Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2018-08-18

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Fix a BPF selftest failure in test_cgroup_storage due to rlimit
   restrictions, from Yonghong.

2) Fix a suspicious RCU rcu_dereference_check() warning triggered
   from removing a device's XDP memory allocator by using the correct
   rhashtable lookup function, from Tariq.

3) A batch of BPF sockmap and ULP fixes mainly fixing leaks and races
   as well as enforcing module aliases for ULPs. Another fix for BPF
   map redirect to make them work again with tail calls, from Daniel.

4) Fix XDP BPF samples to unload their programs upon SIGTERM, from Jesper.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 73 insertions, 74 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 4d09e610777f..3f5bf1af0826 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1579,7 +1579,7 @@ static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array,
 	struct bpf_prog_array_item *item;
 	int i = 0;
 
-	item = rcu_dereference(array)->items;
+	item = rcu_dereference_check(array, 1)->items;
 	for (; item->prog; item++) {
 		if (item->prog == &dummy_bpf_prog.prog)
 			continue;
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 620bc5024d7d..24aac0d0f412 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -479,6 +479,8 @@ static void cpu_map_free(struct bpf_map *map)
 	 * It does __not__ ensure pending flush operations (if any) are
 	 * complete.
 	 */
+
+	bpf_clear_redirect_map(map);
 	synchronize_rcu();
 
 	/* To ensure all pending flush operations have completed wait for flush
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index ac1df79f3788..141710b82a6c 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -161,6 +161,7 @@ static void dev_map_free(struct bpf_map *map)
 	list_del_rcu(&dtab->list);
 	spin_unlock(&dev_map_lock);
 
+	bpf_clear_redirect_map(map);
 	synchronize_rcu();
 
 	/* To ensure all pending flush operations have completed wait for flush
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 0c1a696b041b..98e621a29e8e 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -58,6 +58,7 @@ struct bpf_stab {
 	struct bpf_map map;
 	struct sock **sock_map;
 	struct bpf_sock_progs progs;
+	raw_spinlock_t lock;
 };
 
 struct bucket {
@@ -89,9 +90,9 @@ enum smap_psock_state {
 
 struct smap_psock_map_entry {
 	struct list_head list;
+	struct bpf_map *map;
 	struct sock **entry;
 	struct htab_elem __rcu *hash_link;
-	struct bpf_htab __rcu *htab;
 };
 
 struct smap_psock {
@@ -343,13 +344,18 @@ static void bpf_tcp_close(struct sock *sk, long timeout)
 	e = psock_map_pop(sk, psock);
 	while (e) {
 		if (e->entry) {
-			osk = cmpxchg(e->entry, sk, NULL);
+			struct bpf_stab *stab = container_of(e->map, struct bpf_stab, map);
+
+			raw_spin_lock_bh(&stab->lock);
+			osk = *e->entry;
 			if (osk == sk) {
+				*e->entry = NULL;
 				smap_release_sock(psock, sk);
 			}
+			raw_spin_unlock_bh(&stab->lock);
 		} else {
 			struct htab_elem *link = rcu_dereference(e->hash_link);
-			struct bpf_htab *htab = rcu_dereference(e->htab);
+			struct bpf_htab *htab = container_of(e->map, struct bpf_htab, map);
 			struct hlist_head *head;
 			struct htab_elem *l;
 			struct bucket *b;
@@ -370,6 +376,7 @@ static void bpf_tcp_close(struct sock *sk, long timeout)
 			}
 			raw_spin_unlock_bh(&b->lock);
 		}
+		kfree(e);
 		e = psock_map_pop(sk, psock);
 	}
 	rcu_read_unlock();
@@ -1641,6 +1648,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
 		return ERR_PTR(-ENOMEM);
 
 	bpf_map_init_from_attr(&stab->map, attr);
+	raw_spin_lock_init(&stab->lock);
 
 	/* make sure page count doesn't overflow */
 	cost = (u64) stab->map.max_entries * sizeof(struct sock *);
@@ -1675,8 +1683,10 @@ static void smap_list_map_remove(struct smap_psock *psock,
 
 	spin_lock_bh(&psock->maps_lock);
 	list_for_each_entry_safe(e, tmp, &psock->maps, list) {
-		if (e->entry == entry)
+		if (e->entry == entry) {
 			list_del(&e->list);
+			kfree(e);
+		}
 	}
 	spin_unlock_bh(&psock->maps_lock);
 }
@@ -1690,8 +1700,10 @@ static void smap_list_hash_remove(struct smap_psock *psock,
 	list_for_each_entry_safe(e, tmp, &psock->maps, list) {
 		struct htab_elem *c = rcu_dereference(e->hash_link);
 
