bpf, sockmap: allow verdict only sk_skb progs

.travis.yml

@@ -0,0 +1,33 @@
+sudo: required
+language: bash
+dist: bionic
+services:
+    - docker
+
+env:
+    global:
+        - PROJECT_NAME='libbpf'
+        - AUTHOR_EMAIL="$(git log -1 --pretty=\"%aE\")"
+        - REPO_ROOT="$TRAVIS_BUILD_DIR"
+        - CI_ROOT="$REPO_ROOT/travis-ci"
+        - VMTEST_ROOT="$CI_ROOT/vmtest"
+
+addons:
+    apt:
+        packages:
+            - qemu-kvm
+            - zstd
+            - binutils-dev
+            - elfutils
+            - libcap-dev
+            - libelf-dev
+            - libdw-dev
+            - python3-docutils
+
+jobs:
+    include:
+        - stage: Builds & Tests
+          name: Kernel LATEST + selftests
+          language: bash
+          env: KERNEL=LATEST
+          script:  $CI_ROOT/vmtest/run_vmtest.sh || travis_terminate 1

include/linux/skmsg.h

@@ -308,6 +308,8 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node);
 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock);
 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock);
 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock);
+void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock);
+void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
 
 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
 			 struct sk_msg *msg);

net/core/skmsg.c

@@ -627,6 +627,8 @@ void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
 	rcu_assign_sk_user_data(sk, NULL);
 	if (psock->progs.skb_parser)
 		sk_psock_stop_strp(sk, psock);
+	else if (psock->progs.skb_verdict)
+		sk_psock_stop_verdict(sk, psock);
 	write_unlock_bh(&sk->sk_callback_lock);
 	sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
 
@@ -871,6 +873,57 @@ static void sk_psock_strp_data_ready(struct sock *sk)
 	rcu_read_unlock();
 }
 
+static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
+				 unsigned int offset, size_t orig_len)
+{
+	struct sock *sk = (struct sock *)desc->arg.data;
+	struct sk_psock *psock;
+	struct bpf_prog *prog;
+	int ret = __SK_DROP;
+	int len = skb->len;
+
+	/* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (!skb) {
+		desc->error = -ENOMEM;
+		return 0;
+	}
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (unlikely(!psock)) {
+		len = 0;
+		kfree_skb(skb);
+		goto out;
+	}
+	skb_set_owner_r(skb, sk);
+	prog = READ_ONCE(psock->progs.skb_verdict);
+	if (likely(prog)) {
+		tcp_skb_bpf_redirect_clear(skb);
+		ret = sk_psock_bpf_run(psock, prog, skb);
+		ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
+	}
+	sk_psock_verdict_apply(psock, skb, ret);
+out:
+	rcu_read_unlock();
+	return len;
+}
+
+static void sk_psock_verdict_data_ready(struct sock *sk)
+{
+	struct socket *sock = sk->sk_socket;
+	read_descriptor_t desc;
+
+	if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
+		return;
+
+	desc.arg.data = sk;
+	desc.error = 0;
+	desc.count = 1;
+
+	sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv);
+}
+
 static void sk_psock_write_space(struct sock *sk)
 {
 	struct sk_psock *psock;
@@ -900,6 +953,19 @@ int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
 	return strp_init(&psock->parser.strp, sk, &cb);
 }
 
+void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock)
+{
+	struct sk_psock_parser *parser = &psock->parser;
+
+	if (parser->enabled)
+		return;
+
+	parser->saved_data_ready = sk->sk_data_ready;
+	sk->sk_data_ready = sk_psock_verdict_data_ready;
+	sk->sk_write_space = sk_psock_write_space;
+	parser->enabled = true;
+}
+
 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 {
 	struct sk_psock_parser *parser = &psock->parser;
@@ -925,3 +991,15 @@ void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
 	strp_stop(&parser->strp);
 	parser->enabled = false;
 }
+
+void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock)
+{
+	struct sk_psock_parser *parser = &psock->parser;
+
+	if (!parser->enabled)
+		return;
+
+	sk->sk_data_ready = parser->saved_data_ready;
+	parser->saved_data_ready = NULL;
+	parser->enabled = false;
+}

