Description
A lower-priority DNR block rule that matches a request is being applied before a higher-priority DNR redirect rule that matches the same request, preventing the redirect from occurring. The only way to get the high-priority redirect rule to occur is to remove the DNR block rule.
Steps to reproduce:
- Create/install a web extension on Safari with the declarativeNetRequest and declarativeNetRequestWithHostAccess permissions
- Open the Web Extension Background Content console and add a redirect rule with a high priority number. For example:
await chrome.declarativeNetRequest.updateDynamicRules({addRules: [
{id: 5000, condition: {urlFilter: "||www.google-analytics.com*/ga.js", resourceTypes: ["script"], domainType: "thirdParty"}, priority: 80, action: {type: "redirect", redirect: {url: “http://www.apple.com/”}}}
]})
- Add a block rule of lower priority for the same urlFilter:
await chrome.declarativeNetRequest.updateDynamicRules({addRules: [
{id: 5001, condition: {urlFilter: "||www.google-analytics.com^", domainType: "thirdParty"}, priority: 1, action: {type: "block"}}
]})
-
Visit https://efforg.github.io/privacybadger-test-fixtures/html/ga_surrogate.html
-
Check the network tab and see that neither a request to Google Analytics nor apple.com appear. This means that the request to Google Analytics was blocked instead of being / before being redirected
-
Remove the block rule:
await chrome.declarativeNetRequest.updateDynamicRules({removeRuleIds: [5001]}) -
Reload https://efforg.github.io/privacybadger-test-fixtures/html/ga_surrogate.html.
-
Check the network tab and confirm that there is a request to apple.com, showing that the redirect rule is only applied if the lower-priority block rule is removed. The priority of the DNR rules should handle this without having to remove a DNR rule.
Demo Xcode extension: https://github.com/lenacohen/Safari-Test-Extensions/tree/main/dnr-redirect-block-priority
- Test demo extension on https://efforg.github.io/privacybadger-test-fixtures/html/ga_surrogate.html
- google-analytics.com request should be redirected but is blocked instead
Apple Feedback Assistant Bug Report: FB16535579
Apple Developer Forum Post
Safari version 18.3
MacOS Sequoia 15.3.1