Which permission needed to perform move action on objects within the same S3 bucket?
To clarify, we have a bucket named BCK and two folders inside named DIR1 & DIR2. An IAM user needs to move objects within DIR1 to DIR2 and when they perform the action from the management console management they get the an error "access denied".
The only policy attached to the user is:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "VisualEditor0",
"Effect": "Allow",
"Action": [
"s3:GetObject",
"s3:PutObject",
"s3:DeleteObject",
"s3:ListBucket",
"s3:ListBucketVersions"
],
"Resource": [
"arn:aws:s3:::BCK/*",
"arn:aws:s3:::BCK"
]
},
{
"Sid": "VisualEditor2",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets",
"s3:HeadBucket"
],
"Resource": "*"
}
]
}
There is no "move" command in Amazon S3. Instead, it requires a combination of CopyObject and DeleteObject. You have already provided these permissions.
The Amazon S3 management console also performs additional steps during the copy operation, such as viewing/setting permissions on each object. Therefore, add these permissions:
s3:GetObjectAcl
s3:PutObjectAcl
Related
I am trying to create an IAM policy to allow a user access only to a specific folder in an S3 bucket.
How do I do this using visual policy editor?
In the resource section if I mention the arn for the folder, the user is being denied access to the whole bucket.
Here is a policy that grants access to a specific folder within a bucket:
{
"Version": "2012-10-17",
"Statement": [
{
"Action": ["s3:ListBucket"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::mybucket"],
"Condition": {"StringLike": {"s3:prefix": ["folder1/*"]}}
},
{
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::mybucket/folder1/*"]
}
]
}
Things to note:
The ListBucket operation that allows listing a bucket is a permission on the bucket itself (not a path). To restrict which folders they can list, the folder must be specified via the s3:prefix.
The GetObject and PutObject operations operate on objects, so the folder can be referenced in the ARN.
It is also possible to use IAM Policy Elements: Variables and Tags to refer to a username. This policy can be applied to an IAM Group and will allow each user access to a folder with their own name:
{
"Version": "2012-10-17",
"Statement": [
{
"Action": ["s3:ListBucket"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::mybucket"],
"Condition": {"StringLike": {"s3:prefix": ["${aws:username}/*"]}}
},
{
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::mybucket/${aws:username}/*"]
}
]
}
I have a bucket with empty bucket policy, block public access turned ON (ACLs and Bucket) and trying to list buckets using IAM policy tied to user using STS AssumeRole with following attached policy.
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"s3:GetObject",
"s3:GetBucket*",
"s3:ListBucket*",
"s3:ListAllMyBuckets"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::my-test-bucket/*"
]
}
]
}
The assumed role credentials are used during the STS session in python (boto3)
s3c = boto3.client('s3',
aws_access_key_id=credentials['AccessKeyId'],
aws_secret_access_key=credentials['SecretAccessKey'],
aws_session_token=credentials['SessionToken'])
s3c.list_buckets()
I get this exception:
botocore.exceptions.ClientError: An error occurred (AccessDenied) when calling the ListBuckets operation: Access Denied
When I tried to use IAM Policy simulator, it indicates "Implicitly denied". Im thinking if I need to access a bucket policy for this user? My understanding has been if both IAM and Bucket policy, it is an intersection. If either is not present, the other takes precedence.
Calling list_buckets() uses the s3:ListAllMyBuckets permission.
This permission cannot be restricted to a specific bucket. A user can either list all of the buckets in the account, or none of them.
Calling operations on a bucket (ListBucket, GetBucket*) requires permission for the bucket itself.
Operations on objects requires permission for the objects (or /* after the bucket name to permit actions on all objects).
Therefore, you can change your policy to:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "s3:ListAllMyBuckets",
"Resource": "*"
},
{
"Effect": "Allow",
"Action": [
"s3:ListBucket",
"s3:GetBucket*"
],
"Resource": "arn:aws:s3:::my-test-bucket"
},
{
"Effect": "Allow",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my-test-bucket/*"
}
]
}
This is a pretty common issue because people tend to miss the difference between a "bucket" resource and an "object" resource. A bucket ends in the name of the bucket (arn:aws:s3:::my-test-bucket) whereas an object includes the bucket and key, and is often granted with a star after the initial slash. So, just change your policy to the following.
