Re: [PATCH v6 3/6] seccomp: Sysctl to configure actions that are allowed to be logged

On Thu, Aug 10, 2017 at 9:33 PM, Tyler Hicks [off-list ref] wrote:

+static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
+                                         void __user *buffer, size_t *lenp,
+                                         loff_t *ppos)
+{
+       char names[sizeof(seccomp_actions_avail)];
+       struct ctl_table table;
+       int ret;
+
+       if (write && !capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       memset(names, 0, sizeof(names));
+
+       if (!write) {
+               if (!seccomp_names_from_actions_logged(names, sizeof(names),
+                                                      seccomp_actions_logged))
+                       return -EINVAL;
+       }
+
+       table = *ro_table;
+       table.data = names;
+       table.maxlen = sizeof(names);
+       ret = proc_dostring(&table, write, buffer, lenp, ppos);
+       if (ret)
+               return ret;
+
+       if (write) {
+               u32 actions_logged;
+
+               if (!seccomp_actions_logged_from_names(&actions_logged,
+                                                      table.data))
+                       return -EINVAL;
+
+               if (actions_logged & SECCOMP_LOG_ALLOW)
+                       return -EINVAL;
+
+               seccomp_actions_logged = actions_logged;
+       }
+
+       return 0;
+}

One thought here: should "kill" be always forced on during a write?
This flag effectively cannot be disabled, so listing it (or not) in
the sysctl may be confusing...

-Kees

-- 
Kees Cook
Pixel Security