-		if (c == hash_link)
+		if (c == hash_link) {
 			list_del(&e->list);
+			kfree(e);
+		}
 	}
 	spin_unlock_bh(&psock->maps_lock);
 }
@@ -1711,14 +1723,15 @@ static void sock_map_free(struct bpf_map *map)
 	 * and a grace period expire to ensure psock is really safe to remove.
 	 */
 	rcu_read_lock();
+	raw_spin_lock_bh(&stab->lock);
 	for (i = 0; i < stab->map.max_entries; i++) {
 		struct smap_psock *psock;
 		struct sock *sock;
 
-		sock = xchg(&stab->sock_map[i], NULL);
+		sock = stab->sock_map[i];
 		if (!sock)
 			continue;
-
+		stab->sock_map[i] = NULL;
 		psock = smap_psock_sk(sock);
 		/* This check handles a racing sock event that can get the
 		 * sk_callback_lock before this case but after xchg happens
@@ -1730,6 +1743,7 @@ static void sock_map_free(struct bpf_map *map)
 			smap_release_sock(psock, sock);
 		}
 	}
+	raw_spin_unlock_bh(&stab->lock);
 	rcu_read_unlock();
 
 	sock_map_remove_complete(stab);
@@ -1773,19 +1787,23 @@ static int sock_map_delete_elem(struct bpf_map *map, void *key)
 	if (k >= map->max_entries)
 		return -EINVAL;
 
-	sock = xchg(&stab->sock_map[k], NULL);
+	raw_spin_lock_bh(&stab->lock);
+	sock = stab->sock_map[k];
+	stab->sock_map[k] = NULL;
+	raw_spin_unlock_bh(&stab->lock);
 	if (!sock)
 		return -EINVAL;
 
 	psock = smap_psock_sk(sock);
 	if (!psock)
-		goto out;
-
-	if (psock->bpf_parse)
+		return 0;
+	if (psock->bpf_parse) {
+		write_lock_bh(&sock->sk_callback_lock);
 		smap_stop_sock(psock, sock);
+		write_unlock_bh(&sock->sk_callback_lock);
+	}
 	smap_list_map_remove(psock, &stab->sock_map[k]);
 	smap_release_sock(psock, sock);
-out:
 	return 0;
 }
 
@@ -1821,11 +1839,9 @@ out:
 static int __sock_map_ctx_update_elem(struct bpf_map *map,
 				      struct bpf_sock_progs *progs,
 				      struct sock *sock,
-				      struct sock **map_link,
 				      void *key)
 {
 	struct bpf_prog *verdict, *parse, *tx_msg;
-	struct smap_psock_map_entry *e = NULL;
 	struct smap_psock *psock;
 	bool new = false;
 	int err = 0;
@@ -1898,14 +1914,6 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
 		new = true;
 	}
 
-	if (map_link) {
-		e = kzalloc(sizeof(*e), GFP_ATOMIC | __GFP_NOWARN);
-		if (!e) {
-			err = -ENOMEM;
-			goto out_free;
-		}
-	}
-
 	/* 3. At this point we have a reference to a valid psock that is
 	 * running. Attach any BPF programs needed.
 	 */
@@ -1927,17 +1935,6 @@ static int __sock_map_ctx_update_elem(struct bpf_map *map,
 		write_unlock_bh(&sock->sk_callback_lock);
 	}
 
-	/* 4. Place psock in sockmap for use and stop any programs on
-	 * the old sock assuming its not the same sock we are replacing
-	 * it with. Because we can only have a single set of programs if
-	 * old_sock has a strp we can stop it.
-	 */
-	if (map_link) {
-		e->entry = map_link;
-		spin_lock_bh(&psock->maps_lock);
-		list_add_tail(&e->list, &psock->maps);
-		spin_unlock_bh(&psock->maps_lock);
-	}
 	return err;
 out_free:
 	smap_release_sock(psock, sock);
@@ -1948,7 +1945,6 @@ out_progs:
 	}
 	if (tx_msg)
 		bpf_prog_put(tx_msg);
-	kfree(e);
 	return err;
 }
 
@@ -1958,36 +1954,57 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 {
 	struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
 	struct bpf_sock_progs *progs = &stab->progs;
-	struct sock *osock, *sock;
+	struct sock *osock, *sock = skops->sk;
+	struct smap_psock_map_entry *e;
+	struct smap_psock *psock;
 	u32 i = *(u32 *)key;
 	int err;
 
 	if (unlikely(flags > BPF_EXIST))
 		return -EINVAL;
-
 	if (unlikely(i >= stab->map.max_entries))
 		return -E2BIG;
 
