[PATCH 1/2] libselinux: add restore option to modify user and role portions

[Christian Göttsche <cgoettsche@xxxxxxxxxxxxx>]

From: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>

Useful for data of MCS separated applications, like containers.

Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
 libselinux/include/selinux/restorecon.h |  6 ++
 libselinux/src/selinux_restorecon.c     | 77 +++++++++++++++++--------
 2 files changed, 59 insertions(+), 24 deletions(-)

diff --git a/libselinux/include/selinux/restorecon.h b/libselinux/include/selinux/restorecon.h
index 5be6542c..0ccf73a6 100644
--- a/libselinux/include/selinux/restorecon.h
+++ b/libselinux/include/selinux/restorecon.h
@@ -128,6 +128,12 @@ extern int selinux_restorecon_parallel(const char *pathname,
  */
 #define SELINUX_RESTORECON_COUNT_ERRORS			0x20000
 
+/*
+ * In addition to the type component also change the user and
+ * role component of security contexts.
+ */
+#define SELINUX_RESTORECON_SET_USER_ROLE		0x40000
+
 /**
  * selinux_restorecon_set_sehandle - Set the global fc handle.
  * @hndl: specifies handle to set as the global fc handle.
diff --git a/libselinux/src/selinux_restorecon.c b/libselinux/src/selinux_restorecon.c
index ab1c5216..72242c90 100644
--- a/libselinux/src/selinux_restorecon.c
+++ b/libselinux/src/selinux_restorecon.c
@@ -76,6 +76,7 @@ struct rest_flags {
 	bool progress;
 	bool mass_relabel;
 	bool set_specctx;
+	bool set_user_role;
 	bool add_assoc;
 	bool recurse;
 	bool userealpath;
@@ -585,43 +586,65 @@ static void filespec_destroy(void)
 /*
  * Called if SELINUX_RESTORECON_SET_SPECFILE_CTX is not set to check if
  * the type components differ, updating newtypecon if so.
+ * Also update user and role components if
+ * SELINUX_RESTORECON_SET_USER_ROLE is set.
  */
-static int compare_types(const char *curcon, const char *newcon, char **newtypecon)
+static int compare_portions(const char *curcon, const char *newcon,
+			    bool set_user_role, char **newtypecon)
 {
-	int types_differ = 0;
-	context_t cona;
-	context_t conb;
+	context_t curctx;
+	context_t newctx;
+	bool update = false;
 	int rc = 0;
 
-	cona = context_new(curcon);
-	if (!cona) {
+	curctx = context_new(curcon);
+	if (!curctx) {
 		rc = -1;
 		goto out;
 	}
-	conb = context_new(newcon);
-	if (!conb) {
-		context_free(cona);
+	newctx = context_new(newcon);
+	if (!newctx) {
+		context_free(curctx);
 		rc = -1;
 		goto out;
 	}
 
-	types_differ = strcmp(context_type_get(cona), context_type_get(conb));
-	if (types_differ) {
-		rc |= context_user_set(conb, context_user_get(cona));
-		rc |= context_role_set(conb, context_role_get(cona));
-		rc |= context_range_set(conb, context_range_get(cona));
-		if (!rc) {
-			*newtypecon = strdup(context_str(conb));
-			if (!*newtypecon) {
-				rc = -1;
+	if (strcmp(context_type_get(curctx), context_type_get(newctx)) != 0) {
+		update = true;
+		rc = context_type_set(curctx, context_type_get(newctx));
+		if (rc)
+		    goto err;
+	}
+
+	if (set_user_role) {
+		if (strcmp(context_user_get(curctx), context_user_get(newctx)) != 0) {
+			update = true;
+			rc = context_user_set(curctx, context_user_get(newctx));
+			if (rc)
+				goto err;
+		}
+
+		if (strcmp(context_role_get(curctx), context_role_get(newctx)) != 0) {
+			update = true;
+			rc = context_role_set(curctx, context_role_get(newctx));
+			if (rc)
 				goto err;
-			}
 		}
 	}
 
+	if (update) {
+		*newtypecon = strdup(context_str(curctx));
+		if (!*newtypecon) {
+			rc = -1;
+			goto err;
+		}
+	} else {
+		*newtypecon = NULL;
+	}
+
 err:
-	context_free(cona);
-	context_free(conb);
+	context_free(curctx);
+	context_free(newctx);
 out:
 	return rc;
 }
@@ -631,7 +654,6 @@ static int restorecon_sb(const char *pathname, const struct stat *sb,
 {
 	char *newcon = NULL;
 	char *curcon = NULL;
-	char *newtypecon = NULL;
 	int rc;
 	const char *lookup_path = pathname;
 
@@ -724,8 +746,13 @@ static int restorecon_sb(const char *pathname, const struct stat *sb,
 		}
 
 		if (!flags->set_specctx && curcon) {
-			/* If types different then update newcon. */
-			rc = compare_types(curcon, newcon, &newtypecon);
+			char *newtypecon;
+
+			/* If types are different then update newcon.
+			 * Also update if SELINUX_RESTORECON_SET_USER_ROLE
+			 * is set and user or role differs.
+			 */
+			rc = compare_portions(curcon, newcon, flags->set_user_role, &newtypecon);
 			if (rc)
 				goto err;
 
@@ -1025,6 +1052,8 @@ static int selinux_restorecon_common(const char *pathname_orig,
 		    SELINUX_RESTORECON_RECURSE) ? true : false;
 	state.flags.set_specctx = (restorecon_flags &
 		    SELINUX_RESTORECON_SET_SPECFILE_CTX) ? true : false;
+	state.flags.set_user_role = (restorecon_flags &
+		    SELINUX_RESTORECON_SET_USER_ROLE) ? true : false;
 	state.flags.userealpath = (restorecon_flags &
 		   SELINUX_RESTORECON_REALPATH) ? true : false;
 	state.flags.set_xdev = (restorecon_flags &
-- 
2.48.1