source: trunk/PrefsPane/src/AuthHelper.m @ 1046

/* Copyright (C) 2008-2009 Peter Speck
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
    This file implements the setuid-root helper tool.
*/

#include <stdio.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <openssl/md5.h>
#include <SystemConfiguration/SCDynamicStoreCopySpecific.h>
#include "GBDebug.h"

@interface AuthHelper : NSObject {
@private
    NSString* _selfRepairPlistPath;
    NSString* _mainBundlePath;
}

- (id)init;
- (void)dealloc;

- (void)exitWithError:(NSString*)msg;

@end

@implementation AuthHelper

static NSString* updateAppPath = @"/Library/PreferencePanes/GlimmerBlocker.prefPane/Contents/GlimmerBlockerUpdater.app";

- (id)init
{
    if (!(self = [super init]))
        return nil;
    NSString *_selfRepairJobLabel = @"org.glimmerblocker.self-repair";
    _selfRepairPlistPath = [[NSString stringWithFormat:@"/Library/LaunchDaemons/%@.plist", _selfRepairJobLabel] retain];
    _mainBundlePath = @"/Library/PreferencePanes/GlimmerBlocker.prefPane";
    return self;
}

- (void)dealloc
{
    [_selfRepairPlistPath release];
    [_mainBundlePath release];
    [super dealloc];
}

- (void)exitWithError:(NSString*)msg
{
    NSLog(@"AuthHelper failed: %@", msg);
    [NSException raise:msg format:@"AuthHelperFormat"];
}

- (void)readBytes:(int)numBytesNeeded
      readingWhat:(NSString*)what
       withBuffer:(char*)buffer
{
    int numBytesRead = 0;
    while (numBytesRead < numBytesNeeded) {
        if (feof(stdin))
            [self exitWithError:[NSString stringWithFormat:@"EOF on stdin while reading %@", what]];
        int x = fread(buffer + numBytesRead, 1, numBytesNeeded - numBytesRead, stdin);
        numBytesRead += x;
        if (ferror(stdin))
            [self exitWithError:[NSString stringWithFormat:@"error on stdin while reading %@", what]];
    }
}

- (NSData*)readData:(NSString*)description
{
    long long len = 0;
    NSAssert(sizeof(len) == 8, @"longlong != 64");
    [self readBytes:sizeof(len) readingWhat:description withBuffer:(char*)&len];
    if (len < 0 || len > 1024 * 1024) {
        NSString* fmt = @"Invalid NSData chunk size in stdin: %lld bytes";
        [self exitWithError:[NSString stringWithFormat:fmt, len]];
    }
    char* buffer = malloc(len);
    if (!buffer)
        [self exitWithError:[NSString stringWithFormat:@"Out of memory, can't malloc %d bytes", len]];
    [self readBytes:len readingWhat:description withBuffer:buffer];
    NSData* data = [NSData dataWithBytes:buffer length:len];
    free(buffer);
    return data;
}

- (void)readAuth
{
    NSData* data = [self readData:@"AuthorizationExternalForm"];
    AuthorizationExternalForm extAuth;
    NSAssert([data length] == sizeof(extAuth), @"AuthDataSize");
    memcpy(&extAuth, [data bytes], sizeof(extAuth));
    AuthorizationRef authRef = NULL;
    OSStatus stat = AuthorizationCreateFromExternalForm(&extAuth, &authRef);
    if (stat != errAuthorizationSuccess)
        [self exitWithError:@"Authorization invalid/expired"];
    DebugNSLog(@"AuthHelper.auth ok");
}

- (int)executeCommandlineTool:(NSString*)cmd
                     withArgs:(NSArray*)args
         withFatalDescription:(NSString*)fatal
{
    [args retain];
    NSTask* task = [[NSTask alloc] init];
    [task setLaunchPath:cmd];
    if (args)
        [task setArguments:args];
    [task setCurrentDirectoryPath:@"/tmp"];
    [task launch];
    [task waitUntilExit];
    int status = [task terminationStatus];
    [task release];
    [args release];
    if (status && fatal) {
        NSString* s = args ? [NSString stringWithFormat:@"%@ %@", cmd, [args componentsJoinedByString:@" "]] : cmd;
        NSLog(@"Got exit code %d: %@", status, s);
        [self exitWithError:fatal];
    }
    return status;
}

