platform.c

   1 /* $Id: platform.c,v 1.17 2010/11/23 23:09:13 dtucker Exp $ */
   2
   3 /*
   4  * Copyright (c) 2006 Darren Tucker.  All rights reserved.
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "includes.h"
  20
  21 #include <sys/types.h>
  22
  23 #include <stdarg.h>
  24 #include <unistd.h>
  25
  26 #include "log.h"
  27 #include "buffer.h"
  28 #include "servconf.h"
  29 #include "platform.h"
  30
  31 #include "openbsd-compat/openbsd-compat.h"
  32
  33 extern int use_privsep;
  34 extern ServerOptions options;
  35
  36 void
  37 platform_pre_listen(void)
  38 {
  39 #ifdef LINUX_OOM_ADJUST
  40         /* Adjust out-of-memory killer so listening process is not killed */
  41         oom_adjust_setup();
  42 #endif
  43 }
  44
  45 void
  46 platform_pre_fork(void)
  47 {
  48 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  49         solaris_contract_pre_fork();
  50 #endif
  51 }
  52
  53 void
  54 platform_post_fork_parent(pid_t child_pid)
  55 {
  56 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  57         solaris_contract_post_fork_parent(child_pid);
  58 #endif
  59 }
  60
  61 void
  62 platform_post_fork_child(void)
  63 {
  64 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  65         solaris_contract_post_fork_child();
  66 #endif
  67 #ifdef LINUX_OOM_ADJUST
  68         oom_adjust_restore();
  69 #endif
  70 }
  71
  72 /* return 1 if we are running with privilege to swap UIDs, 0 otherwise */
  73 int
  74 platform_privileged_uidswap(void)
  75 {
  76 #ifdef HAVE_CYGWIN
  77         /* uid 0 is not special on Cygwin so always try */
  78         return 1;
  79 #else
  80         return (getuid() == 0 || geteuid() == 0);
  81 #endif
  82 }
  83
  84 /*
  85  * This gets called before switching UIDs, and is called even when sshd is
  86  * not running as root.
  87  */
  88 void
  89 platform_setusercontext(struct passwd *pw)
  90 {
  91 #ifdef WITH_SELINUX
  92         /* Cache selinux status for later use */
  93         (void)ssh_selinux_enabled();
  94 #endif
  95
  96 #ifdef USE_SOLARIS_PROJECTS
  97         /* if solaris projects were detected, set the default now */
  98         if (getuid() == 0 || geteuid() == 0)
  99                 solaris_set_default_project(pw);
 100 #endif
 101
 102 #if defined(HAVE_LOGIN_CAP) && defined (__bsdi__)
 103         if (getuid() == 0 || geteuid() == 0)
 104                 setpgid(0, 0);
 105 # endif
 106
 107 #if defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 108         /*
 109          * If we have both LOGIN_CAP and PAM, we want to establish creds
 110          * before calling setusercontext (in session.c:do_setusercontext).
 111          */
 112         if (getuid() == 0 || geteuid() == 0) {
 113                 if (options.use_pam) {
 114                         do_pam_setcred(use_privsep);
 115                 }
 116         }
 117 # endif /* USE_PAM */
 118
 119 #if !defined(HAVE_LOGIN_CAP) && defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
 120         if (getuid() == 0 || geteuid() == 0) {
 121                 /* Sets login uid for accounting */
 122                 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
 123                         error("setluid: %s", strerror(errno));
 124         }
 125 #endif
 126 }
 127
 128 /*
 129  * This gets called after we've established the user's groups, and is only
 130  * called if sshd is running as root.
 131  */
 132 void
 133 platform_setusercontext_post_groups(struct passwd *pw)
 134 {
 135 #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 136         /*
 137          * PAM credentials may take the form of supplementary groups.
 138          * These will have been wiped by the above initgroups() call.
 139          * Reestablish them here.
 140          */
 141         if (options.use_pam) {
 142                 do_pam_setcred(use_privsep);
 143         }
 144 #endif /* USE_PAM */
 145
 146 #if !defined(HAVE_LOGIN_CAP) && (defined(WITH_IRIX_PROJECT) || \
 147     defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY))
 148         irix_setusercontext(pw);
 149 #endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
 150
 151 #ifdef _AIX
 152         aix_usrinfo(pw);
 153 #endif /* _AIX */
 154
 155 #if !defined(HAVE_LOGIN_CAP) && defined(USE_LIBIAF)
 156         if (set_id(pw->pw_name) != 0) {
 157                 exit(1);
 158         }
 159 # endif /* USE_LIBIAF */
 160
 161 #ifdef HAVE_SETPCRED
 162         /*
 163          * If we have a chroot directory, we set all creds except real
 164          * uid which we will need for chroot.  If we don't have a
 165          * chroot directory, we don't override anything.
 166          */
 167         {
 168                 char **creds = NULL, *chroot_creds[] =
 169                     { "REAL_USER=root", NULL };
 170
 171                 if (options.chroot_directory != NULL &&
 172                     strcasecmp(options.chroot_directory, "none") != 0)
 173                         creds = chroot_creds;
 174
 175                 if (setpcred(pw->pw_name, creds) == -1)
 176                         fatal("Failed to set process credentials");
 177         }
 178 #endif /* HAVE_SETPCRED */
 179 #ifdef WITH_SELINUX
 180         ssh_selinux_setup_exec_context(pw->pw_name);
 181 #endif
 182 }
 183
 184 char *
 185 platform_krb5_get_principal_name(const char *pw_name)
 186 {
 187 #ifdef USE_AIX_KRB_NAME
 188         return aix_krb5_get_principal_name(pw_name);
 189 #else
 190         return NULL;
 191 #endif
 192 }