[PATCH] PATCH selinux for udev

Daniel Walsh's working selinux patch

Makefile

@@ -25,6 +25,8 @@ USE_LOG = true
 # Leave this set to `false' for production use.
 DEBUG = false
 
+# Set this to compile with Security-Enhanced Linux support.
+USE_SELINUX = false
 
 ROOT =		udev
 DAEMON =	udevd
@@ -170,6 +172,11 @@ else
 	LDFLAGS =
 endif
 
+ifeq ($(strip $(USE_SELINUX)),true)
+	CFLAGS += -DUSE_SELINUX
+	LIB_OBJS += -lselinux
+endif
+
 CFLAGS += -I$(PWD)/libsysfs
 
 # config files automatically generated
@@ -222,6 +229,7 @@ HEADERS =	udev.h		\
 		udevdb.h	\
 		klibc_fixups.h	\
 		logging.h	\
+		selinux.h	\
 		list.h
 
 ifeq ($(strip $(USE_KLIBC)),true)

selinux.h

@@ -0,0 +1,131 @@
+#ifndef SELINUX_H
+#define SELINUX_H
+
+#ifndef USE_SELINUX
+
+static inline void selinux_setfilecon(char *file, unsigned int mode) { }
+static inline void selinux_setfscreatecon(char *file, unsigned int mode) {}
+static inline void selinux_init(void) {}
+static inline void selinux_restore(void) {}
+
+#else
+
+#include <selinux/selinux.h>
+#include <stdio.h>
+#include <limits.h>
+#include <ctype.h>
+
+
+static int selinux_enabled=-1;
+static security_context_t prev_scontext=NULL;
+
+static inline int is_selinux_running(void) {
+	if ( selinux_enabled==-1 ) 
+		return selinux_enabled=is_selinux_enabled()>0;
+	return selinux_enabled;
+}
+
+static inline int selinux_get_media(char *path, int mode, char **media)
+{
+  FILE *fp;
+  char buf[PATH_MAX];
+  char mediabuf[PATH_MAX];
+  *media=NULL;
+  if (!( mode && S_IFBLK )) {
+	  return -1;
+  }
+  snprintf(buf,sizeof(buf), "/proc/ide/%s/media", basename(path));
+  fp=fopen(buf,"r");
+  if (fp) {
+	  if (fgets(mediabuf,sizeof(mediabuf), fp)) {
+		  int size=strlen(mediabuf);
+		  while (size-- > 0) {
+			  if (isspace(mediabuf[size])) {
+				  mediabuf[size]='\0';
+			  } else {
+				  break;
+			  }
+		  }
+		  *media=strdup(mediabuf);
+		  info("selinux_get_media(%s)->%s \n", path, *media);
+	  }
+    fclose(fp);
+    return 0;
+  } else {
+    return -1;
+  }
+}
+
+static inline void selinux_setfilecon(char *file, unsigned int mode) { 
+	if (is_selinux_running()) {
+		security_context_t scontext=NULL;
+		char *media;
+		int ret=selinux_get_media(file, mode, &media);
+		if ( ret== 0) {
+			ret = matchmediacon(media, &scontext);
+			free(media);
+		} 
+		if (ret==-1) 
+			if (matchpathcon(file, mode, &scontext) < 0) {
+				dbg("matchpathcon(%s) failed\n", file);
+				return;
+			} 
+		if (setfilecon(file, scontext) < 0)
+			dbg("setfiles %s failed with error '%s'",
+			    file, strerror(errno));
+		freecon(scontext);
+	}
+}
+
+static inline void selinux_setfscreatecon(char *file, unsigned int mode) {
+	int retval = 0;
+	security_context_t scontext=NULL;
+
+	if (is_selinux_running()) {
+		char *media;
+		int ret=selinux_get_media(file, mode, &media);
+		if ( ret== 0) {
+			ret = matchmediacon(media, &scontext);
+			free(media);
+		} 
+
+		if (ret==-1) 
+			if (matchpathcon(file, mode, &scontext) < 0) {
+				dbg("matchpathcon(%s) failed\n", file);
+				return;
+			} 
+
+		retval=setfscreatecon(scontext);
+		if (retval < 0)
+			dbg("setfiles %s failed with error '%s'",
+			    file, strerror(errno));
+		freecon(scontext);
+	}
+}
+static inline void selinux_init(void) {
+	/* record the present security context, for file-creation
+	 * restoration creation purposes.
+	 *
+	 */
+
+	if (is_selinux_running())
+	{
+		if (getfscreatecon(&prev_scontext) < 0) {
+			dbg("getfscreatecon failed\n");
+		}
+		prev_scontext=NULL;
+	}
+}
+static inline void selinux_restore(void) {
+	if (is_selinux_running()) {
+		/* reset the file create context to its former glory */
+		if ( setfscreatecon(prev_scontext) < 0 )
+			dbg("setfscreatecon failed\n");
+		if (prev_scontext) {
+			freecon(prev_scontext);
+			prev_scontext=NULL;
+		}
+	}
+}
+#endif /* USE_SELINUX */
+#endif /* SELINUX_H */

udev-add.c

@@ -50,6 +50,8 @@
 
 #define LOCAL_USER "$local"
 
+#include "selinux.h"
+
 /* 
  * Right now the major/minor of a device is stored in a file called
  * "dev" in sysfs.
@@ -92,6 +94,7 @@ static int create_path(char *file)
 			break;
 		*pos = 0x00;
 		if (stat(p, &stats)) {
+			selinux_setfscreatecon(p, S_IFDIR);
 			retval = mkdir(p, 0755);
 			if (retval != 0) {
 				dbg("mkdir(%s) failed with error '%s'",
@@ -99,6 +102,8 @@ static int create_path(char *file)
 				return retval;
 			}
 			dbg("created '%s'", p);
+		} else {
+			selinux_setfilecon(p, S_IFDIR);
 		}
 		*pos = '/';
 	}
@@ -117,6 +122,7 @@ static int make_node(char *file, int major, int minor, unsigned int mode, uid_t
 	if (((stats.st_mode & S_IFMT) == S_IFBLK || (stats.st_mode & S_IFMT) == S_IFCHR) &&
 	    (stats.st_rdev == makedev(major, minor))) {
 		dbg("preserve file '%s', cause it has correct dev_t", file);
+		selinux_setfilecon(file,stats.st_mode);
 		goto perms;
 	}
 
@@ -126,6 +132,7 @@ static int make_node(char *file, int major, int minor, unsigned int mode, uid_t
 		dbg("already present file '%s' unlinked", file);
 
 create:
+	selinux_setfscreatecon(file, mode);
 	retval = mknod(file, mode, makedev(major, minor));
 	if (retval != 0) {
 		dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
@@ -304,6 +311,7 @@ static int create_node(struct udevice *dev, int fake)
 
 		dbg("symlink(%s, %s)", linktarget, filename);
 		if (!fake) {
+			selinux_setfscreatecon(filename, S_IFLNK);
 			unlink(filename);
 			if (symlink(linktarget, filename) != 0)
 				dbg("symlink(%s, %s) failed with error '%s'",
@@ -438,6 +446,7 @@ int udev_add_device(const char *path, const char *subsystem, int fake)
 
 	dbg("name='%s'", dev.name);
 
+	selinux_init();
 	switch (dev.type) {
 	case 'b':
 	case 'c':
@@ -475,6 +484,7 @@ int udev_add_device(const char *path, const char *subsystem, int fake)
 	}
 
 exit:
+	selinux_restore();
 	sysfs_close_class_device(class_dev);
 
 	return retval;