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OvmfPkg/EnrollDefaultKeys: enroll PK/KEK1 from the Type 11 SMBIOS table 

Disconnect the certificate that is enrolled as both Platform Key and first
Key Exchange Key from Red Hat: expect the hypervisor to specify it, as
part of SMBIOS.

Example usage with QEMU:

* Generate self-signed X509 certificate:

  openssl req \
    -x509 \
    -newkey rsa:2048 \
    -outform PEM \
    -keyout PkKek1.private.key \
    -out PkKek1.pem

  (where "PEM" simply means "DER + base64 + header + footer").

* Strip the header, footer, and newline characters; prepend the
  application prefix:

  sed \
    -e 's/^-----BEGIN CERTIFICATE-----$/4e32566d-8e9e-4f52-81d3-5bb9715f9727:/' \
    -e '/^-----END CERTIFICATE-----$/d' \
    PkKek1.pem \
  | tr -d '\n' \
  > PkKek1.oemstr

* Pass the certificate to EnrollDefaultKeys with the following QEMU
  option:

  -smbios type=11,value="$(< PkKek1.oemstr)"

  (Note: for the above option to work correctly, a QEMU version is needed
  that includes commit 950c4e6c94b1 ("opts: don't silently truncate long
  option values", 2018-05-09). The first upstream release with that commit
  was v3.0.0.

  Once <https://bugs.launchpad.net/qemu/+bug/1826200> is fixed, QEMU will
  learn to read the file directly; passing the blob on the command will be
  necessary no more.)

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien.grall@arm.com>
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1747
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Gary Lin <glin@suse.com>
This commit is contained in:
Laszlo Ersek 2019-04-25 23:15:14 +02:00
parent 392404167f
commit be9470b3c9
2 changed files with 217 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