net/core/sock_map.c

@@ -148,8 +148,8 @@ static void sock_map_add_link(struct sk_psock *psock,
 static void sock_map_del_link(struct sock *sk,
 			      struct sk_psock *psock, void *link_raw)
 {
+	bool strp_stop = false, verdict_stop = false;
 	struct sk_psock_link *link, *tmp;
-	bool strp_stop = false;
 
 	spin_lock_bh(&psock->link_lock);
 	list_for_each_entry_safe(link, tmp, &psock->link, list) {
@@ -159,14 +159,19 @@ static void sock_map_del_link(struct sock *sk,
 							     map);
 			if (psock->parser.enabled && stab->progs.skb_parser)
 				strp_stop = true;
+			if (psock->parser.enabled && stab->progs.skb_verdict)
+				verdict_stop = true;
 			list_del(&link->list);
 			sk_psock_free_link(link);
 		}
 	}
 	spin_unlock_bh(&psock->link_lock);
-	if (strp_stop) {
+	if (strp_stop || verdict_stop) {
 		write_lock_bh(&sk->sk_callback_lock);
-		sk_psock_stop_strp(sk, psock);
+		if (strp_stop)
+			sk_psock_stop_strp(sk, psock);
+		else
+			sk_psock_stop_verdict(sk, psock);
 		write_unlock_bh(&sk->sk_callback_lock);
 	}
 }
@@ -230,16 +235,16 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
 {
 	struct bpf_prog *msg_parser, *skb_parser, *skb_verdict;
 	struct sk_psock *psock;
-	bool skb_progs;
 	int ret;
 
 	skb_verdict = READ_ONCE(progs->skb_verdict);
 	skb_parser = READ_ONCE(progs->skb_parser);
-	skb_progs = skb_parser && skb_verdict;
-	if (skb_progs) {
+	if (skb_verdict) {
 		skb_verdict = bpf_prog_inc_not_zero(skb_verdict);
 		if (IS_ERR(skb_verdict))
 			return PTR_ERR(skb_verdict);
+	}
+	if (skb_parser) {
 		skb_parser = bpf_prog_inc_not_zero(skb_parser);
 		if (IS_ERR(skb_parser)) {
 			bpf_prog_put(skb_verdict);
@@ -264,7 +269,8 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
 
 	if (psock) {
 		if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) ||
-		    (skb_progs  && READ_ONCE(psock->progs.skb_parser))) {
+		    (skb_parser  && READ_ONCE(psock->progs.skb_parser)) ||
+		    (skb_verdict && READ_ONCE(psock->progs.skb_verdict))) {
 			sk_psock_put(sk, psock);
 			ret = -EBUSY;
 			goto out_progs;
@@ -285,28 +291,31 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
 		goto out_drop;
 
 	write_lock_bh(&sk->sk_callback_lock);
-	if (skb_progs && !psock->parser.enabled) {
+	if (skb_parser && skb_verdict && !psock->parser.enabled) {
 		ret = sk_psock_init_strp(sk, psock);
-		if (ret) {
-			write_unlock_bh(&sk->sk_callback_lock);
-			goto out_drop;
-		}
+		if (ret)
+			goto out_unlock_drop;
 		psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
 		psock_set_prog(&psock->progs.skb_parser, skb_parser);
 		sk_psock_start_strp(sk, psock);
+	} else if (!skb_parser && skb_verdict && !psock->parser.enabled) {
+		psock_set_prog(&psock->progs.skb_verdict, skb_verdict);
+		sk_psock_start_verdict(sk,psock);
 	}
 	write_unlock_bh(&sk->sk_callback_lock);
 	return 0;
+out_unlock_drop:
+	write_unlock_bh(&sk->sk_callback_lock);
 out_drop:
 	sk_psock_put(sk, psock);
 out_progs:
 	if (msg_parser)
 		bpf_prog_put(msg_parser);
 out:
-	if (skb_progs) {
+	if (skb_verdict)
 		bpf_prog_put(skb_verdict);
+	if (skb_parser)
 		bpf_prog_put(skb_parser);
-	}
 	return ret;
 }
 

tools/testing/selftests/bpf/test_sockmap.c

@@ -86,6 +86,7 @@ int txmsg_ktls_skb_redir;
 int ktls;
 int peek_flag;
 int skb_use_parser;
+int txmsg_omit_skb_parser;
 
