Missing KMS-CMK S3 condition key: CreateBucket - security

Currently, the available IAM condition keys for the CreateBucket action are as follows:
s3:x-amz-grant-read-acp
s3:TlsVersion
s3:signatureAge
s3:locationconstraint
s3:x-amz-grant-full-control
s3:x-amz-grant-write
s3:x-amz-content-sha256
s3:x-amz-grant-write-acp
s3:x-amz-object-ownership
s3:x-amz-grant-read
s3:authType
s3:ResourceAccount
s3:x-amz-acl
s3:signatureversion
As far as I can tell, none of those do what I'm trying to do, which is enforcing a policy that denies the action of creating a bucket with the specified parameters below (i.e. user must select the KMS-CMK option):
Indeed, one has the option of doing a similar action when putting a new object in a bucket, but that' not what I'm attempting to do here. Do I need to just stick with regulating how objects are written to S3 instead of governing how an S3 bucket is initially configured in terms of KMS-CMK?

Related

Is DiffSuppressFunc or being more restrictive when saving to TF state is preferable in Terraform SDKv2?

context: I'm adding a new resource to TF Provider (using SDKv2) with roughly the following schema:
resource "player" "football" {
type = "FOOTBALL"
...
config = {
"dribbling" = "50"
"speed" = "90"
"position" = "GOALKEEPER"
}
}
that I represent as:
"config": {
Type: schema.TypeMap,
Elem: &schema.Schema{
Type: schema.TypeString,
},
Required: true,
ForceNew: true,
},
The important detail here for different palyer instances' types there'll be a different set of required attributes (dribbling, speed, position for football and height, can_dunk, arm_span for basketball) -- all players share the same API endpoint so I introduced just one resource to cover them all.
I'd like to support the ability of importing players and apparently READ response includes a bunch of fields that are optional on create (and I suspect most of the users won't have them in Terraform configuration file) which results in the fact that I've got a state difference when saving the whole config like:
d.Set("config", player.GetConfig()) # GetConfig includes a bunch of new attributes (optional on a create or even computed)
So I've got a question: which of the following 2 options is preferable:
Implement DiffSuppressFunc for a config attribute where I'll be ignoring these optional fields (the downside is I'll have an implicit drift between main.tf and TF state file).
Be more restrictive when writing configs to TF state file:
instead of
d.Set("config", player.GetConfig())
# filtered config will match config in main.tf
filteredConfig = ...
d.Set("config", filteredConfig)
In some other Terraform providers that deal with similar situations (where a particular argument has a mixture of configuration-provided and remote-system-provided nested values), the resource type implementation takes a compromise position of effectively exposing the same data in two different attributes, where one of them represents what the user configured and the other represents the full data returned by the remote system. For example, you might have config to be set in the configuration, and expanded_config representing the full set of elements the server decided.
There is a challenge with that approach in that you'll probably need a special rule in your Read function to somehow decide if a change you detect in the remote system constitutes "drift" relative to the configuration or if it's just an additional element added by the server.
From what you described it seems like the rule could be that any key that's present in config in the prior state (that is, the values visible to d.Get inside Read before you call d.Set) would have its value overwritten by what the server returned, but any keys that were not present before are ignored entirely. This would create the effect then that any key the author specified in the configuration is considered "managed by Terraform" while any other key is only read by Terraform and not directly managed.
If you adopt that strategy then it's worth keeping in mind what will happen in a situation where the user has changed the configuration to include a new key or to remove a previously-present key. The Read operation is in terms of the previous state rather than the configuration, so that function will see the keys that were present at the end of the last apply, not the keys currently present in the configuration. In particular this means that if an author adds a new key that the server was already tracking then it will appear in the subsequent plan as being added, even though it might technically be more appropriate to show it as an in-place update ~ or a no-op. This is an example of the compromises we sometimes need to make in order to adapt remote APIs to fit within Terraform's model of resource instances.

