1 # Permission Checks and Requests
5 ## PermissionController
8 [PermissionController](https://cs.chromium.org/chromium/src/content/public/browser/permission_controller.h)
9 is the entry point for clients of the permissions infrastructure from both the
10 `//content` and the embedder (e.g. `//chrome`) layers.
11 [PermissionController](https://cs.chromium.org/chromium/src/content/public/browser/permission_controller.h)
12 provides access to the permissions API and can be reached as
13 `content::BrowserContext::GetPermissionController()` or
14 `Profile::GetPermissionController()`.
16 [PermissionController](https://cs.chromium.org/chromium/src/content/public/browser/permission_controller.h)
17 has the following API:
18 * `blink::mojom::PermissionStatus PermissionController::GetPermissionStatusForWorker`
19 * `blink::mojom::PermissionStatus PermissionController::GetPermissionStatusForCurrentDocument`
20 * `blink::mojom::PermissionStatus PermissionController::GetPermissionStatusForOriginWithoutContext`
21 Use this API only in special cases when there is no active document or
22 worker. E.g., `PermissionType::PAYMENT_HANDLER` permission verification of
23 payment providers in a PWA's manifest.
24 * `PermissionController::RequestPermissionFromCurrentDocument`
25 * `PermissionController::RequestPermissionsFromCurrentDocument`
27 ## PermissionControllerImpl
29 The [PermissionControllerImpl](https://cs.chromium.org/chromium/src/content/browser/permissions/permission_controller_impl.h)
30 is the implementation of the
31 [PermissionController](https://cs.chromium.org/chromium/src/content/public/browser/permission_controller.h).
32 [PermissionControllerImpl](https://cs.chromium.org/chromium/src/content/browser/permissions/permission_controller_impl.h)
33 is meant to be used only internally in `//content` and is not available for
36 [PermissionControllerImpl](https://cs.chromium.org/chromium/src/content/browser/permissions/permission_controller_impl.h)
37 provides various functionality such as:
39 * Reset a permission's state to the default
40 * Observe permissions changes
41 * Override permission status for DevTools.
43 ## PermissionManager and PermissionContextBase
46 [PermissionManager](https://cs.chromium.org/chromium/src/components/permissions/permission_manager.h)
47 is an implementation of
48 [PermissionControllerDelegate](https://cs.chromium.org/chromium/src/content/public/browser/permission_controller_delegate.h).
49 [PermissionManager](https://cs.chromium.org/chromium/src/components/permissions/permission_manager.h)
51 [KeyedService](https://cs.chromium.org/chromium/src/components/keyed_service/core/keyed_service.h)
52 which means it is attached to a
53 [BrowserContext](https://cs.chromium.org/chromium/src/content/public/browser/browser_context.h).
54 It allows to get permission status for
55 [ContentSettingsType](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h).
56 That API should be used only to display permission status in UI like PageInfo
60 [PermissionManager](https://cs.chromium.org/chromium/src/components/permissions/permission_manager.h)
61 holds a list of PermissionsContexts, one per
62 [ContentSettingType](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h?l=17).
63 [PermissionContextBase](https://cs.chromium.org/chromium/src/components/permissions/permission_context_base.h)
64 is the base class for these contexts, and for every
65 [ContentSettingsType](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h)
66 there is a specific `...PermissionsContext` subclass.
69 > [NotificationPermissionContext](https://cs.chromium.org/chromium/src/chrome/browser/notifications/notification_permission_context.h)
71 > "[NOTIFICATIONS](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h?l=33)"
74 In order to query, set, and reset the state of a permission, the
75 [HostContentSettingsMap](#HostContentSettingsMap) KeyedService is used, which
76 internally handles the more complicated things related to Content Settings.
78 In order to present the user with a permission prompt when a permission is
79 requested, [PermissionRequestManager](#PermissionRequestManager) is used.
81 ## [HostContentSettingsMap](https://cs.chromium.org/chromium/src/components/content_settings/core/browser/host_content_settings_map.h)
85 In order to determine whether a permission is granted, blocked, needs a user
86 decision, etc, the appropriate content setting is checked. Content settings are
87 saved and retrieved using a key consisting of a 3-tuple of values:
89 * Primary pattern: this is a
90 [ContentSettingsPattern](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_pattern.h)
91 that represents the primary resource's URL. For permissions this refers to
92 the URL of the document requesting/using the permission.
