xfrm: add missing extack for XFRMA_SA_PCPU in add_acquire and allocspi

We're returning an error caused by invalid user input without setting
an extack. Add one.

Fixes: 1ddf991 ("xfrm: Add support for per cpu xfrm state handling.")
Signed-off-by: Sabrina Dubroca <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>

Author: qsn

net/xfrm/xfrm_user.c

@@ -1850,6 +1850,7 @@ static int xfrm_alloc_userspi(struct sk_buff *skb, struct nlmsghdr *nlh,
 		pcpu_num = nla_get_u32(attrs[XFRMA_SA_PCPU]);
 		if (pcpu_num >= num_possible_cpus()) {
 			err = -EINVAL;
+			NL_SET_ERR_MSG(extack, "pCPU number too big");
 			goto out_noput;
 		}
 	}
@@ -3001,8 +3002,10 @@ static int xfrm_add_acquire(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (attrs[XFRMA_SA_PCPU]) {
 		x->pcpu_num = nla_get_u32(attrs[XFRMA_SA_PCPU]);
 		err = -EINVAL;
-		if (x->pcpu_num >= num_possible_cpus())
+		if (x->pcpu_num >= num_possible_cpus()) {
+			NL_SET_ERR_MSG(extack, "pCPU number too big");
 			goto free_state;
+		}
 	}
 
 	err = verify_newpolicy_info(&ua->policy, extack);