By trying to get s3 object(of account1) from ec2 instance(of account2), the Sts session creation is failed with error:
"User arn:aws:sts::99*804963:assumed-role/i-9B6331541002f46-us-west is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::85*****15:role/MyS3DataReadRole
To provide access to fetch s3 object:
I've created permission in account2 with GetObject access to the s3 object(arn).
I've provided trust relationship for the role, where Principal.AWS = arn:aws:sts::99*804963:role/i-9B6331541002f46-us-west
The only suspicious point here is "assumed-role" instead of "role" in the user instance arn. AFAIK The user arn is calculated automatically by AWS SDK automatically, but I can't understand why "assumed-" prefix is added before the "role". I.e. in error message is mentioned: "arn:aws:sts::99804963:assumed-role/i-9B6331541002f46-us-west"
but in trust relationship I've provided correct arn, i.e. "arn:aws:sts::99804963:role/i-9B6331541002f46-us-west"
You also have to create the assume role policy and attach it to the EC2 instance role (99*804963) so that EC2 instance role can have permissions to assume the role (85*****15:role) which has read permissions for the S3 object.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "sts:AssumeRole",
"Resource": "arn:aws:iam::85*****15:role/MyS3DataReadRole"
}
]
}
Please update the account id in the above policy with actual one.
Related
I am trying to upload an object to an S3 bucket using boto3 and a service account created by a user with readwrite permissions. The IAM policy for the user is:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:*"
],
"Resource": [
"arn:aws:s3:::*"
]
}
]
}
However, I am getting the following error:
boto3.exceptions.S3UploadFailedError: Failed to upload /tmp/tmpfnkhwptw/model/requirements.txt to ml-artifacts/1/02e5b8a81a834b6e83a3412745f4ff6a/artifacts/sklearn-model/requirements.txt: An error occurred (AccessDenied) when calling the PutObject operation: Access Denied.
I've verified that the user is trying to upload the object to the correct bucket and prefix, and that the user has the correct permissions to write in the bucket -- this comes from a MLFlow example for a simple model using a wine dataset (can provide the code if wanted, but there's nothing special about it).
I am using MinIO as the object storage and the endpoint URL. The code works correctly if I use admin credentials, but not with user service account credentials.
What could be causing this error and how can I resolve it?
I'm afraid I didn't give the whole information on my question. I thought service accounts were always necessary (I'm inexperienced) and didn't say that I was using the service account credentials.
The answer is as simple as using the user credentials and not the service account (created by said user) credentials.
Another thing I have learned is that the service account didn't work because, for some reason, my MinIO version didn't give the same privileges as the user who created it to the account. When I opted for giving specific access privileges to the service account and pasted the "readwrite" JSON config into it, it worked.
We have been trying to crack an issue with resource permissions related to S3 and Lambda.
We have a root account which inturn has -
Account A - Bucket owner
Account B - Used to upload (through CORS) and give access to S3 images
ROLE L - We have a lambda function which assigned this role with Full S3 access
The buckets have access policy like below -
{
"Version": "2012-10-17",
"Id": "Policyxxxxxxxxx",
"Statement": [
{
"Sid": "Stmt44444444444",
"Effect": "Deny",
"NotPrincipal": {
"AWS": [
"arn:aws:iam::xxxxxxxxxxxx:user/account-A",
"arn:aws:iam::xxxxxxxxxxxx:role/role-L"
]
},
"Action": [
"s3:*",
],
"Resource": [
"arn:aws:s3:::bucket",
"arn:aws:s3:::bucket/*"
]
}
]
}
The issue -
The lambda is able to access S3 resource only if object ACL is set to Public/read-only. But Lambda fails when the resource is set to 'private'.
Bucket policy just gives access to the bucket. Is there a way to give Role L read access to the resource?
Objects stored in Amazon S3 buckets are private by default. There is no need to use a Deny policy unless you wish to override another policy that grants access to the content.
