AWS S3 - permission to edit bucket policy - amazon-web-services

I recently created an S3 bucket on AWS through the console, with the default settigns (except the name, obviously). I try editing the Bucket Policy, but getting this error: "Error Access denied", both with my admin IAM user, and the root account.
How can I get access to edit S3 Bucket policies?

Answering my own question: by default, buckets have the following option set: "Block new public bucket policies". Turning this off will enable updating the Bucket Policy.

Related

Unable to configure SageMaker execution Role with access to S3 bucket in another AWS account

Requirement: Create SakeMaker GroundTruth labeling job with input/output location pointing to S3 bucket in another AWS account
High Level Steps Followed: Lets say, Account_A: SageMaker GroundTruth labeling job and Account_B: S3 bucket
Create role AmazonSageMaker-ExecutionRole in Account_A with 3 policies attached:
AmazonSageMakerFullAccess
Account_B_S3_AccessPolicy: Policy with necessary S3 permissions to access S3 bucket in Account_B
AssumeRolePolicy: Assume role policy for arn:aws:iam::Account_B:role/Cross-Account-S3-Access-Role
Create role Cross-Account-S3-Access-Role in Account_B with 1 policy and 1 trust relationship attached:
S3_AccessPolicy: Policy with necessary S3 permissions to access S3 bucket in the this Account_B
TrustRelationship: For principal arn:aws:iam::Account_A:role/AmazonSageMaker-ExecutionRole
Error: While trying to create SakeMaker GroundTruth labeling job with IAM role as AmazonSageMaker-ExecutionRole, it throws error AccessDenied: Access Denied - The S3 bucket 'Account_B_S3_bucket_name' you entered in Input dataset location cannot be reached. Either the bucket does not exist, or you do not have permission to access it. If the bucket does not exist, update Input dataset location with a new S3 URI. If the bucket exists, give the IAM entity you are using to create this labeling job permission to read and write to this S3 bucket, and try your request again.
In your high level step 2, the approach should change to using a Resource Policy on your S3 bucket that allows account A to write to it. Rather than expecting Account A to assume a role in Account B, which I don't believe Sagemeker will do. Therefore the general approach is to do the following:
Account A Sagemaker service is given has a iam policy with a that allows access to Account B bucket. (Basically what you've done).
Account B bucket is given a resource policy that allows Account A to access it.
The following article gives additional help on this topic: How can I provide cross-account access to objects that are in Amazon S3 buckets?
Reverted back to original approach where access to the SageMaker execution role was provided through direct S3 bucket policy.
While creating the GT job from console:
(i) Expects the user creating the job also to have access to the data in cross account S3 bucket; Updated bucket policy to have access for both SageMaker execution role as well as user
(ii) Expects the manifest in own account's S3 bucket; Fails with 403 if manifest is in cross account S3 bucket even though SageMaker execution role had access to the cross account S3 bucket
While creating the GT job from CLI: Above restrictions doesn't apply and was able to create the GT job.

S3 Bucket without ACL - No permission

I found an issue with a S3 bucket.
The bucket don't have any ACL associated, and the user that create the bucket was deleted.
How it's possible add some ACL in the bucket to get the control back?
For any command using AWS CLI, the result are the same always: An error occurred (AccessDenied) when calling the operation: Access Denied
Also in AWS console the access is denied.
First things first , AccessDenied error in AWS indicates that your AWS user does not have access to S3 service , Get S3 permission to your IAM user account , if in case you had access to AWS S3 service.
The thing is since you are using cli make sure AWS client KEY and secret are still correctly in local.
Now the interesting use case :
You have access to S3 service but cannot access the bucket since the bucket had some policies set
In this case if user who set the policies left and no user was able to access this bucket, the best way is to ask AWS root account holder to change the bucket permissions
An IAM user with the managed policy named AdministratorAccess should be able to access all S3 buckets within the same AWS account. Unless you have applied some unusual S3 bucket policy or ACL, in which case you might need to log in as the account's root user and modify that bucket policy or ACL.
See Why am I getting an "Access Denied" error from the S3 when I try to modify a bucket policy?
I just posted this on a related thread...
https://stackoverflow.com/a/73977525/999943
https://aws.amazon.com/premiumsupport/knowledge-center/s3-bucket-owner-full-control-acl/
Basically when putting objects from the non-bucket owner, you need to set the acl at the same time.
--acl bucket-owner-full-control

How to see policies for S3 buckets which showing `Access Denied` error in AWS Console?

