I am new to Amazon S3 and just created my first bucket. I need two important policies to be implemented on the bucket which are as follows:
First, policy for allowing only downloads from my own website (via HTTP referrer)
Secondly, I want to make all objects in the bucket public.
I have got two different codes of policies for my needs, but now I can't put them together to achieve the said goals. Please help me joining these too policies together so I achieve what I want.
For allowing referrer downloads:
{
"Version": "2012-10-17",
"Id": "http referer policy example",
"Statement": [
{
"Sid": "Allow get requests originated from www.example.com and example.com",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::bucket/*",
"Condition": {
"StringLike": {
"aws:Referer": [
"URL/*",
]
}
}
}
]
}
For making objects public:
{
"Sid": "...",
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::bucket/*",
"Principal": {
"AWS": [ "*" ]
}
}
Related
I have a bucket that has these prefixes:
1_user/
2_user/
10_user/
Users have access to all bucket by default, but I want to deny access to this specific bucket to all prefixes except those listed above (read/write), for which I tried something like this:
{
"Version": "2012-10-17",
"Id": "BlockReadWriteListAccessExceptUser",
"Statement": [
{
"Sid": "BlockReadWriteAccess",
"Effect": "Deny",
"Principal": "*",
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Resource": [
"arn:aws:s3:::mybucket",
"arn:aws:s3:::mybucket/*"
]
},
{
"Sid": "AllowReadWriteAccess",
"Effect": "Allow",
"Principal": "*",
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Resource": "arn:aws:s3:::mybucket/*_user"
}
]
}
I realized that for get and put, I cannot use conditions, so how can I achieve that?
Your bucket policy will not work because explicit deny always overrides the allows. I want to make this crystal clear. For example, say you want to add an object 999_user. The object ARN is arn:aws:s3:::mybucket/999_user, which matches the deny statement with sid "BlockReadWriteAccess". S3 will deny this request right away without even looking at the "AllowReadWriteAccess" statement.
How to achieve the behaviour you want? The policy element NotResource comes in handy in this case.
{
"Version": "2012-10-17",
"Id": "BlockReadWriteListAccessExceptUser",
"Statement": [
{
"Sid": "BlockReadWriteAccess",
"Effect": "Deny",
"Principal": "*",
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"NotResource": "arn:aws:s3:::mybucket/*_user*"
}
]
}
I know this question has been asked a few times and I have gone through a some documents and examples on this. But I am still not able to get it working.
I want to block access to my S3 bucket from one particular IP address and allow all others. I do not want to block instances belonging to an IAM role and hence I am using NotIpAddress Condition for this. Below is the policy I applied on my bucket:
{
"Version": "2012-10-17",
"Id": "Policy1486984747194",
"Statement": [
{
"Sid": "AllowAllExceptOneIP",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::my-test-bucket",
"Condition": {
"NotIpAddress": {
"aws:SourceIp": "52.38.90.46"
}
}
}
]
}
But this policy isn't working. I am able to upload files to my bucket from this machine, I am using s3-curl.pl to temporarily upload my files.
Can someone please help me find what is wrong here. Thanks.
To block all actions to an S3 bucket from a particular IP, policy needs to have separate deny effect statement for that IP, sample:
{
"Version": "2012-10-17",
"Id": "Policy1487062767078",
"Statement": [
{
"Sid": "AllowAll",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::my-test-bucket",
"arn:aws:s3:::my-test-bucket/*"
]
},
{
"Sid": "DenyIP",
"Effect": "Deny",
"Principal": "*",
"Action": "s3:*",
"Resource": [
"arn:aws:s3:::my-test-bucket",
"arn:aws:s3:::my-test-bucket/*"
],
"Condition": {
"IpAddress": {
"aws:SourceIp": "52.38.90.46"
}
}
}
]
}
Action and Resource can be changed based on what one needs to block.
Thanks a lot #SergeyKovalev for helping me with this solution.
I have a Amazon S3 bucket mybucket and only want to enable access to content in a specific nested folder (or in S3 terms, with a specific "prefix").
I tried the following S3 bucket policy but it doesn't work. After adding the condition I started getting access denied errors in the browser.
{
"Version": "2012-10-17",
"Id": "Policy for mybucket",
"Statement": [
{
"Sid": "Allow access to public content only from my.domain.com",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::mybucket/public/content/*",
"Condition": {
"StringLike": {
"aws:Referer": [
"http://my.domain.com/*"
]
}
}
}
]
}
What should the policy look like to achieve this?
