securityd/src/authhost.cpp

   1 /*
   2  * Copyright (c) 2000-2007,2009-2010,2012 Apple 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 #include <security_utilities/logging.h>
  29 #include <security_utilities/debugging.h>
  30 #include <security_agent_client/sa_request.h>
  31 #include <security_agent_client/utils.h>
  32 #include <bsm/audit.h>
  33 #include <bootstrap_priv.h>
  34
  35 #include <grp.h>
  36 #include <pwd.h>
  37 #include <sys/types.h>
  38 #include <sys/sysctl.h>
  39 #include <syslog.h>
  40 #include <pthread.h>
  41
  42 static pthread_once_t agent_cred_init = PTHREAD_ONCE_INIT;
  43 static gid_t agent_gid = 92;
  44 static uid_t agent_uid = 92;
  45
  46 void initialize_agent_creds()
  47 {
  48     struct passwd *agentUser = getpwnam("securityagent");
  49     if (agentUser)
  50     {
  51         agent_uid = agentUser->pw_uid;
  52         agent_gid = agentUser->pw_gid;
  53         endpwent();
  54     }
  55 }
  56
  57 AuthHostInstance::AuthHostInstance(Session &session, AuthHostType host) :
  58         mHostType(host)
  59 {
  60         secdebug("authhost", "authhost born (%p)", this);
  61         referent(session);
  62         session.addReference(*this);
  63     if (host == securityAgent)
  64         pthread_once(&agent_cred_init, initialize_agent_creds);
  65 }
  66
  67 AuthHostInstance::~AuthHostInstance()
  68 {
  69         secdebug("authhost", "authhost died (%p)", this);
  70 }
  71
  72 Session &AuthHostInstance::session() const
  73 {
  74         return referent<Session>();
  75 }
  76
  77 bool AuthHostInstance::inDarkWake()
  78 {
  79         return session().server().inDarkWake();
  80 }
  81
  82 void
  83 AuthHostInstance::childAction()
  84 {
  85         // switch to desired session
  86         CommonCriteria::AuditInfo &audit = this->session().auditInfo();
  87         audit.get(audit.sessionId());
  88         audit.set();
  89         //this->session().auditInfo().set();
  90
  91         // Setup the environment for the SecurityAgent
  92         unsetenv("USER");
  93         unsetenv("LOGNAME");
  94         unsetenv("HOME");
  95
  96         // close down any files that might have been open at this point
  97         int maxDescriptors = getdtablesize ();
  98         int i;
  99
 100         int devnull = open(_PATH_DEVNULL, O_RDWR, 0);
 101         if (devnull >= 0) for (i = 0; i < 3; ++i)
 102         {
 103                 dup2(devnull, i);
 104         }
 105
 106         for (i = 3; i < maxDescriptors; ++i)
 107         {
 108                 close (i);
 109         }
 110
 111         // construct path to SecurityAgent
 112         char agentExecutable[PATH_MAX + 1];
 113         const char *path = getenv("SECURITYAGENT");
 114         if (!path)
 115                 path = "/System/Library/CoreServices/SecurityAgent.app";
 116         secdebug("adhoc", "hostType = %d", mHostType);
 117
 118         if ((mHostType == userAuthHost) || (mHostType == privilegedAuthHost))
 119         {
 120                 snprintf(agentExecutable, sizeof(agentExecutable), "%s/Contents/Resources/authorizationhost", path);
 121                 secdebug("AuthHostInstance", "execl(%s)", agentExecutable);
 122                 execl(agentExecutable, agentExecutable, NULL);
 123         }
 124         else
 125         {
 126                 snprintf(agentExecutable, sizeof(agentExecutable), "%s/Contents/MacOS/SecurityAgent", path);
 127
 128                 pid_t pid = getpid();
 129                 if ((pid <= 0) ||
 130             sysctlbyname("vfs.generic.noremotehang", NULL, NULL, &pid, sizeof(pid)))
 131                                 syslog(LOG_ERR, "Failed to set vfs.generic.noremotehang for pid(%d)", pid);
 132
 133                 setgroups(1, &agent_gid);
 134                 setgid(agent_gid);
 135                 setuid(agent_uid);
 136
 137                 secdebug("AuthHostInstance", "execl(%s) as user (%d,%d)", agentExecutable, agent_uid, agent_gid);
 138                 execl(agentExecutable, agentExecutable, NULL);
 139         }
 140
 141         secdebug("AuthHostInstance", "execl failed, errno=%d", errno);
 142         // Unconditional suicide follows.