93 * Secondary pattern: this is a
94 [ContentSettingsPattern](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_pattern.h)
95 that is used for some types to provide some context around the primary
96 resource. For permissions this refers to the URL of the top-level document
97 of the page (except for "NOTIFICATIONS" in which case it's unused).
98 * Content type: this is a
99 [ContentSettingsType](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h)
100 that specifies which setting this operation refers to.
103 [ContentSettingsPattern](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_pattern.h)
104 is basically a URL where every part (scheme, host port, path) is allowed to be
105 either `Wildcard` or a specified value. Any other form or regex is not
108 A key that has `Wildcard` for both the primary and secondary patterns represents
109 the "Default" value for a specific
110 [ContentSettingsType](https://cs.chromium.org/chromium/src/components/content_settings/core/common/content_settings_types.h).
111 This is the least specific content setting that will match anything and serves
112 as a backup for when no more-specific setting has been set.
116 When setting or retrieving a content setting, the
117 [HostContentSettingsMap](https://cs.chromium.org/chromium/src/components/content_settings/core/browser/host_content_settings_map.h)
118 uses a list of registered
119 [providers](https://cs.chromium.org/chromium/src/components/content_settings/core/browser/host_content_settings_map.h?type=cs&g=0&l=54).
120 This enum is sorted from highest priority to lowest. If a provider is able to
121 handle a specific operation it will do so and the following providers are
122 ignored, otherwise the next provider is queried and so on.
124 The underlying storage mechanism is provider-dependent.
126 ## [PermissionRequestManager](https://cs.chromium.org/chromium/src/components/permissions/permission_request_manager.h)
129 [PermissionRequestManager](https://cs.chromium.org/chromium/src/components/permissions/permission_request_manager.h)
130 facilitates making permission requests via `AddRequest()`. Only one request
131 prompt is allowed to be in progress at a time, the manager holds a deque of
132 pending requests for all requests that are kept waiting until the current prompt
136 [PermissionRequestManager](https://cs.chromium.org/chromium/src/components/permissions/permission_request_manager.h)
137 is attached and scoped to the lifetime of a
138 [WebContents](https://cs.chromium.org/chromium/src/content/public/browser/web_contents.h?l=111).
140 [WebContents](https://cs.chromium.org/chromium/src/content/public/browser/web_contents.h?l=111)
141 object is destroyed all current and queued requests are finalized as
142 "[IGNORED](https://cs.chromium.org/chromium/src/components/permissions/permission_util.h?l=26)".
144 It is possible to have more than one request be tied in to the same prompt. This
145 only happens when the requests are allowed to be grouped together and they all
146 requested one after another. Currently this is only the case for the Camera and
147 Microphone permissions which can be grouped into one Camera+Microphone prompt.
149 ### Automatic actions
151 * The `--deny-permission-prompts` command line switch will cause all
152 permissions to be automatically denied.
153 * Notification permission requests that arrive too soon after a previous
154 notifications prompt has been resolved are automatically
155 "[DENIED](https://cs.chromium.org/chromium/src/components/permissions/permission_util.h?l=24)".
156 When a user denies a notifications permission prompt, the manager enters a
157 "notifications cooldown mode" and a user-initiated navigation needs to
158 happen before allowing another notifications permission prompt. This
159 prevents an abusive pattern observed in the wild where a site is cycling
160 through multiple subdomains and asking to show permissions until the user
161 gives up or gives in.
162 * On ChromeOS in WebKiosk mode, permission requests for the origin of the
163 installed app are automatically
164 "[GRANTED](https://cs.chromium.org/chromium/src/components/permissions/permission_util.h?l=23)".
165 This needs to be done because there is no "user" to grant a permissions when
166 the browser is simply used to continuously display some presentation app
167 (for example: a TV in a store that displays on screen the camera feed).
168 * Requests that duplicate a currently pending requests are put into a separate
169 list instead of the regular queue. When a request is resolved, its
170 duplicates are also resolved.
171 * Based on various indicators (user's behavior, settings, site score etc) a
172 request can be downgraded to use a quiet UI or be dropped entirely. For more
173 info see the [Quiet permissions prompts](#Quiet-permissions-prompts)
175 * If the current permission prompt is [quiet](#Quiet-permissions-prompts), it
177 "[IGNORED](https://cs.chromium.org/chromium/src/components/permissions/permission_util.h?l=26)"
178 when a new request is added. This prevents the permission requests being
179 stuck around a prompt that is easily ignored by the user.
181 If the request has not been automatically resolved, it is added to deque of
182 `queued_requests_` from which it will be picked up as appropriate.
