# Prerequisites for signing container images PrerequisitesSigner open source library now available Adds a link to the Signer open source library. You now have the option of using the Signer binary or the open source library. Before you begin signing, you need to set up an environment that bridges AWS Signer with Amazon ECR. Complete the following steps. **To prepare your signing environment** 1. **Prepare the AWS CLI** Install and configure the latest version of the AWS CLI. For more information, see [Installing or updating the latest version of the AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html) in the *AWS Command Line Interface User Guide*. 1. **Prepare Amazon ECR** Have an existing container image stored in an Amazon ECR private repository to sign. For more information, see [Pushing an image](https://docs.aws.amazon.com/AmazonECR/latest/userguide/image-push.html) in the *Amazon Elastic Container Registry User Guide*. 1. **Download the container-signing tools** Two software packages need to be installed in your local environment for you to sign images: + The open source supply chain security program Notation, developed by the [Notary Project](https://notaryproject.dev/) + The AWS Signer plugin for Notation. You can either use our plugin binary, or our open source library. ------ #### [ Plugin binary ] The AWS Signer installer installs both the Notation client and the AWS Signer plugin for Notation. Separate binaries are available to install only the AWS Signer plugin. The installer includes the following. + Notation binary and third party license. + AWS Signer plugin binary and third party license. + Notation license. + Trust store set up with AWS Signer's Notation signing [root certificate](https://d2hvyiie56hcat.cloudfront.net/aws-signer-notation-root.cert). + GovCloud trust store and [root certificate](https://d2hvyiie56hcat.cloudfront.net/aws-us-gov-signer-notation-root.cert), for use in the AWS GovCloud (US) Region. + A configurable trust policy. For information about configuring the trust policy, see [Locally verify an image after signing](image-verification.md). The following table provides the installer and related files for each supported operating system and architecture. You can download our latest [CHANGELOG](https://d2hvyiie56hcat.cloudfront.net/CHANGELOG) to see the versions of the Notation CLI and plugin included in each installer release. **Notation binary and AWS Signer Plugin installer files** [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/signer/latest/developerguide/image-signing-prerequisites.html) ------ #### [ Open source library ] The open source Signer plugin is available as a library for use with your toolchain to generate and verify container artifacts signatures. Access the source code and instructions to build the Signer plugin in the [Signer Notation plugin Github repository](https://github.com/aws/aws-signer-notation-plugin). ------ 1. **(Optional) Verify signed packages.** For instructions to complete this step, select the tab for your platform. ------ #### [ Linux ] 1. Download the public key. ``` $ ​wget https://d2hvyiie56hcat.cloudfront.net/linux/public.key ``` 1. Import the public key into your keyring. If you're using the unzip the AWS Signer plugin, first unzip downloaded file and then run command against the binary file within the zip file. ``` $ gpg --import public.key gpg: key A3B52DA65461CF90: public key "AWS Signer Notation" imported gpg: Total number processed: 1 gpg: imported: 1 ``` ​Make a note of the key value, as you need it in the next step. In the preceding example, the key value is `A3B52DA65461CF90`. 1. Verify the fingerprint by running the following command, replacing **key-value** with the value from the preceding step: ``` $ gpg --fingerprint key-value pub rsa3072 2023-04-24 [SC] E84A F8A2 A9B5 2F1F 4435 AE71 A3B5 2DA6 5461 CF90 uid [ unknown] AWS Signer Notation​ ``` The fingerprint string should be `E84A F8A2 A9B5 2F1F 4435 AE71 A3B5 2DA6 5461 CF90`. If the fingerprint string doesn't match, don't run the installer. Contact Amazon Web Services. After you have verified the fingerprint, you can use it to verify the signature of the AWS Signer Notation package. 1. Download the package signature file using **wget**. To determine the correct signature file, see the preceding table. ``` $ ​wget signature-file-link ``` 1. To verify the signature, run gpg --verify: ``` $ gpg --verify sig-filename downloaded-filename gpg: Signature made Mon May 22 16:16:34 2023 PDT gpg: using RSA key A3B52DA65461CF90 gpg: Good signature from "AWS Signer Notation" [unknown] gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: E84A F8A2 A9B5 2F1F 4435 AE71 A3B5 2DA6 5461 CF90​ ``` If the output includes the phrase *BAD signature*, check whether you performed the procedure correctly. If you continue to get this response, contact Amazon Web Services and avoid using the downloaded file.