Add auth checking at signal agent

Only root or 'app_fw' user can send to agent.

Change-Id: If3ec8662fa9290af7f0d7ffc22b73b39dcfb9a4f
Signed-off-by: Sangyoon Jang <s89.jang@samsung.com>

diff --git a/installer/pkgmgr_installer_signal_agent.c b/installer/pkgmgr_installer_signal_agent.c
index 5c49f9a..ca43fad 100644 (file)
--- a/installer/pkgmgr_installer_signal_agent.c
+++ b/installer/pkgmgr_installer_signal_agent.c
@@ -15,6 +15,8 @@
  *
  */
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -24,6 +26,7 @@
 #include <sys/types.h>
 #include <sys/un.h>
 #include <linux/limits.h>
+#include <pwd.h>
 
 #include <glib.h>
 #include <glib-unix.h>
@@ -40,6 +43,8 @@
 #define LOG_TAG "PKGMGR_INSTALLER_SIGNAL_AGENT"
 
 #define BUFMAX 4096
+#define PWBUFSIZE sysconf(_SC_GETPW_R_SIZE_MAX)
+#define APPFW_USERNAME "app_fw"
 
 static int server_fd;
 static GMainLoop *loop;
@@ -141,6 +146,41 @@ static gboolean __quit(gpointer user_data)
        return FALSE;
 }
 
+static int __check_authority(int fd)
+{
+       int r;
+       struct ucred cr;
+       socklen_t len;
+       struct passwd pwd;
+       struct passwd *pwd_r;
+       char buf[PWBUFSIZE];
+
+       len = sizeof(struct ucred);
+       r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
+       if (r != 0) {
+               LOGE("getsockopt failed: %d", errno);
+               return -1;
+       }
+
+       /* allow root user */
+       if (cr.uid == 0)
+               return 0;
+
+       r = getpwuid_r(cr.uid, &pwd, buf, sizeof(buf), &pwd_r);
+       if (r != 0 || pwd_r == NULL) {
+               LOGE("getpwuid failed: %d", r);
+               return -1;
+       }
+
+       /* only app_fw user can send signal to agent */
+       if (strcmp(pwd_r->pw_name, APPFW_USERNAME) != 0) {
+               LOGE("unauthorized client");
+               return -1;
+       }
+
+       return 0;
+}
+
 /**
  * packet format:
  * +----------------+-------------+-----------+-------------------+
@@ -166,6 +206,11 @@ static gboolean __handle_signal(gint fd, GIOCondition cond, gpointer user_data)
                return FALSE;
        }
 
+       if (__check_authority(clifd)) {
+               close(clifd);
+               return TRUE;
+       }
+
        r = recv(clifd, buf, sizeof(size_t) + sizeof(gsize), 0);
        if (r < 0) {
                LOGE("recv failed: %d", errno);