Hi,
Please find attached here a patch that add SELinux support for at. This
is a slightly modified version of the fedora patch[0]. The only
modifications are to autofoo files to fix a FTBFS and to make it apply
cleanly.
I've tested it and now at reproduces the cron behavior:
- When cron_userdomain_transition is set to off, a process for an
unconfined user will transition to unconfined_cronjob_t. For confined
user, the job is run as cronjob_t.
- When cron_userdomain_transition is set to on, the processes are run
under the user default context.
Please note that this patch is not setting the context before calling
sendmail as by default it will transition to system_mail_t anyway.
Cheers,
Laurent Bigonville
[0]http://pkgs.fedoraproject.org/cgit/at.git/tree/at-3.1.14-selinux.patch
only in patch2:
unchanged:
--- at-3.1.14.orig/Makefile.in
+++ at-3.1.14/Makefile.in
@@ -40,6 +40,7 @@
LIBOBJS = @LIBOBJS@
INSTALL = @INSTALL@
PAMLIB = @PAMLIB@
+SELINUXLIB = @SELINUXLIB@
CLONES = atq atrm
ATOBJECTS = at.o panic.o perm.o posixtm.o y.tab.o lex.yy.o
@@ -73,7 +74,7 @@
$(LN_S) -f at atrm
atd: $(RUNOBJECTS)
- $(CC) $(LDFLAGS) -o atd $(RUNOBJECTS) $(LIBS) $(PAMLIB)
+ $(CC) $(LDFLAGS) -o atd $(RUNOBJECTS) $(LIBS) $(PAMLIB) $(SELINUXLIB)
y.tab.c y.tab.h: parsetime.y
$(YACC) -d parsetime.y
only in patch2:
unchanged:
--- at-3.1.14.orig/atd.c
+++ at-3.1.14/atd.c
@@ -83,6 +83,14 @@
#include "getloadavg.h"
#endif
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/get_context_list.h>
+int selinux_enabled=0;
+#include <selinux/flask.h>
+#include <selinux/av_permissions.h>
+#endif
+
/* Macros */
#define BATCH_INTERVAL_DEFAULT 60
@@ -195,6 +203,68 @@
#define fork myfork
#endif
+#ifdef WITH_SELINUX
+static int set_selinux_context(const char *name, const char *filename) {
+ security_context_t user_context=NULL;
+ security_context_t file_context=NULL;
+ struct av_decision avd;
+ int retval=-1;
+ char *seuser=NULL;
+ char *level=NULL;
+
+ if (getseuserbyname(name, &seuser, &level) == 0) {
+ retval=get_default_context_with_level(seuser, level, NULL, &user_context);
+ free(seuser);
+ free(level);
+ if (retval) {
+ if (security_getenforce()==1) {
+ perr("execle: couldn't get security context for user %s\n", name);
+ } else {
+ syslog(LOG_ERR, "execle: couldn't get security context for user %s\n", name);
+ return -1;
+ }
+ }
+ }
+
+ /*
+ * Since crontab files are not directly executed,
+ * crond must ensure that the crontab file has
+ * a context that is appropriate for the context of
+ * the user cron job. It performs an entrypoint
+ * permission check for this purpose.
+ */
+ if (fgetfilecon(STDIN_FILENO, &file_context) < 0)
+ perr("fgetfilecon FAILED %s", filename);
+
+ retval = security_compute_av(user_context,
+ file_context,
+ SECCLASS_FILE,
+ FILE__ENTRYPOINT,
+ &avd);
+ freecon(file_context);
+ if (retval || ((FILE__ENTRYPOINT & avd.allowed) != FILE__ENTRYPOINT)) {
+ if (security_getenforce()==1) {
+ perr("Not allowed to set exec context to %s for user %s\n", user_context,name);
+ } else {
+ syslog(LOG_ERR, "Not allowed to set exec context to %s for user %s\n", user_context,name);
+ retval = -1;
+ goto err;
+ }
+ }
+ if (setexeccon(user_context) < 0) {
+ if (security_getenforce()==1) {
+ perr("Could not set exec context to %s for user %s\n", user_context,name);
+ retval = -1;
+ } else {
+ syslog(LOG_ERR, "Could not set exec context to %s for user %s\n", user_context,name);
+ }
+ }
+ err:
+ freecon(user_context);
+ return 0;
+}
+#endif
+
static void
run_file(const char *filename, uid_t uid, gid_t gid)
{
@@ -424,6 +494,13 @@
nice((tolower((int) queue) - 'a' + 1) * 2);
+#ifdef WITH_SELINUX
+ if (selinux_enabled > 0) {
+ if (set_selinux_context(pentry->pw_name, filename) < 0)
+ perr("SELinux Failed to set context\n");
+ }
+#endif
+
if (initgroups(pentry->pw_name, pentry->pw_gid))
perr("Cannot initialize the supplementary group access list");
@@ -707,6 +784,10 @@
struct passwd *pwe;
struct group *ge;
+#ifdef WITH_SELINUX
+ selinux_enabled=is_selinux_enabled();
+#endif
+
/* We don't need root privileges all the time; running under uid and gid
* daemon is fine.
*/
only in patch2:
unchanged:
--- at-3.1.14.orig/config.h.in
+++ at-3.1.14/config.h.in
@@ -192,6 +192,9 @@
<sys/cpustats.h>. */
#undef UMAX4_3
+/* Define if you are building with_selinux */
+#undef WITH_SELINUX
+
/* Define to 1 if `lex' declares `yytext' as a `char *' by default, not a
`char[]'. */
#undef YYTEXT_POINTER
only in patch2:
unchanged:
--- at-3.1.14.orig/configure.ac
+++ at-3.1.14/configure.ac
@@ -239,6 +239,14 @@
)
AC_SUBST(DAEMON_USERNAME)
+AC_ARG_WITH(selinux,
+[ --with-selinux Define to run with selinux],
+AC_DEFINE(WITH_SELINUX, 1, [Define if you are building with_selinux]),
+)
+AC_CHECK_LIB(selinux, is_selinux_enabled, SELINUXLIB=-lselinux)
+AC_SUBST(SELINUXLIB)
+AC_SUBST(WITH_SELINUX)
+
AC_MSG_CHECKING(groupname to run under)
AC_ARG_WITH(daemon_groupname,
[ --with-daemon_groupname=DAEMON_GROUPNAME Groupname to run under (default daemon) ],
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