tzip: fix privilege issuesubmit/tizen/20160929.102549accepted/tizen/wearable/20160929.234307accepted/tizen/tv/20160929.234258accepted/tizen/mobile/20160929.234409accepted/tizen/ivi/20160929.234350accepted/tizen/common/20160930.174616

- Just apps who have "System" smack label are permitted
  to use TZIP
- Just TZ_SYS_HOME and TZ_SYS_RW_APP are permitted
  to mount TZIP

Change-Id: I4531577b423a478243038c86571fcc0b4d4c7331
Signed-off-by: taeyoung <ty317.kim@samsung.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/src/tzip/tzip.c b/src/tzip/tzip.c
index cdd9cb78..d1654043 100644
--- a/src/tzip/tzip.c
+++ b/src/tzip/tzip.c
@@ -37,10 +37,14 @@
 #include <sys/stat.h>
 #include <assert.h>
 #include <attr/xattr.h>
+#include <linux/limits.h>
+#include <tzplatform_config.h>
 
 #include "tzip.h"
 #include "tzip-utility.h"
 
+#define APP_ATTR_PATH "/proc/%d/attr/current"
+
 static pthread_t thread;
 static pthread_t mount_thread;
 static pthread_attr_t attr;
@@ -48,6 +52,73 @@ static struct fuse *fuse_handle = NULL;
 static struct fuse_chan *channel = NULL;
 static GAsyncQueue *async_queue;
 
+static int check_smack_label(pid_t pid)
+{
+	char path[PATH_MAX];
+	char attr[64];
+	size_t len;
+	FILE *fp;
+
+	snprintf(path, sizeof(path), APP_ATTR_PATH, pid);
+
+	fp = fopen(path, "r");
+	if (!fp)
+		return 0;
+
+	len = fread(attr, 1, sizeof(attr) - 1, fp);
+	fclose(fp);
+	if (len == 0)
+		return 0;
+
+	attr[len] = '\0';
+
+	if (!strncmp("System", attr, len + 1))
+		return 1;
+
+	if (!strncmp("User", attr, len + 1))
+		return 1;
+
+	if (!strncmp("System::Privileged", attr, len + 1))
+		return 1;
+
+	return 0;
+}
+
+static int check_path_available(char *mountpath)
+{
+	size_t len;
+
+	if (!mountpath)
+		return 0;
+
+	len = strlen(mountpath);
+
+	if (!strncmp(mountpath, tzplatform_getenv(TZ_SYS_HOME), len))
+		return 1;
+
+	if (!strncmp(mountpath, tzplatform_getenv(TZ_SYS_RW_APP), len))
+		return 1;
+
+	return 0;
+}
+
+static int is_app_privileged(pid_t pid, char *mountpath)
+{
+	int priv;
+
+	priv = check_path_available(mountpath);
+	if (priv == 0) {
+		_E("TZIP mount path is invalid (%s)", mountpath);
+		return priv;
+	}
+
+	priv = check_smack_label(pid);
+	if (priv == 0)
+		_E("PID (%d) cannot use TZIP due to smack label");
+
+	return priv;
+}
+
 static int tzip_getattr(const char *path, struct stat *stbuf)
 {
 	int res = 0;
@@ -615,6 +686,7 @@ static DBusMessage *edbus_request_mount_tzip(E_DBus_Object *obj, DBusMessage *ms
 	char *smack;
 	int ret;
 	struct tzip_msg_data *msgdata = NULL;
+	pid_t pid;
 
 	dbus_error_init(&err);
 
@@ -634,6 +706,13 @@ static DBusMessage *edbus_request_mount_tzip(E_DBus_Object *obj, DBusMessage *ms
 		goto out;
 	}
 
+	pid = get_edbus_sender_pid(msg);
+	if (!is_app_privileged(pid, mountpath)) {
+		_E("PID (%d) is not privileged to use tzip", pid);
+		ret = -EPERM;
+		goto out;
+	}
+
 	if (!fuse_handle)
 		tzip_server_init();
 
@@ -693,6 +772,7 @@ static DBusMessage *edbus_request_unmount_tzip(E_DBus_Object *obj, DBusMessage *
 	char *mountpath;
 	int ret;
 	struct tzip_msg_data *msgdata = NULL;
+	pid_t pid;
 
 	dbus_error_init(&err);
 
@@ -709,6 +789,13 @@ static DBusMessage *edbus_request_unmount_tzip(E_DBus_Object *obj, DBusMessage *
 		goto out;
 	}
 
+	pid = get_edbus_sender_pid(msg);
+	if (!is_app_privileged(pid, mountpath)) {
+		_E("PID (%d) is not privileged to use tzip", pid);
+		ret = -EPERM;
+		goto out;
+	}
+
 	if (!fuse_handle)
 		tzip_server_init();