Based on https://gist.github.com/NicolasRitouet/7b8367b79734e01deb36ef707dae91a4 and https://github.com/serverless/serverless/issues/1439

serverless-cf-policies.yml

---
AWSTemplateFormatVersion: '2010-09-09'
Description: 'Cloudformation stack to manage permission to deploy a serverless service'

Parameters:
  ServiceName:
    Description: Name of the Service you want to deploy
    Type: String

Resources:
  ## Users
  ServerlessDeployUser:
    Type: AWS::IAM::User
    Properties:
      ManagedPolicyArns: # Max 10 policies
      - !Ref ServelessDeployCFPolicy
      - !Ref ServelessDeployS3Policy
      - !Ref ServelessDeployLogsPolicy
      - !Ref ServelessDeployIAMPolicy
      - !Ref ServelessDeployLambdaPolicy

  ## Managed policies
  ServelessDeployCFPolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action: 'cloudformation:ValidateTemplate'
            Resource: '*'

          - Effect: Allow
            Action:
            - 'cloudformation:Describe*'
            - 'cloudformation:List*'
            - 'cloudformation:Get*'
            - 'cloudformation:PreviewStackUpdate'
            - 'cloudformation:CreateStack'
            - 'cloudformation:UpdateStack'
            - 'cloudformation:DeleteStack'
            Resource:
            - !Sub 'arn:aws:cloudformation:${AWS::Region}:${AWS::AccountId}:stack/${ServiceName}-*'

  ServelessDeployS3Policy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
            - 's3:Get*'
            - 's3:List*'
            - 's3:CreateBucket'
            - 's3:DeleteBucket'
            Resource:
            - !Sub 'arn:aws:s3:::${ServiceName}-*'

          - Effect: Allow
            Action:
            - 's3:*'
            Resource:
            - !Sub 'arn:aws:s3:::${ServiceName}-*/*'

  ServelessDeployLogsPolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
            - 'logs:DescribeLogGroups'
            Resource: !Sub 'arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group::log-stream:*'

          - Effect: Allow
            Action:
            - 'logs:CreateLogGroup'
            - 'logs:CreateLogStream'
            - 'logs:DeleteLogGroup'
            - 'logs:DeleteLogStream'
            - 'logs:DescribeLogStreams'
            - 'logs:FilterLogEvents'
            Resource: !Sub 'arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/*:log-stream:*'

  ServelessDeployIAMPolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
            - 'iam:GetRole'
            - 'iam:PassRole'
            - 'iam:CreateRole'
            - 'iam:DeleteRole'
            - 'iam:DetachRolePolicy'
            - 'iam:PutRolePolicy'
            - 'iam:AttachRolePolicy'
            - 'iam:DeleteRolePolicy'
            Resource:
            - !Sub 'arn:aws:iam::${AWS::AccountId}:role/${ServiceName}-*-lambdaRole'

  ServelessDeployLambdaPolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
            - 'lambda:*'
            Resource:
            - !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:${ServiceName}-*'

          - Effect: Allow
            Action:
            - 'ec2:DescribeSecurityGroups'
            - 'ec2:DescribeSubnets'
            - 'ec2:DescribeVpcs'
            Resource: '*'

          - Effect: Allow
            Action:
            - 'events:Put*'
            - 'events:Remove*'
            - 'events:Delete*'
            - 'events:Describe*'
            Resource:
            - !Sub 'arn:aws:events:${AWS::Region}:${AWS::AccountId}:rule/${ServiceName}-*'