​ Note the warning about *trust*. A key is trusted only if you or someone who you trust has signed it. This doesn't mean that the signature is invalid, only that you have not verified the public key. ------ #### [ Windows ] To verify the signature of the MSI installer or the plugin EXE file, using Windows PowerShell run the following command: ``` C:\> ​Get-AuthenticodeSignature filename ``` You can also verify the signature by right-clicking on the file in an Explorer window, choosing **Properties**, and then choosing **Digital Signatures**. ​You should see a result similar to the following:​ ``` SignerCertificate Status Path ----------------- ------ ---- [40-character hexamecimal number] Valid downloaded-file​​ ``` ------ #### [ MacOS ] 1. To verify the signature of the PKG installer, run the following command. This example uses the amd64 package, but the signature of the arm64 package can be verified similarly. ``` $ ​pkgutil --check-signature ​aws-signer-notation-cli_amd64.pkg ``` You should see a result similar to the following: ``` ​Package "aws-signer-notation-cli_amd64.pkg": Status: signed by a developer certificate issued by Apple for distribution Notarization: trusted by the Apple notary service Signed with a trusted timestamp on: 2023-05-19 15:17:15 +0000 Certificate Chain: 1. Developer ID Installer: AMZN Mobile LLC (94KV3E626L) Expires: 2027-06-28 22:57:06 +0000 SHA256 Fingerprint: 49 68 39 4A BA 83 3B F0 CC 5E 98 3B E7 C1 72 AC 85 97 65 18 B9 4C BA 34 62 BF E9 23 76 98 C5 DA ------------------------------------------------------------------------ 2. Developer ID Certification Authority Expires: 2031-09-17 00:00:00 +0000 SHA256 Fingerprint: F1 6C D3 C5 4C 7F 83 CE A4 BF 1A 3E 6A 08 19 C8 AA A8 E4 A1 52 8F D1 44 71 5F 35 06 43 D2 DF 3A ------------------------------------------------------------------------ 3. Apple Root CA Expires: 2035-02-09 21:40:36 +0000 SHA256 Fingerprint: B0 B1 73 0E CB C7 FF 45 05 14 2C 49 F1 29 5E 6E DA 6B CA ED 7E 2C 68 C5 BE 91 B5 A1 10 01 F0 24​ ``` 1. To verify the signature of the AWS Signer Notation plugin executable, run the following command. ``` $ ​codesign -dv --verbose=4 ./notation-com.amazonaws.signer.notation.plugin ``` ​You should see a result similar to the following. ``` Executable=/path/to/notation-com.amazonaws.signer.notation.plugin Identifier=notation-com.amazonaws.signer.notation.plugin_darwin_arm64 Format=Mach-O thin (arm64) CodeDirectory v=20500 size=74278 flags=0x10000(runtime) hashes=2314+2 location=embedded VersionPlatform=1 VersionMin=720896 VersionSDK=720896 Hash type=sha256 size=32 CandidateCDHash sha256=e4000dbdf4e6243be9d290b1520d95bf9027a5e4 CandidateCDHashFull sha256=e4000dbdf4e6243be9d290b1520d95bf9027a5e42b699a354fc39ac0f498477f Hash choices=sha256 CMSDigest=e4000dbdf4e6243be9d290b1520d95bf9027a5e42b699a354fc39ac0f498477f CMSDigestType=2 Executable Segment base=0 Executable Segment limit=3571712 Executable Segment flags=0x1 Page size=4096Launch Constraints:None CDHash=e4000dbdf4e6243be9d290b1520d95bf9027a5e4 Signature size=9070 Authority=Developer ID Application: AMZN Mobile LLC (94KV3E626L) Authority=Developer ID Certification Authority Authority=Apple Root CATimestamp=May 19, 2023 at 7:51:07 AM Info.plist=not bound TeamIdentifier=94KV3E626L Runtime Version=11.0.0 Sealed Resources=none Internal requirements count=1 size=220 ``` ------ 1. **Install the packages** For instructions to complete this step, select the tab for your platform. ------ #### [ Linux (RPM) ] If you downloaded an RPM package on a Linux server, change to the directory containing the package and enter the following: ``` $ ​sudo rpm -U filename ``` ------ #### [ Linux (DEB) ] If you downloaded a DEB package on a Linux server, change to the directory containing the package and enter the following: ``` $ ​sudo dpkg -i -E filename ``` ------ #### [ Windows ] Install the package with the following command. ``` C:\> msiexec /i filename ``` This command also works from within PowerShell. For more information, see [Microsoft Standard Installer command-line options ](https://learn.microsoft.com/en-us/windows/win32/msi/standard-installer-command-line-options)in the Microsoft Windows documentation. ------ #### [ MacOS ] If you downloaded a PKG package on a macOS server, change to the directory containing the package and enter the following: ``` $ ​sudo installer -pkg filename -target / ``` ------ 1. **Verify the package installation** After downloading and installing the package, to verify the installation was successful, do the following. 1. Verify that the Notation directory structure for your operating system was created. 1. Use the following command to display the Notation client version. ``` notation version ``` 1. Use the following command to list the installed plugins for the Notation client and verify that you see the `com.amazonaws.signer.notation.plugin` plugin. ``` notation plugin ls ``` ## Required AWS Identity and Access Management permissions to sign and verify a container image To sign and verify an image present in Amazon Elastic Container Registry, you need an AWS Identity and Access Management policy that allows Notation to interact with Amazon ECR and Signer. The following is an example of a user managed policy that allows Notation to interact with Amazon ECR and Signer: ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "ManageRepositoryContents", "Effect": "Allow", "Action": [ "ecr:GetDownloadUrlForLayer", "ecr:BatchGetImage", "ecr:CompleteLayerUpload", "ecr:DescribeRepositories", "ecr:UploadLayerPart", "ecr:InitiateLayerUpload", "ecr:BatchCheckLayerAvailability", "ecr:PutImage" ], "Resource": "arn:aws:ecr:us-east-1:111122223333:repository/my-repo" }, { "Sid": "GetAuthorizationToken", "Effect": "Allow", "Action": [ "ecr:GetAuthorizationToken" ], "Resource": "*" }, { "Sid": "SignAndRevocationCheck", "Effect": "Allow", "Action": [ "signer:PutSigningProfile", "signer:SignPayload", "signer:GetRevocationStatus" ], "Resource": "*" } ] } ``` ------