 static const struct option long_options[] = {
 	{"help",	no_argument,		NULL, 'h' },
@@ -111,6 +112,7 @@ static const struct option long_options[] = {
 	{"txmsg_redir_skb", no_argument,	&txmsg_redir_skb, 1 },
 	{"ktls", no_argument,			&ktls, 1 },
 	{"peek", no_argument,			&peek_flag, 1 },
+	{"txmsg_omit_skb_parser", no_argument,      &txmsg_omit_skb_parser, 1},
 	{"whitelist", required_argument,	NULL, 'n' },
 	{"blacklist", required_argument,	NULL, 'b' },
 	{0, 0, NULL, 0 }
@@ -175,6 +177,7 @@ static void test_reset(void)
 	txmsg_apply = txmsg_cork = 0;
 	txmsg_ingress = txmsg_redir_skb = 0;
 	txmsg_ktls_skb = txmsg_ktls_skb_drop = txmsg_ktls_skb_redir = 0;
+	txmsg_omit_skb_parser = 0;
 	skb_use_parser = 0;
 }
 
@@ -912,13 +915,15 @@ static int run_options(struct sockmap_options *options, int cg_fd,  int test)
 		goto run;
 
 	/* Attach programs to sockmap */
-	err = bpf_prog_attach(prog_fd[0], map_fd[0],
-				BPF_SK_SKB_STREAM_PARSER, 0);
-	if (err) {
-		fprintf(stderr,
-			"ERROR: bpf_prog_attach (sockmap %i->%i): %d (%s)\n",
-			prog_fd[0], map_fd[0], err, strerror(errno));
-		return err;
+	if (!txmsg_omit_skb_parser) {
+		err = bpf_prog_attach(prog_fd[0], map_fd[0],
+				      BPF_SK_SKB_STREAM_PARSER, 0);
+		if (err) {
+			fprintf(stderr,
+				"ERROR: bpf_prog_attach (sockmap %i->%i): %d (%s)\n",
+				prog_fd[0], map_fd[0], err, strerror(errno));
+			return err;
+		}
 	}
 
 	err = bpf_prog_attach(prog_fd[1], map_fd[0],
@@ -931,13 +936,15 @@ static int run_options(struct sockmap_options *options, int cg_fd,  int test)
 
 	/* Attach programs to TLS sockmap */
 	if (txmsg_ktls_skb) {
-		err = bpf_prog_attach(prog_fd[0], map_fd[8],
-					BPF_SK_SKB_STREAM_PARSER, 0);
-		if (err) {
-			fprintf(stderr,
-				"ERROR: bpf_prog_attach (TLS sockmap %i->%i): %d (%s)\n",
-				prog_fd[0], map_fd[8], err, strerror(errno));
-			return err;
+		if (!txmsg_omit_skb_parser) {
+			err = bpf_prog_attach(prog_fd[0], map_fd[8],
+					      BPF_SK_SKB_STREAM_PARSER, 0);
+			if (err) {
+				fprintf(stderr,
+					"ERROR: bpf_prog_attach (TLS sockmap %i->%i): %d (%s)\n",
+					prog_fd[0], map_fd[8], err, strerror(errno));
+				return err;
+			}
 		}
 
 		err = bpf_prog_attach(prog_fd[2], map_fd[8],
@@ -1465,12 +1472,29 @@ static void test_txmsg_skb(int cgrp, struct sockmap_options *opt)
 	txmsg_ktls_skb_drop = 0;
 	txmsg_ktls_skb_redir = 1;
 	test_exec(cgrp, opt);
+	txmsg_ktls_skb_redir = 0;
+
+	/* Tests that omit skb_parser */
+	txmsg_omit_skb_parser = 1;
+	ktls = 0;
+	txmsg_ktls_skb = 0;
+	test_exec(cgrp, opt);
+
+	txmsg_ktls_skb_drop = 1;
+	test_exec(cgrp, opt);
+	txmsg_ktls_skb_drop = 0;
+
+	txmsg_ktls_skb_redir = 1;
+	test_exec(cgrp, opt);
+
+	ktls = 1;
+	test_exec(cgrp, opt);
+	txmsg_omit_skb_parser = 0;
 
 	opt->data_test = data;
 	ktls = k;
 }
 
-
 /* Test cork with hung data. This tests poor usage patterns where
  * cork can leave data on the ring if user program is buggy and
  * doesn't flush them somehow. They do take some time however