Common examples of RAM policies - Object Storage Service

You can configure Resource Access Management (RAM) policies to manage the permissions of users, such as employees, systems, or applications, and the resources that can be accessed by the users. For example, you can create a RAM policy to authorize users to list and read the objects that are stored in a specific bucket.

Attach a custom policy to a RAM user

Create a custom policy.
You can refer to the examples described in this topic based on the actual scenarios and create a custom policy by using scripts. For more information, see Create custom policies.
A RAM policy contains a version number and a statement. Each statement contains the following elements: Effect, Action, Resource, and Condition. The Condition element is optional. For more information, see RAM policies.
Important
In Object Storage Service (OSS), you can set the Resource element to an asterisk (*) wildcard character to specify resources of a specific type. The value of the Resource element is in the following format: acs:oss:{region}:{bucket_owner}:{bucket_name}/{object_name}. For example, if the Resource element is set to acs:oss:*:*:mybucket/*, all resources in the mybucket bucket are specified. If the Resource element is set to acs:oss:*:*:mybucket/abc*.txt, all .txt objects whose names contain the abc prefix in the mybucket bucket are specified.
Attach the custom policy to a RAM user.
Attach the RAM policy that is created in Step 1 to the RAM user. For more information, see Grant permissions to a RAM user.

Example 1: Authorize a RAM user to fully control a bucket

The following RAM policy grants a RAM user full control over the mybucket bucket.

Warning

To ensure data security, we recommend that you do not grant RAM users full control over a bucket used by mobile apps.

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "oss:*",
            "Resource": [
                "acs:oss:*:*:mybucket",
                "acs:oss:*:*:mybucket/*"
            ]
        }
    ]
}

Example 2: Prohibit a RAM user from deleting multiple objects in a bucket

The following RAM policy prohibits a RAM user from deleting all .txt objects whose names contain the abc prefix in the mybucket bucket:

{
  "Version": "1",
  "Statement": [
        {
         "Effect": "Deny",
         "Action": [
           "oss:DeleteObject"
         ],
         "Resource": [
           "acs:oss:*:*:mybucket/abc*.txt"
         ]
     }
   ]
}

Example 3: Authorize a RAM user to list and read objects in a bucket

Authorize a RAM user to list and read objects in a bucket by using OSS SDKs or ossutil

The following RAM policy authorizes a RAM user to list and read all objects in the mybucket bucket by using OSS SDKs or ossutil:

Note

The Resource element for the ListObjects action must specify all resources in the desired bucket.

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "oss:ListObjects",
            "Resource": "acs:oss:*:*:mybucket"
        },
        {
            "Effect": "Allow",
            "Action": "oss:GetObject",
            "Resource": "acs:oss:*:*:mybucket/*"
        }
    ]
}

Authorize a RAM user to list and read objects in a bucket by using the OSS console

The following RAM policy authorizes a RAM user to list and read all objects in the mybucket bucket by using the OSS console:

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                      "oss:ListBuckets",
                      "oss:GetBucketStat",
                      "oss:GetBucketInfo",
                      "oss:GetBucketTagging",
                      "oss:GetBucketLifecycle",
                      "oss:GetBucketWorm",                      
                      "oss:GetBucketVersioning", 
                      "oss:GetBucketAcl" 
                      ],    
            "Resource": "acs:oss:*:*:*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:ListObjects",
                "oss:GetBucketAcl"
            ],
            "Resource": "acs:oss:*:*:mybucket"
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:GetObject",
                "oss:GetObjectAcl"
            ],
            "Resource": "acs:oss:*:*:mybucket/*"
        }
    ]
}

Example 4: Prohibit a RAM user from deleting a bucket

The following RAM policy prohibits a RAM user from deleting the mybucket bucket:

