Boot Manager (bootmgr) Security Policy
This Security Policy is non-proprietary and may be reproduced only in its original entirety (without revision)
Windows Vista Boot Manager
(bootmgr) Security Policy
For FIPS 140-2 Validation
v 3.5
06/01/09
1 INTRODUCTION ............................................................................................................... 2
1.1 Cryptographic Boundary for BOOTMGR..................................................................................2
2 SECURITY POLICY ........................................................................................................... 2
2.1 Boot Manager Security Policy ..................................................................................................2
3 BOOTMGR PORTS AND INTERFACES ............................................................................ 3
3.1 Control Input Interface ............................................................................................................3
3.2 Status Output Interface ...........................................................................................................3
3.3 Data Output Interface ..............................................................................................................4
3.4 Data Input Interface.................................................................................................................4
4 SPECIFICATION OF ROLES............................................................................................. 4
4.1 Maintenance Roles ....................................................................................................................4
4.2 Multiple Concurrent Interactive Operators............................................................................4
5 CRYPTOGRAPHIC KEY MANAGEMENT .......................................................................... 4
6 BOOTMGR SELF TESTS .................................................................................................... 5
7 ADDITIONAL DETAILS .................................................................................................... 5
This Security Policy is non-proprietary and may be reproduced only in its original entirety (without revision) 2
1 Introduction
The Windows Vista Boot Manager (BOOTMGR, version 6.0.6001.18000 and 6.0.6002.18005) is the
system boot manager, called by the bootstrapping code that resides in the boot sector. BOOTMGR is
responsible for loading and verifying the integrity of the Windows OS Loader, Winload.exe.
1.1 Cryptographic Boundary for BOOTMGR
The Windows Vista Boot Manager consists of a single executable. The cryptographic boundary for
BOOTMGR is defined as the enclosure of the computer system, on which BOOTMGR is to be executed.
The physical configuration of BOOTMGR, as defined in FIPS-140-2, is multi-chip standalone.
2 SecurityPolicy
2.1 Boot Manager Security Policy
BOOTMGR operates under several rules that encapsulate its security policy.
• BOOTMGR is supported on Windows Vista Service Pack 1 and Service Pack 2.
• Windows Vista is an operating system supporting a “single user” mode where there is only one
interactive user during a logon session.
• BOOTMGR is only in its Approved mode of operation when Windows is booted normally, meaning
Debug mode is disabled and Driver Signing enforcement is enabled.
The following diagram illustrates the master components of the BOOTMGR module
This Security Policy is non-proprietary and may be reproduced only in its original entirety (without revision) 3
• BOOTMGR’s primary service is to load the Windows Vista operating system loader (Winload),
after it determines Winload’s integrity using its cryptographic algorithm implementations using
the FIPS 140-2 approved algorithms mentioned below. After the verified Winload binary image
file is loaded, BOOTMGR passes the execution control to Winload and no longer executes until
the next reboot. The Crypto office and User have access to the service BOOTMGR supports.
• If the integrity of Winload is not verified, BOOTMGR does not transfer the execution from itself to
Winload.
• BOOTMGR is also responsible for loading the WinResume component when booting from
hibernation.
• Boot Manager also loads any boot utilities (such as memtest) as part of its non-Approved
services.
• Boot Manager implements a self-integrity check using an RSA digital signature during its
initialization process. Boot Manager will not complete its initialization if the signature is invalid.
• BOOTMGR implements the following FIPS-140-2 Approved algorithms.
o RSA PKCS#1 (v1.5) digital signature verification (Cert. #354)
o SHS (Cert. #753)
o AES (Certs. #739 and 760)
o HMAC-SHA-256 (Cert. #415)1
Cryptographic bypass is not supported by BOOTMGR.
BOOTMGR was validated using the following machine configurations:
x86 Microsoft Windows Vista Ultimate Edition SP1 (x86 version) – Dell SC430 (Intel Pentium D 2.8GHz)
x64 Microsoft Windows Vista Ultimate Edition SP1 (x64 version) – Dell SC430 (Intel Pentium D 2.8GHz)
Additionally, Microsoft affirms that BOOTMGR maintains compliance when using the following
configurations:
x86 Microsoft Windows Vista Ultimate Edition SP2 (x86 version)
x64 Microsoft Windows Vista Ultimate Edition SP2 (x64 version)
3 BOOTMGRPorts andInterfaces
3.1 Control Input Interface
The BOOTMGR Data Input Interface is the set of internal functions responsible for intercepting control
input. These functions are:
• BlBdInitialize – Determines if a boot debugger is attached.
