You have given permission to perform commands on objects inside the S3 bucket, but you have not given permission to perform any actions on the bucket itself.

Slightly modifying your policy would look like this:

{
  "Version": "version_id",
  "Statement": [
    {
        "Sid": "some_id",
        "Effect": "Allow",
        "Action": [
            "s3:*"
        ],
        "Resource": [
            "arn:aws:s3:::bucketname",
            "arn:aws:s3:::bucketname/*"
        ]
    }
  ] 
}

However, that probably gives more permission than is needed. Following the AWS IAM best practice of Granting Least Privilege would look something like this:

{
  "Version": "2012-10-17",
  "Statement": [
      {
          "Effect": "Allow",
          "Action": [
              "s3:ListBucket"
          ],
          "Resource": [
              "arn:aws:s3:::bucketname"
          ]
      },
      {
          "Effect": "Allow",
          "Action": [
              "s3:GetObject"
          ],
          "Resource": [
              "arn:aws:s3:::bucketname/*"
          ]
      }
  ]
}

I was unable to access to S3 because

• first I configured key access on the instance (it was impossible to attach role after the launch then)
• forgot about it for a few months
• attached role to instance
• tried to access. The configured key had higher priority than role, and access was denied because the user wasn't granted with necessary S3 permissions.

Solution: rm -rf .aws/credentials, then aws uses role.

You have to specify Resource for the bucket via "arn:aws:s3:::bucketname" or "arn:aws:3:::bucketname*". The latter is preferred since it allows manipulations on the bucket's objects too. Notice there is no slash!

Listing objects is an operation on Bucket. Therefore, action "s3:ListBucket" is required. Adding an object to the Bucket is an operation on Object. Therefore, action "s3:PutObject" is needed. Certainly, you may want to add other actions as you require.

{
"Version": "version_id",
"Statement": [
    {
        "Sid": "some_id",
        "Effect": "Allow",
        "Action": [
            "s3:ListBucket",
            "s3:PutObject"
        ],
        "Resource": [
            "arn:aws:s3:::bucketname*"
        ]
    }
] 
}

If you wanted to copy all s3 bucket objects using the command "aws s3 cp s3://bucket-name/data/all-data/ . --recursive" as you mentioned, here is a safe and minimal policy to do that:

{
  "Version": "2012-10-17",
  "Statement": [
      {
          "Effect": "Allow",
          "Action": [
              "s3:ListBucket"
          ],
          "Resource": [
              "arn:aws:s3:::bucket-name"
          ],
          "Condition": {
              "StringLike": {
                  "s3:prefix": "data/all-data/*"
              }
          }
      },
      {
          "Effect": "Allow",
          "Action": [
              "s3:GetObject"
          ],
          "Resource": [
              "arn:aws:s3:::bucket-name/data/all-data/*"
          ]
      }
  ]
}

The first statement in this policy allows for listing objects inside a specific bucket's sub directory. The resource needs to be the arn of the S3 bucket, and to limit listing to only a sub-directory in that bucket you can edit the "s3:prefix" value.

The second statement in this policy allows for getting objects inside of the bucket at a specific sub-directory. This means that anything inside the "s3://bucket-name/data/all-data/" path you will be able to copy. Be aware that this doesn't allow you to copy from parent paths such as "s3://bucket-name/data/".

This solution is specific to limiting use for AWS CLI commands; if you need to limit S3 access through the AWS console or API, then more policies will be needed. I suggest taking a look here: https://aws.amazon.com/blogs/security/writing-iam-policies-grant-access-to-user-specific-folders-in-an-amazon-s3-bucket/.

A similar issue to this can be found here which led me to the solution I am giving. https://github.com/aws/aws-cli/issues/2408

Hope this helps!

I got the same error when using policy as below, although i have "s3:ListBucket" for s3:ListObjects operation.

{
"Version": "2012-10-17",
"Statement": [
    {
        "Action": [
            "s3:ListBucket",
            "s3:GetObject",
            "s3:GetObjectAcl"
        ],
        "Resource": [
            "arn:aws:s3:::<bucketname>/*",
            "arn:aws:s3:::*-bucket/*"
        ],
        "Effect": "Allow"
    }
  ]
 }

Then i fixed it by adding one line "arn:aws:s3:::bucketname"

{
"Version": "2012-10-17",
"Statement": [
    {
        "Action": [
            "s3:ListBucket",
            "s3:GetObject",
            "s3:GetObjectAcl"
        ],
        "Resource": [
             "arn:aws:s3:::<bucketname>",
            "arn:aws:s3:::<bucketname>/*",
            "arn:aws:s3:::*-bucket/*"
        ],
        "Effect": "Allow"
    }
 ]
}

I faced with the same issue. I just added credentials config:

aws_access_key_id = your_aws_access_key_id
aws_secret_access_key = your_aws_secret_access_key

into "~/.aws/credentials" + restart terminal for default profile.

In the case of multi profiles --profile arg needs to be added:

aws s3 sync ./localDir s3://bucketName --profile=${PROFILE_NAME}

where PROFILE_NAME:

.bash_profile ( or .bashrc) -> export PROFILE_NAME="yourProfileName"

More info about how to config credentials and multi profiles can be found here

I was thinking the error is due to "s3:ListObjects" action but I had to add the action "s3:ListBucket" to solve the issue "AccessDenied for ListObjects for S3 bucket"

I like this better than any of the previous answers. It shows how to use the YAML format and lets you use a variable to specify the bucket.

