src/authhost.cpp

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <paths.h>
  25 #include <fcntl.h>
  26 #include "authhost.h"
  27 #include "server.h"
  28
  29 #include <grp.h>
  30 #include <pwd.h>
  31
  32
  33 AuthHostInstance::AuthHostInstance(Session &session, AuthHostType host) :
  34         mHostType(host)
  35 {
  36         secdebug("authhost", "authhost born (%p)", this);
  37         referent(session);
  38         session.addReference(*this);
  39 }
  40
  41 AuthHostInstance::~AuthHostInstance()
  42 {
  43         secdebug("authhost", "authhost died (%p)", this);
  44
  45         // clean up
  46         servicePort ().destroy ();
  47 }
  48
  49 Session &AuthHostInstance::session() const
  50 {
  51         return referent<Session>();
  52 }
  53
  54 void
  55 AuthHostInstance::childAction()
  56 {
  57         // Setup the environment for the SecurityAgent
  58         unsetenv("USER");
  59         unsetenv("LOGNAME");
  60         unsetenv("HOME");
  61
  62         // close down any files that might have been open at this point
  63         int maxDescriptors = getdtablesize ();
  64         int i;
  65
  66         int devnull = open(_PATH_DEVNULL, O_RDWR, 0);
  67         if (devnull >= 0) for (i = 0; i < 3; ++i)
  68         {
  69                 dup2(devnull, i);
  70         }
  71
  72         for (i = 3; i < maxDescriptors; ++i)
  73         {
  74                 close (i);
  75         }
  76
  77         // construct path to SecurityAgent
  78         char agentExecutable[PATH_MAX + 1];
  79         const char *path = getenv("SECURITYAGENT");
  80         if (!path)
  81                 path = "/System/Library/CoreServices/SecurityAgent.app";
  82
  83         if ((mHostType == userAuthHost) || (mHostType == privilegedAuthHost))
  84         {
  85                 snprintf(agentExecutable, sizeof(agentExecutable), "%s/Contents/Resources/authorizationhost", path);
  86
  87                 secdebug("AuthHostInstance", "execl(%s)", agentExecutable);
  88                 execl(agentExecutable, agentExecutable, NULL);
  89         }
  90         else
  91         {
  92                 snprintf(agentExecutable, sizeof(agentExecutable), "%s/Contents/MacOS/SecurityAgent", path);
  93
  94                 struct group *agentGroup = getgrnam("securityagent");
  95                 gid_t agentGID = static_cast<gid_t>(-2);
  96                 if (agentGroup)
  97                 {
  98                         agentGID = agentGroup->gr_gid;
  99                         endgrent();
 100                 }
 101
 102                 struct passwd *agentUser = getpwnam("securityagent");
 103                 uid_t agentUID = static_cast<uid_t>(-2);
 104                 if (agentUser)
 105                 {
 106                         agentUID = agentUser->pw_uid;
 107                         endpwent();
 108                 }
 109
 110                 setuid(agentUID);
 111                 setgid(agentGID);
 112
 113                 CFRef<CFDataRef> userPrefs(session().copyUserPrefs());
 114
 115                 FILE *mbox = tmpfile();
 116
 117                 if (userPrefs && mbox)
 118                 {
 119                         if (fwrite(CFDataGetBytePtr(userPrefs), CFDataGetLength(userPrefs), 1, mbox) != 1)
 120                                 fclose(mbox);
 121                         else
 122                         {
 123                                 char mboxFdString[20];
 124                                 fflush(mbox);
 125                                 if ((int)sizeof(mboxFdString) > snprintf(mboxFdString, sizeof(mboxFdString), "%d", fileno(mbox)))
 126                                         setenv("SECURITYAGENT_USERPREFS_FD", mboxFdString, 1);
 127                         }
 128                 }
 129
 130                 secdebug("AuthHostInstance", "execl(%s) as user (%d,%d)", agentExecutable, agentUID, agentGID);
 131                 execl(agentExecutable, agentExecutable, NULL);
 132         }
 133
 134         secdebug("AuthHostInstance", "execl failed, errno=%d", errno);
 135         // Unconditional suicide follows.
 136         // See comments below on why we can't use abort()
 137 #if 1
 138         _exit(1);
 139 #else
 140         // NOTE: OS X abort() is implemented as kill(getuid()), which fails
 141         // for a setuid-root process that has setuid'd. Go back to root to die...
 142         setuid(0);
 143         abort();
 144 #endif
 145 }
 146
 147 Port
 148 AuthHostInstance::activate()
 149 {
 150         StLock<Mutex> _(*this);
 151         if (state() != alive)
 152         {
 153                 if (!(session().attributes() & sessionHasGraphicAccess))
 154                         CssmError::throwMe(CSSM_ERRCODE_NO_USER_INTERACTION);
 155
 156                 Security::MachPlusPlus::StBootstrap bootSaver(session().bootstrapPort());
 157
 158                 fork();
 159                 switch (ServerChild::state()) {
 160                 case Child::alive:
 161                         secdebug("AuthHostInstance", "%p (pid %d) has launched", this, pid());
 162                         break;
 163                 case Child::dead:
 164                         secdebug("AuthHostInstance", "%p (pid %d) failed on startup", this, pid());
 165                         break;
 166                 default:
 167                         assert(false);
 168                 }
 169         }
 170
 171         if (!ready())
 172                 CssmError::throwMe(CSSM_ERRCODE_NO_USER_INTERACTION);
 173
 174         return servicePort();
 175 }