On 04/17, Kirill Tkhai wrote:
quoted hunk ↗ jump to hunk
+struct pidns_ioc_req {
+/* Set vector of last pids in namespace hierarchy */
+#define PIDNS_REQ_SET_LAST_PID_VEC 0x1
+ unsigned int req;
+ void __user *data;
+ unsigned int data_size;
+ char std_fields[0];
+};
see below,
quoted hunk ↗ jump to hunk
+static long set_last_pid_vec(struct pid_namespace *pid_ns,
+ struct pidns_ioc_req *req)
+{
+ char *str, *p;
+ int ret = 0;
+ pid_t pid;
+
+ read_lock(&tasklist_lock);
+ if (!pid_ns->child_reaper)
+ ret = -EINVAL;
+ read_unlock(&tasklist_lock);
+ if (ret)
+ return ret;
why do you need to check ->child_reaper under tasklist_lock? this looks pointless.
In fact I do not understand how it is possible to hit pid_ns->child_reaper == NULL,
there must be at least one task in this namespace, otherwise you can't open a file
which has f_op == ns_file_operations, no?
quoted hunk ↗ jump to hunk
+ if (req->data_size >= PAGE_SIZE)
+ return -EINVAL;
+ str = vmalloc(req->data_size + 1);
then I don't understand why it makes sense to use vmalloc()
quoted hunk ↗ jump to hunk
+ if (!str)
+ return -ENOMEM;
+ if (copy_from_user(str, req->data, req->data_size)) {
+ ret = -EFAULT;
+ goto out_vfree;
+ }
+ str[req->data_size] = '\0';
+
+ p = str;
+ while (p && *p != '\0') {
+ if (!ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto out_vfree;
+ }
+
+ if (sscanf(p, "%d", &pid) != 1 || pid < 0 || pid > pid_max) {
+ ret = -EINVAL;
+ goto out_vfree;
+ }
Well, this is ioctl(), do we really want to parse the strings?
Can't we make
struct pidns_ioc_req {
...
int nr_pids;
pid_t pids[0];
}
and just use get_user() in a loop? This way we can avoid vmalloc() or anything
else altogether.
Oleg.