- (void)savePlist:(NSString*)xml
           inPath:(NSString*)path
{
    NSFileManager* fm = [NSFileManager defaultManager];
    NSData* data = [xml dataUsingEncoding:NSUTF8StringEncoding];
    if ([[NSData dataWithContentsOfFile:path] isEqual:data]) {
        DebugNSLog(@"AuthHelper.write-plist: no changed.");
    } else {
        NSDictionary* attrs = [NSDictionary dictionaryWithObjectsAndKeys:
                               [NSNumber numberWithLong:0644], NSFilePosixPermissions,
                               NULL];
        BOOL b = [fm createFileAtPath:path contents:data attributes:attrs];
        if (!b)
            [self exitWithError:@"Can't create plist"];
        DebugNSLog(@"AuthHelper.write-plist ok");
    }
    @try {
        [self executeCommandlineTool:@"/bin/launchctl"
                            withArgs:[NSArray arrayWithObjects:@"load", path, NULL]
                withFatalDescription:@"launchctl won't load plist."];
    }
    @catch (NSException* ex) {
        [fm removeItemAtPath:path error:NULL];
        @throw ex;
    }
}

- (void)zapPlist:(NSString*)path
{
    NSFileManager* fm = [NSFileManager defaultManager];
    if (![fm fileExistsAtPath:path])
        return;
    [self executeCommandlineTool:@"/bin/launchctl"
                        withArgs:[NSArray arrayWithObjects:@"unload", path, NULL]
            withFatalDescription:NULL];
    [fm removeItemAtPath:path error:NULL];
    if ([fm fileExistsAtPath:path])
        [self exitWithError:@"Failed deleting launchd plist file"];
}

- (NSString*)makeUpdaterPlistContents:(NSArray*)args
{
    NSFileManager* fm = [NSFileManager defaultManager];
    return [NSString stringWithFormat:@""
            "<?xml version='1.0' encoding='UTF-8'?>\n"
            "<!DOCTYPE plist PUBLIC '-//Apple Computer//DTD PLIST 1.0//EN' 'http://www.apple.com/DTDs/PropertyList-1.0.dtd'>\n"
            "<plist version='1.0'>\n"
            "<dict>\n"
            "   <key>Disabled</key>\n"
            "   <false/>\n"
            "   <key>Label</key>\n"
            "   <string>%@</string>\n"
            "   <key>InitGroups</key>\n"
            "   <true/>\n"
            "   <key>ProgramArguments</key>\n"
            "   <array>\n"
            "       <string>%@/Contents/MacOS/GlimmerBlockerUpdater</string>\n"
            "       <string>--background</string>\n"
            "%@"
            "   </array>\n"
            "   <key>Umask</key>\n"
            "   <integer>18</integer>\n" // 022, files not writeable by group/other.
            "   <key>StartInterval</key>\n"
            "   <integer>%d</integer>\n"
            "   <key>KeepAlive</key>\n"
            "   <false/>\n"
            "   <key>WorkingDirectory</key>\n"
            "   <string>%@/Contents/GlimmerBlockerUpdater.app/Contents/Resources</string>\n"
            "   <key>StandardErrorPath</key>\n"
            "   <string>/Library/Logs/GlimmerBlocker/Launchd.log</string>\n"
            "</dict>\n"
            "</plist>\n",
            UPDATER_JOB_LABEL,
            [GBDebug updaterBundlePath],
            [args containsObject:@"--beta"] ? @"    <string>--beta</string>\n" : @"",
            [fm fileExistsAtPath:@"/Library/GlimmerBlocker/UseSparkleDevChannel"] ? 300 : 24 * 60 * 60,
            _mainBundlePath];
}

