2006036 - fbo.fubon.com - Unsupported browser warning blocks access to the page

Status: ASSIGNED

(Web Compatibility :: Site Reports, defect, P1)

Description

[Raul Bucata]

Environment:
Operating system: Windows 10
Firefox version: Firefox 146.0

Steps to reproduce:

1. Navigate to: https://fbo.fubon.com/fboPortal/index.jsp
2. Observe

Expected Behavior:
The page loads

Actual Behavior:
Unsupported Browser warning message blocks access

Notes:

• Reproduces regardless of the status of ETP
• Reproduces in firefox-nightly, and firefox-release
• Does not reproduce in chrome

Created from https://github.com/webcompat/web-bugs/issues/195275

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Since nightly and release are affected, beta will likely be affected too.
For more information, please visit BugBot documentation.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

ChromeMask doesn't work here because the site is using client hints to detect Chrome:

  // 判斷是否有 Client Hints，並額外處理brave瀏覽器
            if (navigator.userAgentData && navigator.userAgentData.brands) {

                // 【路徑 A】有 Client Hints 的瀏覽器 (Chrome, Edge, Brave...)
                try {
                    var brands = navigator.userAgentData.brands.map(function(b) { return b.brand.toLowerCase(); });
                    var isBrave = brands.indexOf("brave") > -1;

                    if (isBrave) {
                        // 1. 如果是 Brave，明確拒絕
                        console.warn("Brave browser blocked by Client Hints.");
                        browserIsAllowed = false;
                    } else {
                        // 2. 如果不是 Brave，檢查是否為 Chrome 或 Edge
                        var platform = navigator.userAgentData.platform.toLowerCase();
                        var hasAllowedBrand = brands.indexOf("google chrome") > -1 || brands.indexOf("microsoft edge") > -1;
                        var allowedPlatforms = ["windows", "macos", "android"];
                        var hasAllowedPlatform = allowedPlatforms.includes(platform);

                        if (hasAllowedBrand && hasAllowedPlatform && checkCoreFeatures()) {
                            browserIsAllowed = true;
                        }
                    }
                } catch (e) {
                    console.warn("Client Hints check error:", e);
                    browserIsAllowed = false; // 出錯則不允許
                }

            } else {

                // 【路徑 B】沒有 Client Hints 的瀏覽器 (Safari, Firefox...)
                var isEdgePC = ua.indexOf("edg") > -1;
                var isChrome = ua.indexOf("chrome") > -1 && !isEdgePC;
                var isSafari = ua.indexOf("safari") > -1 && ua.indexOf("version") > -1 && !isChrome && !isEdgePC;

                // 主要目標是放行 Safari 和 Edge 的 iOS/Android 版
                var isEdgeIos = ua.indexOf("edgios") > -1;
                var isEdgeAndroid = ua.indexOf("edga") > -1;
                var isChromeIos = ua.indexOf("crios") > -1;


                if ((isSafari || isEdgePC || isEdgeIos || isEdgeAndroid || isChromeIos) && checkCoreFeatures()) {
                    browserIsAllowed = true;
                }
            }

Comment 3

[Thomas Wisniewski [:twisniewski]]

Even if we spoof userAgentData, the site won't load. They're doing some.. interesting stuff with XMLHttpRequests which causes Firefox to break on purpose, and even then it breaks if we avoid the line which sets a timeout on a sync XHR (which isn't allowed and causes an exception):

		this.portRequest.open('POST', this.SendURL, false); //FIXME(TWCA) 待確認同步模式
			if (userAgent.indexOf("Firefox") > -1) {
				this.portRequest.timeout = 1000;
			}

I think we'll need to diagnose more fully here. But I can at least post a patch which lets us test further, so I'll do so.

Comment 4

[Thomas Wisniewski [:twisniewski]]

Attachment: WIP: Bug 2006036 - test intervention to help diagnose fbo.fubon.com

Comment 5

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 2006036 - add a JS webcompat intervention for fbo.fubon.com; r?denschub

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/3cc8242be1b6
https://hg.mozilla.org/integration/autoland/rev/5e3a52b53345
add a JS webcompat intervention for fbo.fubon.com; r=webcompat-reviewers,ksenia

Comment 7

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/5e3a52b53345

Comment 8

[Thomas Wisniewski [:twisniewski]]

They are blocking Linux now, even on Chrome. I'll adjust the intervention to not bother applying on Linux, since it doesn't achieve anything.

Comment 9

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 2006036 - don't bother with a UA override for fbo.fubon.com on Linux; r?ksenia

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/4f83d4bdf28e
https://hg.mozilla.org/integration/autoland/rev/10d2d19a7ab0
don't bother with a UA override for fbo.fubon.com on Linux; r=webcompat-reviewers,denschub

Comment 11

[Serban Stanca [:SerbanS]]

Reverted this because it was causing mochitests failures in browser_ua_helpers.js.

• Revert link
• Push with failures
• Failure Log
• Failure line: TEST-UNEXPECTED-FAIL | browser/extensions/webcompat/tests/browser/browser_ua_helpers.js | test_ua_helpers - getDeviceAppropriateChromeUA({"ua":"Linux","config":{"OS":"windows","noFxQuantum":true},"expected":"Mozilla/5.0 (Windows NT 11.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36"}) - Got "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36",

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/afcfcd93d96e
https://hg.mozilla.org/integration/autoland/rev/ce14aa02e1a0
don't bother with a UA override for fbo.fubon.com on Linux; r=webcompat-reviewers,denschub

Comment 13

[Silaghi Andreea]

https://hg.mozilla.org/mozilla-central/rev/ce14aa02e1a0