    - PolicyName: "AllowIncomingBucket"
      PolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Action: "s3:*"
            Resource:
              - !Ref S3BucketArn
              - !Join ["/", [!Ref S3BucketArn, '*']]

I'm adding an answer with the same direction as the accepted answer but with small (important) differences and adding more details.

Consider the configuration below:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["s3:ListBucket"],
      "Resource": ["arn:aws:s3:::<Bucket-Name>"]
    },
    {
      "Effect": "Allow",
      "Action": [
        "s3:PutObject",
        "s3:DeleteObject"
      ],
      "Resource": ["arn:aws:s3:::<Bucket-Name>/*"]
    }
  ]
}

The policy grants programmatic write-delete access and is separated into two parts:
The ListBucket action provides permissions on the bucket level and the other PutObject/DeleteObject actions require permissions on the objects inside the bucket.

The first Resource element specifies arn:aws:s3:::<Bucket-Name> for the ListBucket action so that applications can list all objects in the bucket.

The second Resource element specifies arn:aws:s3:::<Bucket-Name>/* for the PutObject, and DeletObject actions so that applications can write or delete any objects in the bucket.

The separation into two different 'arns' is important from security reasons in order to specify bucket-level and object-level fine grained permissions.

Notice that if I would have specified just GetObject in the 2nd block what would happen is that in cases of programmatic access I would receive an error like:

Upload failed: <file-name> to <bucket-name>:<path-in-bucket> An error occurred (AccessDenied) when calling the PutObject operation: Access Denied.

To allow permissions in s3 bucket go to the permissions tab in s3 bucket and in bucket policy change the action to this which will allow all actions to be performed:

"Action":"*"

I had this issue my requirement i wanted to allow user to write to specific path

{
            "Sid": "raspiiotallowspecificBucket",
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:PutObject",
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::<bucketname>/scripts",
                "arn:aws:s3:::<bucketname>/scripts/*"
            ]
        },

and problem was solved with this change

{
            "Sid": "raspiiotallowspecificBucket",
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:PutObject",
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::<bucketname>",
                "arn:aws:s3:::<bucketname>/*"
            ]
        },

Ran into a similar issues, for me the problem was that I had different AWS keys set in my bash_profile.

I answered a similar question here: https://stackoverflow.com/a/57317494/11871462

If you have conflicting AWS keys in your bash_profile, AWS CLI defaults to these instead.

I tried the following:

aws s3 ls s3.console.aws.amazon.com/s3/buckets/{bucket name}

This gave me the error:

An error occurred (AccessDenied) when calling the ListObjectsV2 operation: Access Denied

Using this form worked:

aws s3 ls {bucket name}

Okay for those who have done all the above and still getting this issue, try this:

Bucket Policy should look like this:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowBucketSync",
            "Effect": "Allow",
            "Principal": "*",
            "Action": [
                "s3:PutObject",
                "s3:GetObject",
                "s3:PutObjectAcl",
                "s3:DeleteObject",
                "s3:ListBucket"
            ],
            "Resource": [
                "arn:aws:s3:::BUCKET_NAME",
                "arn:aws:s3:::BUCKET_NAME/*"
            ]
        }
    ]
}

Then save and ensure your Instance or Lightsail is connected to the right profile on AWS Configure.

First: try adding --recursive at the end, any luck? No okay try the one below.

Second: Okay now try this instead: --no-sign-request

so it should look like this:

sudo aws s3 sync s3://BUCKET_NAME /yourpath/path/folder --no-sign-request

You're welcome 😂

I had a similar problem while trying to sync an entire s3 bucket locally. For me MFA (Multi-factor authentication) was enforced on my account, which is required while making commands via AWS CLI.

So the solution for me was - provide mfa credentials using a profile (mfa documentation) while using any AWS CLI commands.

I had the same issue. I had to provide the right resource and action, resource is your bucket's arn and action in your desired permission. Also please ensure you have your right user arn. Below is my solution.

{
    "Version": "2012-10-17",
    "Id": "Policy1546414123454",
    "Statement": [
        {
            "Sid": "Stmt1546414471931",
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::123456789101:root"
            },
            "Action": ["s3:ListBucket", "s3:ListBucketVersions"],
            "Resource": "arn:aws:s3:::bucket-name"
        }
    ]
}

Here's the policy that worked for me.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": "*",
      "Action": [
        "s3:ListBucket"
      ],
      "Resource": [
        "arn:aws:s3:::bucket-name"
      ]
    },
    {
      "Effect": "Allow",
      "Principal": "*",
      "Action": [
        "s3:GetObject"
      ],
      "Resource": [
        "arn:aws:s3:::bucket-name/*"
      ]
    }
  ]
}

My issue was having set

env: 
  AWS_ACCESS_KEY_ID: {{ secrets.AWS_ACCESS_KEY_ID }} 
  AWS_SECRET_ACCESS_KEY: {{ secrets.AWS_SECRET_ACCESS_KEY }}

again, under the aws-sync GitHub Action as environment variables. They were coming from my GitHub settings. Though in my case I had assumed a role in the previous step which would set me some new keys into those same name environment variables. So i was overwriting the good assumed keys with the bad GitHub basic keys.

Please take care of this if you're assuming roles.