I would like to set a policy for a S3 bucket that is restricted to a VPC-ID(using a S3 endpoint). I have two accounts, A and B. I want a IAM user in A to access a bucket in B.
https://docs.aws.amazon.com/AmazonS3/latest/userguide/example-bucket-policies-vpc-endpoint.html
{ "Version": "2012-10-17", "Id": "Policy1415115909153", "Statement": [
{
"Sid": "Access-to-specific-VPC-only",
"Principal": "*",
"Action": "s3:*",
"Effect": "Deny",
"Resource": ["arn:aws:s3:::awsexamplebucket1",
"arn:aws:s3:::awsexamplebucket1/*"],
"Condition": {
"StringNotEquals": {
"aws:SourceVpc": "vpc-111bbb22"
}
}
} ] }
Above won't work, but following will:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::bucket",
"arn:aws:s3:::bucket/*"
],
"Condition": {
"StringEquals": {
"aws:SourceVpc": "vpc-111111111111"
}
}
}
]
}
Feels like best practices is to use a deny policy. Anyone has an idea why and how solve it?
As pointed out you need to allow as-well. Combine both policies and it will work.
I wanted to allow all s3 actions on a particular bucket "test-bucket" for a specific role "test-role". Deny the bucket for all others. The s3 policy I have written :
{
"Version": "2012-10-17",
"Id": "Policy1601973417173",
"Statement": [
{
"Sid": "Allow role test-role",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::xxxxxxxx:role/test-role"
},
"Action": "s3:*",
"Resource": "arn:aws:s3:::test-bucket/*"
},
{
"Sid": "Deny rest",
"Effect": "Deny",
"NotPrincipal": {
"AWS": "arn:aws:iam::xxxxxxxx:role/test-role"
},
"Action": "s3:*",
"Resource": "arn:aws:s3:::test-bucket/*"
}
]
}
Even after applying the above policy, the sso users which are mapped to the role "test-role" is getting Access denied on the bucket.
Note : The AWS console shows logged in user as "Federated Login: test-role/sam#abc.com".
I have also tried the "assumed-role" options are still failing. Any help appreciated.
Try this:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Deny",
"Principal": "*",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::test-bucket",
"arn:aws:s3:::test-bucket/*"
],
"Condition": {
"StringNotLike": {
"aws:userId": [
"AIDA<udserid-1-suppressed>:*",
"AIDA<udserid-1-suppressed>",
"AIDA<udserid-2-suppressed>:*",
"AIDA<udserid-2-suppressed>",
"AIDA<udserid-n-suppressed>:*",
"AIDA<udserid-n-suppressed>",
"111111111111"
]
}
}
}
]
}
I have a public S3 bucket which has 2 folders inside it, public-folder and private-folder
I want everyone to access the public-folder and I want only user1 to access private-folder programmatically.
Inside the S3 bucket, I have added the following policy:
{
"Version": "2012-10-17",
"Id": "Policy1568654876568",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my-bucket/*"
},
{
"Effect": "Deny",
"NotPrincipal": {
"AWS": [
"arn-of-user1"
]
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my-bucket/private-folder/*"
}
]
}
from the IAM, I have created a policy for user1 to be able to access the bucket:
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket"
},
{
"Action": [
"s3:DeleteObject",
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/*"
}
]
}
Is there a better way to achieve this goal? Would be possible to deny everyone to access the private-folder using S3 policy and then override that using IAM policy that I have defined for user1?
Wouldn't the following be easier and more natural to do if you have public-folder and private-folder. The following is based on the fact that buckets and its objects are private by default.
Bucket policy
It allows public access to public-folder:
{
"Version": "2012-10-17",
"Id": "Policy1568654876568",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my-bucket/public-folder/*"
}
]
}
User policy
It allows putting, getting and deleting objects in private-folder, as well as listing the bucket.
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket"
},
{
"Action": [
"s3:DeleteObject",
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/private-folder/*"
}
]
}
Would be possible to deny everyone to access the private-folder using S3 policy and then override that using IAM policy that I have defined for user1?
Explicit deny overwrites any allow. Thus if you deny access to everyone, you can't use any IAM policy to allow access.
I have an S3 bucket called my-bucket... I have several sub-folders inside this bucket, let's call them: sub-folder1, sub-folder2, etc
I want my-bucket-user to have read permission to the bucket and full control permission to all of the sub-folders (so this user cannot write at the root level).
I have tried the following bucket policy, which specifically grants permission on each of the sub folders... but this policy would become too long if I have a lot of sub-folders.