{
  "Version": "1",
  "Statement": [
      {
          "Effect": "Allow",
          "Action": "oss:*",
          "Resource": [
              "acs:oss:*:*:mybucket",
              "acs:oss:*:*:mybucket/*"
          ]
      },
        {
         "Effect": "Deny",
         "Action": [
           "oss:DeleteBucket"
         ],
         "Resource": [
           "acs:oss:*:*:mybucket"
         ]
     }
   ]
}

Example 5: Authorize a RAM user to access multiple directories in a bucket

In this example, a bucket named mybucket is used to store photos. The bucket contains multiple directories that are named based on the locations where the photos were captured. Each directory contains subdirectories that are named based on the years when the photos were captured.

mybucket[Bucket]
  ├── beijing
  │   ├── 2014
  │   └── 2015
  ├── hangzhou
  │   ├── 2013
  │   ├── 2014
  │   └── 2015 
  └── qingdao
      ├── 2014
      └── 2015

For example, you want to grant a RAM user read-only permissions on the mybucket/hangzhou/2014/ and mybucket/hangzhou/2015/ directories. Directory-level authorization is an advanced feature of RAM policies and requires RAM policies at different complexity levels based on actual scenarios. The following RAM policies are suitable for different scenarios and are provided for reference only.

Grant a RAM user read-only permissions on objects in the mybucket/hangzhou/2014/ and mybucket/hangzhou/2015/ directories
In this scenario, the RAM user knows the full paths of the objects that can be accessed. We recommend that you configure the RAM policy to authorize the RAM user to access the objects by using the full paths of the objects.
```
{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "oss:GetObject"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket/hangzhou/2014/*",
                "acs:oss:*:*:mybucket/hangzhou/2015/*"
            ]
        }
    ]
}
```

Grant a RAM user the permissions to access the mybucket/hangzhou/2014/ and mybucket/hangzhou/2015/ directories and list the objects in the directories by using ossutil

In this scenario, the RAM user does not know the objects in the directories and can use ossutil or call API operations to obtain information about the objects in the directories. In this case, the ListObjects permission must be specified in the policy.

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "oss:GetObject"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket/hangzhou/2014/*",
                "acs:oss:*:*:mybucket/hangzhou/2015/*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:ListObjects"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket"
            ],
            "Condition":{
                "StringLike":{
                    "oss:Prefix": [
                        "hangzhou/2014/*",
                        "hangzhou/2015/*"
                     ]
                }
            }
        }
    ]
}

Grant a RAM user the permissions to access directories by using the OSS console

In this scenario, the RAM user can use the OSS console to access the mybucket/hangzhou/2014/ and mybucket/hangzhou/2015/ directories from the root directory by level.

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                      "oss:ListBuckets",
                      "oss:GetBucketStat",
                      "oss:GetBucketInfo",
                      "oss:GetBucketTagging",
                      "oss:GetBucketLifecycle",
                      "oss:GetBucketWorm",                      
                      "oss:GetBucketVersioning", 
                      "oss:GetBucketAcl" 
                      ], 
            "Resource": [
                "acs:oss:*:*:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:GetObject",
                "oss:GetObjectAcl"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket/hangzhou/2014/*",
                "acs:oss:*:*:mybucket/hangzhou/2015/*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:ListObjects"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket"
            ],
            "Condition": {
                "StringLike": {
                    "oss:Delimiter": "/",
                    "oss:Prefix": [
                        "",
                        "hangzhou/",
                        "hangzhou/2014/*",
                        "hangzhou/2015/*"
                    ]
                }
            }
        }
    ]
}

Example 6: Prohibit a RAM user from deleting an object from a bucket

The following RAM policy prohibits a RAM user from deleting an object from the mybucket bucket:

{
  "Version": "1",
  "Statement": [
        {
         "Effect": "Deny",
         "Action": [
           "oss:DeleteObject"
         ],
         "Resource": [
           "acs:oss:*:*:mybucket/*"
         ]
     }
   ]
}