223
OvmfPkg/EnrollDefaultKeys/EnrollDefaultKeys.c
View File

@ -9,16 +9,191 @@
#include <Guid/GlobalVariable.h> // EFI_SETUP_MODE_NAME
#include <Guid/ImageAuthentication.h> // EFI_IMAGE_SECURITY_DATABASE
#include <Guid/MicrosoftVendor.h> // gMicrosoftVendorGuid
#include <Guid/OvmfPkKek1AppPrefix.h> // gOvmfPkKek1AppPrefixGuid
#include <IndustryStandard/SmBios.h> // SMBIOS_HANDLE_PI_RESERVED
#include <Library/BaseLib.h> // GUID_STRING_LENGTH
#include <Library/BaseMemoryLib.h> // CopyGuid()
#include <Library/DebugLib.h> // ASSERT()
#include <Library/MemoryAllocationLib.h> // FreePool()
#include <Library/PrintLib.h> // AsciiSPrint()
#include <Library/ShellCEntryLib.h> // ShellAppMain()
#include <Library/UefiBootServicesTableLib.h> // gBS
#include <Library/UefiLib.h> // AsciiPrint()
#include <Library/UefiRuntimeServicesTableLib.h> // gRT
#include <Protocol/Smbios.h> // EFI_SMBIOS_PROTOCOL
#include "EnrollDefaultKeys.h"
/**
Fetch the X509 certificate (to be used as Platform Key and first Key Exchange
Key) from SMBIOS.
@param[out] PkKek1 The X509 certificate in DER encoding from the
hypervisor, to be enrolled as PK and first KEK
entry. On success, the caller is responsible for
releasing PkKek1 with FreePool().
@param[out] SizeOfPkKek1 The size of PkKek1 in bytes.
@retval EFI_SUCCESS PkKek1 and SizeOfPkKek1 have been set
successfully.
@retval EFI_NOT_FOUND An OEM String matching
OVMF_PK_KEK1_APP_PREFIX_GUID has not been
found.
@retval EFI_PROTOCOL_ERROR In the OEM String matching
OVMF_PK_KEK1_APP_PREFIX_GUID, the certificate
is empty, or it has invalid base64 encoding.
@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
@return Error codes from gBS->LocateProtocol().
**/
STATIC
EFI_STATUS
GetPkKek1 (
OUT UINT8 **PkKek1,
OUT UINTN *SizeOfPkKek1
)
{
CONST CHAR8 *Base64Cert;
CHAR8 OvmfPkKek1AppPrefix[GUID_STRING_LENGTH + 1 + 1];
EFI_STATUS Status;
EFI_SMBIOS_PROTOCOL *Smbios;
EFI_SMBIOS_HANDLE Handle;
EFI_SMBIOS_TYPE Type;
EFI_SMBIOS_TABLE_HEADER *Header;
SMBIOS_TABLE_TYPE11 *OemStringsTable;
UINTN Base64CertLen;
UINTN DecodedCertSize;
UINT8 *DecodedCert;
Base64Cert = NULL;
//
// Format the application prefix, for OEM String matching.
//
AsciiSPrint (OvmfPkKek1AppPrefix, sizeof OvmfPkKek1AppPrefix, "%g:",
&gOvmfPkKek1AppPrefixGuid);
//
// Scan all "OEM Strings" tables.
//
Status = gBS->LocateProtocol (&gEfiSmbiosProtocolGuid, NULL,
(VOID **)&Smbios);
if (EFI_ERROR (Status)) {
AsciiPrint ("error: failed to locate EFI_SMBIOS_PROTOCOL: %r\n", Status);
return Status;
}
Handle = SMBIOS_HANDLE_PI_RESERVED;
Type = SMBIOS_TYPE_OEM_STRINGS;
for (Status = Smbios->GetNext (Smbios, &Handle, &Type, &Header, NULL);
!EFI_ERROR (Status);
Status = Smbios->GetNext (Smbios, &Handle, &Type, &Header, NULL)) {
CONST CHAR8 *OemString;
UINTN Idx;
if (Header->Length < sizeof *OemStringsTable) {
//
// Malformed table header, skip to next.
//
continue;
}
OemStringsTable = (SMBIOS_TABLE_TYPE11 *)Header;
//
// Scan all strings in the unformatted area of the current "OEM Strings"
// table.
//
OemString = (CONST CHAR8 *)(OemStringsTable + 1);
for (Idx = 0; Idx < OemStringsTable->StringCount; ++Idx) {
CHAR8 CandidatePrefix[sizeof OvmfPkKek1AppPrefix];
//
// NUL-terminate the candidate prefix for case-insensitive comparison.
//
AsciiStrnCpyS (CandidatePrefix, sizeof CandidatePrefix, OemString,
GUID_STRING_LENGTH + 1);
if (AsciiStriCmp (OvmfPkKek1AppPrefix, CandidatePrefix) == 0) {
//
// The current string matches the prefix.
//
Base64Cert = OemString + GUID_STRING_LENGTH + 1;
break;
}
OemString += AsciiStrSize (OemString);
}
if (Idx < OemStringsTable->StringCount) {
//
// The current table has a matching string.
//
break;
}
}
if (EFI_ERROR (Status)) {
//
// No table with a matching string has been found.
//
AsciiPrint ("error: OEM String with app prefix %g not found: %r\n",
&gOvmfPkKek1AppPrefixGuid, Status);
return EFI_NOT_FOUND;
}
ASSERT (Base64Cert != NULL);
Base64CertLen = AsciiStrLen (Base64Cert);
//
// Verify the base64 encoding, and determine the decoded size.