{
"Id": "MyBucketPolicy",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "ListPermissionOnMyBucket",
"Action": [
"s3:GetBucketLocation",
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/*",
"Principal": {
"AWS": [
"arn:aws:iam::773643377756:user/my-bucket-user"
]
}
},
{
"Sid": "FullControlAccessOnSubFolder1",
"Action": "s3:*",
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/sub-folder1/*",
"Principal": {
"AWS": [
"arn:aws:iam::773643377756:user/my-bucket-user"
]
}
},
{
"Sid": "FullControlAccessOnSubFolder2",
"Action": "s3:*",
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/sub-folder2/*",
"Principal": {
"AWS": [
"arn:aws:iam::773643377756:user/my-bucket-user"
]
}
}
]
}
Is there a better way of writing this policy?
This policy permits listing the entire contents of the bucket, but only uploading/downloading to a sub-folder (not the root of the bucket):
{
"Version": "2012-10-17",
"Statement": [
{
"Action": "s3:ListBucket",
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket"
},
{
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my-bucket/*/*"
}
]
}
Basically, the expression my-bucket/*/* forces the requirement of a / in the Key of the object, meaning it is in a sub-folder.
I'm following the instructions from this answer to generate the follow S3 bucket policy:
{
"Id": "Policy1495981680273",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1495981517155",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::surplace-audio",
"Principal": "*"
}
]
}
I get back the following error:
Action does not apply to any resource(s) in statement
What am I missing from my policy?
From IAM docs, http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html#Action
Some services do not let you specify actions for individual resources; instead, any actions that you list in the Action or NotAction element apply to all resources in that service. In these cases, you use the wildcard * in the Resource element.
With this information, resource should have a value like below:
"Resource": "arn:aws:s3:::surplace-audio/*"
Just removing the s3:ListBucket permission wasn't really a good enough solution for me, and probably isn't for many others.
If you want the s3:ListBucket permission, you need to just have the plain arn of the bucket (without the /* at the end) as this permission applies to the bucket itself and not items within the bucket.
As shown below, you have to have the s3:ListBucket permission as a separate statement from the permissions pertaining to items within the bucket like s3:GetObject and s3:PutObject:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:ListBucket"
],
"Principal": {
"AWS": "[IAM ARN HERE]"
},
"Resource": "arn:aws:s3:::my-bucket-name"
},
{
"Effect": "Allow",
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Principal": {
"AWS": "[IAM ARN HERE]"
},
"Resource": "arn:aws:s3:::my-bucket-name/*"
}
]
}
Error Action does not apply to any resource(s) in statement
Simply it means that the action (you wrote in policy) doesn't apply to the resource. I was trying to make public my bucket so that anybody can download from my bucket. I was getting error until I remove ( "s3:ListBucket") from my statement.
{
"Id": "Policyxxxx961",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmtxxxxx4365",
"Action": [
"s3:GetObject",
"s3:ListBucket",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket-name/*",
"Principal": "*"
}
]
}
Because list bucket doesn't apply inside the bucket, thus by deleting this action policy worked fine.
Just ran into this issue and found a shorter solution for those that want to have ListBucket and GetObject in the same policy. The important thing is to list both the bucket-name and bucket-name/* under Resource.
{
"Id": "Policyxxxx961",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmtxxxxx4365",
"Action": [
"s3:GetObject",
"s3:ListBucket",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::bucket-name",
"arn:aws:s3:::bucket-name/*"
],
"Principal": "*"
}
]
}
To fix this issue, what you need to do in policy rule, locate the Resource, and add your arn bucket in array, one with * and the second on without * at the end. This will fix the error.
{
"Version": "2012-10-17",
"Id": "Policy3783783783738",
"Statement": [
{
"Sid": "Stmt1615891730703",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::76367367633:user/magazine-demo-root-user"
},
"Action": [
"s3:ListBucket",
"s3:ListBucketVersions",
"s3:GetBucketLocation",
"s3:DeleteObject",
"s3:AbortMultipartUpload",
"s3:Get*",
"s3:Put*"
],
"Resource": [
"arn:aws:s3:::magazine-demo",
"arn:aws:s3:::magazine-demo/*"
]
}
]
}
Just do one change in json policy resource.
"Resource": ["arn:aws:s3:::bucket-name/*"]
Note : Add /* after bucket-name
Ref Docs :
https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html
I have also faced the similar issue while creating the bucket
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AddPerm",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::mrt9949"
]
}
]
}
I have changed the above code to
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AddPerm",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::mrt9949/*"
]
}
]
}
add /* to your bucket name it will solve the issue
Here my bucket name is mrt9949
In my case the solution to this error was trying to remove some of Actions that I was applying. Some of them are not relevant to, or cannot work with this resource.
