How do I put object to amazon s3 using presigned url?

Pravin picture Pravin · Mar 4, 2016 · Viewed 22.9k times · Source

I am trying to use signed url to upload images to s3 bucket. Following is my bucket policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "",
            "Effect": "Allow",
            "Principal": {
                "AWS": [
                    "arn:aws:iam::12345678:user/myuser",
                    "arn:aws:iam::12345678:root"
                ]
            },
        "Action": [
                "s3:List*",
                "s3:Put*",
                "s3:Get*"
            ],
            "Resource": [
                "arn:aws:s3:::myBucket",
                "arn:aws:s3:::myBucket/*"
            ]
        }
    ]
}

I am generating the signed url from the server as follows:

var aws = require('aws-sdk');
aws.config = {
    accessKeyId: myAccessKeyId,
    secretAccessKey: mySecretAccessKey
};

var s3 = new aws.s3();
s3.getSignedUrl('putObject', {
    Bucket: 'myBucket',
    Expires: 60*60,
    key: 'myKey'
}, function (err, url) {
    console.log(url);
});

I get the url. But when I try to put an object I get the following error:

<Error>
    <Code>AccessDenied</Code>
    <Message>Access Denied</Message>
    <RequestId>FXXXXXXXXX</RequestId>
    <HostId>fXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</HostId>
</Error>

Update 1

Here is myuser's policy:

{
  "Version": "2012-10-17",
  "Statement": [
    {
        "Sid": "",
        "Effect": "Allow",
        "Principal": {
            "AWS": [
                "arn:aws:iam::2xxxxxxxxxxx:user/myuser",
                "arn:aws:iam::2xxxxxxxxxxx:root"
            ]
        },
        "Action": [
            "s3:*"
        ],
        "Resource": [
            "arn:aws:s3:::myBucket",
            "arn:aws:s3:::myBucket/*"
        ]
    }
  ]
}

Update 2 I can upload only when following option is set. I dont understand whats the use of bucket policy if only the manual selection of permission work.

Permission for everyone

Update 3

The following code works. Now the only problem is the signed url

 #!/bin/bash

 file="$1"

 bucket="mybucket"
 resource="/${bucket}/${file}"
 contentType="image/png"
 dateValue=`date -R`
 stringToSign="PUT\n\n${contentType}\n${dateValue}\n${resource}"
 s3Key="AKxxxxxxxxxxxxxxxxx"
 s3Secret="/Wuxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
 signature=`echo -en ${stringToSign} | openssl sha1 -hmac ${s3Secret}     -binary | base64`
 curl -X PUT -T "${file}" \
   -H "Host: ${bucket}.s3.amazonaws.com" \
   -H "Date: ${dateValue}" \
   -H "Content-Type: ${contentType}" \
   -H "Authorization: AWS ${s3Key}:${signature}" \
   https://${bucket}.s3.amazonaws.com/${file}

Answer

Volkan Paksoy picture Volkan Paksoy · Mar 10, 2016

I managed to succesfully upload a file by using your code.

Here are the steps I followed:

  1. Created a new bucket and a new IAM user

  2. Set IAM user's policy as below:

    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Sid": "Stmt1418647210000",
                "Effect": "Allow",
                "Action": [
                    "s3:Put*"
                ],
                "Resource": [
                    "arn:aws:s3:::myBucket/*"
                ]
            }
        ]
    }
    
  3. Did NOT create a bucket policy

  4. Used your code to generate the pre-signed URL:

    var aws = require('aws-sdk');
    aws.config = {
        accessKeyId: myAccessKeyId,
        secretAccessKey: mySecretAccessKey
    };
    
    var s3 = new aws.s3();
    s3.getSignedUrl('putObject', {
        Bucket: 'myBucket',
        Expires: 60*60,
        Key: 'myKey'
    }, function (err, url) {
        console.log(url);
    });
    
  5. Copied the URL on the screen and used curl to test the upload as below:

    curl.exe -k -X PUT -T "someFile" "https://myBucket.s3.amazonaws.com/myKey?AWSAccessKeyId=ACCESS_KEY_ID&Expires=1457632663&Signature=Dhgp40j84yfjBS5v5qSNE4Q6l6U%3D"
    

In my case it generally took 5-10 seconds for the policy changes to take effect so if it fails the first time make sure to keep sending it for a while.

Hope this helps.