MsiGetFileSignatureInformation function

The MsiGetFileSignatureInformation function takes the path to a file that has been digitally signed and returns the file's signer certificate and hash. MsiGetFileSignatureInformation may be called to obtain the signer certificate and hash needed to populate the MsiDigitalCertificate, MsiPatchCertificate, and MsiDigitalSignature tables.

Windows Installer 3.0 and later:  Beginning with Windows Installer 3.0, the Windows Installer can verify the digital signatures of patches (.msp files) by using the MsiPatchCertificate and MsiDigitalCertificate tables. For more information see Guidelines for Authoring Secure Installations and User Account Control (UAC) Patching.

Windows Installer 2.0:  Digital signatures of patches is not supported. Windows Installer 2.0 uses digital signatures as a means to detect corrupted resources, and can only verify the digital signatures of external cabinets, and only by the use of the MsiDigitalSignature and MsiDigitalCertificate tables.

Syntax


HRESULT MsiGetFileSignatureInformation(
  _In_    LPCTSTR        szSignedObjectPath,
  _In_    DWORD          dwFlags,
  _Out_   PCCERT_CONTEXT *ppcCertContext,
  _Out_   BYTE           *pbHashData,
  _Inout_ DWORD          *pcbHashData
);

Parameters

szSignedObjectPath [in]

Pointer to a null-terminated string specifying the full path to the file that contains the digital signature.

dwFlags [in]

Special error case flags.

FlagMeaning
MSI_INVALID_HASH_IS_FATAL
0x1

Without this flag set, and when requesting only the certificate context, an invalid hash in the digital signature does not cause MsiGetFileSignatureInformation to return a fatal error.

To return a fatal error for an invalid hash, set the MSI_INVALID_HASH_IS_FATAL flag.

 

ppcCertContext [out]

Returned signer certificate context

pbHashData [out]

Returned hash buffer. This parameter can be NULL if the hash data is not being requested.

pcbHashData [in, out]

Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the pbHashData parameter. This parameter cannot be NULL if pbHashData is non-NULL. If ERROR_MORE_DATA is returned, pbHashData gives the size of the buffer required to hold the hash data. If ERROR_SUCCESS is returned, it gives the number of bytes written to the hash buffer. The pcbHashData parameter is ignored if pbHashData is NULL.

Return value

ValueMeaning
ERROR_SUCCESS/S_OK

Successful completion.

ERROR_INVALID_PARAMETER

Invalid parameter was specified.

ERROR_FUNCTION_FAILED

WinVerifyTrust is not available on the system. MsiGetFileSignatureInformation requires the presence of the Wintrust.dll file on the system.

ERROR_MORE_DATA

A buffer is too small to hold the requested data. If ERROR_MORE_DATA is returned, pcbHashData gives the size of the buffer required to hold the hash data.

TRUST_E_NOSIGNATURE

File is not signed

TRUST_E_BAD_DIGEST

The file's current hash is invalid according to the hash stored in the file's digital signature.

CERT_E_REVOKED

The file's signer certificate has been revoked. The file's digital signature is compromised.

TRUST_E_SUBJECT_NOT_TRUSTED

The subject failed the specified verification action. Most trust providers return a more detailed error code that describes the reason for the failure.

TRUST_E_PROVIDER_UNKNOWN

The trust provider is not recognized on this system.

TRUST_E_ACTION_UNKNOWN

The trust provider does not support the specified action.

TRUST_E_SUBJECT_FORM_UNKNOWN

The trust provider does not support the form specified for the subject.

 

 

MsiGetFileSignatureInformation also returns all the Win32 error values mapped to their equivalent HRESULT data type by HRESULT_FROM_WIN32.

Remarks

When requesting only the certificate context, an invalid hash in the digital signature does not cause MsiGetFileSignatureInformation to return a fatal error. To return a fatal error for an invalid hash, set the MSI_INVALID_HASH_IS_FATAL flag in the dwFlags parameter.

The certificate context and hash information is extracted from the file by a call to WinVerifyTrust. The ppcCertContext parameter is a duplicate of the signer certificate context from the signature. It is the responsibility of the caller to call CertFreeCertificateContext to free the certificate context when finished.

Note that MsiGetFileSignatureInformation requires the presence of the Wintrust.dll file on the system.

Requirements

Version

Windows Installer 5.0 on Windows Server 2012, Windows 8, Windows Server 2008 R2 or Windows 7. Windows Installer 4.0 or Windows Installer 4.5 on Windows Server 2008 or Windows Vista. Windows Installer on Windows Server 2003 or Windows XP. See the Windows Installer Run-Time Requirements for information about the minimum Windows service pack that is required by a Windows Installer version.

Header

Msi.h

Library

Msi.lib

DLL

Msi.dll

Unicode and ANSI names

MsiGetFileSignatureInformationW (Unicode) and MsiGetFileSignatureInformationA (ANSI)

See also

MsiDigitalCertificate table
MsiDigitalSignature table
Digital Signatures and Windows Installer

 

 

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