- (NSString*)makeProxyPlistContents
{
    return [NSString stringWithFormat:@""
            "<?xml version='1.0' encoding='UTF-8'?>\n"
            "<!DOCTYPE plist PUBLIC '-//Apple Computer//DTD PLIST 1.0//EN' 'http://www.apple.com/DTDs/PropertyList-1.0.dtd'>\n"
            "<plist version='1.0'>\n"
            "<dict>\n"
            "   <key>Disabled</key>\n"
            "   <false/>\n"
            "   <key>Label</key>\n"
            "   <string>%@</string>\n"
            "   <key>UserName</key>\n"
            "   <string>_glimmerblocker</string>\n"
            "   <key>InitGroups</key>\n"
            "   <true/>\n"
            "   <key>ProgramArguments</key>\n"
            "   <array>\n"
            "       <string>%@/Contents/GlimmerBlockerProxy.app/Contents/MacOS/GlimmerBlocker</string>\n"
            "       %@\n"
            "   </array>\n"
            "   <key>OnDemand</key>\n"
            "   <false/>\n"
            "   <key>Umask</key>\n"
            "   <integer>63</integer>\n" // 077, files only readable by _glimmerblocker
            "   <key>KeepAlive</key>\n"
            "   <true/>\n"
            "   <key>WorkingDirectory</key>\n"
            "   <string>%@/Contents/GlimmerBlockerProxy.app/Contents/Resources</string>\n"
            "   <key>StandardErrorPath</key>\n"
            "   <string>/Library/Logs/GlimmerBlocker/Launchd.log</string>\n"
            "</dict>\n"
            "</plist>\n",
            PROXY_JOB_LABEL,
            _mainBundlePath,
            [GBDebug fingerprintOptionForInstalledPanel:[NSBundle mainBundle]],
            _mainBundlePath];
}

- (void)stop:(NSString*)plistPath
{
    [self readAuth];
    // launchctl doesn't return error code if unloading fails....
    [self zapPlist:plistPath];
    [self zapPlist:_selfRepairPlistPath];
}

- (void)start:(NSString*)plistPath  withContents:(NSString*)contents
{
    [self readAuth];
    [self zapPlist:plistPath];
    [self savePlist:contents inPath:plistPath];
    //
    [self zapPlist:_selfRepairPlistPath];
}

- (NSString*)makeDir:(NSString*)path
           withPerms:(int)perms
{
    NSFileManager* fm = [NSFileManager defaultManager];
    BOOL isDirectory = NO;
    if ([fm fileExistsAtPath:path isDirectory:&isDirectory]) {
        if (!isDirectory) {
            NSString* msg = [NSString stringWithFormat:@"Has non-directory item when expected directory: %@", path];
            [NSException raise:msg format:@"AuthHelperFormat"];
        }
        return path;
    }
    NSDictionary* attrs = [NSDictionary dictionaryWithObjectsAndKeys:
                           [NSNumber numberWithLong:perms], NSFilePosixPermissions,
                           NULL];
    NSError *error = NULL;
    if (![fm createDirectoryAtPath:path withIntermediateDirectories:YES attributes:attrs error:&error]) {
        NSString* msg = [NSString stringWithFormat:@"Can't create directory (%@): %@", error, path];
        [NSException raise:msg format:@"AuthHelperFormat"];
    }
    NSArray* args = [NSArray arrayWithObjects:@"_glimmerblocker:_glimmerblocker", path, NULL];
    [self executeCommandlineTool:@"/usr/sbin/chown"
                        withArgs:args
            withFatalDescription:@"chmod of directory."];
    return path;
}

- (NSString*)makePrefsDir
{
    return [self makeDir:@"/Library/GlimmerBlocker" withPerms:0755];
}

- (void)savePrefs
{
    [self readAuth];
    NSData* prefsData = [self readData:@"Prefs data"];
    NSData* expectedMD5 = [self readData:@"Prefs MD5"];
    // checking MD5 makes sure we got all of the data.
    NSData* actualMD5 = [NSData dataWithBytes:MD5([prefsData bytes], [prefsData length], NULL) length:MD5_DIGEST_LENGTH];
    if (![actualMD5 isEqual:expectedMD5])
        [self exitWithError:[NSString stringWithFormat:@"Prefs data MD5 = %@ but expected %@", actualMD5, expectedMD5]];
    DebugNSLog(@"Got valid prefs");
    NSString* path = [NSString stringWithFormat:@"%@/PanelSettings.xml", [self makePrefsDir]];
    [GBDebug safeSaveFileAtPath:path contents:prefsData];
    NSFileManager* fm = [NSFileManager defaultManager];
    NSDictionary* attrs = [NSDictionary dictionaryWithObjectsAndKeys:
                           [NSNumber numberWithLong:0644], NSFilePosixPermissions,
                           NULL];
    [fm setAttributes:attrs ofItemAtPath:path error:NULL];
    [self executeCommandlineTool:@"/usr/sbin/chown"
                        withArgs:[NSArray arrayWithObjects:@"_glimmerblocker:_glimmerblocker", path, NULL]
            withFatalDescription:@"chmod of panel-prefs."];
}

