使用不同 AWS 账户拥有的 CMK 在 Auto Scaling 组中使用加密的 EBS 卷

Question

我正在尝试使用 AWS 中的 Auto Scaling 组来创建和管理从具有加密快照的 AMI 创建的实例，这些实例已由不同 AWS 账户拥有的 CMK 加密。

我一直收到错误 "Client.InternalError: Client error on launch"。根据 https://docs.aws.amazon.com/autoscaling/ec2/userguide/ts-as-instancelaunchfailure.html#ts-as-instancelaunchfailure-12 处的场景 2，我需要使用 Auto Scaling 组服务相关角色作为被授权委托人创建对 CMK 的授权。

我尝试按照 AWS 文档和 https://forums.aws.amazon.com/thread.jspa?threadID=277523 中的指导方针设置赠款。

但是，我不断收到 AccessDeniedException，说我的用户无权在 CMK 上执行 kms:CreateGrant。

我觉得我完全按照说明操作了，但它不起作用。我希望有人能够提供一些见解。

Answer 1

我和一位 AWS 员工聊天，他运行遇到了同样的问题，直到他重新阅读论坛 post。 Case 2 Step 4中的关键行是"The kms:GrantIsForAWSResource condition is not included to allow an IAM user or role in account 111122223333 to create the grant in the next step.".

换句话说，您需要从客户管理的 CMK 的默认密钥策略中删除此条件。

说明本可以使该要求更加明确，但从技术上讲它已经存在并且可以解决问题。

编辑：为澄清起见，我将在下面包含默认值和修改后的 JSON。

以下是 https://docs.aws.amazon.com/kms/latest/developerguide/key-policies.html#key-policy-default

处显示的默认密钥策略

    {
      "Version": "2012-10-17",
      "Id": "key-consolepolicy-2",
      "Statement": [
        {
          "Sid": "Enable IAM User Permissions",
          "Effect": "Allow",
          "Principal": {"AWS": "arn:aws:iam::111122223333:root"},
          "Action": "kms:*",
          "Resource": "*"
        },
        {
          "Sid": "Allow access for Key Administrators",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSAdminUser",
            "arn:aws:iam::111122223333:role/KMSAdminRole"
          ]},
          "Action": [
            "kms:Create*",
            "kms:Describe*",
            "kms:Enable*",
            "kms:List*",
            "kms:Put*",
            "kms:Update*",
            "kms:Revoke*",
            "kms:Disable*",
            "kms:Get*",
            "kms:Delete*",
            "kms:TagResource",
            "kms:UntagResource",
            "kms:ScheduleKeyDeletion",
            "kms:CancelKeyDeletion"
          ],
          "Resource": "*"
        },
        {
          "Sid": "Allow use of the key",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSUser",
            "arn:aws:iam::111122223333:role/KMSRole",
            "arn:aws:iam::444455556666:root"
          ]},
          "Action": [
            "kms:Encrypt",
            "kms:Decrypt",
            "kms:ReEncrypt*",
            "kms:GenerateDataKey*",
            "kms:DescribeKey"
          ],
          "Resource": "*"
        },
        {
          "Sid": "Allow attachment of persistent resources",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSUser",
            "arn:aws:iam::111122223333:role/KMSRole",
            "arn:aws:iam::444455556666:root"
          ]},
          "Action": [
            "kms:CreateGrant",
            "kms:ListGrants",
            "kms:RevokeGrant"
          ],
          "Resource": "*",
          "Condition": {"Bool": {"kms:GrantIsForAWSResource": "true"}}
        }
      ]
    }

