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/net/ipv4/tcp.c b/net/ipv4/tcp.c
index d8876f0..5c8d0fb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -477,9 +477,19 @@
 static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
 					  int target, struct sock *sk)
 {
-	return (READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq) >= target) ||
-		(sk->sk_prot->stream_memory_read ?
-		sk->sk_prot->stream_memory_read(sk) : false);
+	int avail = READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq);
+
+	if (avail > 0) {
+		if (avail >= target)
+			return true;
+		if (tcp_rmem_pressure(sk))
+			return true;
+		if (tcp_receive_window(tp) <= inet_csk(sk)->icsk_ack.rcv_mss)
+			return true;
+	}
+	if (sk->sk_prot->stream_memory_read)
+		return sk->sk_prot->stream_memory_read(sk);
+	return false;
 }
 
 /*
@@ -963,7 +973,8 @@
 	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
 
 	if (IS_ENABLED(CONFIG_DEBUG_VM) &&
-	    WARN_ONCE(PageSlab(page), "page must not be a Slab one"))
+	    WARN_ONCE(!sendpage_ok(page),
+		      "page must not be a Slab one and have page_count > 0"))
 		return -EINVAL;
 
 	/* Wait for a connection to finish. One exception is TCP Fast Open
@@ -1087,8 +1098,7 @@
 		goto out;
 out_err:
 	/* make sure we wake any epoll edge trigger waiter */
-	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
-		     err == -EAGAIN)) {
+	if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {
 		sk->sk_write_space(sk);
 		tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
 	}
@@ -1419,8 +1429,7 @@
 	sock_zerocopy_put_abort(uarg, true);
 	err = sk_stream_error(sk, flags, err);
 	/* make sure we wake any epoll edge trigger waiter */
-	if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
-		     err == -EAGAIN)) {
+	if (unlikely(tcp_rtx_and_write_queues_empty(sk) && err == -EAGAIN)) {
 		sk->sk_write_space(sk);
 		tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
 	}
@@ -1759,10 +1768,11 @@
 
 	down_read(&current->mm->mmap_sem);
 
-	ret = -EINVAL;
 	vma = find_vma(current->mm, address);
-	if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops)
-		goto out;
+	if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops) {
+		up_read(&current->mm->mmap_sem);
+		return -EINVAL;
+	}
 	zc->length = min_t(unsigned long, zc->length, vma->vm_end - address);
 
 	tp = tcp_sk(sk);
@@ -1958,8 +1968,7 @@
 	struct sk_buff *skb, *last;
 	u32 urg_hole = 0;
 	struct scm_timestamping_internal tss;
-	bool has_tss = false;
-	bool has_cmsg;
+	int cmsg_flags;
 
 	if (unlikely(flags & MSG_ERRQUEUE))
 		return inet_recv_error(sk, msg, len, addr_len);
@@ -1974,7 +1983,7 @@
 	if (sk->sk_state == TCP_LISTEN)
 		goto out;
 
-	has_cmsg = tp->recvmsg_inq;
+	cmsg_flags = tp->recvmsg_inq ? 1 : 0;
 	timeo = sock_rcvtimeo(sk, nonblock);
 
 	/* Urgent data needs to be handled specially. */
@@ -2047,7 +2056,7 @@
 
 		/* Well, if we have backlog, try to process it now yet. */
 
-		if (copied >= target && !sk->sk_backlog.tail)
+		if (copied >= target && !READ_ONCE(sk->sk_backlog.tail))
 			break;
 
 		if (copied) {
@@ -2152,14 +2161,15 @@
 			tp->urg_data = 0;
 			tcp_fast_path_check(sk);
 		}
-		if (used + offset < skb->len)
-			continue;
 
 		if (TCP_SKB_CB(skb)->has_rxtstamp) {
 			tcp_update_recv_tstamps(skb, &tss);
-			has_tss = true;
-			has_cmsg = true;
+			cmsg_flags |= 2;
 		}
+
+		if (used + offset < skb->len)
+			continue;
+
 		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 			goto found_fin_ok;
 		if (!(flags & MSG_PEEK))
@@ -2183,10 +2193,10 @@
 
 	release_sock(sk);
 
-	if (has_cmsg) {
-		if (has_tss)
+	if (cmsg_flags) {
+		if (cmsg_flags & 2)
 			tcp_recv_timestamp(msg, sk, &tss);
-		if (tp->recvmsg_inq) {
+		if (cmsg_flags & 1) {
 			inq = tcp_inq_hint(sk);
 			put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
 		}
@@ -2524,6 +2534,7 @@
 {
 	struct rb_node *p = rb_first(&sk->tcp_rtx_queue);
 
+	tcp_sk(sk)->highest_sack = NULL;
 	while (p) {
 		struct sk_buff *skb = rb_to_skb(p);
 