-	sock = READ_ONCE(stab->sock_map[i]);
-	if (flags == BPF_EXIST && !sock)
-		return -ENOENT;
-	else if (flags == BPF_NOEXIST && sock)
-		return -EEXIST;
+	e = kzalloc(sizeof(*e), GFP_ATOMIC | __GFP_NOWARN);
+	if (!e)
+		return -ENOMEM;
 
-	sock = skops->sk;
-	err = __sock_map_ctx_update_elem(map, progs, sock, &stab->sock_map[i],
-					 key);
+	err = __sock_map_ctx_update_elem(map, progs, sock, key);
 	if (err)
 		goto out;
 
-	osock = xchg(&stab->sock_map[i], sock);
-	if (osock) {
-		struct smap_psock *opsock = smap_psock_sk(osock);
+	/* psock guaranteed to be present. */
+	psock = smap_psock_sk(sock);
+	raw_spin_lock_bh(&stab->lock);
+	osock = stab->sock_map[i];
+	if (osock && flags == BPF_NOEXIST) {
+		err = -EEXIST;
+		goto out_unlock;
+	}
+	if (!osock && flags == BPF_EXIST) {
+		err = -ENOENT;
+		goto out_unlock;
+	}
 
-		smap_list_map_remove(opsock, &stab->sock_map[i]);
-		smap_release_sock(opsock, osock);
+	e->entry = &stab->sock_map[i];
+	e->map = map;
+	spin_lock_bh(&psock->maps_lock);
+	list_add_tail(&e->list, &psock->maps);
+	spin_unlock_bh(&psock->maps_lock);
+
+	stab->sock_map[i] = sock;
+	if (osock) {
+		psock = smap_psock_sk(osock);
+		smap_list_map_remove(psock, &stab->sock_map[i]);
+		smap_release_sock(psock, osock);
 	}
+	raw_spin_unlock_bh(&stab->lock);
+	return 0;
+out_unlock:
+	smap_release_sock(psock, sock);
+	raw_spin_unlock_bh(&stab->lock);
 out:
+	kfree(e);
 	return err;
 }
 
@@ -2350,7 +2367,7 @@ static int sock_hash_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 	b = __select_bucket(htab, hash);
 	head = &b->head;
 
-	err = __sock_map_ctx_update_elem(map, progs, sock, NULL, key);
+	err = __sock_map_ctx_update_elem(map, progs, sock, key);
 	if (err)
 		goto err;
 
@@ -2376,8 +2393,7 @@ static int sock_hash_ctx_update_elem(struct bpf_sock_ops_kern *skops,
 	}
 
 	rcu_assign_pointer(e->hash_link, l_new);
-	rcu_assign_pointer(e->htab,
-			   container_of(map, struct bpf_htab, map));
+	e->map = map;
 	spin_lock_bh(&psock->maps_lock);
 	list_add_tail(&e->list, &psock->maps);
 	spin_unlock_bh(&psock->maps_lock);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ca90679a7fe5..92246117d2b0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5844,27 +5844,6 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
 			goto patch_call_imm;
 		}
 
-		if (insn->imm == BPF_FUNC_redirect_map) {
-			/* Note, we cannot use prog directly as imm as subsequent
-			 * rewrites would still change the prog pointer. The only
-			 * stable address we can use is aux, which also works with
-			 * prog clones during blinding.
-			 */
-			u64 addr = (unsigned long)prog->aux;
-			struct bpf_insn r4_ld[] = {
-				BPF_LD_IMM64(BPF_REG_4, addr),
-				*insn,
-			};
-			cnt = ARRAY_SIZE(r4_ld);
-
-			new_prog = bpf_patch_insn_data(env, i + delta, r4_ld, cnt);
-			if (!new_prog)
-				return -ENOMEM;
-
-			delta    += cnt - 1;
-			env->prog = prog = new_prog;
-			insn      = new_prog->insnsi + i + delta;
-		}
 patch_call_imm:
 		fn = env->ops->get_func_proto(insn->imm, env->prog);
 		/* all functions that have prototype and verifier allowed
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 4ddf61e158f6..9f8463afda9c 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -75,6 +75,7 @@ static void xsk_map_free(struct bpf_map *map)
 	struct xsk_map *m = container_of(map, struct xsk_map, map);
 	int i;
 
+	bpf_clear_redirect_map(map);
 	synchronize_net();
 
 	for (i = 0; i < map->max_entries; i++) {