Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9cab73c8 authored by Tri Vo's avatar Tri Vo
Browse files

Add an implementation defined limit on number of keys in CSR 

Rationale here is that many IRPC implementations are memory constrained.
We add a way for implementations to report the maximum number of
supported keys. This way we can guarantee consistent behavior across
different devices.

For implementation of IRPC version 3 and later we define the lowest
number of keys supported to be 20. This specific value was chosen
because the current implementation of RemoteProvisioner already combines
keys into batches of exactly 20.

Bug: 254137722
Test: atest VtsHalRemotelyProvisionedComponentTargetTest
Change-Id: Ib6fb6d6ec7c74004524a5505a37aa82c9e44ef91
parent 85ee679e

security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp

+14 −2
Original line number Diff line number Diff line
@@ -251,6 +251,19 @@ TEST_P(GetHardwareInfoTests, uniqueId) { 
    EXPECT_LE(hwInfo.uniqueId->size(), 32);

}



/**

 * Verify implementation supports at least MIN_SUPPORTED_NUM_KEYS_IN_CSR keys in a CSR.

 */

TEST_P(GetHardwareInfoTests, supportedNumKeysInCsr) {

    if (rpcHardwareInfo.versionNumber < VERSION_WITHOUT_TEST_MODE) {

        return;

    }



    RpcHardwareInfo hwInfo;

    ASSERT_TRUE(provisionable_->getHardwareInfo(&hwInfo).isOk());

    ASSERT_GE(hwInfo.supportedNumKeysInCsr, RpcHardwareInfo::MIN_SUPPORTED_NUM_KEYS_IN_CSR);

}



using GenerateKeyTests = VtsRemotelyProvisionedComponentTests;



INSTANTIATE_REM_PROV_AIDL_TEST(GenerateKeyTests);
@@ -730,8 +743,7 @@ TEST_P(CertificateRequestV2Test, NonEmptyRequestReproducible) { 
 * Generate a non-empty certificate request with multiple keys.

 */

TEST_P(CertificateRequestV2Test, NonEmptyRequestMultipleKeys) {

    // TODO(b/254137722): define a minimum number of keys that must be supported.

    generateKeys(false /* testMode */, 5 /* numKeys */);

    generateKeys(false /* testMode */, rpcHardwareInfo.supportedNumKeysInCsr /* numKeys */);



    bytevec csr;

security/rkp/CHANGELOG.md

+2 −1
Original line number Diff line number Diff line
@@ -36,4 +36,5 @@ This document provides an exact description of which changes have occurred in th 
    * the chain of signing, MACing, and encryption operations has been replaced with a single

      COSE_Sign1 object.

    * CertificateType has been added to identify the type of certificate being requested.

* RpcHardwareInfo

  * `supportedNumKeysInCsr` added to report the maximum number of keys supported in a CSR.

security/rkp/aidl/aidl_api/android.hardware.security.rkp/current/android/hardware/security/keymint/RpcHardwareInfo.aidl

+2 −0
Original line number Diff line number Diff line
@@ -39,7 +39,9 @@ parcelable RpcHardwareInfo { 
  @utf8InCpp String rpcAuthorName;

  int supportedEekCurve = 0;

  @nullable @utf8InCpp String uniqueId;

  int supportedNumKeysInCsr = 4;

  const int CURVE_NONE = 0;

  const int CURVE_P256 = 1;

  const int CURVE_25519 = 2;

  const int MIN_SUPPORTED_NUM_KEYS_IN_CSR = 20;

}

security/rkp/aidl/android/hardware/security/keymint/RpcHardwareInfo.aidl

+13 −0
Original line number Diff line number Diff line
@@ -74,4 +74,17 @@ parcelable RpcHardwareInfo { 
     *

     */

    @nullable @utf8InCpp String uniqueId;



    /**

     * supportedNumKeysInCsr is the maximum number of keys in a CSR that this implementation can

     * support. This value is implementation defined.

     *

     * From version 3 onwards, supportedNumKeysInCsr must be larger or equal to

     * MIN_SUPPORTED_NUM_KEYS_IN_CSR.

     *

     * The default value was chosen as the value enforced by the VTS test in versions 1 and 2 of

     * this interface.

     */

    const int MIN_SUPPORTED_NUM_KEYS_IN_CSR = 20;

    int supportedNumKeysInCsr = 4;

}