Identity and Access Management for AWS CodeCommit - AWS CodeCommit

Identity and Access Management for AWS CodeCommit

AWS Identity and Access Management (IAM) is an AWS service that helps an administrator securely control access to AWS resources. IAM administrators control who can be authenticated (signed in) and authorized (have permissions) to use CodeCommit resources. IAM is an AWS service that you can use with no additional charge.

Audience

How you use AWS Identity and Access Management (IAM) differs, depending on the work that you do in CodeCommit.

Service user – If you use the CodeCommit service to do your job, then your administrator provides you with the credentials and permissions that you need. As you use more CodeCommit features to do your work, you might need additional permissions. Understanding how access is managed can help you request the right permissions from your administrator. If you cannot access a feature in CodeCommit, see Troubleshooting AWS CodeCommit identity and access.

Service administrator – If you're in charge of CodeCommit resources at your company, you probably have full access to CodeCommit. It's your job to determine which CodeCommit features and resources your service users should access. You must then submit requests to your IAM administrator to change the permissions of your service users. Review the information on this page to understand the basic concepts of IAM. To learn more about how your company can use IAM with CodeCommit, see How AWS CodeCommit works with IAM.

IAM administrator – If you're an IAM administrator, you might want to learn details about how you can write policies to manage access to CodeCommit. To view example CodeCommit identity-based policies that you can use in IAM, see AWS CodeCommit identity-based policy examples.

Authenticating with identities

Authentication is how you sign in to AWS using your identity credentials. You must be authenticated (signed in to AWS) as the AWS account root user, as an IAM user, or by assuming an IAM role.

You can sign in to AWS as a federated identity by using credentials provided through an identity source. AWS IAM Identity Center (successor to AWS Single Sign-On) (IAM Identity Center) users, your company's single sign-on authentication, and your Google or Facebook credentials are examples of federated identities. When you sign in as a federated identity, your administrator previously set up identity federation using IAM roles. When you access AWS by using federation, you are indirectly assuming a role.

Depending on the type of user you are, you can sign in to the AWS Management Console or the AWS access portal. For more information about signing in to AWS, see How to sign in to your AWS account in the AWS Sign-In User Guide.

If you access AWS programmatically, AWS provides a software development kit (SDK) and a command line interface (CLI) to cryptographically sign your requests using your credentials. If you don't use AWS tools, you must sign requests yourself. For more information about using the recommended method to sign requests yourself, see Signature Version 4 signing process in the AWS General Reference.

Regardless of the authentication method that you use, you might be required to provide additional security information. For example, AWS recommends that you use multi-factor authentication (MFA) to increase the security of your account. To learn more, see Multi-factor authentication in the AWS IAM Identity Center (successor to AWS Single Sign-On) User Guide and Using multi-factor authentication (MFA) in AWS in the IAM User Guide.

AWS account root user

When you create an AWS account, you begin with one sign-in identity that has complete access to all AWS services and resources in the account. This identity is called the AWS account root user and is accessed by signing in with the email address and password that you used to create the account. We strongly recommend that you don't use the root user for your everyday tasks. Safeguard your root user credentials and use them to perform the tasks that only the root user can perform. For the complete list of tasks that require you to sign in as the root user, see Tasks that require root user credentials in the AWS Account Management Reference Guide.

IAM users and groups

An IAM user is an identity within your AWS account that has specific permissions for a single person or application. Where possible, we recommend relying on temporary credentials instead of creating IAM users who have long-term credentials such as passwords and access keys. However, if you have specific use cases that require long-term credentials with IAM users, we recommend that you rotate access keys. For more information, see Rotate access keys regularly for use cases that require long-term credentials in the IAM User Guide.

An IAM group is an identity that specifies a collection of IAM users. You can't sign in as a group. You can use groups to specify permissions for multiple users at a time. Groups make permissions easier to manage for large sets of users. For example, you could have a group named IAMAdmins and give that group permissions to administer IAM resources.