- (BOOL)isUpdaterAlreadyRunning
{
    for (NSDictionary* dict in [[NSWorkspace sharedWorkspace] launchedApplications]) {
        NSString* bid = [dict objectForKey:@"NSApplicationBundleIdentifier"];
        if ([bid isEqual:@"org.glimmerblocker.upgradeApp"])
            return YES;
    }
    return NO;
}

- (BOOL)isAdmin
{
    NSArray* args = [NSArray arrayWithObjects:@"-c", @"groups | perl -ne 'exit 42 if /\\badmin\\b/;'", NULL];
    int status = [self executeCommandlineTool:@"/bin/sh" withArgs:args withFatalDescription:NULL];
    //NSLog(@"isAdmin: %d", status);
    return status == 42;
}

- (int)runNotificationHelper:(NSArray*)args
{
    if ([self isUpdaterAlreadyRunning]) {
        NSLog(@"Ignores notification helper request as updater already is running.");
        exit(501); // see UpdateDaemon.java for exit codes
    }
    // http://developer.apple.com/qa/qa2001/qa1133.html
    // user-id, message
    uid_t uid = -1;// = [userIdText intValue];
    NSString* userName = (NSString*)SCDynamicStoreCopyConsoleUser(NULL, &uid, NULL);
    [userName autorelease];
    DebugNSLog(@"Current user: %d = %@", uid, userName);
    if (uid <= 0 || ![userName length] || [userName isEqual:@"loginwindow"]) {
        // loginwindow might be 10.4 stuff, no such user in 10.5
        NSLog(@"Seems to have no logged-in user.");
        exit(502); // see UpdateDaemon.java for exit codes
    }
    if (setuid(uid) < 0)
        NSLog(@"Failed setting uid to %d", uid);
    if (getuid() != uid)
        [self exitWithError:[NSString stringWithFormat:@"Can't change uid to %d, is still %d", uid, getuid()]];
    if (REQUIRED_VALID_CODESIGN && ![GBDebug verifyCodesign])
        exit(503); // see UpdateDaemon.java for exit codes
    if (![self isAdmin])
        exit(504); // see UpdateDaemon.java for exit codes
    //
    // AuthorizationCopyRights succeeds only when the application is starting using the "open" command
    // instead of being started directly.
    //
    NSMutableArray* openArgs = [NSMutableArray arrayWithCapacity:10];
    [openArgs addObject:@"-n"]; // open new instance
    [openArgs addObject:@"-W"]; // wait until app quit.
    [openArgs addObject:@"-g"]; // open in background
    [openArgs addObject:@"-a"]; // open with app
    [openArgs addObject:[NSString stringWithFormat:@"%@/Contents/MacOS/GlimmerBlockerUpdater", updateAppPath]];
    [openArgs addObjectsFromArray:args];
    int status = [self executeCommandlineTool:@"/usr/bin/open" withArgs:openArgs withFatalDescription:NULL];
    return status;
}

- (void)checkForUpdates:(NSArray*)args
{
    NSString* resourcesPath = [NSString stringWithFormat:@"%@/Contents/Resources", updateAppPath];
    NSMutableArray* openArgs = [[NSMutableArray arrayWithCapacity:5] retain];
    for (NSString* s in args) {
        if ([s isEqual:@"--background"])
            [openArgs addObject:[NSString stringWithFormat:@"%@/option-background.txt", resourcesPath]];
        else if ([s isEqual:@"--beta"])
            [openArgs addObject:[NSString stringWithFormat:@"%@/option-beta.txt", resourcesPath]];
        else if (![s isEqual:@"--foreground"] && ![s isEqual:@"--final"])
            NSLog(@"Unknown sub-option for --check-for-updates: '%@'", s);
    }
    int status = [self runNotificationHelper:openArgs];
    exit(status);
}