• BlInitializeLibrary – Intercepts parameters from diskboot.asm.
• BmOpenBootIni – Parses information contained in boot.ini.
• BmGetOptionList – Loads application options from the Boot Configuration Data store.
• BlXmiRead – Reads the operator selection from the Boot Manager UI.
3.2 Status Output Interface
1
HMAC-SHA-256 is only used to self-test SHA-256. Please see section 6 for details.
This Security Policy is non-proprietary and may be reproduced only in its original entirety (without revision) 4
The Status Output Interface is the BlXmiWrite function that is responsible for displaying the integrity
verification errors to the screen. The Status Output Interface is also defined as the BlLogData
responsible for writing status to the bootlog.
3.3 Data Output Interface
The Data Output Interface is made up of the following functions:
Archx86TransferTo32BitApplicationAsm, Archx86TransferTo64BitApplicationAsm,
Archpx64TransferTo64BitApplicationAsm. These functions are responsible for transferring the execution
from Boot Manager to the initial execution point of Winload. Data exits the module in the form of the
initial instruction address of Winload.
The Data Output Interface is also represented by the ImgpInitializeBootApplicationParameters function.
This function is responsible for passing application parameters from Boot Manager to Winload.
3.4 Data Input Interface
The Data Input Interface is represented by the BlFileReadEx function and the BlDeviceRead function.
BlFileReadEx is responsible for reading the binary data of unverified components from the computer hard
drive. BlDeviceRead is used for reading data directly from devices.
Additionally, the GPC’s USB port also forms a part of the Data Input interface. This interface is used to
enter the ExK key used by the BitLocker™ Drive Encryption application shipped with the Enterprise and
Ultimate Editions of Windows Vista.
4 Specificationof Roles
BOOTMGR supports both User and Cryptographic Officer roles (as defined in FIPS-140-2). Both roles
have access to all services implemented in BOOTMGR. The module does not implement any
authentication services. Therefore, roles are assumed implicitly by booting the Windows Vista operating
system.
4.1 Maintenance Roles
Maintenance roles are not supported by BOOTMGR.
4.2 Multiple Concurrent Interactive Operators
There is only one interactive operator during a boot session. Multiple concurrent interactive operators
sharing a logon session are not supported.
5 Cryptographic KeyManagement
BOOTMGR does not store any secret or private cryptographic keys across power-cycles. However, it does
use three AES keys in support of the BitLocker feature. These keys are:
• External Key (ExK) – 256-bit AES key stored outside the cryptographic boundary (e.g. – USB
memory device). This key is entered into the module via the USB port and used to decrypt the
VMK.
• Volume Master Key (VMK) – 256-bit AES key used to decrypt the FVEK and winload.exe.
• Full Volume Encryption Key (FVEK) – 128 or 256-bit AES key used to decrypt data on disk
sectors.
Note that both the VMK and FVEK are stored in encrypted form across power cycles and thus not subject
to the zeroization requirements. The ExK, is stored only in memory and is zeroized by rebooting the OS.
This Security Policy is non-proprietary and may be reproduced only in its original entirety (without revision) 5
BOOTMGR also uses public keys stored on the computer hard disk to verify digital signatures using its
implementation of RSA PKCS#1 (v1.5) verify. These public keys are available to both roles. Zeroization
is performed by deleting the bootmgr module.
All the keys (mentioned above) are accessed only by the BOOTMGR service that loads the Windows Vista
operating system loader (Winload). This service only has execute access to the keys mentioned above.
6 BOOTMGRSelfTests
BOOTMGR performs the following power-on (start up) self-tests.
• SHS (SHA-1) Known Answer Tests. As allowed by FIPS 140-2 IG 9.2, SHA-256 is tested via
HMAC-SHA-256 Known Answer Test
• RSA PKCS#1 (v1.5) verify with public key
• AES Known Answer Tests
7 Additionaldetails
For the latest information on Windows Vista, check out the Microsoft web site at
http://www.microsoft.com.