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Diffstat (limited to '')
| -rw-r--r-- | lib/selinux.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/lib/selinux.c b/lib/selinux.c new file mode 100644 index 0000000..8cc444f --- /dev/null +++ b/lib/selinux.c @@ -0,0 +1,203 @@ +/* + * Copyright (c) 2011 , Peter Vrabec <pvrabec@redhat.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the copyright holders or contributors may not be used to + * endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <config.h> + +#ifdef WITH_SELINUX + +#include <stdio.h> +#include "defines.h" + +#include <selinux/selinux.h> +#include <selinux/context.h> +#include "prototypes.h" + +static bool selinux_checked = false; +static bool selinux_enabled; + +/* + * set_selinux_file_context - Set the security context before any file or + * directory creation. + * + * set_selinux_file_context () should be called before any creation + * of file, symlink, directory, ... + * + * Callers may have to Reset SELinux to create files with default + * contexts with reset_selinux_file_context + */ +int set_selinux_file_context (const char *dst_name) +{ + /*@null@*/security_context_t scontext = NULL; + + if (!selinux_checked) { + selinux_enabled = is_selinux_enabled () > 0; + selinux_checked = true; + } + + if (selinux_enabled) { + /* Get the default security context for this file */ + if (matchpathcon (dst_name, 0, &scontext) < 0) { + if (security_getenforce () != 0) { + return 1; + } + } + /* Set the security context for the next created file */ + if (setfscreatecon (scontext) < 0) { + if (security_getenforce () != 0) { + return 1; + } + } + freecon (scontext); + } + return 0; +} + +/* + * reset_selinux_file_context - Reset the security context to the default + * policy behavior + * + * reset_selinux_file_context () should be called after the context + * was changed with set_selinux_file_context () + */ +int reset_selinux_file_context (void) +{ + if (!selinux_checked) { + selinux_enabled = is_selinux_enabled () > 0; + selinux_checked = true; + } + if (selinux_enabled) { + if (setfscreatecon (NULL) != 0) { + return 1; + } + } + return 0; +} + +/* + * Log callback for libselinux internal error reporting. + */ +__attribute__((__format__ (printf, 2, 3))) +static int selinux_log_cb (int type, const char *fmt, ...) { + va_list ap; + char *buf; + int r; +#ifdef WITH_AUDIT + static int selinux_audit_fd = -2; +#endif + + va_start (ap, fmt); + r = vasprintf (&buf, fmt, ap); + va_end (ap); + + if (r < 0) { + return 0; + } + +#ifdef WITH_AUDIT + if (-2 == selinux_audit_fd) { + selinux_audit_fd = audit_open (); + + if (-1 == selinux_audit_fd) { + /* You get these only when the kernel doesn't have + * audit compiled in. */ + if ( (errno != EINVAL) + && (errno != EPROTONOSUPPORT) + && (errno != EAFNOSUPPORT)) { + + (void) fputs (_("Cannot open audit interface.\n"), + stderr); + SYSLOG ((LOG_WARN, "Cannot open audit interface.")); + } + } + } + + if (-1 != selinux_audit_fd) { + if (SELINUX_AVC == type) { + if (audit_log_user_avc_message (selinux_audit_fd, + AUDIT_USER_AVC, buf, NULL, NULL, + NULL, 0) > 0) { + goto skip_syslog; + } + } else if (SELINUX_ERROR == type) { + if (audit_log_user_avc_message (selinux_audit_fd, + AUDIT_USER_SELINUX_ERR, buf, NULL, NULL, + NULL, 0) > 0) { + goto skip_syslog; + } + } + } +#endif + + SYSLOG ((LOG_WARN, "libselinux: %s", buf)); + +skip_syslog: + free (buf); + + return 0; +} + +/* + * check_selinux_permit - Check whether SELinux grants the given + * operation + * + * Parameter is the SELinux permission name, e.g. rootok + * + * Returns 0 when permission is granted + * or something failed but running in + * permissive mode + */ +int check_selinux_permit (const char *perm_name) +{ + char *user_context_str; + int r; + + if (0 == is_selinux_enabled ()) { + return 0; + } + + selinux_set_callback (SELINUX_CB_LOG, (union selinux_callback) selinux_log_cb); + + if (getprevcon (&user_context_str) != 0) { + fprintf (stderr, + _("%s: can not get previous SELinux process context: %s\n"), + Prog, strerror (errno)); + SYSLOG ((LOG_WARN, + "can not get previous SELinux process context: %s", + strerror (errno))); + return (security_getenforce () != 0); + } + + r = selinux_check_access (user_context_str, user_context_str, "passwd", perm_name, NULL); + freecon (user_context_str); + return r; +} + +#else /* !WITH_SELINUX */ +extern int errno; /* warning: ANSI C forbids an empty source file */ +#endif /* !WITH_SELINUX */ |