Users are different from roles. A user is uniquely associated with one person or application, but a role is intended to be assumable by anyone who needs it. Users have permanent long-term credentials, but roles provide temporary credentials. To learn more, see When to create an IAM user (instead of a role) in the IAM User Guide.

IAM roles

An IAM role is an identity within your AWS account that has specific permissions. It is similar to an IAM user, but is not associated with a specific person. You can temporarily assume an IAM role in the AWS Management Console by switching roles. You can assume a role by calling an AWS CLI or AWS API operation or by using a custom URL. For more information about methods for using roles, see Using IAM roles in the IAM User Guide.

IAM roles with temporary credentials are useful in the following situations:

  • Federated user access – To assign permissions to a federated identity, you create a role and define permissions for the role. When a federated identity authenticates, the identity is associated with the role and is granted the permissions that are defined by the role. For information about roles for federation, see Creating a role for a third-party Identity Provider in the IAM User Guide. If you use IAM Identity Center, you configure a permission set. To control what your identities can access after they authenticate, IAM Identity Center correlates the permission set to a role in IAM. For information about permissions sets, see Permission sets in the AWS IAM Identity Center (successor to AWS Single Sign-On) User Guide.

  • Temporary IAM user permissions – An IAM user or role can assume an IAM role to temporarily take on different permissions for a specific task.

  • Cross-account access – You can use an IAM role to allow someone (a trusted principal) in a different account to access resources in your account. Roles are the primary way to grant cross-account access. However, with some AWS services, you can attach a policy directly to a resource (instead of using a role as a proxy). To learn the difference between roles and resource-based policies for cross-account access, see How IAM roles differ from resource-based policies in the IAM User Guide.

  • Cross-service access – Some AWS services use features in other AWS services. For example, when you make a call in a service, it's common for that service to run applications in Amazon EC2 or store objects in Amazon S3. A service might do this using the calling principal's permissions, using a service role, or using a service-linked role.

    • Principal permissions – When you use an IAM user or role to perform actions in AWS, you are considered a principal. Policies grant permissions to a principal. When you use some services, you might perform an action that then triggers another action in a different service. In this case, you must have permissions to perform both actions. To see whether an action requires additional dependent actions in a policy, see Actions, Resources, and Condition Keys for AWS CodeCommit in the Service Authorization Reference.

    • Service role – A service role is an IAM role that a service assumes to perform actions on your behalf. An IAM administrator can create, modify, and delete a service role from within IAM. For more information, see Creating a role to delegate permissions to an AWS service in the IAM User Guide.

    • Service-linked role – A service-linked role is a type of service role that is linked to an AWS service. The service can assume the role to perform an action on your behalf. Service-linked roles appear in your IAM account and are owned by the service. An IAM administrator can view, but not edit the permissions for service-linked roles.

  • Applications running on Amazon EC2 – You can use an IAM role to manage temporary credentials for applications that are running on an EC2 instance and making AWS CLI or AWS API requests. This is preferable to storing access keys within the EC2 instance. To assign an AWS role to an EC2 instance and make it available to all of its applications, you create an instance profile that is attached to the instance. An instance profile contains the role and enables programs that are running on the EC2 instance to get temporary credentials. For more information, see Using an IAM role to grant permissions to applications running on Amazon EC2 instances in the IAM User Guide.

To learn whether to use IAM roles or IAM users, see When to create an IAM role (instead of a user) in the IAM User Guide.

Managing access using policies

You control access in AWS by creating policies and attaching them to AWS identities or resources. A policy is an object in AWS that, when associated with an identity or resource, defines their permissions. AWS evaluates these policies when a principal (user, root user, or role session) makes a request. Permissions in the policies determine whether the request is allowed or denied. Most policies are stored in AWS as JSON documents. For more information about the structure and contents of JSON policy documents, see Overview of JSON policies in the IAM User Guide.

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

Every IAM entity (user or role) starts with no permissions. By default, users can do nothing, not even change their own password. To give a user permission to do something, an administrator must attach a permissions policy to a user. Or the administrator can add the user to a group that has the intended permissions. When an administrator gives permissions to a group, all users in that group are granted those permissions.

