[patch] vixie-cron-4.1-selinux-2.patch

vixie-cron-4.1-selinux-2.patch (text/plain), 6.41 KB, created by Jason Zaman on 2017-04-30 03:07:40 UTC

diff -ur vixie-cron-4.1/Makefile vixie-cron-4.1-selinux/Makefile
--- vixie-cron-4.1/Makefile	2004-08-28 02:09:33.000000000 +0800
+++ vixie-cron-4.1-selinux/Makefile	2017-04-26 22:16:53.321394815 +0800
@@ -68,7 +68,8 @@
 #<<want to use a nonstandard CC?>>
 CC		=	gcc -Wall -Wno-unused -Wno-comment
 #<<manifest defines>>
-DEFS		=
+DEFS		= -s -DWITH_SELINUX
+LIBS		+= 	-lselinux
 #(SGI IRIX systems need this)
 #DEFS		=	-D_BSD_SIGNALS -Dconst=
 #<<the name of the BSD-like install program>>
diff -ur vixie-cron-4.1/database.c vixie-cron-4.1-selinux/database.c
--- vixie-cron-4.1/database.c	2004-08-28 02:09:34.000000000 +0800
+++ vixie-cron-4.1-selinux/database.c	2017-04-27 01:31:34.757942605 +0800
@@ -28,6 +28,15 @@
 
 #include "cron.h"
 
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/context.h>
+#include <selinux/get_context_list.h>
+#define SYSUSERNAME "system_u"
+#else
+#define SYSUSERNAME "*system*"
+#endif
+
 #define TMAX(a,b) ((a)>(b)?(a):(b))
 
 static	void		process_crontab(const char *, const char *,
@@ -183,7 +192,7 @@
 	if (fname == NULL) {
 		/* must be set to something for logging purposes.
 		 */
-		fname = "*system*";
+		fname = SYSUSERNAME;
 	} else if ((pw = getpwnam(uname)) == NULL) {
 		/* file doesn't have a user in passwd file.
 		 */
@@ -245,6 +254,117 @@
 		free_user(u);
 		log_it(fname, getpid(), "RELOAD", tabname);
 	}
+#ifdef WITH_SELINUX
+	if (is_selinux_enabled()) {
+		security_context_t file_context=NULL;
+		security_context_t user_context=NULL;
+		context_t current_context = NULL;
+		char *current_context_str = NULL;
+		struct av_decision avd;
+		int retval=0;
+		char *seuser=NULL;
+		char *level=NULL;
+		int sys_user = 0;
+
+		sys_user = strcmp(SYSUSERNAME, fname);
+
+		if (fgetfilecon(crontab_fd, &file_context) < OK) {
+			log_it(fname, getpid(), "getfilecon FAILED", tabname);
+			goto next_crontab;
+		}
+
+		if (sys_user != 0) {
+			if (getseuserbyname(fname, &seuser, &level) < 0) {
+				log_it(fname, getpid(), "NO SEUSER", tabname);
+				goto next_crontab;
+			}
+		} else {
+			if (getcon(&current_context_str) < 0) {
+				log_it(fname, getpid(), "getcon FAILED", tabname);
+				goto next_crontab;
+			}
+
+			current_context = context_new(current_context_str);
+			if (current_context == 0) {
+				log_it(fname, getpid(), "context new FAILED", tabname);
+				freecon(current_context_str);
+				goto next_crontab;
+			}
+
+			seuser = context_user_get(current_context);
+			level = context_range_get(current_context);
+		}
+
+		if (get_default_context_with_level(seuser, level, NULL, &user_context) < 0) {
+			log_it(fname, getpid(), "NO CONTEXT", tabname);
+			freecon(file_context);
+			if (sys_user != 0) {
+				free(seuser);
+				free(level);
+			}
+			freecon(current_context_str);
+			context_free(current_context);
+			goto next_crontab;
+		}
+
+		/*
+		 * 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.
+		 */
+		security_class_t file_class;
+		access_vector_t entrypoint_bit;
+		file_class = string_to_security_class("file");
+		if (file_class == 0) {
+			log_it(fname, getpid(), "file CLASS NOT DEFINED", tabname);
+			freecon(current_context_str);
+			context_free(current_context);
+			freecon(user_context);
+			freecon(file_context);
+			if (sys_user != 0) {
+				free(seuser);
+				free(level);
+			}
+			goto next_crontab;
+		}
+
+		entrypoint_bit = string_to_av_perm(file_class, "entrypoint");
+		if (entrypoint_bit == 0) {
+			log_it(fname, getpid(), "file:entrypoint AV NOT DEFINED", tabname);
+			freecon(current_context_str);
+			context_free(current_context);
+			freecon(user_context);
+			freecon(file_context);
+			if (sys_user != 0) {
+				free(seuser);
+				free(level);
+			}
+			goto next_crontab;
+		}
+
+		retval = security_compute_av_raw(user_context,
+			file_context,
+			file_class,
+			entrypoint_bit,
+			&avd);
+
+		freecon(user_context);
+		freecon(file_context);
+		if (sys_user != 0) {
+			free(seuser);
+			free(level);
+		}
+		context_free(current_context);
+		freecon(current_context_str);
+
+		if (retval || ((entrypoint_bit & avd.allowed) != entrypoint_bit)) {
+			log_it(fname, getpid(), "ENTRYPOINT FAILED", tabname);
+			goto next_crontab;
+		}
+	}
+#endif
 	u = load_user(crontab_fd, pw, fname);
 	if (u != NULL) {
 		u->mtime = statbuf->st_mtime;
diff -ur vixie-cron-4.1/do_command.c vixie-cron-4.1-selinux/do_command.c
--- vixie-cron-4.1/do_command.c	2004-08-28 02:09:34.000000000 +0800
+++ vixie-cron-4.1-selinux/do_command.c	2017-04-27 01:30:49.045144698 +0800
@@ -25,6 +25,12 @@
 