In this case it wouldn't let me include these:
GetBucketAcl
ListBucket
ListBucketMultipartUploads
Whenever you are trying to apply use bucket policies. Remember this thing, If you are using actions like "s3:ListBucket", "s3:GetBucketPolicy", "s3:GetBucketAcl" etc. which are related to bucket, the resource attribute in policy should be mentioned as <"Resource": "arn:aws:s3:::bucket_name">.
Ex.
{
"Version": "2012-10-17",
"Id": "Policy1608224885249",
"Statement": [
{
"Sid": "Stmt1608226298927",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:GetBucketPolicy",
"s3:GetBucketAcl",
"s3:ListBucket"
],
"Resource": "arn:aws:s3:::bucket_name"
}
]
}
If you are using actions like "s3:GetObject", "s3:DeleteObject", "s3:GetObject" etc. which are related to object, the resource attribute in policy should be mentioned as <"Resource": "arn:aws:s3:::bucket_name/*">.
ex.
{
"Id": "Policy1608228066771",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1608228057071",
"Action": [
"s3:DeleteObject",
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket_name/*",
"Principal": "*"
}
]
}
Finally if you are using actions like "s3:ListBucket", "s3:GetObject" etc. these actions are related to both bucket and object then the resource attribute in policy should be mentioned as <"Resource": ["arn:aws:s3:::bucket_name/*", "Resource": "arn:aws:s3:::bucket_name">.
ex.
{
"Version": "2012-10-17",
"Id": "Policy1608224885249",
"Statement": [
{
"Sid": "Stmt1608226298927",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:ListBucket",
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::bucket_name",
"arn:aws:s3:::bucket_name/*"
]
}
] }
Go to Amazon S3 in your instance.
Go to Permissions -> Public Access tab.
Select Edit and uncheck Block all public access and save.
You will see 'Public' tag in Permission tab and Access Control List.
You might have several policy statements and this error is a very generic one. Best is to comment all other statements except any one (like just GetObject, or ListBuckets, Or PutObject) and execute the code and see. If it works fine, it means the ARN path is right. Else, the ARN should include the bucket name alone or a bucketname with /*.
Some resources like ListBucket accept ARN with the full name like "arn:aws:s3:::bucket_name", while GetObject or PutObject expects a /* after the bucket_name. Change the ARNs according to the service and it should work now!
You have to check the pattern of the arn defined under the Resource tag for the Policy-
"Resource": "arn:aws:s3:::s3mybucketname/*"
With the addition of "/*" at the end would help to resolve the issue if you face it even after having your Public Access Policy Unblocked for your Bucket.
From AWS > Documentation > AWS Identity and Access Management > User Guide
https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_resource.html
It is clearly defined in a note, Some services do not let you specify actions for individual resources.
you use the wildcard * in the Resource element
"Resource": "arn:aws:s3:::surplace-audio/*"
You can also configure ListBuckets for each folder, like so
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowSESPuts-1521238702575",
"Effect": "Allow",
"Principal": {
"Service": "ses.amazonaws.com"
},
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::buckets.email/*",
"Condition": {
"StringEquals": {
"aws:Referer": "[red]"
}
}
},
{
"Sid": "Stmt1586754972129",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::596322993031:user/[red]"
},
"Action": "s3:ListBucket",
"Resource": "arn:aws:s3:::buckets.email",
"Condition": {
"StringEquals": {
"s3:delimiter": "/",
"s3:prefix": [
"",
"domain.co",
"domain.co/user"
]
}
}
},
{
"Sid": "Stmt1586754972129",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::596322993031:user/[red]"
},
"Action": "s3:ListBucket",
"Resource": "arn:aws:s3:::buckets.email",
"Condition": {
"StringLike": {
"s3:prefix": "domain.co/user/*"
}
}
},
{
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::596322993031:user/[red]"
},
"Action": [
"s3:GetObject",
"s3:PutObject",
"s3:DeleteObject"
],
"Resource": "arn:aws:s3:::buckets.email/domain.co/user/*"
}
]
}
These rules are used together with SES to receive an email, but allows an external user to view the files that were put in the bucket by SES.
I followed the instructions from here: https://aws.amazon.com/blogs/security/writing-iam-policies-grant-access-to-user-specific-folders-in-an-amazon-s3-bucket/
Also, you must specify prefix as domain.co/user/ WITH slash at the end when using the SDK, otherwise you'll get access denied. hope it helps anyone
This is so simple just add "/*" at the end. You have given only the root directory link, but the action needs to be applied to the object.
Type,
"Resource": "arn:aws:s3:::surplace-audio/*"
I found that my ListBuckets was not working because the IAM Principle did not have ListAllMyBuckets permission.