OvmfPkg/SecureBootConfigDxe: Avoid illegal access

When enrolling the certificate from a file, the suffix check function
check the last 4 characters to filter out non-DER files. However,
if the length of the file name is less than 4, the address prior to
the file name will be accessed while it shouldn't. This commit checks
the length of the file name to avoid illegal access.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Gary Ching-Pang Lin <glin@suse.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Guo Dong <guo.dong@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14556 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Gary Ching-Pang Lin 2013-08-18 07:04:02 +00:00 committed by jljusten
parent 4388b0ee0c
commit dfd3119ab2
1 changed files with 18 additions and 3 deletions

View File

@ -373,6 +373,7 @@ EnrollPlatformKey (
UINTN DataSize; UINTN DataSize;
EFI_SIGNATURE_LIST *PkCert; EFI_SIGNATURE_LIST *PkCert;
UINT16* FilePostFix; UINT16* FilePostFix;
UINTN NameLength;
if (Private->FileContext->FileName == NULL) { if (Private->FileContext->FileName == NULL) {
return EFI_INVALID_PARAMETER; return EFI_INVALID_PARAMETER;
@ -383,7 +384,11 @@ EnrollPlatformKey (
// //
// Parse the file's postfix. Only support DER encoded X.509 certificate files. // Parse the file's postfix. Only support DER encoded X.509 certificate files.
// //
FilePostFix = Private->FileContext->FileName + StrLen (Private->FileContext->FileName) - 4; NameLength = StrLen (Private->FileContext->FileName);
if (NameLength <= 4) {
return EFI_INVALID_PARAMETER;
}
FilePostFix = Private->FileContext->FileName + NameLength - 4;
if (!IsDerEncodeCertificate(FilePostFix)) { if (!IsDerEncodeCertificate(FilePostFix)) {
DEBUG ((EFI_D_ERROR, "Unsupported file type, only DER encoded certificate (%s) is supported.", mSupportX509Suffix)); DEBUG ((EFI_D_ERROR, "Unsupported file type, only DER encoded certificate (%s) is supported.", mSupportX509Suffix));
return EFI_INVALID_PARAMETER; return EFI_INVALID_PARAMETER;
@ -766,6 +771,7 @@ EnrollKeyExchangeKey (
) )
{ {
UINT16* FilePostFix; UINT16* FilePostFix;
UINTN NameLength;
if ((Private->FileContext->FileName == NULL) || (Private->SignatureGUID == NULL)) { if ((Private->FileContext->FileName == NULL) || (Private->SignatureGUID == NULL)) {
return EFI_INVALID_PARAMETER; return EFI_INVALID_PARAMETER;
@ -775,7 +781,11 @@ EnrollKeyExchangeKey (
// Parse the file's postfix. Supports DER-encoded X509 certificate, // Parse the file's postfix. Supports DER-encoded X509 certificate,
// and .pbk as RSA public key file. // and .pbk as RSA public key file.
// //
FilePostFix = Private->FileContext->FileName + StrLen (Private->FileContext->FileName) - 4; NameLength = StrLen (Private->FileContext->FileName);
if (NameLength <= 4) {
return EFI_INVALID_PARAMETER;
}
FilePostFix = Private->FileContext->FileName + NameLength - 4;
if (IsDerEncodeCertificate(FilePostFix)) { if (IsDerEncodeCertificate(FilePostFix)) {
return EnrollX509ToKek (Private); return EnrollX509ToKek (Private);
} else if (CompareMem (FilePostFix, L".pbk",4) == 0) { } else if (CompareMem (FilePostFix, L".pbk",4) == 0) {
@ -1508,6 +1518,7 @@ EnrollSignatureDatabase (
) )
{ {
UINT16* FilePostFix; UINT16* FilePostFix;
UINTN NameLength;
if ((Private->FileContext->FileName == NULL) || (Private->FileContext->FHandle == NULL) || (Private->SignatureGUID == NULL)) { if ((Private->FileContext->FileName == NULL) || (Private->FileContext->FHandle == NULL) || (Private->SignatureGUID == NULL)) {
return EFI_INVALID_PARAMETER; return EFI_INVALID_PARAMETER;
@ -1516,7 +1527,11 @@ EnrollSignatureDatabase (
// //
// Parse the file's postfix. // Parse the file's postfix.
// //
FilePostFix = Private->FileContext->FileName + StrLen (Private->FileContext->FileName) - 4; NameLength = StrLen (Private->FileContext->FileName);
if (NameLength <= 4) {
return EFI_INVALID_PARAMETER;
}
FilePostFix = Private->FileContext->FileName + NameLength - 4;
if (IsDerEncodeCertificate(FilePostFix)) { if (IsDerEncodeCertificate(FilePostFix)) {
// //
// Supports DER-encoded X509 certificate. // Supports DER-encoded X509 certificate.