关键是删除 "kms:GrantIsForAWSResource" 的条件，如下所示。

    {
      "Version": "2012-10-17",
      "Id": "key-consolepolicy-2",
      "Statement": [
        {
          "Sid": "Enable IAM User Permissions",
          "Effect": "Allow",
          "Principal": {"AWS": "arn:aws:iam::111122223333:root"},
          "Action": "kms:*",
          "Resource": "*"
        },
        {
          "Sid": "Allow access for Key Administrators",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSAdminUser",
            "arn:aws:iam::111122223333:role/KMSAdminRole"
          ]},
          "Action": [
            "kms:Create*",
            "kms:Describe*",
            "kms:Enable*",
            "kms:List*",
            "kms:Put*",
            "kms:Update*",
            "kms:Revoke*",
            "kms:Disable*",
            "kms:Get*",
            "kms:Delete*",
            "kms:TagResource",
            "kms:UntagResource",
            "kms:ScheduleKeyDeletion",
            "kms:CancelKeyDeletion"
          ],
          "Resource": "*"
        },
        {
          "Sid": "Allow use of the key",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSUser",
            "arn:aws:iam::111122223333:role/KMSRole",
            "arn:aws:iam::444455556666:root"
          ]},
          "Action": [
            "kms:Encrypt",
            "kms:Decrypt",
            "kms:ReEncrypt*",
            "kms:GenerateDataKey*",
            "kms:DescribeKey"
          ],
          "Resource": "*"
        },
        {
          "Sid": "Allow attachment of persistent resources",
          "Effect": "Allow",
          "Principal": {"AWS": [
            "arn:aws:iam::111122223333:user/KMSUser",
            "arn:aws:iam::111122223333:role/KMSRole",
            "arn:aws:iam::444455556666:root"
          ]},
          "Action": [
            "kms:CreateGrant",
            "kms:ListGrants",
            "kms:RevokeGrant"
          ],
          "Resource": "*"
        }
      ]
    }