186 When a trigger causes the `DequeueRequestIfNeeded` function to be called it will
187 check if the necessary conditions are met to show a new permission prompt and it
188 will trigger showing the prompt. The conditions are:
190 * The document needs to be loaded and visible
191 * There is no permission prompt currently being shown to the user
192 * There is a queued request waiting to be shown to the user
194 `DequeueRequestIfNeeded` is triggered when:
197 * The document becomes visible
198 * A new request is added
199 * A permission prompt is resolved
200 * An async decision about a permission request is made
202 When the prompt needs to be shown to the user, a platform specific subclass of
203 [PermissionPrompt](https://cs.chromium.org/chromium/src/chrome/browser/ui/permission_bubble/permission_prompt.h)
204 is created which handles the creation and lifetime of the UI element and will
205 report user actions back to the
206 [PermissionRequestManager](https://cs.chromium.org/chromium/src/components/permissions/permission_request_manager.h).
208 The PermissionPrompt is responsible for deciding the exact UI surface and text
209 to present to the user based on information about the request.
211 ### Quiet permissions prompts
213 For specific permission prompt requests a decision could be made to enforce a
214 quiet UI version of the permission prompt. Currently this only applies to
215 NOTIFICATIONS permission requests.
217 A quiet UI prompt can be triggered if any of these conditions are met:
219 * The user has enabled quiet prompts in settings.
220 * The site requesting the permissions is marked by Safe Browsing as having a
224 [AdaptiveQuietNotificationPermissionUiEnabler](https://cs.chromium.org/chromium/src/chrome/browser/permissions/adaptive_quiet_notification_permission_ui_enabler.h)
225 is responsible for recording the permission prompts outcomes and, if needed,
226 enabling the quiet UI in settings. The
227 [ContextualNotificationPermissionUiSelector](https://cs.chromium.org/chromium/src/chrome/browser/permissions/contextual_notification_permission_ui_selector.h)
228 checks if the quiet UI is enabled in settings (among other things) when choosing
229 the appropriate UI flavor.
231 A quiet UI prompt will use a right-side omnibox indicator on desktop or a
232 mini-infobar on Android.
234 ## [PermissionsSecurityModelInteractiveUITest](https://cs.chromium.org/chromium/src/chrome/browser/permissions/permissions_security_model_interactive_uitest.cc)
238 Requesting and verification of permissions does not feature unified behavior in
239 different environments. In other words, based on the preconditions, a permission
240 request could be shown or automatically declined. To make sure that all cases
241 work as intended, we introduced [PermissionsSecurityModelInteractiveUITest](https://cs.chromium.org/chromium/src/chrome/browser/permissions/permissions_security_model_interactive_uitest.cc).
243 ### Add your own test
245 If you're adding a new environment that requires non-default behavior for
246 permissions, then you need to add a test in
247 [PermissionsSecurityModelInteractiveUITest](https://cs.chromium.org/chromium/src/chrome/browser/permissions/permissions_security_model_interactive_uitest.cc).
251 * Create a new test fixture and activate your environment and get a
252 [WebContents](https://source.chromium.org/chromium/chromium/src/+/main:content/public/browser/web_contents.h)
253 or a [RenderFrameHost](https://source.chromium.org/chromium/chromium/src/+/main:content/public/browser/render_frame_host.h).
254 * Create a method `VerifyPermissionForXYZ`, where `XYZ` is the name of your
255 environment. You can use the already defined `VerifyPermission` method if you
256 expect to have default behavior for permissions. In `VerifyPermissionForXYZ`
257 define a new behavior you expect to have.
258 * Call `VerifyPermissionForXYZ` from your newly created test fixture.
261 > [PermissionRequestWithPortalTest](https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/permissions/permissions_security_model_interactive_uitest.cc;drc=c662f11e160976c04682f41941aaeccad92ace48;bpv=0;bpt=1;l=1063)
262 > enables the [Portals](https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/common/features.cc;l=179;drc=c662f11e160976c04682f41941aaeccad92ace48).
263 > The [PortalActivation] test verifies that permissions are disabled in Portals.
264 > [VerifyPermissionsDeniedForPortal](https://source.chromium.org/chromium/chromium/src/+/main:chrome/browser/permissions/permissions_security_model_interactive_uitest.cc;drc=c662f11e160976c04682f41941aaeccad92ace48;l=429) incapsulates all logic
265 > needed for a particular permission verification.
267 ## Add new permission
269 See [add_new_permission.md](https://source.chromium.org/chromium/chromium/src/+/main:components/permissions/add_new_permission.md)