tor-browser

ContentAreaDropListener.sys.mjs (10832B)

---

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

const lazy = {};

ChromeUtils.defineESModuleGetters(lazy, {
 OpaqueDrag: "moz-src:///toolkit/modules/DragDropFilter.sys.mjs",
});

// This component is used for handling dragover and drop of urls.
//
// It checks to see whether a drop of a url is allowed. For instance, a url
// cannot be dropped if it is not a valid uri or the source of the drag cannot
// access the uri. This prevents, for example, a source document from tricking
// the user into dragging a chrome url.

export function ContentAreaDropListener() {}

ContentAreaDropListener.prototype = {
 classID: Components.ID("{1f34bc80-1bc7-11d6-a384-d705dd0746fc}"),
 QueryInterface: ChromeUtils.generateQI(["nsIDroppedLinkHandler"]),

 _addLink(links, url, name, type) {
   links.push({ url, name, type });
 },

 _addLinksFromItem(links, dt, i) {
   let types = dt.mozTypesAt(i);
   let type, data;

   type = "text/uri-list";
   if (types.contains(type)) {
     data = dt.mozGetDataAt(type, i);
     if (data) {
       let urls = data.split("\n");
       for (let url of urls) {
         // lines beginning with # are comments
         if (url.startsWith("#")) {
           continue;
         }
         url = url.replace(/^\s+|\s+$/g, "");
         this._addLink(links, url, url, type);
       }
       return;
     }
   }

   for (let type of ["text/x-moz-url", "application/x-torbrowser-opaque"]) {
     if (!types.contains(type)) {
       continue;
     }
     data = dt.mozGetDataAt(type, i);
     if (data) {
       if (type === "application/x-torbrowser-opaque") {
         ({ type, value: data = "" } = lazy.OpaqueDrag.retrieve(data));
       }
       let lines = data.split("\n");
       for (let i = 0, length = lines.length; i < length; i += 2) {
         this._addLink(links, lines[i], lines[i + 1], type);
       }
       return;
     }
   }

   for (let type of ["text/plain", "text/x-moz-text-internal"]) {
     if (types.contains(type)) {
       data = dt.mozGetDataAt(type, i);
       if (data) {
         let lines = data.replace(/^\s+|\s+$/gm, "").split("\n");
         if (!lines.length) {
           return;
         }

         // For plain text, there are 2 cases:
         //   * if there is at least one URI:
         //       Add all URIs, ignoring non-URI lines, so that all URIs
         //       are opened in tabs.
         //   * if there's no URI:
         //       Add the entire text as a single entry, so that the entire
         //       text is searched.
         let hasURI = false;
         // We don't care whether we are in a private context, because we are
         // only using fixedURI and thus there's no risk to use the wrong
         // search engine.
         let flags =
           Ci.nsIURIFixup.FIXUP_FLAG_FIX_SCHEME_TYPOS |
           Ci.nsIURIFixup.FIXUP_FLAG_ALLOW_KEYWORD_LOOKUP;
         for (let line of lines) {
           let info = Services.uriFixup.getFixupURIInfo(line, flags);
           if (info.fixedURI) {
             // Use the original line here, and let the caller decide
             // whether to perform fixup or not.
             hasURI = true;
             this._addLink(links, line, line, type);
           }
         }

         if (!hasURI) {
           this._addLink(links, data, data, type);
         }
         return;
       }
     }
   }

   // For shortcuts, we want to check for the file type last, so that the
   // url pointed to in one of the url types is found first before the file
   // type, which points to the actual file.
   let files = dt.files;
   if (files && i < files.length) {
     this._addLink(
       links,
       PathUtils.toFileURI(files[i].mozFullPath),
       files[i].name,
       "application/x-moz-file"
     );
   }
 },

 _getDropLinks(dt) {
   let links = [];
   for (let i = 0; i < dt.mozItemCount; i++) {
     this._addLinksFromItem(links, dt, i);
   }
   return links;
 },

 _validateURI(dataTransfer, uriString, disallowInherit, triggeringPrincipal) {
   if (!uriString) {
     return "";
   }

   // Strip leading and trailing whitespace, then try to create a
   // URI from the dropped string. If that succeeds, we're
   // dropping a URI and we need to do a security check to make
   // sure the source document can load the dropped URI.
   uriString = uriString.replace(/^\s*|\s*$/g, "");

   // Apply URI fixup so that this validation prevents bad URIs even if the
   // similar fixup is applied later, especialy fixing typos up will convert
   // non-URI to URI.
   // We don't know if the uri comes from a private context, but luckily we
   // are only using fixedURI, so there's no risk to use the wrong search
   // engine.
   let fixupFlags =
     Ci.nsIURIFixup.FIXUP_FLAG_FIX_SCHEME_TYPOS |
     Ci.nsIURIFixup.FIXUP_FLAG_ALLOW_KEYWORD_LOOKUP;
   let info = Services.uriFixup.getFixupURIInfo(uriString, fixupFlags);
   if (!info.fixedURI || info.keywordProviderName) {
     // Loading a keyword search should always be fine for all cases.
     return uriString;
   }
   let uri = info.fixedURI;

   let secMan = Services.scriptSecurityManager;
   let flags = secMan.STANDARD;
   if (disallowInherit) {
     flags |= secMan.DISALLOW_INHERIT_PRINCIPAL;
   }

   secMan.checkLoadURIWithPrincipal(triggeringPrincipal, uri, flags);

