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/* selinux routines
* Copyright (C) 2011 Avesh Agarwal <avagarwa@redhat.com>
* Copyright (C) 2019 Andrew Cagney <cagney@gnu.org>
* Copyright (C) 2020 Richard Haines <richard_c_haines@btinternet.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <https://www.gnu.org/licenses/gpl2.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
*/
#include <errno.h>
#include "labeled_ipsec.h"
#include "defs.h" /* for so_serial_t */
#include "log.h"
#include "connections.h"
#ifdef HAVE_LABELED_IPSEC
#include <selinux/selinux.h> /* rpm:libselinux-devel */
#endif
err_t vet_seclabel(shunk_t sl)
{
#ifdef HAVE_LABELED_IPSEC
if (sl.len > MAX_SECCTX_LEN)
return "security label is too long";
if (sl.len <= 1)
return "security label is empty";
size_t strl = hunk_strnlen(sl);
if (strl == sl.len)
return "security label is missing the NUL terminator";
if (strl + 1 < sl.len)
return "security label has an embedded NUL";
return NULL;
#else
dbg("%s() not implemented: %zu", __func__, sl.len);
return "Labeled IPsec not supported";
#endif
}
void init_labeled_ipsec(const struct logger *logger)
{
#ifdef HAVE_LABELED_IPSEC
if (!is_selinux_enabled()) {
llog(RC_LOG, logger, "selinux support is NOT enabled.");
return;
}
llog(RC_LOG, logger, "SELinux support is enabled in %s mode.",
security_getenforce() ? "ENFORCING" : "PERMISSIVE");
#else
ldbg(logger, "%s() not implemented", __func__);
#endif
}
#ifdef HAVE_LABELED_IPSEC
static bool check_access(const char *perm,
const char *source, const char *scontext,
const char *target, const char *tcontext,
const struct logger *logger)
{
const char tclass[] = "association";
errno = 0; /* selinux_check_access(3) is not documented to set errno */
int rtn = selinux_check_access(scontext, tcontext, tclass, perm, /*auditdata*/NULL);
if (rtn != 0) {
/* make error look like an audit record */
llog_errno(RC_LOG, logger, errno,
"selinux denied { %s } %s scontext=%s %s tcontext=%s tclass=%s: ",
perm, source, scontext, target, tcontext, tclass);
return false;
}
ldbg(logger,
"selinux granted { %s } %s sec_label=scontext=%s %s sec_label=tcontext=%s tclass=%s",
perm, source, scontext, target, tcontext, tclass);
return true;
}
#endif
bool sec_label_within_range(const char *source, shunk_t label, chunk_t range,
const struct logger *logger)
{
#ifdef HAVE_LABELED_IPSEC
if (label.len == 0 || range.len == 0) {
return false;
}
/*
* NUL must be part of HUNK. Too weak?
*
* Translate names into selinux speak.
*/
passert(hunk_strnlen(label) < label.len);
passert(hunk_strnlen(range) < range.len);
const char *scontext = label.ptr;
const char *tcontext = (const char*)range.ptr;
/*
* Check access permission for sl (connection policy label from SAD)
* and range (connection flow label from SPD but initially the
* conn policy-label= entry of the ipsec.conf(5) configuration file).
*
* XXX: Check access permission for SCONTEXT (sec_label from
* acquire, or remote traffic selector) within TCONTEXT
* (sec_label from the connection template).
*/
if (!check_access("polmatch", source, scontext,
"connection", tcontext, logger)) {
return false;
}
char *domain;
errno = 0; /* getcon(3) is not documented to set errno */
if(getcon(&domain) != 0) {
/* note: getcon(3) does not specify that errno is set */
llog_errno(RC_LOG, logger, errno, "getcon(): ");
return false;
}
dbg("our SElinux context is '%s'", domain);
/*
* Check if `pluto`'s SELinux domain can `setcontext` against the child/IPsec SA label.
*
* XXX: Pluto's context is within the acquire/ts context.
* XXX: is this the right way around.
*/
if (!check_access("setcontext", "Pluto's SELinux domain", domain,
source, scontext, logger)) {
return false;
}
freecon(domain);
return true;
#else
ldbg(logger, "%s() not implemented: %s "PRI_SHUNK" "PRI_SHUNK,
__func__, source, pri_shunk(label), pri_shunk(range));
return false;
#endif
}
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