You need to split the policy in to two statements. One to allow access to the folder (prefix), and one to deny access when the referer is not one of the white listed domains:
{
"Version": "2012-10-17",
"Id": "Policy for mybucket",
"Statement": [
{
"Sid": "Allow access to public content",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::mybucket/public/content/*"
},
{
"Sid": "Deny access to public content when not on my.domain.com",
"Effect": "Deny",
"Principal": "*",
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::mybucket/public/content/*",
"Condition": {
"StringNotLike": {
"aws:Referer": [
"http://my.domain.com/*"
]
}
}
}
]
}
Using AWS S3. I have a mixture of video and photo files. All of which are in their respective sub-directories. All files are set to private. I am getting AccessDenied when I try to access a video file. The other files are fine.
I tried this to no avail:
{
"Id": "Policy1331547131417",
"Statement": [
{
"Sid": "Stmt1331546963174",
"Action": [
"*"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::actual_bucket_name_here/uploads/users/*/videos/*",
"Principal": {
"AWS": [
"*"
]
}
},
{
"Sid": "Stmt1331547083926",
"Action": [
"*"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::actual_bucket_name_here/uploads/users/*/photos/*",
"Principal": {
"AWS": [
"*"
]
}
},
{
"Sid": "Stmt1331547130024",
"Action": [
"*"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::actual_bucket_name_here/uploads/users/*/banners/*",
"Principal": {
"AWS": [
"*"
]
}
}
]
}
My bucket policy is the same for videos, photos, and banners. ACL permissions are also the same for all files. So why am I not able to access files from my videos directory?
How do you actually try to access your video files, i.e. by means of which tool, service, API?
The access method in use might actually require permission for the s3:ListBucket action as well, e.g. a JavaScript video player widget might implicitly look for various file formats of the video in question to present a respective selection to your user - you'll need to be aware of the difference between Operations on Buckets (e.g. ListBucket) and Operations on Objects (e.g. GetObject), see my answer to Problems specifying a single bucket in a simple AWS user policy for more details on this.
Extending your video bucket policy accordingly might remedy this issue, e.g. (policy fragment only):
{
"Statement": [
{
"Action": [
"s3:ListBucket"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::actual_bucket_name_here/uploads/users/*/videos",
"Principal": {
"AWS": [
"*"
]
}
}
]
}
Please note that this policy fragment addresses the bucket, where yours only addresses the objects therein and both fragments are required - as mentioned above, this subtle difference is explained in my answer to Problems specifying a single bucket in a simple AWS user policy.
In addition to Steffen Opel answer.
Below is what worked for me.
{
"Statement": [
{
"Action": [
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::BUCKET_NAME/*",
"Principal": {
"AWS": [
"*"
]
}
}
]
}
I have the following bucket policy set on my bucket:
{
"Version": "2008-10-17",
"Id": "My access policy",
"Statement": [
{
"Sid": "Allow only requests from our site",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my_bucket/*",
"Condition": {
"StringLike": {
"aws:Referer": [
" http://example.com/*",
" http://www.example.com/*"
]
}
}
},
{
"Sid": "Dont allow direct acces to files when no referer is present",
"Effect": "Deny",
"Principal": {
"AWS": "*"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::my_bucket/*",
"Condition": {
"Null": {
"aws:Referer": true
}
}
}
]
}
I also configured query string authentication, but it looks like I can't have both. If I have my bucket policies set to deny any request that doesn't originate from example.com, my temporary url using query string authentication will also not get served. So my question is, how can i have both ? Is there a way to check for url parameters and see if it has a parameter called "Signature" and in that case not apply the referer policy?
Remove the space in the referrers string " http://example.com/*" that's wrong... the Amazon examples made that mistake too (using "mydomain" instead of "example").
For the second statement the easier way to solve it is to remove that entire statement and have your files permissions (ACLs) set to private (Owner-Read/Write and World-NoRead/NoWrite)
I am not sure, but in appears that even if you have a Deny Statement a file can still be read if it has a public permission (World Read).
Also, if you are distributing the files on CloudFront remember to allow it to read the bucket too. So a complete bucket policy will look like:
{
"Version": "2008-10-17",
"Id": "YourNetwork",
"Statement": [
{
"Sid": "Allow get requests to specific referrers",
"Effect": "Allow",
"Principal": {
"AWS": "*"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::yourbucket/*",
"Condition": {
"StringLike": {
"aws:Referer": [
"http://www.yourwebsite.com/*",
"http://yourwebsite.com/*"
]
}
}
},
{
"Sid": "Allow CloudFront get requests",
"Effect": "Allow",
"Principal": {
"AWS": "arn:aws:iam::12345678:root"
},
"Action": "s3:GetObject",
"Resource": "arn:aws:s3:::yourbucket/*"
}
]
}
(change the 12345678 to your AWS account ID number without the dashes)