//
DecodedCertSize = 0;
Status = Base64Decode (Base64Cert, Base64CertLen, NULL, &DecodedCertSize);
switch (Status) {
case EFI_BUFFER_TOO_SMALL:
if (DecodedCertSize > 0) {
break;
}
//
// Fall through: the above Base64Decode() call is ill-specified in BaseLib
// if Source decodes to zero bytes (for example if it consists of ignored
// whitespace only).
//
case EFI_SUCCESS:
AsciiPrint ("error: empty certificate after app prefix %g\n",
&gOvmfPkKek1AppPrefixGuid);
return EFI_PROTOCOL_ERROR;
default:
AsciiPrint ("error: invalid base64 string after app prefix %g\n",
&gOvmfPkKek1AppPrefixGuid);
return EFI_PROTOCOL_ERROR;
}
//
// Allocate the output buffer.
//
DecodedCert = AllocatePool (DecodedCertSize);
if (DecodedCert == NULL) {
AsciiPrint ("error: failed to allocate memory\n");
return EFI_OUT_OF_RESOURCES;
}
//
// Decoding will succeed at this point.
//
Status = Base64Decode (Base64Cert, Base64CertLen, DecodedCert,
&DecodedCertSize);
ASSERT_EFI_ERROR (Status);
*PkKek1 = DecodedCert;
*SizeOfPkKek1 = DecodedCertSize;
return EFI_SUCCESS;
}
/**
Enroll a set of certificates in a global variable, overwriting it.
@ -358,21 +533,38 @@ ShellAppMain (
IN CHAR16 **Argv
)
{
INTN RetVal;
EFI_STATUS Status;
SETTINGS Settings;
UINT8 *PkKek1;
UINTN SizeOfPkKek1;
//
// Prepare for failure.
//
RetVal = 1;
//
// If we're not in Setup Mode, we can't do anything.
//
Status = GetSettings (&Settings);
if (EFI_ERROR (Status)) {
return 1;
return RetVal;
}
PrintSettings (&Settings);
if (Settings.SetupMode != 1) {
AsciiPrint ("error: already in User Mode\n");
return 1;
return RetVal;
}
//
// Fetch the X509 certificate (to be used as Platform Key and first Key
// Exchange Key) from SMBIOS.
//
Status = GetPkKek1 (&PkKek1, &SizeOfPkKek1);
if (EFI_ERROR (Status)) {
return RetVal;
}
//
@ -388,7 +580,7 @@ ShellAppMain (
if (EFI_ERROR (Status)) {
AsciiPrint ("error: SetVariable(\"%s\", %g): %r\n", EFI_CUSTOM_MODE_NAME,
&gEfiCustomModeEnableGuid, Status);
return 1;
goto FreePkKek1;
}
}
@ -403,7 +595,7 @@ ShellAppMain (
mMicrosoftUefiCa, mSizeOfMicrosoftUefiCa, &gMicrosoftVendorGuid,
NULL);
if (EFI_ERROR (Status)) {
return 1;
goto FreePkKek1;
}
//
@ -416,7 +608,7 @@ ShellAppMain (
mSha256OfDevNull, mSizeOfSha256OfDevNull, &gEfiCallerIdGuid,
NULL);
if (EFI_ERROR (Status)) {
return 1;
goto FreePkKek1;
}
//
@ -426,11 +618,11 @@ ShellAppMain (
EFI_KEY_EXCHANGE_KEY_NAME,
&gEfiGlobalVariableGuid,
&gEfiCertX509Guid,
mRedHatPkKek1, mSizeOfRedHatPkKek1, &gEfiCallerIdGuid,
PkKek1, SizeOfPkKek1, &gEfiCallerIdGuid,
mMicrosoftKek, mSizeOfMicrosoftKek, &gMicrosoftVendorGuid,
NULL);
if (EFI_ERROR (Status)) {
return 1;
goto FreePkKek1;
}
//
@ -440,10 +632,10 @@ ShellAppMain (
EFI_PLATFORM_KEY_NAME,
&gEfiGlobalVariableGuid,
&gEfiCertX509Guid,
mRedHatPkKek1, mSizeOfRedHatPkKek1, &gEfiGlobalVariableGuid,
PkKek1, SizeOfPkKek1, &gEfiGlobalVariableGuid,
NULL);
if (EFI_ERROR (Status)) {
return 1;
goto FreePkKek1;
}
//
@ -457,7 +649,7 @@ ShellAppMain (
if (EFI_ERROR (Status)) {
AsciiPrint ("error: SetVariable(\"%s\", %g): %r\n", EFI_CUSTOM_MODE_NAME,
&gEfiCustomModeEnableGuid, Status);
return 1;
goto FreePkKek1;
}
//
@ -493,7 +685,7 @@ ShellAppMain (
//
Status = GetSettings (&Settings);
if (EFI_ERROR (Status)) {
return 1;
goto FreePkKek1;
}
PrintSettings (&Settings);
@ -501,9 +693,14 @@ ShellAppMain (
Settings.SecureBootEnable != 1 || Settings.CustomMode != 0 ||
Settings.VendorKeys != 0) {
AsciiPrint ("error: unexpected\n");
return 1;
goto FreePkKek1;
}
AsciiPrint ("info: success\n");
return 0;
RetVal = 0;
FreePkKek1:
FreePool (PkKek1);
return RetVal;
}

7
OvmfPkg/EnrollDefaultKeys/EnrollDefaultKeys.inf
View File

@ -35,11 +35,18 @@
gEfiImageSecurityDatabaseGuid
gEfiSecureBootEnableDisableGuid
gMicrosoftVendorGuid
gOvmfPkKek1AppPrefixGuid
[Protocols]
gEfiSmbiosProtocolGuid ## CONSUMES
[LibraryClasses]
BaseLib
BaseMemoryLib
DebugLib
MemoryAllocationLib
PrintLib
ShellCEntryLib
UefiBootServicesTableLib
UefiLib
UefiRuntimeServicesTableLib