smack: rework security labeling for multiple frameworks

src/shared/label.c

@@ -27,41 +27,41 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#ifdef HAVE_XATTR
+#include <sys/xattr.h>
+#endif
+#ifdef HAVE_SELINUX
+#include <selinux/selinux.h>
+#include <selinux/label.h>
+#endif
 
 #include "label.h"
 #include "strv.h"
 #include "util.h"
 #include "path-util.h"
+#include "selinux-util.h"
+#include "smack-util.h"
 
 #ifdef HAVE_SELINUX
-#include "selinux-util.h"
-#include <selinux/selinux.h>
-#include <selinux/label.h>
-
 static struct selabel_handle *label_hnd = NULL;
-
 #endif
-#ifdef HAVE_SMACK
-#include <sys/xattr.h>
-#include <string.h>
-#define FLOOR_LABEL	"_"
-#define STAR_LABEL	"*"
 
-static void smack_relabel_in_dev(const char *path) {
+static int smack_relabel_in_dev(const char *path) {
+        int r = 0;
+
+#ifdef HAVE_SMACK
         struct stat sb;
         const char *label;
-        int r;
 
         /*
          * Path must be in /dev and must exist
          */
-        if (!path_equal(path, "/dev") &&
-            !path_startswith(path, "/dev"))
-                return;
+        if (!path_startswith(path, "/dev"))
+                return 0;
 
         r = lstat(path, &sb);
         if (r < 0)
-                return;
+                return -errno;
 
         /*
          * Label directories and character devices "*".
@@ -69,21 +69,24 @@ static void smack_relabel_in_dev(const char *path) {
          * Don't change anything else.
          */
         if (S_ISDIR(sb.st_mode))
-                label = STAR_LABEL;
+                label = SMACK_STAR_LABEL;
         else if (S_ISLNK(sb.st_mode))
-                label = FLOOR_LABEL;
+                label = SMACK_FLOOR_LABEL;
         else if (S_ISCHR(sb.st_mode))
-                label = STAR_LABEL;
+                label = SMACK_STAR_LABEL;
         else
-                return;
+                return 0;
 
         r = setxattr(path, "security.SMACK64", label, strlen(label), 0);
-        if (r < 0)
+        if (r < 0) {
                 log_error("Smack relabeling \"%s\" %s", path, strerror(errno));
-        return;
-}
+                return -errno;
+        }
 #endif
 
+        return r;
+}
+
 int label_init(const char *prefix) {
         int r = 0;
 
@@ -131,14 +134,14 @@ int label_init(const char *prefix) {
         return r;
 }
 
-int label_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
+static int label_fix_selinux(const char *path, bool ignore_enoent, bool ignore_erofs) {
         int r = 0;
 
 #ifdef HAVE_SELINUX
         struct stat st;
         security_context_t fcon;
 
-        if (!use_selinux() || !label_hnd)
+        if (!label_hnd)
                 return 0;
 
         r = lstat(path, &st);
@@ -172,9 +175,24 @@ int label_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
                 r = security_getenforce() == 1 ? -errno : 0;
         }
 #endif
-#ifdef HAVE_SMACK
-        smack_relabel_in_dev(path);
-#endif
+
+        return r;
+}
+
+int label_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
+        int r = 0;
+
+        if (use_selinux()) {
+                r = label_fix_selinux(path, ignore_enoent, ignore_erofs);
+                if (r < 0)
+                        return r;
+        }
+
+        if (use_smack()) {
+                r = smack_relabel_in_dev(path);
+                if (r < 0)
+                        return r;
+        }
 
         return r;
 }
@@ -252,9 +270,6 @@ int label_context_set(const char *path, mode_t mode) {
         if (r < 0 && security_getenforce() == 0)
                 r = 0;
 #endif
-#ifdef HAVE_SMACK
-        smack_relabel_in_dev(path);
-#endif
 
         return r;
 }
@@ -307,15 +322,15 @@ void label_free(const char *label) {
 #endif
 }
 
-int label_mkdir(const char *path, mode_t mode) {
-        int r;
+static int label_mkdir_selinux(const char *path, mode_t mode) {
+        int r = 0;
 
 #ifdef HAVE_SELINUX
         /* Creates a directory and labels it according to the SELinux policy */
         security_context_t fcon = NULL;
 
-        if (!use_selinux() || !label_hnd)
-                goto skipped;
+        if (!label_hnd)
+                return 0;
 
         if (path_is_absolute(path))
                 r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFDIR);
@@ -348,17 +363,34 @@ int label_mkdir(const char *path, mode_t mode) {
 finish:
         setfscreatecon(NULL);
         freecon(fcon);
+#endif
 
         return r;
+}
+
+int label_mkdir(const char *path, mode_t mode) {
+        int r;
+
+        if (use_selinux()) {
+                r = label_mkdir_selinux(path, mode);
+                if (r < 0)
+                        return r;
+        }
+
+        if (use_smack()) {
+                r = mkdir(path, mode);
+                if (r < 0 && errno != EEXIST)
+                        return -errno;
+
+                r = smack_relabel_in_dev(path);
+                if (r < 0)
+                        return r;
+        }
 
-skipped:
-#endif
         r = mkdir(path, mode);
-        if (r)
+        if (r < 0 && errno != EEXIST)
                 return -errno;
-#ifdef HAVE_SMACK
-        smack_relabel_in_dev(path);
-#endif
+
         return 0;
 }
 

src/shared/smack-util.h

@@ -25,7 +25,11 @@
 
 #include <stdbool.h>
 
+#define SMACK_FLOOR_LABEL "_"
+#define SMACK_STAR_LABEL  "*"
+
 bool use_smack(void);
+
 int smack_label_path(const char *path, const char *label);
 int smack_label_fd(int fd, const char *label);
 int smack_label_ip_in_fd(int fd, const char *label);