I would recommend:
Remove your Deny policy
Create an IAM Role for your AWS Lambda function and grant permission to access the S3 bucket within that role.
Feel free to add a Bucket Policy for normal use as appropriate, but that should not impact your Lambda function's access that is granted via the Role.
I've been trying all possible options but with no results. My Bucket Policy works well with aws:Referer but it doesn't work at all with Source Ip as the condition.
My Server is hosted with EC2 and I am using the Public IP in this format xxx.xxx.xxx.xxx/32 (Public_Ip/32) as the Source Ip parameter.
Can anyone tell me what I am doing wrong?
Currently my Policy is the following
{
"Version": "2008-10-17",
"Id": "S3PolicyId1",
"Statement": [
{
"Sid": "IPDeny",
"Effect": "Deny",
"Principal": {
"AWS": "*"
},
"Action": "s3:*",
"Resource": "arn:aws:s3:::my_bucket/*",
"Condition": {
"NotIpAddress": {
"aws:SourceIp": "xx.xx.xxx.xxx/32"
}
}
}
]
}
I read all examples and case studies but it doesn't seem to allow access based on Source IP...
Thanks a lot!!!
While I won't disagree that policies are better than IP address wherever possible, the accepted answer didn't actually achieve the original question's goal. I needed to do this (I need access from a machine that wasn't EC2, and thus didn't have policies).
Here is a policy that only allows a certain (or multiple IPs) to access a bucket's object. This assumes that there is no other policy to allow access to the bucket (by default, buckets grant no public access).
This policy also does not allow listing. Only if you know if the full url to the object you need. If you need more permissions, just add them to the Action bit.
{
"Id": "Policy123456789",
"Statement": [
{
"Sid": "IPAllow",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:GetObject"
],
"Resource": "arn:aws:s3:::mybucket/*",
"Condition" : {
"IpAddress" : {
"aws:SourceIp": [
"xx.xx.xx.xx/32"
]
}
}
}
]
}
From the discussion on the comments on the question, it looks like your situation can be rephrased as follows:
How can I give an specific EC2 instance full access to an S3 bucket, and deny access from every other source?
Usually, the best approach is to create an IAM Role and launch your EC2 instance associated with that IAM Role. As I'm going to explain, it is usually much better to use IAM Roles to define your access policies than it is to specify source IP addresses.
IAM Roles
IAM, or Identity and Access Management, is a service that can be used to create users, groups and roles, manage access policies associated with those three kinds of entities, manage credentials, and more.
Once you have your IAM role created, you are able to launch an EC2 instance "within" that role. In simple terms, it means that the EC2 instance will inherit the access policy you associated with that role. Note that you cannot change the IAM Role associated with an instance after you launched the instance. You can, however, modify the Access Policy associated with an IAM Role whenever you want.
The IAM service is free, and you don't pay anything extra when you associate an EC2 instance with an IAM Role.
In your situation
In your situation, what you should do is create an IAM Role to use within EC2 and attach a policy that will give the permissions you need, i.e., that will "Allow" all the "s3:xxx" operations it will need to execute on that specific resource "arn:aws:s3:::my_bucket/*".
Then you launch a new instance with this role (on the current AWS Management Console, on the EC2 Launch Instance wizard, you do this on the 3rd step, right after choosing the Instance Type).
Temporary Credentials
When you associate an IAM Role with an EC2 instance, the instance is able to obtain a set of temporary AWS credentials (let's focus on the results and benefits, and not exactly on how this process works). If you are using the AWS CLI or any of the AWS SDKs, then you simply don't specify any credential at all and the CLI or SDK will figure out it has to look for those temporary credentials somewhere inside the instance.
This way, you don't have to hard code credentials, or inject the credentials into the instance somehow. The instance and the CLI or SDK will manage this for you. As an added benefit, you get increased security: the credentials are temporary and rotated automatically.