 #include "cron.h"
 
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/context.h>
+#include <selinux/get_context_list.h>
+#endif
+
 static void		child_process(entry *, user *);
 static int		safe_p(const char *, const char *);
 
@@ -265,6 +271,49 @@
 				_exit(OK_EXIT);
 			}
 # endif /*DEBUGGING*/
+#ifdef WITH_SELINUX
+			if (is_selinux_enabled()) {
+				char *seuser = NULL;
+				char *level = NULL;
+				char *current_context_str = NULL;
+				security_context_t scontext;
+				context_t current_context = NULL;
+
+				if (strcmp("system_u", u->name) != 0) {
+					if (getseuserbyname(u->name, &seuser, &level) < 0) {
+						fprintf(stderr, "getseuserbyname: Could not determine seuser for user %s\n", u->name);
+						_exit(ERROR_EXIT);
+					}
+				} else {
+					if (getcon(&current_context_str) < 0) {
+						fprintf(stderr, "getcon FAILED\n");
+						_exit(ERROR_EXIT);
+					}
+
+					current_context = context_new(current_context_str);
+					if (current_context == NULL) {
+						fprintf(stderr, "failed to create new context: %s\n", current_context_str);
+						freecon(current_context_str);
+						_exit(ERROR_EXIT);
+					}
+
+					seuser = context_user_get(current_context);
+				}
+
+				if (get_default_context_with_level(seuser, level, NULL, &scontext) < 0) {
+					fprintf(stderr, "get_default_context_with_level: could not get security context for user %s, seuser %s\n", u->name, seuser);
+					_exit(ERROR_EXIT);
+				}
+
+				if (setexeccon(scontext) < 0) {
+					fprintf(stderr, "setexeccon: Could not set exec context to %s for user %s\n", scontext, u->name);
+					_exit(ERROR_EXIT);
+				}
+				free(seuser);
+				free(level);
+				freecon(scontext);
+			}
+#endif
 			execle(shell, shell, "-c", e->cmd, (char *)0, e->envp);
 			fprintf(stderr, "execl: couldn't exec `%s'\n", shell);
 			perror("execl");