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