In your situation
If you are using the AWS CLI, you would simply run the commands without specifying any credentials. You'll be allowed to run the APIs that you specified in the IAM Role Access Policy. For example, you would be able to upload a file to that bucket:
aws s3 cp my_file.txt s3://my_bucket/
If you are using an SDK, say the Java SDK, you would be able to interact with S3 by creating the client objects without specifying any credentials:
AmazonS3 s3 = new AmazonS3Client(); // no credentials on the constructor!
s3.putObject("my_bucket", ........);
I hope this helps you solve your problem. If you have any further related questions, leave a comment and I will try to address them on this answer.
I recently setup an IAM role for accessing a bucket with the following policy:
{
"Statement": [
{
"Sid": "Stmt1359923112752",
"Action": [
"s3:*"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::<BUCKET_NAME>"
]
}
]
}
While I can list the contents of the bucket fine, when I call get_contents_to_filename on a particular key, I receive a boto.exception.S3ResponseError: S3ResponseError: 403 Forbidden exception.
Is there a role permission that I need to add to fetch keys from S3? I have checked the permissions on the individual key, and there appears to be nothing that explicitly forbids access to other users; there is only a single permission that grants the owner full permissions.
For completeness, I verified that removing the role policy above prevents access to the bucket completely thus it's not an issue with the policy being applied.
Thanks!
You have to give permission to the objects in the bucket, not just to the bucket. So your resource would have to be arn:aws:s3:::<bucketname>/*. That matches every object.
Unfortunately, that doesn't match the bucket itself. So you either need to give bucket related permissions to arn:aws:s3:::<bucketname> and object permissions to arn:aws:s3:::<bucketname>/*, or just give permissions to arn:aws:s3:::<bucketname>*. Though in that latter case, giving permissions to a bucket named fred would also give the same permissions to one named freddy.
I'm trying to create a new bucket policy in the Amazon S3 console and get the error
Invalid principal in policy - "AWS" : "my_username"
The username I'm using in principal is my default bucket grantee.
My policy
{
"Id": "Policy14343243265",
"Statement": [
{
"Sid": "SSdgfgf432432432435",
"Action": [
"s3:DeleteObject",
"s3:DeleteObjectVersion",
"s3:GetObject",
"s3:GetObjectVersion",
"s3:GetObjectVersionAcl",
"s3:PutObject",
"s3:PutObjectAcl",
"s3:PutObjectVersionAcl"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::my_bucket/*",
"Principal": {
"AWS": [
"my_username"
]
}
}
]
}
I don;t understand why I'm getting the error. What am I doing wrong?
As the error message says, your principal is incorrect. Check the S3 documentation on specifying Principals for how to fix it. As seen in the example policies, it needs to be something like arn:aws:iam::111122223333:root.
I was also getting the same error in the S3 Bucket policy generator. It turned out that one of the existing policies had a principal that had been deleted. The problem was not with the policy that was being added.
In this instance, to spot the policy that is bad you can look for a principal that does not have an account or a role in the ARN.
So, instead of looking like this:
"Principal": {
"AWS": "arn:aws:iam::123456789101:role/MyCoolRole"
}
It will look something like this:
"Principal": {
"AWS": "ABCDEFGHIJKLMNOP"
}
So instead of a proper ARN it will be an alphanumeric key like ABCDEFGHIJKLMNOP. In this case you will want to identify why the bad principal was there and most likely modify or delete it. Hopefully this will help someone as it was hard to track down for me and I didn't find any documentation to indicate this.
Better solution:
Create an IAM policy that gives access to the bucket
Assign it to a group
Put user into that group
Instead of saying "This bucket is allowed to be touched by this user", you can define "These are the people that can touch this".
It sounds silly right now, but wait till you add 42 more buckets and 60 users to the mix. Having a central spot to manage all resource access will save the day.
The value for Principal should be user arn which you can find in Summary section by clicking on your username in IAM.
It is because so that specific user can bind with the S3 Bucket Policy
In my case, it is arn:aws:iam::332490955950:user/sample ==> sample is the username
I was getting the same error message when I tried creating the bucket, bucket policy and principal (IAM user) inside the same CloudFormation stack. Although I could see that CF completed the IAM user creation before even starting the bucket policy creation, the stack deployment failed. Adding a DependsOn: MyIamUser to the BucketPolicy resource fixed it for me.
Why am I getting the error "Invalid principal in policy" when I try to update my Amazon S3 bucket policy?
Issue
I'm trying to add or edit the bucket policy of my Amazon Simple Storage Service (Amazon S3) bucket using the web console, awscli or terraform (etc). However, I'm getting the error message "Error: Invalid principal in policy." How can I fix this?
Resolution
You receive "Error: Invalid principal in policy" when the value of a Principal in your bucket policy is invalid. To fix this error, review the Principal elements in your bucket policy. Check that they're using one of these supported values:
The Amazon Resource Name (ARN) of an AWS Identity and Access Management (IAM) user or role --
Note: To find the ARN of an IAM user, run the [aws iam get-user][2] command. To find the ARN of an IAM role, run the [aws iam get-role][2] command or just go and check it from the IAM service in your account web console UI.
An AWS account ID
The string "*" to represent all users
Additionally, review the Principal elements in the policy and check that they're formatted correctly. If the Principal is one user, the element must be in this format:
"Principal": {
"AWS": "arn:aws:iam::AWS-account-ID:user/user-name1"
}
If the Principal is more than one user but not all users, the element must be in this format:
"Principal": {
"AWS": [
"arn:aws:iam::AWS-account-ID:user/user-name1",
"arn:aws:iam::AWS-account-ID:user/user-name2"
]
}
If the Principal is all users, the element must be in this format:
{
"Principal": "*"
}
If you find invalid Principal values, you must correct them so that you can save changes to your bucket policy.
Extra points!
AWS Policy Generator
Bucket Policy Examples
Ref-link: https://aws.amazon.com/premiumsupport/knowledge-center/s3-invalid-principal-in-policy-error/
I was facing the same issue when I've created a bash script to initiate my terraform s3 backend. After a few hours I've decided just to put sleep 5 after user creation and that made sense, you can notice it at the line 27 of my script
If you are getting the error Invalid principal in policy in S3 bucket policies, the following 3 steps are the way to resolve it.
1 Your bucket policy uses supported values for a Principal element
The Amazon Resource Name (ARN) of an IAM user or role
An AWS account ID
The string "*" to represent all users
2 The Principal value is formatted correctly
If the Principal is one user
"Principal": {
"AWS": "arn:aws:iam::111111111111:user/user-name1"
}
If the Principal is more than one user but not all users
"Principal": {
"AWS": [
"arn:aws:iam::111111111111:user/user-name1",
"arn:aws:iam::111111111111:user/user-name2"
]
}
If the Principal is all users
{
"Principal": "*"
}
3 The IAM user or role wasn't deleted
If your bucket policy uses IAM users or roles as Principals, then confirm that those IAM identities weren't deleted. When you edit and then try to save a bucket policy with a deleted IAM ARN, you get the "Invalid principal in policy" error.
Read more here.
FYI: If you are trying to give access to a bucket for a region that is not enabled it will give the same error.
From AWS Docs: If your S3 bucket is in an AWS Region that isn't enabled by default, confirm that the IAM principal's account has the AWS Region enabled. For more information, see Managing AWS Regions.
If you are trying to give Account_X_ID access to the my_bucket like below. You need to enable the region of my_bucket on Account_X_ID.
"Principal": {
"AWS": [
"arn:aws:iam::<Account_X_ID>:root"
]
}
"Resource": "arn:aws:s3:::my_bucket/*",
Hope this helps someone.