IAM policies define permissions for an action regardless of the method that you use to perform the operation. For example, suppose that you have a policy that allows the iam:GetRole action. A user with that policy can get role information from the AWS Management Console, the AWS CLI, or the AWS API.

Identity-based policies

Identity-based policies are JSON permissions policy documents that you can attach to an identity, such as an IAM user, group of users, or role. These policies control what actions users and roles can perform, on which resources, and under what conditions. To learn how to create an identity-based policy, see Creating IAM policies in the IAM User Guide.

Identity-based policies can be further categorized as inline policies or managed policies. Inline policies are embedded directly into a single user, group, or role. Managed policies are standalone policies that you can attach to multiple users, groups, and roles in your AWS account. Managed policies include AWS managed policies and customer managed policies. To learn how to choose between a managed policy or an inline policy, see Choosing between managed policies and inline policies in the IAM User Guide.

Resource-based policies

Resource-based policies are JSON policy documents that you attach to a resource. Examples of resource-based policies are IAM role trust policies and Amazon S3 bucket policies. In services that support resource-based policies, service administrators can use them to control access to a specific resource. For the resource where the policy is attached, the policy defines what actions a specified principal can perform on that resource and under what conditions. You must specify a principal in a resource-based policy. Principals can include accounts, users, roles, federated users, or AWS services.

Resource-based policies are inline policies that are located in that service. You can't use AWS managed policies from IAM in a resource-based policy.

Access control lists (ACLs)

Access control lists (ACLs) control which principals (account members, users, or roles) have permissions to access a resource. ACLs are similar to resource-based policies, although they do not use the JSON policy document format.

Amazon S3, AWS WAF, and Amazon VPC are examples of services that support ACLs. To learn more about ACLs, see Access control list (ACL) overview in the Amazon Simple Storage Service Developer Guide.

Other policy types

AWS supports additional, less-common policy types. These policy types can set the maximum permissions granted to you by the more common policy types.

  • Permissions boundaries – A permissions boundary is an advanced feature in which you set the maximum permissions that an identity-based policy can grant to an IAM entity (IAM user or role). You can set a permissions boundary for an entity. The resulting permissions are the intersection of entity's identity-based policies and its permissions boundaries. Resource-based policies that specify the user or role in the Principal field are not limited by the permissions boundary. An explicit deny in any of these policies overrides the allow. For more information about permissions boundaries, see Permissions boundaries for IAM entities in the IAM User Guide.

  • Service control policies (SCPs) – SCPs are JSON policies that specify the maximum permissions for an organization or organizational unit (OU) in AWS Organizations. AWS Organizations is a service for grouping and centrally managing multiple AWS accounts that your business owns. If you enable all features in an organization, then you can apply service control policies (SCPs) to any or all of your accounts. The SCP limits permissions for entities in member accounts, including each AWS account root user. For more information about Organizations and SCPs, see How SCPs work in the AWS Organizations User Guide.

  • Session policies – Session policies are advanced policies that you pass as a parameter when you programmatically create a temporary session for a role or federated user. The resulting session's permissions are the intersection of the user or role's identity-based policies and the session policies. Permissions can also come from a resource-based policy. An explicit deny in any of these policies overrides the allow. For more information, see Session policies in the IAM User Guide.

Multiple policy types

When multiple types of policies apply to a request, the resulting permissions are more complicated to understand. To learn how AWS determines whether to allow a request when multiple policy types are involved, see Policy evaluation logic in the IAM User Guide.

CodeCommit resource-based policies

CodeCommit does not support resource-based policies.

Authorization based on CodeCommit tags

You can attach tags to CodeCommit resources or pass tags in a request to CodeCommit. To control access based on tags, you provide tag information in the condition element of a policy using the codecommit:ResourceTag/key-name, aws:RequestTag/key-name, or aws:TagKeys condition keys. For more information about tagging CodeCommit resources, see Example 5: Deny or allow actions on repositories with tags. For more information about tagging strategies, see Tagging AWS Resources.