@@ -2616,15 +2627,21 @@
 	icsk->icsk_backoff = 0;
 	tp->snd_cwnd = 2;
 	icsk->icsk_probes_out = 0;
+	icsk->icsk_probes_tstamp = 0;
 	icsk->icsk_rto = TCP_TIMEOUT_INIT;
 	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 	tp->snd_cwnd = TCP_INIT_CWND;
 	tp->snd_cwnd_cnt = 0;
 	tp->window_clamp = 0;
+	tp->delivered = 0;
 	tp->delivered_ce = 0;
+	if (icsk->icsk_ca_ops->release)
+		icsk->icsk_ca_ops->release(sk);
+	memset(icsk->icsk_ca_priv, 0, sizeof(icsk->icsk_ca_priv));
 	tcp_set_ca_state(sk, TCP_CA_Open);
 	tp->is_sack_reneg = 0;
 	tcp_clear_retrans(tp);
+	tp->total_retrans = 0;
 	inet_csk_delack_init(sk);
 	/* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
 	 * issue in __tcp_select_window()
@@ -2636,10 +2653,14 @@
 	sk->sk_rx_dst = NULL;
 	tcp_saved_syn_free(tp);
 	tp->compressed_ack = 0;
+	tp->segs_in = 0;
+	tp->segs_out = 0;
 	tp->bytes_sent = 0;
 	tp->bytes_acked = 0;
 	tp->bytes_received = 0;
 	tp->bytes_retrans = 0;
+	tp->data_segs_in = 0;
+	tp->data_segs_out = 0;
 	tp->duplicate_sack[0].start_seq = 0;
 	tp->duplicate_sack[0].end_seq = 0;
 	tp->dsack_dups = 0;
@@ -2936,14 +2957,23 @@
 		break;
 
 	case TCP_QUEUE_SEQ:
-		if (sk->sk_state != TCP_CLOSE)
+		if (sk->sk_state != TCP_CLOSE) {
 			err = -EPERM;
-		else if (tp->repair_queue == TCP_SEND_QUEUE)
-			WRITE_ONCE(tp->write_seq, val);
-		else if (tp->repair_queue == TCP_RECV_QUEUE)
-			WRITE_ONCE(tp->rcv_nxt, val);
-		else
+		} else if (tp->repair_queue == TCP_SEND_QUEUE) {
+			if (!tcp_rtx_queue_empty(sk))
+				err = -EPERM;
+			else
+				WRITE_ONCE(tp->write_seq, val);
+		} else if (tp->repair_queue == TCP_RECV_QUEUE) {
+			if (tp->rcv_nxt != tp->copied_seq) {
+				err = -EPERM;
+			} else {
+				WRITE_ONCE(tp->rcv_nxt, val);
+				WRITE_ONCE(tp->copied_seq, val);
+			}
+		} else {
 			err = -EINVAL;
+		}
 		break;
 
 	case TCP_REPAIR_OPTIONS:
@@ -3069,10 +3099,7 @@
 #ifdef CONFIG_TCP_MD5SIG
 	case TCP_MD5SIG:
 	case TCP_MD5SIG_EXT:
-		if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
-			err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
-		else
-			err = -EINVAL;
+		err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
 		break;
 #endif
 	case TCP_USER_TIMEOUT:
@@ -3511,22 +3538,14 @@
 		return 0;
 
 	case TCP_FASTOPEN_KEY: {
-		__u8 key[TCP_FASTOPEN_KEY_BUF_LENGTH];
-		struct tcp_fastopen_context *ctx;
-		unsigned int key_len = 0;
+		u64 key[TCP_FASTOPEN_KEY_BUF_LENGTH / sizeof(u64)];
+		unsigned int key_len;
 
 		if (get_user(len, optlen))
 			return -EFAULT;
 
-		rcu_read_lock();
-		ctx = rcu_dereference(icsk->icsk_accept_queue.fastopenq.ctx);
-		if (ctx) {
-			key_len = tcp_fastopen_context_len(ctx) *
-					TCP_FASTOPEN_KEY_LENGTH;
-			memcpy(&key[0], &ctx->key[0], key_len);
-		}
-		rcu_read_unlock();
-
+		key_len = tcp_fastopen_get_cipher(net, icsk, key) *
+				TCP_FASTOPEN_KEY_LENGTH;
 		len = min_t(unsigned int, len, key_len);
 		if (put_user(len, optlen))
 			return -EFAULT;
@@ -3828,10 +3847,13 @@
 
 int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
 {
+	u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */
 	struct scatterlist sg;
 
-	sg_init_one(&sg, key->key, key->keylen);
-	ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
+	sg_init_one(&sg, key->key, keylen);
+	ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen);
+
+	/* tcp_md5_do_add() might change key->key under us */
 	return crypto_ahash_update(hp->md5_req);
 }
 EXPORT_SYMBOL(tcp_md5_hash_key);