 143         _exit(1);
 144 }
 145
 146 // @@@  these definitions and the logic in lookup() should move into
 147 // libsecurity_agent
 148 #define SECURITYAGENT_BOOTSTRAP_NAME_BASE       "com.apple.SecurityAgent"
 149 #define AUTHORIZATIONHOST_BOOTSTRAP_NAME_BASE   "com.apple.authorizationhost"
 150
 151 mach_port_t
 152 AuthHostInstance::lookup(SessionId jobId)
 153 {
 154     StLock<Mutex> _(*this);
 155
 156     mach_port_t pluginhostPort = MACH_PORT_NULL;
 157     kern_return_t result;
 158     const char *serviceName;
 159     /* PR-7483709 const */ uuid_t instanceId = UUID_INITIALIZER_FROM_SESSIONID(jobId);
 160     uuid_string_t s;
 161
 162     if ((mHostType == securityAgent)) {
 163         if (!(session().attributes() & sessionHasGraphicAccess))
 164             CssmError::throwMe(CSSM_ERRCODE_NO_USER_INTERACTION);
 165         if (inDarkWake())
 166             CssmError::throwMe(CSSM_ERRCODE_IN_DARK_WAKE);
 167     }
 168
 169     if (mHostType == securityAgent)
 170         serviceName = SECURITYAGENT_BOOTSTRAP_NAME_BASE;
 171     else
 172         serviceName = AUTHORIZATIONHOST_BOOTSTRAP_NAME_BASE;
 173
 174     secdebug("AuthHostInstance", "looking up %s instance %s", serviceName,
 175       uuid_to_string(instanceId, s)); // XXX/gh  debugging
 176     if ((result = bootstrap_look_up3(bootstrap_port, serviceName,
 177       &pluginhostPort, 0, instanceId, BOOTSTRAP_SPECIFIC_INSTANCE)) != KERN_SUCCESS) {
 178
 179         Syslog::error("error %d looking up %s instance %s", result, serviceName,
 180           uuid_to_string(instanceId, s));
 181     } else
 182         secdebug("AuthHostInstance", "port = %x", (unsigned int)pluginhostPort);
 183
 184     return pluginhostPort;
 185 }
 186
 187 Port AuthHostInstance::activate()
 188 {
 189         StLock<Mutex> _(*this);
 190         if (state() != alive)
 191         {
 192                 if ((mHostType == securityAgent)) {
 193                     if (!(session().attributes() & sessionHasGraphicAccess))
 194                         CssmError::throwMe(CSSM_ERRCODE_NO_USER_INTERACTION);
 195                     if (inDarkWake())
 196                         CssmError::throwMe(CSSM_ERRCODE_IN_DARK_WAKE);
 197                 }
 198
 199                 fork();
 200                 switch (ServerChild::state()) {
 201                 case Child::alive:
 202                         secdebug("AuthHostInstance", "%p (pid %d) has launched", this, pid());
 203                         break;
 204                 case Child::dead:
 205                         secdebug("AuthHostInstance", "%p (pid %d) failed on startup", this, pid());
 206                         break;
 207                 default:
 208                         assert(false);
 209                 }
 210         }
 211
 212         if (!ready())
 213                 CssmError::throwMe(CSSM_ERRCODE_NO_USER_INTERACTION);
 214
 215         return servicePort();
 216 }