CodeCommit also supports policies based on session tags. For more information, see Session Tags.

Using tags to provide identity information in CodeCommit

CodeCommit supports the use of session tags, which are key-value pair attributes that you pass when you assume an IAM role, use temporary credentials, or federate a user in AWS Security Token Service (AWS STS). You can also associate tags with an IAM user. You can use the information provided in these tags to make it easier to identify who made a change or caused an event. CodeCommit includes the values for tags with the following key names in CodeCommit events:

Key name Value
displayName The human-readable name to display and associate with the user (for example, Mary Major or Saanvi Sarkar).
emailAddress The email address you want displayed for and associated with the user (for example, mary_major@example.com or saanvi_sarkar@example.com).

If this information is provided, CodeCommit includes it in events sent to Amazon EventBridge and Amazon CloudWatch Events. For more information, see Monitoring CodeCommit events in Amazon EventBridge and Amazon CloudWatch Events.

To use session tagging, roles must have policies that include the sts:TagSession permission set to Allow. If you are using federated access, you can configure display name and email tag information as part of your setup. For example, if you're using Azure Active Directory, you might provide the following claim information:

Claim name Value
https://aws.amazon.com/SAML/Attributes/PrincipalTag:displayName user.displayname
https://aws.amazon.com/SAML/Attributes/PrincipalTag:emailAddress user.mail

You can use the AWS CLI to pass session tags for displayName and emailAddress using AssumeRole. For example, a user who wants to assume a role named Developer who wants to associate her name Mary Major might use the assume-role command similar to the following:

aws sts assume-role \ --role-arn arn:aws:iam::123456789012:role/Developer \ --role-session-name Mary-Major \ –-tags Key=displayName,Value="Mary Major" Key=emailAddress,Value="mary_major@example.com" \ --external-id Example987

For more information, see AssumeRole.

You can use the AssumeRoleWithSAML operation to return a set of temporary credentials that include displayName and emailAddress tags. You can use these tags when you access CodeCommit repositories. This requires that your company or group has already integrated your third-party SAML solution with AWS. If so, you can pass SAML attributes as session tags. For example, if you wanted to pass identity attributes for a display name and email address for a user named Saanvi Sarkar as session tags:

<Attribute Name="https://aws.amazon.com/SAML/Attributes/PrincipalTag:displayName"> <AttributeValue>Saanvi Sarkar</AttributeValue> </Attribute> <Attribute Name="https://aws.amazon.com/SAML/Attributes/PrincipalTag:emailAddress"> <AttributeValue>saanvi_sarkar@example.com</AttributeValue> </Attribute>

For more information, see Passing Session Tags using AssumeRoleWithSAML.

You can use the AssumeRoleWithIdentity operation to return a set of temporary credentials that include displayName and emailAddress tags. You can use these tags when you access CodeCommit repositories. To pass session tags from OpenID Connect (OIDC), you must include the session tags in the JSON Web Token (JWT). For example, the decoded JWP token used to call AssumeRoleWithWebIdentity that includes the displayName and emailAddress session tags for a user named Li Juan:

{ "sub": "lijuan", "aud": "ac_oic_client", "jti": "ZYUCeREXAMPLE", "iss": "https://xyz.com", "iat": 1566583294, "exp": 1566583354, "auth_time": 1566583292, "https://aws.amazon.com/tags": { "principal_tags": { "displayName": ["Li Juan"], "emailAddress": ["li_juan@example.com"], }, "transitive_tag_keys": [ "displayName", "emailAddress" ] } }

For more information, see Passing Session Tags using AssumeRoleWithWebIdentity.

You can use the GetFederationToken operation to return a set of temporary credentials that include displayName and emailAddress tags. You can use these tags when you access CodeCommit repositories. For example, to use the AWS CLI to get a federation token that includes the displayName and emailAddress tags:

aws sts get-federation-token \ --name my-federated-user \ –-tags key=displayName,value="Nikhil Jayashankar" key=emailAddress,value=nikhil_jayashankar@example.com

For more information, see Passing Session Tags using GetFederationToken.