- (void)askFilterUpdate:(NSArray*)args
{
    NSMutableArray* openArgs = [[NSMutableArray arrayWithCapacity:5] retain];
    [openArgs addObject:[args objectAtIndex:0]];
    int status = [self runNotificationHelper:openArgs];
    NSLog(@"Ask filter return status: %d", status);
    exit(status);
}

- (void)javaSettings
{
    [self readAuth];
    NSURL* url = [NSURL fileURLWithPath:@"/Library/GlimmerBlocker/JavaSettings.xml"];
    NSData* data = [NSData dataWithContentsOfURL:url];
    NSFileHandle *stdoutHandle = [NSFileHandle fileHandleWithStandardOutput];
    [stdoutHandle writeData:data];
}

- (void)writeStringToStdout:(NSString*)s
{
    NSData* data = [s dataUsingEncoding:NSUTF8StringEncoding];
    NSFileHandle *stdoutHandle = [NSFileHandle fileHandleWithStandardOutput];
    [stdoutHandle writeData:data];
}

- (void)runWithArgs:(NSArray*)args
{
    if (geteuid()) {
        [self exitWithError:[NSString stringWithFormat:@"Not running as root but with uid = %d and euid = %d",
                             getuid(), geteuid()]];
    }
    if (getuid()) {
        if (setuid(0) < 0)
            NSLog(@"Failed setting uid to 0");
        if (getuid()) {
            [self exitWithError:[NSString stringWithFormat:@"Failed to set uid to 0, is still %d, euid = %d",
                                 getuid(), geteuid()]];
        }
    }
    if ([args count] < 2)
        [self exitWithError:@"No arguments given"];
    NSString* cmd = [args objectAtIndex:1];
    args = [args subarrayWithRange:NSMakeRange(2, [args count] - 2)];
    if ([cmd isEqual:@"--plist-contents"])
        [self writeStringToStdout:[self makeProxyPlistContents]];
    else if ([cmd isEqual:@"--plist-path"])
        [self writeStringToStdout:[GBDebug proxyPlistPath]];
    else if ([cmd isEqual:@"--start"])
        [self start:[GBDebug proxyPlistPath] withContents:[self makeProxyPlistContents]];
    else if ([cmd isEqual:@"--stop"])
        [self stop:[GBDebug proxyPlistPath]];
    else if ([cmd isEqual:@"--updater-plist-path"])
        [self writeStringToStdout:[GBDebug updaterPlistPath]];
    else if ([cmd isEqual:@"--updater-plist-content"])
        [self writeStringToStdout:[self makeUpdaterPlistContents:args]];
    else if ([cmd isEqual:@"--updater-start"])
        [self start:[GBDebug updaterPlistPath] withContents:[self makeUpdaterPlistContents:args]];
    else if ([cmd isEqual:@"--updater-stop"])
        [self stop:[GBDebug updaterPlistPath]];
    else if ([cmd isEqual:@"--save-prefs"])
        [self savePrefs];
    else if ([cmd isEqual:@"--check-for-updates"])
        [self checkForUpdates:args];
    else if ([cmd isEqual:@"--ask-filter-update"])
        [self askFilterUpdate:args];
    else if ([cmd isEqual:@"--java-settings"])
        [self javaSettings];
    else
        [self exitWithError:[NSString stringWithFormat:@"Unknown arg: %@", cmd]];
}

@end

int main (int argc, const char * argv[])
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSArray *args = [[NSProcessInfo processInfo] arguments];
    AuthHelper* h = [[[AuthHelper alloc] init] retain];
    @try {
        [h runWithArgs:args];
    }
    @catch (NSException* ex) {
        if (![[ex reason] isEqual:@"AuthHelperFormat"])
            NSLog(@"Stops due to exception: '%@' / '%@'", [ex name], [ex reason]);
        exit(1);
    }
    [h release];
    [pool release];
    return 0;
}