* Re: [patch] udev-selinux: restores file security context and sets mode in matchpathcon
2004-08-04 9:33 ` [patch] udev-selinux: restores file security context and sets Hannes Reinecke
@ 2004-08-04 11:09 ` Luke Kenneth Casson Leighton
0 siblings, 0 replies; 3+ messages in thread
From: Luke Kenneth Casson Leighton @ 2004-08-04 11:09 UTC (permalink / raw)
To: Hannes Reinecke; +Cc: SE-Linux, Linux Hotplug Dev List
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duh!
On Wed, Aug 04, 2004 at 11:33:07AM +0200, Hannes Reinecke wrote:
> Luke Kenneth Casson Leighton wrote:
> >okay, updated.
> >
> >this is an experimental patch.
> >
> [ .. ]
> >the reason for using this patch is because of speed:
> >if matchpathcon is used in the same process, the lookups etc.
> >are cached.
> >
> >a reason for _not_ using this patch is for a udev in initrd
> >where the smaller klibc is used. it would be necessary to add
> >rexeg to klibc and to compile a special libselinux1 with it.
> >
> >if you do not intend to put udev into an initrd, this patch is
> >perfectly acceptable for use.
> >
> >l.
> So where is it then?
>
> Cheers,
>
> Hannes
> --
> Dr. Hannes Reinecke hare@suse.de
> SuSE Linux AG S390 & zSeries
> Maxfeldstra?e 5 +49 911 74053 688
> 90409 N?rnberg http://www.suse.de
--
--
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--- udev-add.c.orig 2004-07-09 18:59:09.000000000 +0100
+++ udev-add.c 2004-08-03 16:21:59.000000000 +0100
@@ -50,6 +50,10 @@
#define LOCAL_USER "$local"
+#ifdef WITH_SELINUX
+#include <selinux/selinux.h>
+#endif
+
/*
* Right now the major/minor of a device is stored in a file called
* "dev" in sysfs.
@@ -92,7 +96,31 @@
break;
*pos = 0x00;
if (stat(p, &stats)) {
+#ifdef WITH_SELINUX
+ int seretval = 0;
+ security_context_t scontext;
+ if (is_selinux_enabled() > 0)
+ {
+ seretval = matchpathcon(p, S_IFDIR, &scontext);
+ if (seretval < 0) {
+ dbg("matchpathcon(%s) failed\n", p);
+ } else {
+ seretval=setfscreatecon(scontext);
+ if (seretval < 0)
+ dbg("setfiles %s failed with error '%s'",
+ p, strerror(errno));
+ }
+ }
+#endif
retval = mkdir(p, 0755);
+#ifdef WITH_SELINUX
+ if (is_selinux_enabled() > 0)
+ {
+ /* after mkdir, free the context */
+ freecon(scontext);
+ }
+#endif
+
if (retval != 0) {
dbg("mkdir(%s) failed with error '%s'",
p, strerror(errno));
@@ -109,6 +137,10 @@
{
struct stat stats;
int retval = 0;
+ int seretval = 0;
+#ifdef WITH_SELINUX
+ security_context_t scontext;
+#endif
if (stat(file, &stats) != 0)
goto create;
@@ -117,6 +149,24 @@
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);
+#ifdef WITH_SELINUX
+ /* lkcl: maybe someone would like to do the same thing with se/linux
+ * security contexts (check they are the same) but hey, not me!
+ */
+ if (is_selinux_enabled() > 0)
+ {
+ retval = matchpathcon(file, mode, &scontext);
+ if (retval < 0) {
+ dbg("matchpathcon(%s) failed\n", file);
+ } else {
+ retval=setfilecon(scontext, file);
+ if (retval < 0)
+ dbg("setfiles %s failed with error '%s'",
+ file, strerror(errno));
+ freecon(scontext);
+ }
+ }
+#endif
goto perms;
}
@@ -126,6 +176,21 @@
dbg("already present file '%s' unlinked", file);
create:
+#ifdef WITH_SELINUX
+ if (is_selinux_enabled() > 0)
+ {
+ seretval = matchpathcon(file, mode, &scontext);
+ if (seretval < 0) {
+ dbg("matchpathcon(%s) failed\n", file);
+ } else {
+ retval=setfscreatecon(scontext);
+ if (retval < 0)
+ dbg("setfiles %s failed with error '%s'",
+ file, strerror(errno));
+ }
+ }
+#endif
+
retval = mknod(file, mode, makedev(major, minor));
if (retval != 0) {
dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
@@ -133,6 +198,15 @@
goto exit;
}
+#ifdef WITH_SELINUX
+ if (is_selinux_enabled() > 0)
+ {
+ /* after mknod, free the context */
+ if (seretval == 0)
+ freecon(scontext);
+ }
+#endif
+
perms:
dbg("chmod(%s, %#o)", file, mode);
if (chmod(file, mode) != 0) {
@@ -150,7 +224,11 @@
}
exit:
+#ifdef WITH_SELINUX
+ return retval < 0 ? retval : seretval;
+#else
return retval;
+#endif
}
/* get the local logged in user */
@@ -304,10 +382,36 @@
dbg("symlink(%s, %s)", linktarget, filename);
if (!fake) {
+#ifdef WITH_SELINUX
+ int seretval = 0;
+ security_context_t scontext;
+ if (is_selinux_enabled() > 0)
+ {
+ seretval = matchpathcon(filename, S_IFLNK, &scontext);
+ if (seretval < 0) {
+ dbg("matchpathcon(%s) failed\n", filename);
+ } else {
+ seretval=setfscreatecon(scontext);
+ if (seretval < 0)
+ dbg("setfiles %s failed with error '%s'",
+ filename, strerror(errno));
+ }
+ }
+#endif
+
+
unlink(filename);
if (symlink(linktarget, filename) != 0)
dbg("symlink(%s, %s) failed with error '%s'",
linktarget, filename, strerror(errno));
+#ifdef WITH_SELINUX
+ if (is_selinux_enabled() > 0)
+ {
+ /* after symlink, free the context */
+ freecon(scontext);
+ }
+#endif
+
}
}
@@ -403,6 +507,11 @@
char *pos;
int retval;
+#ifdef WITH_SELINUX
+ int seretval;
+ security_context_t prev_scontext;
+#endif
+
memset(&dev, 0x00, sizeof(dev));
dev.type = get_device_type(path, subsystem);
@@ -438,6 +547,23 @@
dbg("name='%s'", dev.name);
+#ifdef WITH_SELINUX
+ /* record the present security context, for file-creation
+ * restoration creation purposes.
+ *
+ * we're going to assume that between now and the time that
+ * this context is restored that the only filecreation of any
+ * kind to occur will be mknod, symlink and mkdirs.
+ */
+
+ if (is_selinux_enabled() > 0)
+ {
+ seretval = getfscreatecon(&prev_scontext);
+ if (seretval < 0) {
+ dbg("getfscreatecon failed\n");
+ }
+ }
+#endif
switch (dev.type) {
case 'b':
case 'c':
@@ -474,6 +600,16 @@
break;
}
+#ifdef WITH_SELINUX
+ if (is_selinux_enabled() > 0)
+ {
+ /* reset the file create context to its former glory */
+ if (seretval == 0)
+ seretval=setfscreatecon(prev_scontext);
+ freecon(prev_scontext);
+ }
+#endif
+
exit:
sysfs_close_class_device(class_dev);
--- Makefile.orig 2004-08-02 22:23:58.000000000 +0100
+++ Makefile 2004-08-02 22:24:01.000000000 +0100
@@ -25,6 +25,8 @@
# Leave this set to `false' for production use.
DEBUG = true
+# Set this to compile with Security-Enhanced Linux support.
+WITH_SELINUX = true
ROOT = udev
DAEMON = udevd
@@ -39,6 +41,7 @@
LOCAL_CFG_DIR = etc/udev
HOTPLUG_EXEC = $(ROOT)
+
DESTDIR =
KERNEL_DIR = /lib/modules/${shell uname -r}/build
@@ -172,6 +175,13 @@
CFLAGS += -I$(PWD)/libsysfs
+ifeq ($(strip $(WITH_SELINUX)),true)
+ LIB_OBJS += \
+ -lselinux
+ CFLAGS += \
+ -DWITH_SELINUX
+endif
+
all: $(ROOT) $(SENDER) $(DAEMON) $(INFO) $(TESTER) $(STARTER)
@extras="$(EXTRAS)" ; for target in $$extras ; do \
echo $$target ; \
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