[edk2-devel] [PATCH 7/9] SecurityPkg/DxeImageVerificationLib: tighten default result of IsForbiddenByDbx()(CVE-2019-14575)
Wang, Jian J
jian.j.wang at intel.com
Thu Feb 6 14:19:31 UTC 2020
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 at intel.com>
Cc: Chao Zhang <chao.b.zhang at intel.com>
Signed-off-by: Jian J Wang <jian.j.wang at intel.com>
Signed-off-by: Laszlo Ersek <lersek at redhat.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 a5dfee0f8e..2236ce98ce 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);
@@ -1366,6 +1373,8 @@ IsForbiddenByDbx (
}
+ IsForbidden = FALSE;
+
Done:
if (Data != NULL) {
FreePool (Data);
--
2.24.0.windows.2
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