Authenticate requests between components

Use a randomly generated token to authenticate requests to the server for all endpoints, including WebSockets. The token is passed to the node server via STDIN, which should sufficiently prevent eavesdropping.
felixhageloh · Aug 21, 2022 · 9c7cf76 · 9c7cf76
1 parent b3f370f
commit 9c7cf76
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Showing 21 changed files with 252 additions and 37 deletions.
diff --git a/Uebersicht/UBAppDelegate.h b/Uebersicht/UBAppDelegate.h
@@ -20,6 +20,7 @@
 
 - (void)widgetDirDidChange;
 - (void)interactionDidChange;
+- (void)enableSecurityDidChange;
 - (void)screensChanged:(NSDictionary*)screens;
 - (IBAction)showPreferences:(id)sender;
 - (IBAction)openWidgetDir:(id)sender;

diff --git a/Uebersicht/UBAppDelegate.m b/Uebersicht/UBAppDelegate.m
@@ -33,10 +33,13 @@ @implementation UBAppDelegate {
     UBWidgetsStore* widgetsStore;
     UBWidgetsController* widgetsController;
     BOOL needsRefresh;
+    NSString *token;
 }
 
 @synthesize statusBarMenu;
 
+static const uint kTokenLength256Bits = 32;
+
 - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
 {
     needsRefresh = YES;
@@ -110,33 +113,58 @@ - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
     [self listenToWallpaperChanges];
 }
 
-- (NSDictionary*)fetchState
+- (void)fetchState:(void (^)(NSDictionary*))callback
 {
-    [[UBWebSocket sharedSocket] open:[self serverUrl:@"ws"]];
+    [[UBWebSocket sharedSocket] open:[self serverUrl:@"ws"]
+                               token:token];
+
     NSURL *urlPath = [[self serverUrl:@"http"] URLByAppendingPathComponent: @"state/"];
-    NSData *jsonData = [NSData dataWithContentsOfURL:urlPath];
-    NSError *error = nil;
-    NSDictionary *dataDictionary = [NSJSONSerialization
-        JSONObjectWithData: jsonData
-        options: NSJSONReadingMutableContainers
-        error: &error
-    ];
-    if (error) NSLog(@"%@", error);
-    return dataDictionary;
+    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:urlPath];
+    [request setValue:@"Übersicht" forHTTPHeaderField:@"Origin"];
+    [request setValue:[NSString stringWithFormat:@"token=%@", token] forHTTPHeaderField:@"Cookie"];
+    NSURLSessionDataTask *t = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
+        if (error) {
+            NSLog(@"error loading state: %@", error);
+            dispatch_async(dispatch_get_main_queue(), ^{
+                callback(@{});
+            });
+            return;
+        }
+
+        NSError *jsonError = nil;
+        NSDictionary *dataDictionary = [NSJSONSerialization
+            JSONObjectWithData: data
+            options: NSJSONReadingMutableContainers
+            error: &jsonError
+        ];
+        if (jsonError) {
+            NSLog(@"error parsing state: %@", error);
+            dispatch_async(dispatch_get_main_queue(), ^{
+                callback(@{});
+            });
+            return;
+        }
+
+        dispatch_async(dispatch_get_main_queue(), ^{
+            callback(dataDictionary);
+        });
+    }];
+    [t resume];
 }
 
 - (void)startUp
 {
 
     NSLog(@"starting server task");
-    
+
     void (^handleData)(NSString*) = ^(NSString* output) {
         // note that these might be called several times
         if ([output rangeOfString:@"server started"].location != NSNotFound) {
-            [self->widgetsStore reset: [self fetchState]];
-            // this will trigger a render
-            [self->screensController syncScreens:self];
-
+            [self fetchState:^(NSDictionary* state) {
+                [self->widgetsStore reset: state];
+                // this will trigger a render
+                [self->screensController syncScreens:self];
+            }];
         } else if ([output rangeOfString:@"EADDRINUSE"].location != NSNotFound) {
             self->portOffset++;
         }
@@ -216,15 +244,28 @@ - (NSTask*)launchWidgetServer:(NSString*)widgetPath
                        onData:(void (^)(NSString*))dataHandler
                        onExit:(void (^)(NSTask*))exitHandler
 {
+    token = generateToken(kTokenLength256Bits);
+
     NSBundle* bundle     = [NSBundle mainBundle];
     NSString* nodePath   = [bundle pathForResource:@"localnode" ofType:nil];
     NSString* serverPath = [bundle pathForResource:@"server" ofType:@"js"];
-    BOOL loginShell = [[NSUserDefaults standardUserDefaults]
-        boolForKey:@"loginShell"
-    ];
 
     NSTask *task = [[NSTask alloc] init];
 
