk2.groups.io; +Cc: Zhang, Chao B
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
> -----Original Message-----
> From: Wang, Jian J <jian.j.wang@intel.com>
> Sent: Friday, February 14, 2020 3:28 PM
> To: devel@edk2.groups.io
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Zhang, Chao B
> <chao.b.zhang@intel.com>
> Subject: [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change
> IsCertHashFoundInDatabase name(CVE-2019-14575)
>
> IsCertHashFoundInDatabase() is actually used only for searching dbx,
> according to the function logic, its comments and its use cases. Changing
> it to IsCertHashFoundInDbx to avoid confusion.
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Chao Zhang <chao.b.zhang@intel.com>
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> ---
> .../DxeImageVerificationLib/DxeImageVerificationLib.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git
> a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> index 0e1587bc3c..b7fa8ea8c5 100644
> --- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> +++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
> @@ -829,7 +829,7 @@ AddImageExeInfo (
>
>
> **/
>
> EFI_STATUS
>
> -IsCertHashFoundInDatabase (
>
> +IsCertHashFoundInDbx (
>
> IN UINT8 *Certificate,
>
> IN UINTN CertSize,
>
> IN EFI_SIGNATURE_LIST *SignatureList,
>
> @@ -1362,7 +1362,7 @@ IsForbiddenByDbx (
> //
>
> CertPtr = CertPtr + sizeof (UINT32) + CertSize;
>
>
>
> - Status = IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST
> *)Data, DataSize, &RevocationTime, &IsFound);
>
> + Status = IsCertHashFoundInDbx (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data,
> DataSize, &RevocationTime, &IsFound);
>
> if (EFI_ERROR (Status)) {
>
> //
>
> // Error in searching dbx. Consider it as 'found'. RevocationTime might
>
> @@ -1528,7 +1528,7 @@ IsAllowedByDb (
> //
>
> // Here We still need to check if this RootCert's Hash is revoked
>
> //
>
> - Status = IsCertHashFoundInDatabase (RootCert, RootCertSize,
> (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
>
> + Status = IsCertHashFoundInDbx (RootCert, RootCertSize,
> (EFI_SIGNATURE_LIST *)DbxData, DbxDataSize, &RevocationTime, &IsFound);
>
> if (EFI_ERROR (Status)) {
>
> //
>
> // Error in searching dbx. Consider it as 'found'. RevocationTime might
>
> --
> 2.24.0.windows.2
^ permalink raw reply [flat|nested] 15+ messages in thread
* Re: [edk2-devel] [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler
2020-02-14 7:27 [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Wang, Jian J
` (9 preceding siblings ...)
2020-02-14 7:27 ` [PATCH v2 10/10] SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase name(CVE-2019-14575) Wang, Jian J
@ 2020-02-17 7:48 ` Laszlo Ersek
2020-02-17 7:51 ` Wang, Jian J
10 siblings, 1 reply; 15+ messages in thread
From: Laszlo Ersek @ 2020-02-17 7:48 UTC (permalink / raw)
To: devel, jian.j.wang; +Cc: Jiewen Yao, Chao Zhang
On 02/14/20 08:27, Wang, Jian J wrote:
>> v2 changes:
>> - Change IsCertHashFoundInDatabase to IsCertHashFoundInDbx (patch 10)
>> - Update result handling to all calling to IsCertHashFoundInDatabase
>> to be consistent (patch 6)
>> - Fix commit message and title length issue caught by PatchCheck tool
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
> Patch branch: https://github.com/jwang36/edk2/tree/fix-bz1608-bypass-blacklist-check-via-signature-v2
>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Chao Zhang <chao.b.zhang@intel.com>
>
> Jian J Wang (9):
> SecurityPkg/DxeImageVerificationLib: Fix memory leaks(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: reject CertStack.CertNumber==0
> per DBX(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: fix wrong fetch dbx in
> IsAllowedByDb(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: avoid bypass in fetching
> dbx(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: refactor db/dbx fetching
> code(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: Differentiate error/search result
> (1)(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: tighten default
> result(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: Differentiate error/search result
> (2)(CVE-2019-14575)
> SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase
> name(CVE-2019-14575)
>
> Laszlo Ersek (1):
> SecurityPkg/DxeImageVerificationLib: plug Data leak in
> IsForbiddenByDbx()(CVE-2019-14575)
>
> .../DxeImageVerificationLib.c | 291 ++++++++++++------
> 1 file changed, 198 insertions(+), 93 deletions(-)
>
Please put a space character in all the subject lines before the
"(CVE-2019-14575)" part.
Thanks
Laszlo
^ permalink raw reply [flat|nested] 15+ messages in thread* Re: [edk2-devel] [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler
2020-02-17 7:48 ` [edk2-devel] [PATCH v2 00/10] Fix false negative issue in DxeImageVerificationHandler Laszlo Ersek
@ 2020-02-17 7:51 ` Wang, Jian J
0 siblings, 0 replies; 15+ messages in thread
From: Wang, Jian J @ 2020-02-17 7:51 UTC (permalink / raw)
To: Laszlo Ersek, devel@edk2.groups.io; +Cc: Yao, Jiewen, Zhang, Chao B
Laszlo,
> -----Original Message-----
> From: Laszlo Ersek <lersek@redhat.com>
> Sent: Monday, February 17, 2020 3:49 PM
> To: devel@edk2.groups.io; Wang, Jian J <jian.j.wang@intel.com>
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Zhang, Chao B
> <chao.b.zhang@intel.com>
> Subject: Re: [edk2-devel] [PATCH v2 00/10] Fix false negative issue in
> DxeImageVerificationHandler
>
> On 02/14/20 08:27, Wang, Jian J wrote:
> >> v2 changes:
> >> - Change IsCertHashFoundInDatabase to IsCertHashFoundInDbx (patch 10)
> >> - Update result handling to all calling to IsCertHashFoundInDatabase
> >> to be consistent (patch 6)
> >> - Fix commit message and title length issue caught by PatchCheck tool
> >
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1608
> > Patch branch: https://github.com/jwang36/edk2/tree/fix-bz1608-bypass-
> blacklist-check-via-signature-v2
> >
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Cc: Chao Zhang <chao.b.zhang@intel.com>
> >
> > Jian J Wang (9):
> > SecurityPkg/DxeImageVerificationLib: Fix memory leaks(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: reject CertStack.CertNumber==0
> > per DBX(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: fix wrong fetch dbx in
> > IsAllowedByDb(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: avoid bypass in fetching
> > dbx(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: refactor db/dbx fetching
> > code(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: Differentiate error/search result
> > (1)(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: tighten default
> > result(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: Differentiate error/search result
> > (2)(CVE-2019-14575)
> > SecurityPkg/DxeImageVerificationLib: change IsCertHashFoundInDatabase
> > name(CVE-2019-14575)
> >
> > Laszlo Ersek (1):
> > SecurityPkg/DxeImageVerificationLib: plug Data leak in
> > IsForbiddenByDbx()(CVE-2019-14575)
> >
> > .../DxeImageVerificationLib.c | 291 ++++++++++++------
> > 1 file changed, 198 insertions(+), 93 deletions(-)
> >
>
> Please put a space character in all the subject lines before the
> "(CVE-2019-14575)" part.
>
Ok, it'll be added before pushing.
Regards,
Jian
> Thanks
> Laszlo
^ permalink raw reply [flat|nested] 15+ messages in thread