AWS IAM 策略：如何更改 AWSLambdaFullAccess 策略以仅允许访问一个 S3 存储桶？答案

【问题标题】：AWS IAM Policies: How do I alter the AWSLambdaFullAccess policy to only allow access to one S3 bucket?AWS IAM 策略：如何更改 AWSLambdaFullAccess 策略以仅允许访问一个 S3 存储桶？
【发布时间】：2016-03-02 15:39:01
【问题描述】：

我正在与我的 IT 团队合作，以限制我的用户帐户（在根帐户下），使其无法访问我不想访问的 S3 存储桶。启用 AWSLambdaFullAccess 策略时，它可以完全访问许多 AWS 功能，包括所有 S3。这是 AWSLambdaFullAccess 政策：

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "cloudwatch:*",
        "cognito-identity:ListIdentityPools",
        "cognito-sync:GetCognitoEvents",
        "cognito-sync:SetCognitoEvents",
        "dynamodb:*",
        "events:*",
        "iam:ListAttachedRolePolicies",
        "iam:ListRolePolicies",
        "iam:ListRoles",
        "iam:PassRole",
        "kinesis:DescribeStream",
        "kinesis:ListStreams",
        "kinesis:PutRecord",
        "lambda:*",
        "logs:*",
        "s3:*",
        "sns:ListSubscriptions",
        "sns:ListSubscriptionsByTopic",
        "sns:ListTopics",
        "sns:Subscribe",
        "sns:Unsubscribe"
      ],
      "Resource": "*"
    }
  ]
}

大部分都很好。我如何将其更改为新策略，以便我只能访问“arn:aws:s3:::lambda-scripts”存储桶？

【问题讨论】：

标签： amazon-web-services amazon-s3 aws-lambda

【解决方案1】：

我能想到的最直接的修改是从您拥有的语句中删除“s3:*”操作，并添加第二条语句，授予 S3 访问该存储桶的权限。

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "cloudwatch:*",
        "cognito-identity:ListIdentityPools",
        "cognito-sync:GetCognitoEvents",
        "cognito-sync:SetCognitoEvents",
        "dynamodb:*",
        "events:*",
        "iam:ListAttachedRolePolicies",
        "iam:ListRolePolicies",
        "iam:ListRoles",
        "iam:PassRole",
        "kinesis:DescribeStream",
        "kinesis:ListStreams",
        "kinesis:PutRecord",
        "lambda:*",
        "logs:*",
        "sns:ListSubscriptions",
        "sns:ListSubscriptionsByTopic",
        "sns:ListTopics",
        "sns:Subscribe",
        "sns:Unsubscribe"
      ],
      "Resource": "*"
    },
    {
        "Sid": "S3LambdaScripts",
        "Effect": "Allow",
        "Action": [
            "s3:*"
        ],
        "Resource": [
            "arn:aws:s3:::lambda-scripts*"
        ]
    }
  ]
}

更好的答案是您确实不应该使用预定义的 AWSLambdaFullAccess 权限。相反，使用针对您真正需要的服务和资源的多个语句构建您自己的。例如，您真的在使用 Dynamo、Kinesis、Cognito 等吗？是的，这很乏味。但是，如果您将较小的增量保存为 IAM 中的用户定义策略，则可以更轻松地从自定义和预定义的内容中拼凑出合理的策略。

【讨论】：

我会采用这个解决方案。确实，AWSLambdaFullAccess 策略提供了比我需要的更多的访问权限。我会制定一个新的政策来减少所有的脂肪。

【解决方案2】：

将 S3 权限拆分为单独的语句，并修改这些语句的资源设置。像这样的：

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "cloudwatch:*",
        "cognito-identity:ListIdentityPools",
        "cognito-sync:GetCognitoEvents",
        "cognito-sync:SetCognitoEvents",
        "dynamodb:*",
        "events:*",
        "iam:ListAttachedRolePolicies",
        "iam:ListRolePolicies",
        "iam:ListRoles",
        "iam:PassRole",
        "kinesis:DescribeStream",
        "kinesis:ListStreams",
        "kinesis:PutRecord",
        "lambda:*",
        "logs:*",
        "sns:ListSubscriptions",
        "sns:ListSubscriptionsByTopic",
        "sns:ListTopics",
        "sns:Subscribe",
        "sns:Unsubscribe"
      ],
      "Resource": "*"
    },
    {
       "Effect":"Allow",
       "Action":[
          "s3:ListBucket",
          "s3:GetBucketLocation"
       ],
       "Resource":"arn:aws:s3:::lambda-scripts"
      },
    {
     "Effect": "Allow",
     "Action": [        
       "s3:PutObject",
       "s3:GetObject",
       "s3:DeleteObject"
     ],
     "Resource": "arn:aws:s3:::lambda-scripts/*"
    }
  ]
}

【讨论】：