+    NSPipe *inPipe = [NSPipe pipe];
+    NSFileHandle *fh = [inPipe fileHandleForWriting];
+    NSMutableDictionary *secrets = [[NSMutableDictionary alloc] init];
+    secrets[@"token"] = token;
+    NSError *jsonErr = NULL;
+    NSData *stdinData = [NSJSONSerialization dataWithJSONObject:secrets options:0 error:&jsonErr];
+    if (!stdinData) {
+        NSLog(@"[FATAL] %@", jsonErr);
+        return NULL;
+    }
+    [fh writeData:stdinData];
+    [fh closeFile];
+    [task setStandardInput:inPipe];
+
     [task setStandardOutput:[NSPipe pipe]];
     [task.standardOutput fileHandleForReading].readabilityHandler = ^(NSFileHandle *handle) {
         NSData *output = [handle availableData];
@@ -252,7 +293,8 @@ - (NSTask*)launchWidgetServer:(NSString*)widgetPath
         @"-d", widgetPath,
         @"-p", [NSString stringWithFormat:@"%d", PORT + portOffset],
         @"-s", [[self getPreferencesDir] path],
-        loginShell ? @"--login-shell" : @""
+        !preferences.enableSecurity ? @"--disable-token" : @"",
+        preferences.loginShell ? @"--login-shell" : @""
     ]];
 
     [task launch];
@@ -294,6 +336,7 @@ - (void)screensChanged:(NSDictionary*)screens
         [windowsController
             updateWindows:screens
             baseUrl: [self serverUrl: @"http"]
+            token:token
             interactionEnabled: preferences.enableInteraction
             forceRefresh: needsRefresh
         ];
@@ -323,6 +366,11 @@ - (void)interactionDidChange
     [screensController syncScreens:self];
 }
 
+- (void)enableSecurityDidChange
+{
+    [self shutdown:true];
+}
+
 - (IBAction)showPreferences:(id)sender
 {
     [preferences showWindow:nil];
@@ -453,6 +501,29 @@ void wallpaperSettingsChanged(
     }
 }
 
+/*!
+    @function generateToken
+
+    @abstract
+    Returns a base64-encoded @p NSString* of specified number of random bytes.
+
+    @param length
+    A reasonably large, non-zero number representing the length in bytes.
+    For example, a value of 32 would generate a 256-bit token.
+
+    @result Returns @p NSString* on success; panics on failure.
+*/
+NSString* generateToken(uint length) {
+    UInt8 buf[length];
+
+    int error = SecRandomCopyBytes(kSecRandomDefault, length, &buf);
+    if (error != errSecSuccess) {
+        panic("failed to generate token");
+    }
+
+    return [[NSData dataWithBytes:buf length:length] base64EncodedStringWithOptions:0];
+}
+
 #
 # pragma mark script support
 #

diff --git a/Uebersicht/UBPreferencesController.h b/Uebersicht/UBPreferencesController.h
@@ -20,6 +20,7 @@
 @property NSURL* widgetDir;
 @property BOOL loginShell;
 @property BOOL enableInteraction;
+@property BOOL enableSecurity;
 
 - (IBAction)showFilePicker:(id)sender;
 

diff --git a/Uebersicht/UBPreferencesController.m b/Uebersicht/UBPreferencesController.m
@@ -16,6 +16,8 @@ @implementation UBPreferencesController {
     LSSharedFileListRef loginItems;
 }
 
+static NSString * const kDefaultsEnableSecurity = @"enableSecurity";
+
 @synthesize filePicker;
 
 - (id)initWithWindowNibName:(NSString *)windowNibName
@@ -26,7 +28,8 @@ - (id)initWithWindowNibName:(NSString *)windowNibName
         NSData* defaultWidgetDir = [self ensureDefaultsWidgetDir];
         NSDictionary *appDefaults = @{
             @"widgetDirectory": defaultWidgetDir,
-            @"enableInteraction": @YES
+            @"enableInteraction": @YES,
+            kDefaultsEnableSecurity: @YES,
         };
         [[NSUserDefaults standardUserDefaults] registerDefaults:appDefaults];
 
@@ -196,6 +199,23 @@ - (void)setEnableInteraction:(BOOL)enabled
     [(UBAppDelegate *)[NSApp delegate] interactionDidChange];
 }
 
