platform.c

   1 /* $Id: platform.c,v 1.18 2011/01/11 06:02:25 djm 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 "key.h"
  30 #include "hostfile.h"
  31 #include "auth.h"
  32 #include "auth-pam.h"
  33 #include "platform.h"
  34
  35 #include "openbsd-compat/openbsd-compat.h"
  36
  37 extern int use_privsep;
  38 extern ServerOptions options;
  39
  40 void
  41 platform_pre_listen(void)
  42 {
  43 #ifdef LINUX_OOM_ADJUST
  44         /* Adjust out-of-memory killer so listening process is not killed */
  45         oom_adjust_setup();
  46 #endif
  47 }
  48
  49 void
  50 platform_pre_fork(void)
  51 {
  52 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  53         solaris_contract_pre_fork();
  54 #endif
  55 }
  56
  57 void
  58 platform_post_fork_parent(pid_t child_pid)
  59 {
  60 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  61         solaris_contract_post_fork_parent(child_pid);
  62 #endif
  63 }
  64
  65 void
  66 platform_post_fork_child(void)
  67 {
  68 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  69         solaris_contract_post_fork_child();
  70 #endif
  71 #ifdef LINUX_OOM_ADJUST
  72         oom_adjust_restore();
  73 #endif
  74 }
  75
  76 /* return 1 if we are running with privilege to swap UIDs, 0 otherwise */
  77 int
  78 platform_privileged_uidswap(void)
  79 {
  80 #ifdef HAVE_CYGWIN
  81         /* uid 0 is not special on Cygwin so always try */
  82         return 1;
  83 #else
  84         return (getuid() == 0 || geteuid() == 0);
  85 #endif
  86 }
  87
  88 /*
  89  * This gets called before switching UIDs, and is called even when sshd is
  90  * not running as root.
  91  */
  92 void
  93 platform_setusercontext(struct passwd *pw)
  94 {
  95 #ifdef WITH_SELINUX
  96         /* Cache selinux status for later use */
  97         (void)ssh_selinux_enabled();
  98 #endif
  99
 100 #ifdef USE_SOLARIS_PROJECTS
 101         /* if solaris projects were detected, set the default now */
 102         if (getuid() == 0 || geteuid() == 0)
 103                 solaris_set_default_project(pw);
 104 #endif
 105
 106 #if defined(HAVE_LOGIN_CAP) && defined (__bsdi__)
 107         if (getuid() == 0 || geteuid() == 0)
 108                 setpgid(0, 0);
 109 # endif
 110
 111 #if defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 112         /*
 113          * If we have both LOGIN_CAP and PAM, we want to establish creds
 114          * before calling setusercontext (in session.c:do_setusercontext).
 115          */
 116         if (getuid() == 0 || geteuid() == 0) {
 117                 if (options.use_pam) {
 118                         do_pam_setcred(use_privsep);
 119                 }
 120         }
 121 # endif /* USE_PAM */
 122
 123 #if !defined(HAVE_LOGIN_CAP) && defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
 124         if (getuid() == 0 || geteuid() == 0) {
 125                 /* Sets login uid for accounting */
 126                 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
 127                         error("setluid: %s", strerror(errno));
 128         }
 129 #endif
 130 }
 131
 132 /*
 133  * This gets called after we've established the user's groups, and is only
 134  * called if sshd is running as root.
 135  */
 136 void
 137 platform_setusercontext_post_groups(struct passwd *pw)
 138 {
 139 #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 140         /*
 141          * PAM credentials may take the form of supplementary groups.
 142          * These will have been wiped by the above initgroups() call.
 143          * Reestablish them here.
 144          */
 145         if (options.use_pam) {
 146                 do_pam_setcred(use_privsep);
 147         }
 148 #endif /* USE_PAM */
 149
 150 #if !defined(HAVE_LOGIN_CAP) && (defined(WITH_IRIX_PROJECT) || \
 151     defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY))
 152         irix_setusercontext(pw);
 153 #endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
 154
 155 #ifdef _AIX
 156         aix_usrinfo(pw);
 157 #endif /* _AIX */
 158
 159 #if !defined(HAVE_LOGIN_CAP) && defined(USE_LIBIAF)
 160         if (set_id(pw->pw_name) != 0) {
 161                 exit(1);
 162         }
 163 # endif /* USE_LIBIAF */
 164
 165 #ifdef HAVE_SETPCRED
 166         /*
 167          * If we have a chroot directory, we set all creds except real
 168          * uid which we will need for chroot.  If we don't have a
 169          * chroot directory, we don't override anything.
 170          */
 171         {
 172                 char **creds = NULL, *chroot_creds[] =
 173                     { "REAL_USER=root", NULL };
 174
 175                 if (options.chroot_directory != NULL &&
 176                     strcasecmp(options.chroot_directory, "none") != 0)
 177                         creds = chroot_creds;
 178
 179                 if (setpcred(pw->pw_name, creds) == -1)
 180                         fatal("Failed to set process credentials");
 181         }
 182 #endif /* HAVE_SETPCRED */
 183 #ifdef WITH_SELINUX
 184         ssh_selinux_setup_exec_context(pw->pw_name);
 185 #endif
 186 }
 187
 188 char *
 189 platform_krb5_get_principal_name(const char *pw_name)
 190 {
 191 #ifdef USE_AIX_KRB_NAME
 192         return aix_krb5_get_principal_name(pw_name);
 193 #else
 194         return NULL;
 195 #endif
 196 }