172 lines
4.3 KiB
C
172 lines
4.3 KiB
C
/* $Id: port-linux.c,v 1.5 2008/03/26 20:27:21 dtucker Exp $ */
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/*
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* Copyright (c) 2005 Daniel Walsh <dwalsh@redhat.com>
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* Copyright (c) 2006 Damien Miller <djm@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Linux-specific portability code - just SELinux support at present
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*/
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#include "includes.h"
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#include <errno.h>
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#include <stdarg.h>
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#include <string.h>
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#ifdef WITH_SELINUX
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#include "log.h"
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#include "port-linux.h"
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#include <selinux/selinux.h>
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#include <selinux/flask.h>
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#include <selinux/get_context_list.h>
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/* Wrapper around is_selinux_enabled() to log its return value once only */
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int
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ssh_selinux_enabled(void)
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{
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static int enabled = -1;
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if (enabled == -1) {
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enabled = is_selinux_enabled();
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debug("SELinux support %s", enabled ? "enabled" : "disabled");
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}
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return (enabled);
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}
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/* Return the default security context for the given username */
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static security_context_t
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ssh_selinux_getctxbyname(char *pwname)
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{
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security_context_t sc;
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char *sename = NULL, *lvl = NULL;
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int r;
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#ifdef HAVE_GETSEUSERBYNAME
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if (getseuserbyname(pwname, &sename, &lvl) != 0)
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return NULL;
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#else
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sename = pwname;
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lvl = NULL;
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#endif
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#ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL
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r = get_default_context_with_level(sename, lvl, NULL, &sc);
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#else
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r = get_default_context(sename, NULL, &sc);
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#endif
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if (r != 0) {
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switch (security_getenforce()) {
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case -1:
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fatal("%s: ssh_selinux_getctxbyname: "
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"security_getenforce() failed", __func__);
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case 0:
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error("%s: Failed to get default SELinux security "
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"context for %s", __func__, pwname);
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break;
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default:
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fatal("%s: Failed to get default SELinux security "
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"context for %s (in enforcing mode)",
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__func__, pwname);
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}
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}
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#ifdef HAVE_GETSEUSERBYNAME
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if (sename != NULL)
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xfree(sename);
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if (lvl != NULL)
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xfree(lvl);
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#endif
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return (sc);
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}
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/* Set the execution context to the default for the specified user */
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void
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ssh_selinux_setup_exec_context(char *pwname)
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{
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security_context_t user_ctx = NULL;
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if (!ssh_selinux_enabled())
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return;
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debug3("%s: setting execution context", __func__);
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user_ctx = ssh_selinux_getctxbyname(pwname);
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if (setexeccon(user_ctx) != 0) {
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switch (security_getenforce()) {
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case -1:
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fatal("%s: security_getenforce() failed", __func__);
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case 0:
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error("%s: Failed to set SELinux execution "
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"context for %s", __func__, pwname);
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break;
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default:
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fatal("%s: Failed to set SELinux execution context "
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"for %s (in enforcing mode)", __func__, pwname);
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}
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}
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if (user_ctx != NULL)
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freecon(user_ctx);
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debug3("%s: done", __func__);
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}
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/* Set the TTY context for the specified user */
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void
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ssh_selinux_setup_pty(char *pwname, const char *tty)
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{
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security_context_t new_tty_ctx = NULL;
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security_context_t user_ctx = NULL;
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security_context_t old_tty_ctx = NULL;
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if (!ssh_selinux_enabled())
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return;
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debug3("%s: setting TTY context on %s", __func__, tty);
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user_ctx = ssh_selinux_getctxbyname(pwname);
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/* XXX: should these calls fatal() upon failure in enforcing mode? */
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if (getfilecon(tty, &old_tty_ctx) == -1) {
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error("%s: getfilecon: %s", __func__, strerror(errno));
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goto out;
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}
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if (security_compute_relabel(user_ctx, old_tty_ctx,
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SECCLASS_CHR_FILE, &new_tty_ctx) != 0) {
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error("%s: security_compute_relabel: %s",
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__func__, strerror(errno));
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goto out;
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}
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if (setfilecon(tty, new_tty_ctx) != 0)
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error("%s: setfilecon: %s", __func__, strerror(errno));
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out:
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if (new_tty_ctx != NULL)
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freecon(new_tty_ctx);
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if (old_tty_ctx != NULL)
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freecon(old_tty_ctx);
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if (user_ctx != NULL)
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freecon(user_ctx);
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debug3("%s: done", __func__);
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}
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#endif /* WITH_SELINUX */
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