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"s3:ListAllMyBuckets"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::my-test-bucket"
]
},
{
"Action": [
"s3:GetObject",
"s3:GetBucket*",
"s3:ListBucket*"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::my-test-bucket/*"
]
}
]
}
Created an IAM user, with S3 full access (S3:*) on a specific ARN (only one bucket). Upload and delete works, but not able to rename or copy/paste.
Here is my IAM policy.
{
"Sid": "Stmt1490288788",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::bucket-name/*"
]
}
I don't know if this is the correct solution, but giving ListAllMyBuckets permission worked for me.
I just added another statement along with the previous one.
{
"Sid": "Stmt1490288788",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::bucket-name/*"
]
}{
"Sid": "Stmt1490289746001",
"Effect": "Allow",
"Action": [
"s3:ListAllMyBuckets"
],
"Resource": [
"arn:aws:s3:::*"
]
}
So this policy lists all the buckets, but only allow put/delete/get access to the specific bucket. Still wondering what's the relation between rename/copy & list all bucket permissions.
While there isn't actually rename functionality in S3 itself, some interfaces may try and implement it by using S3 PUT object copy and DELETE actions behind the scenes. Their implementation may require other bucket-level permissions to complete, which is why it may be failing with your policy. Try this:
{
"Sid": "Stmt1490288788",
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::bucket-name",
"arn:aws:s3:::bucket-name/*"
]
}
The difference being this grants permissions to actions performed on the bucket itself (the first resource declared), as well as the objects in the bucket (the second resource declared).
I have created a bucket name "A" with following permissions:
1. Grantee: B List Update/delete
2. Grantee: Everyone List view/download
From IOS(front-end), they are uploading a video to this Bucket.After uploaded only the 1st permission is applied, second is not, So we nobody can download that video from S3.
Please share your ideas. Thanks in advance.
I can't see any view/download option in the S3 Permissions pane.
As a general rule, AWS recommends using S3 bucket policies or IAM
policies for access control. S3 ACLs is a legacy access control
mechanism that predates IAM.
AWS Security Blog
If you wish to use a bucket policy instead, you can do the following:
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Stmt1420667647000",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": [
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::YOUR-BUCKET-NAME/*"
]
},
{
"Sid": "Stmt1420667680000",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::account-number-without-hyphens:user/username"
},
"Action": [
"s3:DeleteObject",
"s3:PutObject"
],
"Resource": [
"arn:aws:s3:::YOUR-BUCKET-NAME/*"
]
}
]
}
I have an application that uploads videos to an S3 bucket, and then creates a custom policy to allow another user (for the Zencoder service) to grab the files, and upload the transcoded files back into the bucket.
Below is the current custom policy I give to the user during transcoding. Basically I give full read permission to the entire bucket, but I only allow the user to PUT files into a specific nested folder.
{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowUserToListContentsOfBucket",
"Effect": "Allow",
"Action": [
"s3:ListBucket",
"s3:ListBucketMultipartUploads",
"s3:GetBucketLocation"
],
"Resource": [
"arn:aws:s3:::MY-BUCKET"
]
},
{
"Sid": "AllowUserToListContentsOfBucketFolders",
"Effect": "Allow",
"Action": [
"s3:ListBucketMultipartUploads",
"s3:GetObjectAcl",
"s3:GetObject"
],
"Resource": [
"arn:aws:s3:::MY-BUCKET/*"
]
},
{
"Sid": "AllowUserS3ActionsOfSpecificFolder",
"Effect": "Allow",
"Action": [
"s3:PutObjectAcl",
"s3:PutObject"
],
"Resource": [
"arn:aws:s3:::MY-BUCKET/some/nested/folder/*"
]
}
]
}
This works for the most part, but in the ~1,000 files transferred over by Zencoder, there's usually one or two that fail with a 403 Forbidden error. I'm not sure why, since files were correctly transferred both before and after the error.
Is there any reason Amazon AWS S3 / IAM would send a 403 Access Denied when such a permission is provided?