Get AWS SSM Parameters Tags without Get Parameter

I am trying to list of all Parameters along with all their tags, I am trying to do so without listing the value of the parameters.
My initial approach was to do a describe_parameters and then loop through the Key Names and then perform list_tags, while doing so I found out that the ARNs are needed to perform list_tags which are not returned in the describe parameters.
Is there a way to get the parameters along with their tags without actually getting the parameters?
You can do this with the resource groups tagging api IF THEY ARE ALREADY TAGGED. Here's a basic example below without pagination.
import boto3
profile = "your_profile_name"
region = "us-east-1"
session = boto3.session.Session(profile_name=profile, region_name=region)
client = session.client('resourcegroupstaggingapi')
response = client.get_resources(
ResourceTypeFilters=[
'ssm',
],
)
print(response)
If you're wanting to discover untagged parameters, this won't work. Better would be to setup config rules to highlight these issues without you having to manage searching for them.

Can't list bucket objects on Scaleway using boto3

I saw a few similar posts, but unfortunately none helped me.
I have an s3 bucket (on scaleway), and I'm trying to simply list all objects contained in that bucket, using boto3 s3 client as follow:
s3 = boto3.client('s3',
region_name=AWS_S3_REGION_NAME,
endpoint_url=AWS_S3_ENDPOINT_URL,
aws_access_key_id=AWS_ACCESS_KEY_ID,
aws_secret_access_key=AWS_SECRET_ACCESS_KEY
)
all_objects = s3.list_objects_v2(Bucket=AWS_STORAGE_BUCKET_NAME)
This simple piece of code responds with an error:
botocore.errorfactory.NoSuchKey: An error occurred (NoSuchKey) when calling the ListObjects operation: The specified key does not exist.
First, the error seems inapropriate to me since I'm not specifying any key to search. I also tried to pass a Prefix argument to this method to narrow down the search to a specific subdirectory, same error.
Second, I tried to achieve the same thing using boto3 Resource rather than Client, as follow:
session = boto3.Session(
region_name=AWS_S3_REGION_NAME,
aws_access_key_id=AWS_ACCESS_KEY_ID,
aws_secret_access_key=AWS_SECRET_ACCESS_KEY
)
resource = session.resource(
's3',
endpoint_url=AWS_S3_ENDPOINT_URL,
)
for bucket in resource.buckets.all():
print(bucket.name)
That code produces absolutely nothing. One weird thing that strikes me is that I don't pass the bucket_name anywhere here, which seems to be normal according to aws documentation
There's no chance that I misconfigured the client, since I'm able to use the put_object method perfectly with that same client. One strange though: when I want to put a file, I pass the whole path to put_object as Key (as I found it to be the way to go), but the object is inserted with the bucket name prepend to it. So let's say I call put_object(Key='/path/to/myfile.ext'), the object will end up to be /bucket-name/path/to/myfile.ext.
Is this strange behavior the key to my problem ? How can I investigate what's happening, or is there another way I could try to list bucket files ?
Thank you
EDIT: So, after logging the request that boto3 client is sending, I noticed that the bucket name is append to the url, so instead of requesting https://<bucket_name>.s3.<region>.<provider>/, it requests https://<bucket_name>.s3.<region>.<provider>/<bucket-name>/, which is leading to the NoSuchKey error.
I took a look into the botocore library, and I found this:
url = _urljoin(endpoint_url, r['url_path'], host_prefix)
in botocore.awsrequest line 252, where r['url_path'] contains /skichic-bucket?list-type=2. So from here, I should be able to easily patch the library core to make it work for me.
Plus, the Prefix argument is not working, whatever I pass into it I always receive the whole bucket content, but I guess I can easily patch this too.
Now it's not satisfying, since there's no issue related to this on github, I can't believe that the library contains such a bug that I'm the first one to encounter.
Does anyone can explain this whole mess ? >.<
For those who are facing the same issue, try changing your endpoint_url parameter in your boto3 client or resource instantiation from https://<bucket_name>.s3.<region>.<provider> to https://s3.<region>.<provider> ; i.e for Scaleway : https://s3.<region>.scw.cloud.
You can then set the Bucket parameter to select the bucket you want.
list_objects_v2(Bucket=<bucket_name>)
you can try this. you'll have to use your resource instead of my s3sr.
s3sr = resource('s3')
bucket = 'your-bucket'
prefix = 'your-prefix/' # if no prefix, pass ''
def get_keys_from_prefix(bucket, prefix):
'''gets list of keys for given bucket and prefix'''
keys_list = []
paginator = s3sr.meta.client.get_paginator('list_objects_v2')
# use Delimiter to limit search to that level of hierarchy
for page in paginator.paginate(Bucket=bucket, Prefix=prefix, Delimiter='/'):
keys = [content['Key'] for content in page.get('Contents')]
print('keys in page: ', len(keys))
keys_list.extend(keys)
return keys_list
keys_list = get_keys_from_prefix(bucket, prefix)
After looking more closely into things, I've found out that (a lot) of botocore services endpoints patterns starts with the bucket name. For example, here's the definition of the list_objects_v2 service:
"ListObjectsV2":{
"name":"ListObjectsV2",
"http":{
"method":"GET",
"requestUri":"/{Bucket}?list-type=2"
},
My guess is that in the standard implementation of AWS S3, there's a genericendpoint_url (which explains #jordanm comment) and the targeted bucket is reached through the endpoint.
Now, in the case of Scaleway, there's an endpoint_url for each bucket, with the bucket name contained in that url (e.g https://<bucket_name>.s3.<region>.<provider>), and any endpoint should directly starts with a bucket Key.
I made a fork of botocore where I rewrote every endpoint to remove the bucket name, if that can help someone in the future.
Thank's again to all contributors !

