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

Daniel Borkmann says:

====================
pull-request: bpf 2021-04-08

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

We've added 4 non-merge commits during the last 2 day(s) which contain
a total of 4 files changed, 31 insertions(+), 10 deletions(-).

The main changes are:

1) Validate and reject invalid JIT branch displacements, from Piotr Krysiuk.

2) Fix incorrect unhash restore as well as fwd_alloc memory accounting in
   sock map, from John Fastabend.

====================

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

4 files changed, 31 insertions, 10 deletions

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index b35fc802388466..7f1b3a862e1418 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1689,7 +1689,16 @@ emit_jmp:
 		}
 
 		if (image) {
-			if (unlikely(proglen + ilen > oldproglen)) {
+			/*
+			 * When populating the image, assert that:
+			 *
+			 *  i) We do not write beyond the allocated space, and
+			 * ii) addrs[i] did not change from the prior run, in order
+			 *     to validate assumptions made for computing branch
+			 *     displacements.
+			 */
+			if (unlikely(proglen + ilen > oldproglen ||
+				     proglen + ilen != addrs[i])) {
 				pr_err("bpf_jit: fatal error\n");
 				return -EFAULT;
 			}
diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index d17b67c69f89ae..6a99def7d315d0 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -2276,7 +2276,16 @@ notyet:
 		}
 
 		if (image) {
-			if (unlikely(proglen + ilen > oldproglen)) {
+			/*
+			 * When populating the image, assert that:
+			 *
+			 *  i) We do not write beyond the allocated space, and
+			 * ii) addrs[i] did not change from the prior run, in order
+			 *     to validate assumptions made for computing branch
+			 *     displacements.
+			 */
+			if (unlikely(proglen + ilen > oldproglen ||
+				     proglen + ilen != addrs[i])) {
 				pr_err("bpf_jit: fatal error\n");
 				return -EFAULT;
 			}
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 8edbbf5f2f9325..822c048934e3f6 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -349,8 +349,13 @@ static inline void sk_psock_update_proto(struct sock *sk,
 static inline void sk_psock_restore_proto(struct sock *sk,
 					  struct sk_psock *psock)
 {
-	sk->sk_prot->unhash = psock->saved_unhash;
 	if (inet_csk_has_ulp(sk)) {
+		/* TLS does not have an unhash proto in SW cases, but we need
+		 * to ensure we stop using the sock_map unhash routine because
+		 * the associated psock is being removed. So use the original
+		 * unhash handler.
+		 */
+		WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash);
 		tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 	} else {
 		sk->sk_write_space = psock->saved_write_space;
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 1261512d680735..5def3a2e85be9c 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -488,6 +488,7 @@ static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb
 	if (unlikely(!msg))
 		return -EAGAIN;
 	sk_msg_init(msg);
+	skb_set_owner_r(skb, sk);
 	return sk_psock_skb_ingress_enqueue(skb, psock, sk, msg);
 }
 
@@ -790,7 +791,6 @@ static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int
 {
 	switch (verdict) {
 	case __SK_REDIRECT:
-		skb_set_owner_r(skb, sk);
 		sk_psock_skb_redirect(skb);
 		break;
 	case __SK_PASS:
@@ -808,10 +808,6 @@ int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb)
 	rcu_read_lock();
 	prog = READ_ONCE(psock->progs.skb_verdict);
 	if (likely(prog)) {
-		/* We skip full set_owner_r here because if we do a SK_PASS
-		 * or SK_DROP we can skip skb memory accounting and use the
-		 * TLS context.
-		 */
 		skb->sk = psock->sk;
 		tcp_skb_bpf_redirect_clear(skb);
 		ret = sk_psock_bpf_run(psock, prog, skb);
@@ -880,12 +876,13 @@ static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
 		kfree_skb(skb);
 		goto out;
 	}
-	skb_set_owner_r(skb, sk);
 	prog = READ_ONCE(psock->progs.skb_verdict);
 	if (likely(prog)) {
+		skb->sk = sk;
 		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));
+		skb->sk = NULL;
 	}
 	sk_psock_verdict_apply(psock, skb, ret);
 out:
@@ -956,12 +953,13 @@ static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb,
 		kfree_skb(skb);
 		goto out;
 	}
-	skb_set_owner_r(skb, sk);
 	prog = READ_ONCE(psock->progs.skb_verdict);
 	if (likely(prog)) {
+		skb->sk = sk;
 		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));
+		skb->sk = NULL;
 	}
 	sk_psock_verdict_apply(psock, skb, ret);
 out: