security: rework selinux, smack, ima, apparmor detection logic

[elogind.git] / src / udev / udev-node.c

diff --git a/src/udev/udev-node.c b/src/udev/udev-node.c
index 363cee1d1c1dec15268835272004e09996725b6f..c5d629d1ce1793127e845e0c96fb3202a3a4fb15 100644 (file)
--- a/src/udev/udev-node.c
+++ b/src/udev/udev-node.c
@@ -28,7 +28,11 @@
 #include <sys/time.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#ifdef HAVE_XATTR
+#include <attr/xattr.h>
+#endif
 
+#include "smack-util.h"
 #include "udev.h"
 
 static int node_symlink(struct udev_device *dev, const char *node, const char *slink)
@@ -74,7 +78,7 @@ static int node_symlink(struct udev_device *dev, const char *node, const char *s
                         len = readlink(slink, buf, sizeof(buf));
                         if (len > 0 && len < (int)sizeof(buf)) {
                                 buf[len] = '\0';
-                                if (strcmp(target, buf) == 0) {
+                                if (streq(target, buf)) {
                                         log_debug("preserve already existing symlink '%s' to '%s'\n", slink, target);
                                         label_fix(slink, true, false);
                                         utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
@@ -154,7 +158,7 @@ static const char *link_find_prioritized(struct udev_device *dev, bool add, cons
                 log_debug("found '%s' claiming '%s'\n", dent->d_name, stackdir);
 
                 /* did we find ourself? */
-                if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
+                if (streq(dent->d_name, udev_device_get_id_filename(dev)))
                         continue;
 
                 dev_db = udev_device_new_from_device_id(udev, dent->d_name);
@@ -238,7 +242,7 @@ void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev
                 udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
                         const char *name_current = udev_list_entry_get_name(list_entry_current);
 
-                        if (strcmp(name, name_current) == 0) {
+                        if (streq(name, name_current)) {
                                 found = 1;
                                 break;
                         }
@@ -252,14 +256,16 @@ void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev
         }
 }
 
-static int node_permissions_apply(struct udev_device *dev, bool apply, mode_t mode, uid_t uid, gid_t gid)
-{
+static int node_permissions_apply(struct udev_device *dev, bool apply,
+                                  mode_t mode, uid_t uid, gid_t gid,
+                                  struct udev_list *seclabel_list) {
         const char *devnode = udev_device_get_devnode(dev);
         dev_t devnum = udev_device_get_devnum(dev);
         struct stat stats;
+        struct udev_list_entry *entry;
         int err = 0;
 
-        if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
+        if (streq(udev_device_get_subsystem(dev), "block"))
                 mode |= S_IFBLK;
         else
                 mode |= S_IFCHR;
@@ -278,6 +284,11 @@ static int node_permissions_apply(struct udev_device *dev, bool apply, mode_t mo
         }
 
         if (apply) {
+                bool selinux = false;
+#ifdef HAVE_SMACK
+                bool smack = false;
+#endif
+
                 if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
                         log_debug("set permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
                         chmod(devnode, mode);
@@ -285,7 +296,41 @@ static int node_permissions_apply(struct udev_device *dev, bool apply, mode_t mo
                 } else {
                         log_debug("preserve permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
                 }
-                label_fix(devnode, true, false);
+
+                /* apply SECLABEL{$module}=$label */
+                udev_list_entry_foreach(entry, udev_list_get_entry(seclabel_list)) {
+                        const char *name, *label;
+
+                        name = udev_list_entry_get_name(entry);
+                        label = udev_list_entry_get_value(entry);
+
+                        if (streq(name, "selinux")) {
+                                selinux = true;
+                                if (label_apply(devnode, label) < 0)
+                                        log_error("SECLABEL: failed to set SELinux label '%s'", label);
+                                else
+                                        log_debug("SECLABEL: set SELinux label '%s'", label);
+
+#ifdef HAVE_SMACK
+                        } else if (streq(name, "smack") && use_smack()) {
+                                smack = true;
+                                if (lsetxattr(devnode, "security.SMACK64", label, strlen(label), 0) < 0)
+                                        log_error("SECLABEL: failed to set SMACK label '%s'", label);
+                                else
+                                        log_debug("SECLABEL: set SMACK label '%s'", label);
+#endif
+
+                        } else
+                                log_error("SECLABEL: unknown subsystem, ignoring '%s'='%s'", name, label);
+                }
+
+                /* set the defaults */
+                if (!selinux)
+                        label_fix(devnode, true, false);
+#ifdef HAVE_SMACK
+                if (!smack && use_smack())
+                        lremovexattr(devnode, "security.SMACK64");
+#endif
         }
 
         /* always update timestamp when we re-use the node, like on media change events */
@@ -294,20 +339,21 @@ out:
         return err;
 }
 
-void udev_node_add(struct udev_device *dev, bool apply, mode_t mode, uid_t uid, gid_t gid)
-{
+void udev_node_add(struct udev_device *dev, bool apply,
+                   mode_t mode, uid_t uid, gid_t gid,
+                   struct udev_list *seclabel_list) {
         char filename[UTIL_PATH_SIZE];
         struct udev_list_entry *list_entry;
 
         log_debug("handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d\n",
                   udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid);
 
-        if (node_permissions_apply(dev, apply, mode, uid, gid) < 0)
+        if (node_permissions_apply(dev, apply, mode, uid, gid, seclabel_list) < 0)
                 return;
 
         /* always add /dev/{block,char}/$major:$minor */
         snprintf(filename, sizeof(filename), "/dev/%s/%u:%u",
-                 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
+                 streq(udev_device_get_subsystem(dev), "block") ? "block" : "char",
                  major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
         node_symlink(dev, udev_device_get_devnode(dev), filename);
 
@@ -327,7 +373,7 @@ void udev_node_remove(struct udev_device *dev)
 
         /* remove /dev/{block,char}/$major:$minor */
         snprintf(filename, sizeof(filename), "/dev/%s/%u:%u",
-                 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
+                 streq(udev_device_get_subsystem(dev), "block") ? "block" : "char",
                  major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
         unlink(filename);
 }