Lambda-Backed Custom Resource

I'm trying to create a custom resource in a CFT that will run a lambda function on creation of said template. I've looked at the AWS documentation for Lambda-Backed Custom Resources, but I'm still a bit confused on the topic as the documentation was not particularly verbose. I've included the JSON for my custom resource, and I'm just wondering if there's anything else I have to do in order to ensure that this resource will call on the function upon creating the template.
"LambdaRunner": {
"Type": "AWS::CloudFormation::CustomResource",
"Properties": {
"ServiceToken": {
"Fn::GetAtt": [
"DistroDBPop",
"Arn"
]
}
}
Note: The Lambda function it references takes a CSV from an S3 resource and uses the information to create and populate a DynamoDB table.
That looks sufficient as far as calling the function, assuming that the CloudFormation template contains a Lambda function called DistroDBPop.
If you look at Walkthrough: Looking Up Amazon Machine Image IDs - AWS CloudFormation, you'll see that several other elements are also needed:
The Lambda function
A Role for the Lambda function
A special callback in the Lambda function to indicate that it has completed
There's some good example Lambda code at: stelligent/cloudformation-custom-resources - GitHub
There is also a cfnresponse module that makes it easier to callback at the end of the Lambda function. See: cfn-response Module
Finally, make sure the Lambda function understands that it might be called at Create, Update and Delete of the stack, so it might need to 'ignore' certain events unless they are relevant.

Is it possible to filter AWS S3 objects based on certain metadata entry?

I am using Python 3.6 and boto3 library to work with some objects in s3 bucket. I have created some S3 objects with metadata entries. For example,
bucketName = 'Boto3'
objectKey = 'HelloBoto.txt'
metadataDic = {'MetadataCreator':"Ehxn"}
Now I am wondering if it is possible to filter and get only those objects which have a certain metadata entry, for example,
for obj in s3Resource.Bucket(bucketName).objects.filter(Metadata="Ehsan ul haq"):
print('{0}'.format(obj.key))
No. The list_objects() command does not accept a filter.
You would need to call head_object() to obtain the metadata for each individual object.
Alternatively, you could activate Amazon S3 Inventory - Amazon Simple Storage Service, which can provide a daily listing of all objects with metadata.

Resources