I am trying to restrict an IAM role to only be able to access a specific subfolder (key prefix) in an S3 bucket. Here's the policy JSON I'm using, but currently the user can still access other folders in the bucket:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::somebucket",
"arn:aws:s3:::somebucket/*"
]
},
{
"Sid": "VisualEditor2",
"Effect": "Allow",
"Action": [
"s3:ListBucketVersions",
"s3:ListBucketByTags",
"s3:GetBucketAcl"
],
"Resource": [
"arn:aws:s3:::mybucket"
]
},
{
"Sid": "VisualEditor3",
"Effect": "Allow",
"Action": [
"s3:GetObjectAcl",
"s3:GetObject",
"s3:GetObjectVersion"
],
"Resource": [
"arn:aws:s3:::mybucket/datasets/company1/*"
]
}
]
}
Currently, using this role I can still do, e.g.
aws s3 cp s3://mybucket/datasets/company2/dataset.csv
and download the dataset. What am I doing wrong?
When I try and simulate the policy it seems to be correct (trying to getObject on mybucket/datasets/company2/dataset.csv fails implicitly, but this does not happen in practice. There are no other policies attached to this user.
Related
I am setting up the AWS toolkit in the Visual Studio. I have created an IAM user which will be used for development.
But for the IAM user I have configured I am seeing that it cannot see the S3 buckets in the explorer. It gives "Access denied".
This is the custom role assigned to the IAM user:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowListing",
"Effect": "Allow",
"Action": [
"s3:ListBucket"
],
"Resource": "arn:aws:s3:::dev-buckets"
},
{
"Sid": "AllowReadWriteDel",
"Effect": "Allow",
"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"
],
"Resource": "arn:aws:s3:::dev-buckets/*"
}
]
}
The only way I can get it working is by adding "AmazonS3FullAccess" policy to the IAM user. But then it exposes all the buckets in the account. Not just the buckets meant for the developers.
Is it possible to do using a custom policy? I am a beginner.
You cannot only list specific bucket when trying to list buckets.
I think the following policy should help you out:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:GetBucketLocation",
"s3:ListAllMyBuckets"
],
"Resource": "arn:aws:s3:::*"
},
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::dev-buckets",
"arn:aws:s3:::dev-buckets/*"
]
}
]
}
With this policy:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"s3:ListStorageLensConfigurations",
"s3:ListAccessPointsForObjectLambda",
"s3:GetAccessPoint",
"s3:PutAccountPublicAccessBlock",
"s3:GetAccountPublicAccessBlock",
"s3:ListAllMyBuckets",
"s3:ListAccessPoints",
"s3:ListJobs",
"s3:PutStorageLensConfiguration",
"s3:CreateJob"
],
"Resource": "*"
},
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": "s3:*",
"Resource": "*"
}
]
}
I am allowed to access a specific s3 accesspoint. However, when I try using a more specific access which only gives s3:* actions to a specific accesspoint:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"s3:ListStorageLensConfigurations",
"s3:ListAccessPointsForObjectLambda",
"s3:GetAccessPoint",
"s3:PutAccountPublicAccessBlock",
"s3:GetAccountPublicAccessBlock",
"s3:ListAllMyBuckets",
"s3:ListAccessPoints",
"s3:ListJobs",
"s3:PutStorageLensConfiguration",
"s3:CreateJob"
],
"Resource": "*"
},
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": "s3:*",
"Resource": "arn:aws:s3:eu-west-1:598276570227:accesspoint/accesspointname"
}
]
}
This does not work, and the EC2 with this role stops being able to access the s3 access point (just copying a file using the AWS CLI)
First why is this happening? The role still should have access to all the actions on that accesspoint by my reckoning (which must be wrong in some way!).
Secondly, I am trying to make it such that an s3 bucket is only accessible from a certain IAM role. I tried setting this from the access policy from the access point itself. This had the opposite problem that it was too permissive and everything could still access it. What is the correct way of doing this - putting an IAM policy on the accesspoint to restrict access to the IAM role or making an IAM Role which has access to this s3 access point?