I've logged into AWS account as root user. But I'm unable to access some of the buckets in AWS. They are not showing in the S3 Console. I've accessed them by submitting the bucket name in the url
For example let's call the bucket unaccessible-bucket
https://s3.console.aws.amazon.com/s3/buckets/unaccessible-bucket/?region=us-east-1&tab=overview
If I navigates to Permissions > Bucket Policy I'm seeing notice Access denied, I'm unable to download the files. I'm unable to change the policy. I've tried with AWS CLI also.
Can someone please tell me how to edit the policy.
As per our organisation requirement,
We have to add two new IAM users..
For one user...We have to grant access to all buckets including this unaccessible-bucket.
For other user...We have to grant access to only this unaccessible-bucket.
Please check the screenshot
Many Thanks.
Assuming that you are logged into the AWS Console as the root user.
If you cannot see an S3 bucket in the AWS console, then you do not own the bucket and it is owned by another account.
If you can see the bucket in the console then you own the bucket. If you cannot access the contents of the bucket then you will need to edit the S3 Bucket Policy and add the root user as a principal. Replace the account number with your own.
Add this statement (or modify) to your S3 Bucket Policy:
"Principal": { "AWS": "arn:aws:iam::123456789012:root" }

Use of s3:PutBucketPolicy

I was trying few things with aws s3 bucket policy and the documentation for put-bucket-policy says that the user should have PutBucketPolicy on the bucket and should be the owner.
I do not understand the use of PutBucketPolicy permission then.
Also is the bucket owner given a default PutBucketPolicy permission on his bucket?
http://docs.aws.amazon.com/AmazonS3/latest/API/RESTBucketPUTpolicy.html
The confusion here, I suspect, is related to the fact that users don't own buckets. The "owner" of a bucket is an individual AWS account.
You can't successfully grant PutBucketPolicy to any user in a different AWS account -- only your own account's user(s).
There's an illusion of circular logic here: How can I set a bucket policy... allowing myself to set the bucket policy... unless I am already able to set the bucket policy... which would make it unnecessary to set a bucket policy allowing me to set the bucket policy?
This is not as it seems: the problem is resolved by the fact that IAM user policies can grant a user permission to set the bucket policy, and the root account can do this by default -- which is why you should not use your root account credentials routinely: they are too privileged, if they fall into the wrong hands.

Access Denied on AWS S3 bucket with no permission set up

In our S3 configuration we have a bucket that ended up without any permissions, which I reckon my colleague deleted.
Now, we cannot read this bucket, I cannot add permissions to it using the management console, selecting grantee and the permission, as it says "Sorry! You do not have permissions to view this bucket.", When I click on "Add Bucket policy", it opens the dialog which says "Loading" and it keeps loading forever.
I've tried to use aws s3 and aws s3api to grand permission and/or delete the bucket with no success.
I want to either delete this bucket or change it's permissions.
EDIT: We also noticed that the bucket has no owner.
In the Amazon S3 Management Console:
Select the bucket (don't click on its name, just click the line it is on)
Go to the Properties pane on the right
Expand the Permissions section
If there is no line displayed, click Add more permissions, then select the Grantee (possibly your account name?) and tick some permission boxes
These permissions are on the Bucket itself.
Permissions to list the contents of an Amazon S3 bucket are normally granted via Identity and Access Management (IAM) rather than a bucket policy. Traditionally, bucket policies are used to grant access to objects within a bucket.
From your description, it appears that there is no bucket policy in place, which is perfectly okay. All new buckets have no bucket policy anyway.
If the above fix doesn't work, you should check your permissions in IAM to see what you are permitted to do in Amazon S3:
Is there a policy granting you access to everything in S3 (s3:*), or at least a policy granting you access to this bucket?
Is there a policy that is explicitly denying access to this bucket? (Deny overrides Allow)