Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 3d920ff..2ea0c08 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -82,6 +82,7 @@
 
 	struct sigevent notify;
 	struct pid *notify_owner;
+	u32 notify_self_exec_id;
 	struct user_namespace *notify_user_ns;
 	struct user_struct *user;	/* user who created, for accounting */
 	struct sock *notify_sock;
@@ -709,28 +710,44 @@
 	 * synchronously. */
 	if (info->notify_owner &&
 	    info->attr.mq_curmsgs == 1) {
-		struct kernel_siginfo sig_i;
 		switch (info->notify.sigev_notify) {
 		case SIGEV_NONE:
 			break;
-		case SIGEV_SIGNAL:
-			/* sends signal */
+		case SIGEV_SIGNAL: {
+			struct kernel_siginfo sig_i;
+			struct task_struct *task;
+
+			/* do_mq_notify() accepts sigev_signo == 0, why?? */
+			if (!info->notify.sigev_signo)
+				break;
 
 			clear_siginfo(&sig_i);
 			sig_i.si_signo = info->notify.sigev_signo;
 			sig_i.si_errno = 0;
 			sig_i.si_code = SI_MESGQ;
 			sig_i.si_value = info->notify.sigev_value;
-			/* map current pid/uid into info->owner's namespaces */
 			rcu_read_lock();
+			/* map current pid/uid into info->owner's namespaces */
 			sig_i.si_pid = task_tgid_nr_ns(current,
 						ns_of_pid(info->notify_owner));
-			sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
+			sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
+						current_uid());
+			/*
+			 * We can't use kill_pid_info(), this signal should
+			 * bypass check_kill_permission(). It is from kernel
+			 * but si_fromuser() can't know this.
+			 * We do check the self_exec_id, to avoid sending
+			 * signals to programs that don't expect them.
+			 */
+			task = pid_task(info->notify_owner, PIDTYPE_TGID);
+			if (task && task->self_exec_id ==
+						info->notify_self_exec_id) {
+				do_send_sig_info(info->notify.sigev_signo,
+						&sig_i, task, PIDTYPE_TGID);
+			}
 			rcu_read_unlock();
-
-			kill_pid_info(info->notify.sigev_signo,
-				      &sig_i, info->notify_owner);
 			break;
+		}
 		case SIGEV_THREAD:
 			set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 			netlink_sendskb(info->notify_sock, info->notify_cookie);
@@ -1315,6 +1332,7 @@
 			info->notify.sigev_signo = notification->sigev_signo;
 			info->notify.sigev_value = notification->sigev_value;
 			info->notify.sigev_notify = SIGEV_SIGNAL;
+			info->notify_self_exec_id = current->self_exec_id;
 			break;
 		}
 
diff --git a/ipc/msg.c b/ipc/msg.c
index 8dec945..767587a 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -377,7 +377,7 @@
  * NOTE: no locks must be held, the rwsem is taken inside this function.
  */
 static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
-			struct msqid64_ds *msqid64)
+			struct ipc64_perm *perm, int msg_qbytes)
 {
 	struct kern_ipc_perm *ipcp;
 	struct msg_queue *msq;
@@ -387,7 +387,7 @@
 	rcu_read_lock();
 
 	ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
-				      &msqid64->msg_perm, msqid64->msg_qbytes);
+				      perm, msg_qbytes);
 	if (IS_ERR(ipcp)) {
 		err = PTR_ERR(ipcp);
 		goto out_unlock1;
@@ -409,18 +409,18 @@
 	{
 		DEFINE_WAKE_Q(wake_q);
 
-		if (msqid64->msg_qbytes > ns->msg_ctlmnb &&
+		if (msg_qbytes > ns->msg_ctlmnb &&
 		    !capable(CAP_SYS_RESOURCE)) {
 			err = -EPERM;
 			goto out_unlock1;
 		}
 
 		ipc_lock_object(&msq->q_perm);
-		err = ipc_update_perm(&msqid64->msg_perm, ipcp);
+		err = ipc_update_perm(perm, ipcp);
 		if (err)
 			goto out_unlock0;
 
-		msq->q_qbytes = msqid64->msg_qbytes;
+		msq->q_qbytes = msg_qbytes;
 
 		msq->q_ctime = ktime_get_real_seconds();
 		/*
@@ -601,9 +601,10 @@
 	case IPC_SET:
 		if (copy_msqid_from_user(&msqid64, buf, version))
 			return -EFAULT;
-		/* fallthru */
+		return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
+				   msqid64.msg_qbytes);
 	case IPC_RMID:
-		return msgctl_down(ns, msqid, cmd, &msqid64);
+		return msgctl_down(ns, msqid, cmd, NULL, 0);
 	default:
 		return  -EINVAL;
 	}
@@ -735,9 +736,9 @@
 	case IPC_SET:
 		if (copy_compat_msqid_from_user(&msqid64, uptr, version))
 			return -EFAULT;
-		/* fallthru */
+		return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
 	case IPC_RMID:
-		return msgctl_down(ns, msqid, cmd, &msqid64);
+		return msgctl_down(ns, msqid, cmd, NULL, 0);
 	default:
 		return -EINVAL;
 	}
diff --git a/ipc/sem.c b/ipc/sem.c
index ec97a70..fe12ea8 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -2368,11 +2368,9 @@
 		ipc_assert_locked_object(&sma->sem_perm);
 		list_del(&un->list_id);
 
-		/* we are the last process using this ulp, acquiring ulp->lock
-		 * isn't required. Besides that, we are also protected against
-		 * IPC_RMID as we hold sma->sem_perm lock now
-		 */
+		spin_lock(&ulp->lock);
 		list_del_rcu(&un->list_proc);
+		spin_unlock(&ulp->lock);
 
 		/* perform adjustments registered in un */
 		for (i = 0; i < sma->sem_nsems; i++) {
diff --git a/ipc/util.c b/ipc/util.c
index d126d15..1821b63 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -764,21 +764,21 @@
 			total++;
 	}
 
+	ipc = NULL;
 	if (total >= ids->in_use)
-		return NULL;
+		goto out;
 
 	for (; pos < ipc_mni; pos++) {
 		ipc = idr_find(&ids->ipcs_idr, pos);
 		if (ipc != NULL) {
-			*new_pos = pos + 1;
 			rcu_read_lock();
 			ipc_lock_object(ipc);
-			return ipc;
+			break;
 		}
 	}
-
-	/* Out of range - return NULL to terminate iteration */
-	return NULL;
+out:
+	*new_pos = pos + 1;
+	return ipc;
 }
 
 static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)