I got this working by using this:]
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"s3:ListStorageLensConfigurations",
"s3:ListAccessPointsForObjectLambda",
"s3:GetAccessPoint",
"s3:PutAccountPublicAccessBlock",
"s3:GetAccountPublicAccessBlock",
"s3:ListAllMyBuckets",
"s3:ListAccessPoints",
"s3:ListJobs",
"s3:PutStorageLensConfiguration",
"s3:CreateJob"
],
"Resource": "*"
},
{
"Sid": "VisualEditor1",
"Effect": "Allow",
"Action": "s3:*",
"Resource": "*",
"Condition": {
"StringLike": {
"s3:DataAccessPointArn": "arn:aws:s3:eu-west-1:598276570227:accesspoint/accesspointname"
}
}
}
]
}
I have setup an ECS task containing two containers. The containers are fully responsive to request, but they need to put some items into s3, but I get Err foundAccessDenied: Access Denied.
I have attached a new policy as following to ecsTaskExecutionRole role.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:GetBucketLocation",
"s3:ListAllMyBuckets",
"s3:ListBucket"
],
"Resource": "*"
},
{
"Effect": "Allow",
"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"
],
"Resource": [
"*"
]
}
]
}
Also added the following env when creating docker images: ECS_ENABLE_TASK_IAM_ROLE=true
What am I missing here that all the time get the AccessDenied error?!
I have a rails app set up to upload files to S3
I have an IAM user with an inline policy attached to the user.
When I use the following policy everything works just fine:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1494133349000",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"*"
]
}
]
}
Now when I try to specify the ARN of my bucket, I get an access denied error in my app.
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1494133349000",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::my-bucket"
]
}
]
}
The ARN is copied directly from my bucket. No clue why the second policy doesnt work. It should according to everything i've read.
This is your bucket:
"Resource": [
"arn:aws:s3:::my-bucket"
]
This is your bucket and the objects in your bucket:
"Resource": [
"arn:aws:s3:::my-bucket",
"arn:aws:s3:::my-bucket/*"
]
I have set a permission on the bucket that allows "Authenticated Users" to list, upload, and delete from a bucket I created. This seems to allow me to upload files to the bucket, but it appears that downloading files from the bucket is not covered by this permission, and I instead need to define a policy for the bucket. It's not clear to me how to set such a policy. I tried the policy generator with my best guesses at what I should fill in, but the result was not a valid policy when I pasted it in as a new policy for the bucket (it failed with the message Action does not apply to any resource(s) in statement - Action "s3:ListBucket" in Statement "Stmt-some-number"). Can someone explain what is wrong with the following policy and how to set it correctly to allow authenticated users to retrieve files from the bucket?
{
"Id": "Policy-some-number",
"Statement": [
{
"Sid": "Stmt-some-number",
"Action": [
"s3:GetObject",
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/*",
"Principal": {
"AWS": [
"*"
]
}
}
]
}
s3:GetObject applies to the objects in the bucket so the Resource is correct: "Resource": "arn:aws:s3:::my-bucket/*".
s3:ListBucket applies to the Bucket itself and so the Resource should be "Resource": "arn:aws:s3:::my-bucket"
your resulting policy should resemble:
{
"Id": "Policy-some-number",
"Statement": [
{
"Sid": "Stmt-some-number",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/*",
"Principal": {
"AWS": [
"*"
]
}
},
{
"Sid": "Stmt-some-other-number",
"Action": [
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket",
"Principal": {
"AWS": [
"*"
]
}
}
]
}
Just to compliment #c4urself answer. the answer help solve my issue as well, but there is some indication from AWS documentation, which you can add more than one resource, just use [] to make them a list.
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-endpoints.html#vpc-endpoints-s3-bucket-policies
{
"Statement": [
{
"Sid": "Access-to-specific-bucket-only",
"Principal": "*",
"Action": [
"s3:ListBucket",
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::my_secure_bucket",
"arn:aws:s3:::my_secure_bucket/*"]
}
]
}
Update Bucket policy as below
{
"Version": "2012-10-17",
"Id": "Policy1546023103427",
"Statement": [
{
"Sid": "Stmt1546023101836",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:ListBucket",
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::usagereports-atul",
"arn:aws:s3:::usagereports-atul/*"
]
}
]
}
Just make the resource and array/list of resources and add an item to the list with /* as s3:GetObject applies to arn:aws:s3:::my_secure_bucket/*. See below
"Resource": ["arn:aws:s3:::my_secure_bucket",
"arn:aws:s3:::my_secure_bucket/*"