diff options
Diffstat (limited to 'SecurityPkg/Library/AuthVariableLib/AuthService.c')
| -rw-r--r-- | SecurityPkg/Library/AuthVariableLib/AuthService.c | 50 |
1 files changed, 42 insertions, 8 deletions
diff --git a/SecurityPkg/Library/AuthVariableLib/AuthService.c b/SecurityPkg/Library/AuthVariableLib/AuthService.c index 054ee4d1d9..9beeca09ae 100644 --- a/SecurityPkg/Library/AuthVariableLib/AuthService.c +++ b/SecurityPkg/Library/AuthVariableLib/AuthService.c @@ -1925,7 +1925,7 @@ VerifyTimeBasedPayload ( // SignedData.digestAlgorithms shall contain the digest algorithm used when preparing the
// signature. Only a digest algorithm of SHA-256 is accepted.
//
- // According to PKCS#7 Definition:
+ // According to PKCS#7 Definition (https://www.rfc-editor.org/rfc/rfc2315):
// SignedData ::= SEQUENCE {
// version Version,
// digestAlgorithms DigestAlgorithmIdentifiers,
@@ -1933,15 +1933,49 @@ VerifyTimeBasedPayload ( // .... }
// The DigestAlgorithmIdentifiers can be used to determine the hash algorithm
// in VARIABLE_AUTHENTICATION_2 descriptor.
- // This field has the fixed offset (+13) and be calculated based on two bytes of length encoding.
+ // This field has the fixed offset (+13) or (+32) based on whether the DER-encoded
+ // ContentInfo structure is present or not, and can be calculated based on two
+ // bytes of length encoding.
+ //
+ // Both condition can be handled in WrapPkcs7Data() in CryptPkcs7VerifyCommon.c.
+ //
+ // See below examples:
+ //
+ // 1. Without ContentInfo
+ // 30 82 0c da // SEQUENCE (5 element) (3294 BYTES) -- SignedData
+ // 02 01 01 // INTEGER 1 -- Version
+ // 31 0f // SET (1 element) (15 BYTES) -- DigestAlgorithmIdentifiers
+ // 30 0d // SEQUENCE (2 element) (13 BYTES) -- AlgorithmIdentifier
+ // 06 09 // OBJECT-IDENTIFIER (9 BYTES) -- algorithm
+ // 60 86 48 01 65 03 04 02 01 // sha256 [2.16.840.1.101.3.4.2.1]
+ // 05 00 // NULL (0 BYTES) -- parameters
+ //
+ // Example from: https://uefi.org/revocationlistfile
+ //
+ // 2. With ContentInfo
+ // 30 82 05 90 // SEQUENCE (1424 BYTES) -- ContentInfo
+ // 06 09 // OBJECT-IDENTIFIER (9 BYTES) -- ContentType
+ // 2a 86 48 86 f7 0d 01 07 02 // signedData [1.2.840.113549.1.7.2]
+ // a0 82 05 81 // CONTEXT-SPECIFIC CONSTRUCTED TAG 0 (1409 BYTES) -- content
+ // 30 82 05 7d // SEQUENCE (1405 BYTES) -- SignedData
+ // 02 01 01 // INTEGER 1 -- Version
+ // 31 0f // SET (1 element) (15 BYTES) -- DigestAlgorithmIdentifiers
+ // 30 0d // SEQUENCE (13 BYTES) -- AlgorithmIdentifier
+ // 06 09 // OBJECT-IDENTIFIER (9 BYTES) -- algorithm
+ // 60 86 48 01 65 03 04 02 01 // sha256 [2.16.840.1.101.3.4.2.1]
+ // 05 00 // NULL (0 BYTES) -- parameters
+ //
+ // Example generated with: https://wiki.archlinux.org/title/Unified_Extensible_Firmware_Interface/Secure_Boot#Manual_process
//
if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
- if (SigDataSize >= (13 + sizeof (mSha256OidValue))) {
- if (((*(SigData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE) ||
- (CompareMem (SigData + 13, &mSha256OidValue, sizeof (mSha256OidValue)) != 0))
- {
- return EFI_SECURITY_VIOLATION;
- }
+ if ( ( (SigDataSize >= (13 + sizeof (mSha256OidValue)))
+ && ( ((*(SigData + 1) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE)
+ || (CompareMem (SigData + 13, &mSha256OidValue, sizeof (mSha256OidValue)) != 0)))
+ && ( (SigDataSize >= (32 + sizeof (mSha256OidValue)))
+ && ( ((*(SigData + 20) & TWO_BYTE_ENCODE) != TWO_BYTE_ENCODE)
+ || (CompareMem (SigData + 32, &mSha256OidValue, sizeof (mSha256OidValue)) != 0))))
+ {
+ return EFI_SECURITY_VIOLATION;
}
}
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