s390 keyboard.c: don't open-code strndup_user()

... especially not with off-by-ones (strnlen_user() already includes NUL
into its count).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-04-26 17:28:25 -04:00
parent 8f3ba02dec
commit b7310105ab

View file

@ -433,12 +433,7 @@ do_kdgkb_ioctl(struct kbd_data *kbd, struct kbsentry __user *u_kbs,
case KDSKBSENT:
if (!perm)
return -EPERM;
len = strnlen_user(u_kbs->kb_string, sizeof(u_kbs->kb_string));
if (!len)
return -EFAULT;
if (len > sizeof(u_kbs->kb_string))
return -EINVAL;
p = memdup_user_nul(u_kbs->kb_string, len);
p = strndup_user(u_kbs->kb_string, sizeof(u_kbs->kb_string));
if (IS_ERR(p))
return PTR_ERR(p);
kfree(kbd->func_table[kb_func]);