Example 7: Prohibit a RAM user from accessing objects that have specific tags

The following RAM policy contains a Deny statement that prohibits a RAM user from accessing objects that are stored in the examplebucket bucket and have the status:ok and key1:value1 tags:

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Deny",
            "Action": [
                "oss:GetObject"
            ],
            "Resource": [
                "acs:oss:*:174649585760xxxx:examplebucket/*"
            ],
            "Condition": {
                "StringEquals": {
                    "oss:ExistingObjectTag/status":"ok",
                    "oss:ExistingObjectTag/key1":"value1"
                }
            }
        }
    ]
}

Example 8: Authorize a RAM user to access OSS from specific IP addresses

Allow access from specific IP addresses

The following RAM policy authorizes a RAM user to read all objects in the mybucket bucket from only IP addresses in the 192.168.0.0/16 and 198.51.100.0/24 CIDR blocks that are specified in the Allow statement:

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                      "oss:ListBuckets",
                      "oss:GetBucketStat",
                      "oss:GetBucketInfo",
                      "oss:GetBucketTagging",
                      "oss:GetBucketAcl" 
                      ], 
            "Resource": [
                "acs:oss:*:*:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:ListObjects",
                "oss:GetObject"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket",
                "acs:oss:*:*:mybucket/*"
            ],
            "Condition":{
                "IpAddress": {
                    "acs:SourceIp": ["192.168.0.0/16", "198.51.100.0/24"]
                }
            }
        }
    ]
}

Deny access from specific IP addresses

The following RAM policy prohibits a RAM user from accessing OSS resources from IP addresses that are not in the 192.168.0.0/16 CIDR block that is specified in the Deny statement:

{
    "Version": "1",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                      "oss:ListBuckets",
                      "oss:GetBucketStat",
                      "oss:GetBucketInfo",
                      "oss:GetBucketTagging",
                      "oss:GetBucketAcl" 
                      ], 
            "Resource": [
                "acs:oss:*:*:*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "oss:ListObjects",
                "oss:GetObject"
            ],
            "Resource": [
                "acs:oss:*:*:mybucket",
                "acs:oss:*:*:mybucket/*"
            ]
        },
        {
            "Effect": "Deny",
            "Action": "oss:*",
            "Resource": [
                "acs:oss:*:*:*"
            ],
            "Condition":{
                "NotIpAddress": {
                    "acs:SourceIp": ["192.168.0.0/16"]
                }
            }
        }
    ]
}

Note

In a RAM policy, a Deny statement takes precedence over an Allow statement. Therefore, when a RAM user attempts to read data in the mybucket bucket from an IP address that is not in the 192.168.0.0/16 CIDR block, an error message is returned, which indicates that the RAM user does not have the required permissions.

Example 9: Use RAM or STS to authorize users to access OSS resources

Use RAM or Security Token Service (STS) to authorize a user whose IP address is 192.168.0.1 to perform the following operations from the client of OSS SDK for Java:

List objects whose names contain the foo prefix in the examplebucket bucket
Grant the user the permissions to perform the upload, download, and delete operations on objects whose names contain the file prefix in the examplebucket bucket

The following RAM policy can meet the preceding access management requirements:

{
    "Version": "1",
    "Statement": [
        {
            "Action": [
                "oss:GetBucketAcl",
                "oss:ListObjects"
            ],
            "Resource": [
                "acs:oss:*:177530505652xxxx:mybucket"
            ],
            "Effect": "Allow",
            "Condition": {
                "StringEquals": {
                    "acs:UserAgent": "java-sdk",
                    "oss:Prefix": "foo"
                },
                "IpAddress": {
                    "acs:SourceIp": "192.168.0.1"
                }
            }
        },
        {
            "Action": [
                "oss:PutObject",
                "oss:GetObject",
                "oss:DeleteObject"
            ],
            "Resource": [
                "acs:oss:*:177530505652xxxx:mybucket/file*"
            ],
            "Effect": "Allow",
            "Condition": {
               "StringEquals": {
                    "acs:UserAgent": "java-sdk"
                },
                "IpAddress": {
                    "acs:SourceIp": "192.168.0.1"
                }
            }
        }
    ]
}

