follow symlinks to find the true passwd file before updating.

diff --git a/libbb/update_passwd.c b/libbb/update_passwd.c
index 388adf81fb7cc9cb33d9ebdfdcf7514c2ed24e63..e99db40c04b9b470c3005e6d7df679249d4f0088 100644 (file)
--- a/libbb/update_passwd.c
+++ b/libbb/update_passwd.c
@@ -52,6 +52,10 @@ int update_passwd(const char *filename, const char *username,
        int cnt = 0;
        int ret = -1; /* failure */
 
+       filename = xmalloc_readlink_follow(filename);
+       if (filename == NULL)
+               return -1;
+
        check_selinux_update_passwd(username);
 
        /* New passwd file, "/etc/passwd+" for now */
@@ -143,6 +147,7 @@ int update_passwd(const char *filename, const char *username,
 
  free_mem:
        free(fnamesfx);
-       free((char*)username);
+       free((char *)filename);
+       free((char *)username);
        return ret;
 }