{"id":39320,"date":"2022-11-02T07:27:39","date_gmt":"2022-11-02T11:27:39","guid":{"rendered":"https:\/\/centricconsulting.com\/?p=39320"},"modified":"2022-11-28T11:04:59","modified_gmt":"2022-11-28T16:04:59","slug":"snowflake-security-and-privacy-establishing-row-access-policies","status":"publish","type":"post","link":"https:\/\/centricconsulting.com\/blog\/snowflake-security-and-privacy-establishing-row-access-policies\/","title":{"rendered":"Snowflake Security and Privacy: Establishing Row Access Policies"},"content":{"rendered":"
In part one<\/a> of our Snowflake security and privacy blog series<\/a>, we discussed how to think about storing and organizing your data, from the organization level all the way down to individual tables.<\/p>\n In part two<\/a>, we discussed ways to think about data access and control at a granular level. And in part three<\/a>, we outlined how you can use tagging to identify sensitive data and combine it with dynamic data masking to prevent unauthorized access.<\/p>\n In this blog, we\u2019ll dive into how we can restrict access to specific rows within a table using Snowflake row access policies.<\/strong> We\u2019ll follow along with a specific example to show exactly how to put these policies in place.<\/p>\n Combining the storage hierarchy, flexibility and security policies described in parts one to three, it is quite easy for us to limit access to data<\/a> at a highly granular level. For simple restrictions, we can separate data and use custom views.<\/strong><\/p>\n <\/a><\/p>\n In this scenario, no one from MyPartsCo has any access to the \u201cRaw_Data\u201d database \u2013 they cannot even see it exists. They can only see the \u201cParts_Transaction_Data\u201d database. When they query the \u201cSales_Transactions_View,\u201d they see what appears to be the \u201cSales_Transactions\u201d table, but only the rows containing MyPartsCo data. Unless explicitly granted access to the other database, it is impossible for them to see anything else.<\/strong><\/p>\n For more complex restrictions, we\u2019ll use Snowflake\u2019s row access policies. Much like tags, you can create row access policies once and apply them in multiple locations. A row access policy can use the data present in the table, information about the table itself (e.g., tags), information about the current context (who is asking and what role they have), or information it looks up from somewhere else (a mapping table that associates a user to a region), in any combination.<\/p>\n Example table:<\/p>\n <\/a><\/p>\n The simplest policy looks at a single attribute: \u201ccurrent_user = Jane?\u201d If yes, all rows are returned. If no, none are returned.<\/p>\n More realistically, we might compare the current user\u2019s \u201crole\u201d (or the group they belong to) combined with information in the table itself: \u201ccurrent_role = [Region]?\u201d<\/strong><\/p>\n If the user is in the role \u201cNorthAmerica,\u201d no matter what query they run, the results will only include information from rows 1 and 4. This includes queries like \u201cSUM(Amount)\u201d \u2013 the sum will not include the EU amounts. For this user, rows 2 and 3 do not exist.<\/p>\n <\/a>For something like region access, we would extend this further, using a mapping table to tell us who should have access to which region rather than relying on named roles matching regions.<\/p>\n <\/a><\/p>\n Our row access policy can quickly look up the user in the mapping table above, take note of special circumstances like \u201cAll,\u201d and apply filtering from there. We can apply this single lookup function to as many tables and views as we would like.<\/p>\n Finally, you can combine and stack policies with other tools.<\/p>\n Example table:<\/p>\n <\/a><\/p>\n Example view (\u201cWHERE Subsidiary = MyPartsCo\u201d):<\/p>\n <\/a><\/p>\n After applying the row access policy \u201ccurrent_role = [Region]?\u201d to the view:<\/p>\nSnowflake Row-Level Security<\/h2>\n