Example 10: Use RAM policies to deny uploads of objects whose ACL is public-read or public-read-write

The following RAM policy prohibits users from uploading objects whose access control list (ACL) is public-read or public-read-write to the examplebucket bucket:

{
  "Version": "1",
  "Statement": [
    {
      "Effect": "Deny",
      "Action": [
       "oss:PutObject",
       "oss:PutObjectAcl"
       ],
      "Resource": [
        "acs:oss:*:*:examplebucket",
        "acs:oss:*:*:examplebucket/*"
      ],
      "Condition": {
        "StringEquals": {
          "oss:x-oss-object-acl": [
            "public-read",
            "public-read-write"
          ]
        }
      }
    }
  ]
}

Example 11: Authorize a RAM user to use IMM

The following RAM policy grants a RAM user the permissions to use Intelligent Media Management (IMM):

{
  "Version": "1",
  "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "oss:GetObject",
                "oss:PutObject",
                "oss:PostProcessTask",
                "oss:ProcessImm"
            ],
            "Resource": "*"
        },
        {
            "Action": [
                "imm:CreateOfficeConversionTask",
                "imm:GetWebofficeURL"
            ],
            "Resource": "*",
            "Effect": "Allow"
        },
        {
            "Effect": "Allow",
            "Action": "ram:PassRole",
            "Resource": "acs:ram:*:*:role/aliyunimmdefaultrole"
        }
   ]
}

Example 12: Authorize a RAM user to change the storage redundancy type of buckets

Grant a RAM user the permissions to change the storage redundancy type of a bucket

The following RAM policy grants a RAM user the permissions to change the storage redundancy type of the mybucket bucket:

{
  "Version": "1",
  "Statement": [
        {
         "Effect": "Allow",
         "Action": [
           "oss:CreateBucketDataRedundancyTransition",
           "oss:GetBucketDataRedundancyTransition",
           "oss:ListBucketDataRedundancyTransition",
           "oss:DeleteBucketDataRedundancyTransition"
         ],
         "Resource": "acs:oss:*:*:mybucket"
     }
   ]
}

Grant a RAM user the permissions to change the storage redundancy type of all buckets

Important

The following RAM policy grants a RAM user the permissions to change the storage redundancy type of all buckets in the Alibaba Cloud account. Exercise caution when you grant the permissions to a RAM user.

{
  "Version": "1",
  "Statement": [
        {
         "Effect": "Allow",
         "Action": [
           "oss:CreateBucketDataRedundancyTransition",
           "oss:GetBucketDataRedundancyTransition",
           "oss:ListBucketDataRedundancyTransition",
           "oss:DeleteBucketDataRedundancyTransition"
         ],
         "Resource": "acs:oss:*:*:*"
     }
   ]
}

Example 13: Authorize a RAM user to place an order for an OSS resource plan

The following RAM policy grants a RAM user the permissions to place an order for an OSS resource plan:

Warning

After a RAM user places an order for an OSS resource plan, the user needs to contact the owner of the Alibaba Cloud account to which the RAM user belongs to pay for the order. To authorize a RAM user to pay for an order, the owner of the Alibaba Cloud account needs to grant the bss:PayOrder permission to the RAM user. bss:PayOrder is a high-risk permission. We recommend that you do not grant the permission to a RAM user unless necessary.

{
  "Version": "1",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "oss:CreateOrder",
      "Resource": "acs:oss:*:*:*"
    }
  ]
}

Example 14: Authorize a RAM user to activate OSS

The following RAM policy grants a RAM user the permissions to activate OSS:

{
  "Version": "1",
  "Statement": [
        {
         "Effect": "Allow",
         "Action": "oss:ActivateProduct",
         "Resource": "acs:oss:*:*:*"
     }
   ]
}