Answer 2

阅读您提供的有用信息后，我能够解决它，所以我决定 post 也将我的发现分享给其他人。

这正是我为允许 "SharedAccountId" 帐户访问和使用自定义 KMS 密钥 (CMK) 所做的工作。"SharedAccountId"。

对于这个例子，假设 "dev" 帐户在 us-west-2 中，"SharedAccount" 在 us-east-1 中。

Cloudformation 创建密钥：

注意：在 "Dev" 帐户中启动此 cloudformation 堆栈，在此示例中，该帐户位于 us-west-2

{
"Description": "Creates a KMS key used to encrypt snapshots and allows sharing with another account.",
"Outputs": {
    "AMIKeyIdOutput": {
        "Description": "The KMS Key id used to encrypted snapshots.",
        "Export": {
            "Name": {
                "Fn::Sub": "${AWS::StackName}-kmskeyid"
            }
        },
        "Value": {
            "Ref": "AMIKmsKey"
        }
    },
    "AMIKmsAliasOutput": {
        "Description": "The KMS key alias used to encrypted snapshots.",
        "Export": {
            "Name": {
                "Fn::Sub": "${AWS::StackName}-kmsalias"
            }
        },
        "Value": {
            "Ref": "AMIKmsAlias"
        }
    }
},
"Parameters": {
    "SharedAccountId": {
        "AllowedPattern": "^(?!\s*$).+",
        "ConstraintDescription": "You must supply a account id you want to share with.",
        "Description": "The account id you want to share this key with.",
        "Type": "String"
    }
},
"Resources": {
    "AMIKmsAlias": {
        "Properties": {
            "AliasName": {
                "Fn::Sub": "alias/amiencryptionkey"
            },
            "TargetKeyId": {
                "Ref": "AMIKmsKey"
            }
        },
        "Type": "AWS::KMS::Alias"
    },
    "AMIKmsKey": {
        "Properties": {
            "Description": "AMI encryption key.",
            "EnableKeyRotation": "true",
            "Enabled": "true",
            "KeyPolicy": {
                "Statement": [
                    {
                        "Action": [
                            "kms:*"
                        ],
                        "Effect": "Allow",
                        "Principal": {
                            "AWS": {
                                "Fn::Sub": "arn:aws:iam::${AWS::AccountId}:root"
                            }
                        },
                        "Resource": [
                            "*"
                        ],
                        "Sid": "Allow access for Key Administrators"
                    },
                    {
                        "Action": [
                            "kms:Decrypt",
                            "kms:Encrypt",
                            "kms:DescribeKey",
                            "kms:ReEncrypt*",
                            "kms:GenerateDataKey*"
                        ],
                        "Effect": "Allow",
                        "Principal": {
                            "AWS": [
                                {
                                    "Fn::Join": [
                                        "",
                                        [
                                            "arn:aws:iam::",
                                            {"Ref":"SharedAccountId"},
                                            ":root"
                                        ]
                                    ]
                                },
                                {
                                    "Fn::Join": [
                                        "",
                                        [
                                            "arn:aws:iam::",
                                            {"Ref":"SharedAccountId"},
                                            ":role/aws-service-role/autoscaling.amazonaws.com/AWSServiceRoleForAutoScaling"
                                        ]
                                    ]
                                },
                                {
                                    "Fn::Sub": "arn:aws:iam::${AWS::AccountId}:role/aws-service-role/autoscaling.amazonaws.com/AWSServiceRoleForAutoScaling"
                                }
                            ]
                        },
                        "Resource": [
                            "*"
                        ],
                        "Sid": "Allow use of the key"
                    },
                    {
                        "Action": [
                            "kms:CreateGrant",
                            "kms:ListGrants",
                            "kms:RevokeGrant"
                        ],
                        "Effect": "Allow",
                        "Principal": {
                            "AWS": [
                                {
                                    "Fn::Sub": "arn:aws:iam::${AWS::AccountId}:root"
                                },
                                {
                                    "Fn::Join": [
                                        ":",
                                        [
                                            "arn:aws:iam:",
                                            {"Ref":"SharedAccountId"},
                                            "root"
                                        ]
                                    ]
                                },
                                {
                                    "Fn::Join": [
                                        "",
                                        [
                                            "arn:aws:iam::",
                                            {"Ref":"SharedAccountId"},
                                            ":role/aws-service-role/autoscaling.amazonaws.com/AWSServiceRoleForAutoScaling"
                                        ]
                                    ]
                                },
                                {
                                    "Fn::Sub": "arn:aws:iam::${AWS::AccountId}:role/aws-service-role/autoscaling.amazonaws.com/AWSServiceRoleForAutoScaling"
                                }
                            ]
                        },
                        "Resource": [
                            "*"
                        ],
                        "Sid": "Allow attachment of persistent resources."
                    }
                ],
                "Version": "2012-10-17"
            }
        },
        "Type": "AWS::KMS::Key"
    }
}
}

同样重要的是要注意一些原则是不需要的，但它应该足以让你开始。在按照上述逻辑设置您的 kms 密钥之后，您必须运行以下 cli 命令：

注意：在这个例子中
* us-east-1
中的 SharedAccountId * KMS 密钥存在于 "Dev" 帐户中，该帐户位于 us-west-2

aws kms create-grant \
--region us-east-1 \
--profile SharedAccountProfile \
--key-id arn:aws:kms:us-west-2:<DevAccountId>:key/<KMS_KEY_ID From above CF template> \
--grantee-principal arn:aws:iam::<SharedAccountId>:role/aws-service-role/autoscaling.amazonaws.com/AWSServiceRoleForAutoScaling \
--operations "Encrypt" "Decrypt" "ReEncryptFrom" "ReEncryptTo" "GenerateDataKey" "GenerateDataKeyWithoutPlaintext" "DescribeKey" "CreateGrant"

应该可以了。现在您可以在帐户之间共享加密的 AMI，并允许自动缩放组与它们一起启动实例。

使用不同 AWS 账户拥有的 CMK 在 Auto Scaling 组中使用加密的 EBS 卷

Using Encrypted EBS Volumes in Auto Scaling Groups with CMK owned by a different AWS account

amazon-ebs

amazon-web-services

autoscaling

aws-kms