CodeCommit IAM roles

An IAM role is an entity within your Amazon Web Services account that has specific permissions.

Using temporary credentials with CodeCommit

You can use temporary credentials to sign in with federation, assume an IAM role, or to assume a cross-account role. You obtain temporary security credentials by calling AWS STS API operations such as AssumeRole or GetFederationToken.

CodeCommit supports using temporary credentials. For more information, see Connecting to AWS CodeCommit repositories with rotating credentials.

Service-linked roles

Service-linked roles allow AWS services to access resources in other services to complete an action on your behalf. Service-linked roles appear in your IAM account and are owned by the service. An IAM administrator can view but not edit the permissions for service-linked roles.

CodeCommit does not use service-linked roles.

Service roles

This feature allows a service to assume a service role on your behalf. This role allows the service to access resources in other services to complete an action on your behalf. Service roles appear in your IAM account and are owned by the account. This means that an IAM administrator can change the permissions for this role. However, doing so might break the functionality of the service.

CodeCommit does not use service roles.

AWS CodeCommit identity-based policy examples

By default, IAM users and roles don't have permission to create or modify CodeCommit resources. They also can't perform tasks using the AWS Management Console, AWS CLI, or AWS API. An IAM administrator must create IAM policies that grant users and roles permission to perform specific API operations on the specified resources they need. The administrator must then attach those policies to the IAM users or groups that require those permissions.

For examples of policies, see the following:

To learn how to create an IAM identity-based policy using these example JSON policy documents, see Creating Policies on the JSON Tab in the IAM User Guide.

Policy best practices

Identity-based policies determine whether someone can create, access, or delete CodeCommit resources in your account. These actions can incur costs for your AWS account. When you create or edit identity-based policies, follow these guidelines and recommendations:

  • Get started with AWS managed policies and move toward least-privilege permissions – To get started granting permissions to your users and workloads, use the AWS managed policies that grant permissions for many common use cases. They are available in your AWS account. We recommend that you reduce permissions further by defining AWS customer managed policies that are specific to your use cases. For more information, see AWS managed policies or AWS managed policies for job functions in the IAM User Guide.

  • Apply least-privilege permissions – When you set permissions with IAM policies, grant only the permissions required to perform a task. You do this by defining the actions that can be taken on specific resources under specific conditions, also known as least-privilege permissions. For more information about using IAM to apply permissions, see Policies and permissions in IAM in the IAM User Guide.

  • Use conditions in IAM policies to further restrict access – You can add a condition to your policies to limit access to actions and resources. For example, you can write a policy condition to specify that all requests must be sent using SSL. You can also use conditions to grant access to service actions if they are used through a specific AWS service, such as AWS CloudFormation. For more information, see IAM JSON policy elements: Condition in the IAM User Guide.

  • Use IAM Access Analyzer to validate your IAM policies to ensure secure and functional permissions – IAM Access Analyzer validates new and existing policies so that the policies adhere to the IAM policy language (JSON) and IAM best practices. IAM Access Analyzer provides more than 100 policy checks and actionable recommendations to help you author secure and functional policies. For more information, see IAM Access Analyzer policy validation in the IAM User Guide.

  • Require multi-factor authentication (MFA) – If you have a scenario that requires IAM users or root users in your account, turn on MFA for additional security. To require MFA when API operations are called, add MFA conditions to your policies. For more information, see Configuring MFA-protected API access in the IAM User Guide.

For more information about best practices in IAM, see Security best practices in IAM in the IAM User Guide.

Using the CodeCommit console

To access the AWS CodeCommit console, you must have a minimum set of permissions. These permissions must allow you to list and view details about the CodeCommit resources in your Amazon Web Services account. If you create an identity-based policy that is more restrictive than the minimum required permissions, the console won't function as intended for entities (IAM users or roles) with that policy.

To ensure that those entities can still use the CodeCommit console, also attach the following AWS managed policy to the entities. For more information, see Adding Permissions to a User in the IAM User Guide:

For more information, see Using identity-based policies (IAM Policies) for CodeCommit.