+#
+#pragma mark Security
+#
+
+- (BOOL)enableSecurity
+{
+    NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+    return [defaults boolForKey:kDefaultsEnableSecurity];
+}
+
+- (void)setEnableSecurity:(BOOL)enabled
+{
+    NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+    [defaults setBool:enabled forKey:kDefaultsEnableSecurity];
+    [(UBAppDelegate *)[NSApp delegate] enableSecurityDidChange];
+}
+
 #
 #pragma mark Startup
 #

diff --git a/Uebersicht/UBPreferencesController.xib b/Uebersicht/UBPreferencesController.xib
@@ -17,12 +17,12 @@
         <window title="Preferences" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" restorable="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" id="1">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
-            <rect key="contentRect" x="472" y="636" width="580" height="236"/>
+            <rect key="contentRect" x="472" y="636" width="580" height="300"/>
             <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1415"/>
-            <value key="minSize" type="size" width="580" height="236"/>
-            <value key="maxSize" type="size" width="580" height="236"/>
+            <value key="minSize" type="size" width="580" height="300"/>
+            <value key="maxSize" type="size" width="580" height="300"/>
             <view key="contentView" autoresizesSubviews="NO" id="2">
-                <rect key="frame" x="0.0" y="0.0" width="580" height="236"/>
+                <rect key="frame" x="0.0" y="0.0" width="580" height="300"/>
                 <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                 <subviews>
                     <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="5">
@@ -124,6 +124,15 @@
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
+                    <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" fixedFrame="YES" preferredMaxLayoutWidth="268" translatesAutoresizingMaskIntoConstraints="NO" id="BRa-2G-OzE">
+                        <rect key="frame" x="239" y="217" width="330" height="42"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <textFieldCell key="cell" controlSize="small" sendsActionOnEndEditing="YES" title="CAUTION! Disabling this will allow any local user or process to execute commands under your account." id="W8m-Vx-Tdo">
+                            <font key="font" metaFont="label" size="11"/>
+                            <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
                     <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" fixedFrame="YES" preferredMaxLayoutWidth="268" translatesAutoresizingMaskIntoConstraints="NO" id="VVJ-Cl-FSt">
                         <rect key="frame" x="239" y="88" width="312" height="42"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
@@ -133,6 +142,26 @@
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
+                    <button fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="4Cm-6a-MW9">
+                        <rect key="frame" x="220" y="265" width="182" height="18"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <buttonCell key="cell" type="check" title="Enable security measures" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="6iu-kH-BSa">
+                            <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
+                            <font key="font" metaFont="system"/>
+                        </buttonCell>
+                        <connections>
+                            <binding destination="-2" name="value" keyPath="enableSecurity" id="OTS-dV-otR"/>
+                        </connections>
+                    </button>
+                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="HZc-Ku-Lxb">
+                        <rect key="frame" x="158" y="267" width="58" height="16"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Security:" id="7yt-3i-Laz">
+                            <font key="font" metaFont="system"/>
+                            <color key="textColor" name="controlTextColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
                 </subviews>
             </view>
             <connections>

diff --git a/Uebersicht/UBWebSocket.h b/Uebersicht/UBWebSocket.h
@@ -12,7 +12,8 @@
 @interface UBWebSocket : NSObject <SRWebSocketDelegate>
 
 + (id)sharedSocket;
-- (void)open:(NSURL*)aUrl;
+- (void)open:(NSURL*)aUrl
+       token:(NSString*)aToken;
 - (void)close;
 - (void)send:(id)message;
 - (void)listen:(void (^)(id))listener;

diff --git a/Uebersicht/UBWebSocket.m b/Uebersicht/UBWebSocket.m
@@ -13,6 +13,7 @@ @implementation UBWebSocket {
     NSMutableArray* queuedMessages;
     SRWebSocket* ws;
     NSURL* url;
+    NSString *token;
 }
 
 
@@ -49,16 +50,26 @@ - (void)listen:(void (^)(id))listener
 }
 
 - (void)open:(NSURL*)aUrl
+       token:(NSString*)aToken
 {
     if (ws) {
         return;
     }
 
+    token = aToken;
     url = aUrl;
     NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:url];
     [request setValue:@"Übersicht" forHTTPHeaderField:@"Origin"];
     ws = [[SRWebSocket alloc] initWithURLRequest: request];
     ws.delegate = self;
+    ws.requestCookies = @[
+        [NSHTTPCookie cookieWithProperties:@{
+            NSHTTPCookieDomain: url.host,
+            NSHTTPCookiePath: @"/",
+            NSHTTPCookieName: @"token",
+            NSHTTPCookieValue: token,
+        }],
+    ];
     [ws open];
 }
 
@@ -76,7 +87,8 @@ - (void)reopen
 {
     [self close];
     if (url) {
-        [self open:url];
+        [self open:url
+             token:token];
     }
 }
 

diff --git a/Uebersicht/UBWebViewController.h b/Uebersicht/UBWebViewController.h
@@ -15,6 +15,7 @@
 
 - (id)initWithFrame:(NSRect)frame;
 - (void)load:(NSURL*)url;
+- (void)setToken:(NSString*)token;
 - (void)reload;
 - (void)redraw;
 - (void)destroy;