   // Once we validated, return the URI after fixup, instead of the original
   // uriString.
   return uri.spec;
 },

 _getTriggeringPrincipalFromDataTransfer(
   aDataTransfer,
   fallbackToSystemPrincipal
 ) {
   let sourceNode = aDataTransfer.mozSourceNode;
   if (
     sourceNode &&
     (sourceNode.localName !== "browser" ||
       sourceNode.namespaceURI !==
         "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul")
   ) {
     // Use sourceNode's principal only if the sourceNode is not browser.
     //
     // If sourceNode is browser, the actual triggering principal may be
     // differ than sourceNode's principal, since sourceNode's principal is
     // top level document's one and the drag may be triggered from a frame
     // with different principal.
     if (sourceNode.nodePrincipal) {
       return sourceNode.nodePrincipal;
     }
   }

   // First, fallback to mozTriggeringPrincipalURISpec that is set when the
   // drop comes from another content process.
   let principalURISpec = aDataTransfer.mozTriggeringPrincipalURISpec;
   if (!principalURISpec) {
     // Fallback to either system principal or file principal, supposing
     // the drop comes from outside of the browser, so that drops of file
     // URIs are always allowed.
     //
     // TODO: Investigate and describe the difference between them,
     //       or use only one principal. (Bug 1367038)
     if (fallbackToSystemPrincipal) {
       return Services.scriptSecurityManager.getSystemPrincipal();
     }

     principalURISpec = "file:///";
   }
   return Services.scriptSecurityManager.createContentPrincipal(
     Services.io.newURI(principalURISpec),
     {}
   );
 },

 getTriggeringPrincipal(aEvent) {
   let dataTransfer = aEvent.dataTransfer;
   return this._getTriggeringPrincipalFromDataTransfer(dataTransfer, true);
 },

 getPolicyContainer(aEvent) {
   let sourceNode = aEvent.dataTransfer.mozSourceNode;
   if (aEvent.dataTransfer.policyContainer !== null) {
     return aEvent.dataTransfer.policyContainer;
   }

   if (
     sourceNode &&
     (sourceNode.localName !== "browser" ||
       sourceNode.namespaceURI !==
         "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul")
   ) {
     // Use sourceNode's policyContainer only if the sourceNode is not browser.
     //
     // If sourceNode is browser, the actual triggering policyContainer may be differ than sourceNode's policyContainer,
     // since sourceNode's policyContainer is top level document's one and the drag may be triggered from a
     // frame with different policyContainer.
     return sourceNode.policyContainer;
   }
   return null;
 },

 canDropLink(aEvent, aAllowSameDocument) {
   if (this._eventTargetIsDisabled(aEvent)) {
     return false;
   }

   let dataTransfer = aEvent.dataTransfer;
   let types = dataTransfer.types;
   if (
     !types.includes("application/x-moz-file") &&
     !types.includes("text/x-moz-url") &&
     !types.includes("application/x-torbrowser-opaque") &&
     !types.includes("text/uri-list") &&
     !types.includes("text/x-moz-text-internal") &&
     !types.includes("text/plain")
   ) {
     return false;
   }

   if (aAllowSameDocument) {
     return true;
   }

   // If this is an external drag, allow drop.
   let sourceTopWC = dataTransfer.sourceTopWindowContext;
   if (!sourceTopWC) {
     return true;
   }

   // If drag source and drop target are in the same top window, don't allow.
   let eventWC =
     aEvent.originalTarget.ownerGlobal.browsingContext.currentWindowContext;
   if (eventWC && sourceTopWC == eventWC.topWindowContext) {
     return false;
   }

   return true;
 },

 dropLinks(aEvent, aDisallowInherit) {
   if (aEvent && this._eventTargetIsDisabled(aEvent)) {
     return [];
   }

   let dataTransfer = aEvent.dataTransfer;
   let links = this._getDropLinks(dataTransfer);
   let triggeringPrincipal = this._getTriggeringPrincipalFromDataTransfer(
     dataTransfer,
     false
   );

   for (let link of links) {
     try {
       link.url = this._validateURI(
         dataTransfer,
         link.url,
         aDisallowInherit,
         triggeringPrincipal
       );
     } catch (ex) {
       // Prevent the drop entirely if any of the links are invalid even if
       // one of them is valid.
       aEvent.stopPropagation();
       aEvent.preventDefault();
       throw ex;
     }
   }

   return links;
 },

 validateURIsForDrop(aEvent, aURIs, aDisallowInherit) {
   let dataTransfer = aEvent.dataTransfer;
   let triggeringPrincipal = this._getTriggeringPrincipalFromDataTransfer(
     dataTransfer,
     false
   );

   for (let uri of aURIs) {
     this._validateURI(
       dataTransfer,
       uri,
       aDisallowInherit,
       triggeringPrincipal
     );
   }
 },

 queryLinks(aDataTransfer) {
   return this._getDropLinks(aDataTransfer);
 },

 _eventTargetIsDisabled(aEvent) {
   let ownerDoc = aEvent.originalTarget.ownerDocument;
   if (!ownerDoc || !ownerDoc.defaultView) {
     return false;
   }

   return ownerDoc.defaultView.windowUtils.isNodeDisabledForEvents(
     aEvent.originalTarget
   );
 },
};