You don't need to allow minimum console permissions for users that are making calls only to the AWS CLI or the AWS API. Instead, allow access to only the actions that match the API operation that you're trying to perform.

Allow users to view their own permissions

This example shows how you might create a policy that allows IAM users to view the inline and managed policies that are attached to their user identity. This policy includes permissions to complete this action on the console or programmatically using the AWS CLI or AWS API.

{ "Version": "2012-10-17", "Statement": [ { "Sid": "ViewOwnUserInfo", "Effect": "Allow", "Action": [ "iam:GetUserPolicy", "iam:ListGroupsForUser", "iam:ListAttachedUserPolicies", "iam:ListUserPolicies", "iam:GetUser" ], "Resource": ["arn:aws:iam::*:user/${aws:username}"] }, { "Sid": "NavigateInConsole", "Effect": "Allow", "Action": [ "iam:GetGroupPolicy", "iam:GetPolicyVersion", "iam:GetPolicy", "iam:ListAttachedGroupPolicies", "iam:ListGroupPolicies", "iam:ListPolicyVersions", "iam:ListPolicies", "iam:ListUsers" ], "Resource": "*" } ] }

Viewing CodeCommit repositories based on tags

You can use conditions in your identity-based policy to control access to CodeCommit resources based on tags. For an example policy that demonstrates how to do this, see Example 5: Deny or allow actions on repositories with tags.

For more information, see IAM JSON Policy Elements: Condition in the IAM User Guide.

Troubleshooting AWS CodeCommit identity and access

Use the following information to help you diagnose and fix common issues that you might encounter when working with CodeCommit and IAM.

I Am not authorized to perform an action in CodeCommit

If the AWS Management Console tells you that you're not authorized to perform an action, then you must contact your administrator for assistance. Your administrator is the person that provided you with your user name and password.

For more information, see Permissions required to use the CodeCommit console

I Am not authorized to perform iam:PassRole

If you receive an error that you're not authorized to perform the iam:PassRole action, your policies must be updated to allow you to pass a role to CodeCommit.

Some AWS services allow you to pass an existing role to that service instead of creating a new service role or service-linked role. To do this, you must have permissions to pass the role to the service.

The following example error occurs when an IAM user named marymajor tries to use the console to perform an action in CodeCommit. However, the action requires the service to have permissions that are granted by a service role. Mary does not have permissions to pass the role to the service.

User: arn:aws:iam::123456789012:user/marymajor is not authorized to perform: iam:PassRole

In this case, Mary's policies must be updated to allow her to perform the iam:PassRole action.

If you need help, contact your AWS administrator. Your administrator is the person who provided you with your sign-in credentials.

I want to view my access keys

After you create your IAM user access keys, you can view your access key ID at any time. However, you can't view your secret access key again. If you lose your secret key, you must create a new access key pair.

Access keys consist of two parts: an access key ID (for example, AKIAIOSFODNN7EXAMPLE) and a secret access key (for example, wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY). Like a user name and password, you must use both the access key ID and secret access key together to authenticate your requests. Manage your access keys as securely as you do your user name and password.

Important

Do not provide your access keys to a third party, even to help find your canonical user ID. By doing this, you might give someone permanent access to your account.

When you create an access key pair, you are prompted to save the access key ID and secret access key in a secure location. The secret access key is available only at the time you create it. If you lose your secret access key, you must add new access keys to your IAM user. You can have a maximum of two access keys. If you already have two, you must delete one key pair before creating a new one. To view instructions, see Managing access keys in the IAM User Guide.

I'm an administrator and want to allow others to access CodeCommit

To allow others to access CodeCommit, you must create an IAM entity (user or role) for the person or application that needs access. They will use the credentials for that entity to access AWS. You must then attach a policy to the entity that grants them the correct permissions in CodeCommit.

To get started right away, see Creating your first IAM delegated user and group in the IAM User Guide.

I want to allow people outside of my Amazon Web Services account to access my CodeCommit resources

For more information, see Configure cross-account access to an AWS CodeCommit repository using roles.