crypto/openssh/platform.c

   1 /* $Id: platform.c,v 1.22 2014/07/18 04:11:26 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 <stdarg.h>
  22 #include <unistd.h>
  23
  24 #include "log.h"
  25 #include "buffer.h"
  26 #include "misc.h"
  27 #include "servconf.h"
  28 #include "key.h"
  29 #include "hostfile.h"
  30 #include "auth.h"
  31 #include "auth-pam.h"
  32 #include "platform.h"
  33
  34 #include "openbsd-compat/openbsd-compat.h"
  35
  36 extern int use_privsep;
  37 extern ServerOptions options;
  38
  39 void
  40 platform_pre_listen(void)
  41 {
  42 #ifdef LINUX_OOM_ADJUST
  43         /* Adjust out-of-memory killer so listening process is not killed */
  44         oom_adjust_setup();
  45 #endif
  46 }
  47
  48 void
  49 platform_pre_fork(void)
  50 {
  51 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  52         solaris_contract_pre_fork();
  53 #endif
  54 }
  55
  56 void
  57 platform_pre_restart(void)
  58 {
  59 #ifdef LINUX_OOM_ADJUST
  60         oom_adjust_restore();
  61 #endif
  62 }
  63
  64 void
  65 platform_post_fork_parent(pid_t child_pid)
  66 {
  67 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  68         solaris_contract_post_fork_parent(child_pid);
  69 #endif
  70 }
  71
  72 void
  73 platform_post_fork_child(void)
  74 {
  75 #ifdef USE_SOLARIS_PROCESS_CONTRACTS
  76         solaris_contract_post_fork_child();
  77 #endif
  78 #ifdef LINUX_OOM_ADJUST
  79         oom_adjust_restore();
  80 #endif
  81 }
  82
  83 /* return 1 if we are running with privilege to swap UIDs, 0 otherwise */
  84 int
  85 platform_privileged_uidswap(void)
  86 {
  87 #ifdef HAVE_CYGWIN
  88         /* uid 0 is not special on Cygwin so always try */
  89         return 1;
  90 #else
  91         return (getuid() == 0 || geteuid() == 0);
  92 #endif
  93 }
  94
  95 /*
  96  * This gets called before switching UIDs, and is called even when sshd is
  97  * not running as root.
  98  */
  99 void
 100 platform_setusercontext(struct passwd *pw)
 101 {
 102 #ifdef WITH_SELINUX
 103         /* Cache selinux status for later use */
 104         (void)ssh_selinux_enabled();
 105 #endif
 106
 107 #ifdef USE_SOLARIS_PROJECTS
 108         /*
 109          * If solaris projects were detected, set the default now, unless
 110          * we are using PAM in which case it is the responsibility of the
 111          * PAM stack.
 112          */
 113         if (!options.use_pam && (getuid() == 0 || geteuid() == 0))
 114                 solaris_set_default_project(pw);
 115 #endif
 116
 117 #if defined(HAVE_LOGIN_CAP) && defined (__bsdi__)
 118         if (getuid() == 0 || geteuid() == 0)
 119                 setpgid(0, 0);
 120 # endif
 121
 122 #if defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 123         /*
 124          * If we have both LOGIN_CAP and PAM, we want to establish creds
 125          * before calling setusercontext (in session.c:do_setusercontext).
 126          */
 127         if (getuid() == 0 || geteuid() == 0) {
 128                 if (options.use_pam) {
 129                         do_pam_setcred(use_privsep);
 130                 }
 131         }
 132 # endif /* USE_PAM */
 133
 134 #if !defined(HAVE_LOGIN_CAP) && defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
 135         if (getuid() == 0 || geteuid() == 0) {
 136                 /* Sets login uid for accounting */
 137                 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
 138                         error("setluid: %s", strerror(errno));
 139         }
 140 #endif
 141 }
 142
 143 /*
 144  * This gets called after we've established the user's groups, and is only
 145  * called if sshd is running as root.
 146  */
 147 void
 148 platform_setusercontext_post_groups(struct passwd *pw)
 149 {
 150 #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM)
 151         /*
 152          * PAM credentials may take the form of supplementary groups.
 153          * These will have been wiped by the above initgroups() call.
 154          * Reestablish them here.
 155          */
 156         if (options.use_pam) {
 157                 do_pam_setcred(use_privsep);
 158         }
 159 #endif /* USE_PAM */
 160
 161 #if !defined(HAVE_LOGIN_CAP) && (defined(WITH_IRIX_PROJECT) || \
 162     defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY))
 163         irix_setusercontext(pw);
 164 #endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
 165
 166 #ifdef _AIX
 167         aix_usrinfo(pw);
 168 #endif /* _AIX */
 169
 170 #ifdef HAVE_SETPCRED
 171         /*
 172          * If we have a chroot directory, we set all creds except real
 173          * uid which we will need for chroot.  If we don't have a
 174          * chroot directory, we don't override anything.
 175          */
 176         {
 177                 char **creds = NULL, *chroot_creds[] =
 178                     { "REAL_USER=root", NULL };
 179
 180                 if (options.chroot_directory != NULL &&
 181                     strcasecmp(options.chroot_directory, "none") != 0)
 182                         creds = chroot_creds;
 183
 184                 if (setpcred(pw->pw_name, creds) == -1)
 185                         fatal("Failed to set process credentials");
 186         }
 187 #endif /* HAVE_SETPCRED */
 188 #ifdef WITH_SELINUX
 189         ssh_selinux_setup_exec_context(pw->pw_name);
 190 #endif
 191 }
 192
 193 char *
 194 platform_krb5_get_principal_name(const char *pw_name)
 195 {
 196 #ifdef USE_AIX_KRB_NAME
 197         return aix_krb5_get_principal_name(pw_name);
 198 #else
 199         return NULL;
 200 #endif
 201 }
 202
 203 /*
 204  * return 1 if the specified uid is a uid that may own a system directory
 205  * otherwise 0.
 206  */
 207 int
 208 platform_sys_dir_uid(uid_t uid)
 209 {
 210         if (uid == 0)
 211                 return 1;
 212 #ifdef PLATFORM_SYS_DIR_UID
 213         if (uid == PLATFORM_SYS_DIR_UID)
 214                 return 1;
 215 #endif
 216         return 0;
 217 }