[PATCH net 0/6] rxrpc: Syzbot-inspired fixes

[PATCH net 0/6] rxrpc: Syzbot-inspired fixes

[David Howells]

Here's a series of patches that fix a number of issues found by syzbot:

 (1) A reference leak on rxrpc_call structs in a sendmsg error path.

 (2) A tracepoint that looked in the rxrpc_peer record after putting it.

     Analogous with this, though not presently detected, the same bug is
     also fixed in relation to rxrpc_connection and rxrpc_call records.

 (3) Peer records don't pin local endpoint records, despite accessing them.

 (4) Access to connection crypto ops to clean up a call after the call's
     ref on that connection has been put.

The patches are tagged here:

	git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
	rxrpc-fixes-20191007

and can also be found on the following branch:

	http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=rxrpc-fixes

David
---
David Howells (6):
      rxrpc: Fix call ref leak
      rxrpc: Fix trace-after-put looking at the put peer record
      rxrpc: Fix trace-after-put looking at the put connection record
      rxrpc: Fix trace-after-put looking at the put call record
      rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record
      rxrpc: Fix call crypto state cleanup


 include/trace/events/rxrpc.h |   18 +++++++++---------
 net/rxrpc/ar-internal.h      |    1 +
 net/rxrpc/call_accept.c      |    5 +++--
 net/rxrpc/call_object.c      |   34 ++++++++++++++++++++--------------
 net/rxrpc/conn_client.c      |    9 +++++++--
 net/rxrpc/conn_object.c      |   13 +++++++------
 net/rxrpc/conn_service.c     |    2 +-
 net/rxrpc/peer_object.c      |   16 ++++++++++------
 net/rxrpc/recvmsg.c          |    6 +++---
 net/rxrpc/sendmsg.c          |    3 ++-
 10 files changed, 63 insertions(+), 44 deletions(-)

[PATCH net 1/6] rxrpc: Fix call ref leak

[David Howells]

When sendmsg() finds a call to continue on with, if the call is in an
inappropriate state, it doesn't release the ref it just got on that call
before returning an error.

This causes the following symptom to show up with kasan:

	BUG: KASAN: use-after-free in rxrpc_send_keepalive+0x8a2/0x940
	net/rxrpc/output.c:635
	Read of size 8 at addr ffff888064219698 by task kworker/0:3/11077

where line 635 is:

	whdr.epoch	= htonl(peer->local->rxnet->epoch);

The local endpoint (which cannot be pinned by the call) has been released,
but not the peer (which is pinned by the call).

Fix this by releasing the call in the error path.

Fixes: 37411cad633f ("rxrpc: Fix potential NULL-pointer exception")
Reported-by: syzbot+d850c266e3df14da1d31@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
---

 net/rxrpc/sendmsg.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 6a1547b270fe..22f51a7e356e 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -661,6 +661,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		case RXRPC_CALL_SERVER_PREALLOC:
 		case RXRPC_CALL_SERVER_SECURING:
 		case RXRPC_CALL_SERVER_ACCEPTING:
+			rxrpc_put_call(call, rxrpc_call_put);
 			ret = -EBUSY;
 			goto error_release_sock;
 		default:

[PATCH net 2/6] rxrpc: Fix trace-after-put looking at the put peer record

[David Howells]

rxrpc_put_peer() calls trace_rxrpc_peer() after it has done the decrement
of the refcount - which looks at the debug_id in the peer record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

This can cause the following symptoms:

    BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
    [inline]
    BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
    net/rxrpc/peer_object.c:435
    Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216

Fixes: 1159d4b496f5 ("rxrpc: Add a tracepoint to track rxrpc_peer refcounting")
Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
---

 include/trace/events/rxrpc.h |    6 +++---
 net/rxrpc/peer_object.c      |   11 +++++++----
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index edc5c887a44c..45556fe771c3 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -519,10 +519,10 @@ TRACE_EVENT(rxrpc_local,
 	    );
 
 TRACE_EVENT(rxrpc_peer,
-	    TP_PROTO(struct rxrpc_peer *peer, enum rxrpc_peer_trace op,
+	    TP_PROTO(unsigned int peer_debug_id, enum rxrpc_peer_trace op,
 		     int usage, const void *where),
 
-	    TP_ARGS(peer, op, usage, where),
+	    TP_ARGS(peer_debug_id, op, usage, where),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,	peer		)
@@ -532,7 +532,7 @@ TRACE_EVENT(rxrpc_peer,
 			     ),
 
 	    TP_fast_assign(
-		    __entry->peer = peer->debug_id;
+		    __entry->peer = peer_debug_id;
 		    __entry->op = op;
 		    __entry->usage = usage;
 		    __entry->where = where;
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index 9c3ac96f71cb..b700b7ecaa3d 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -382,7 +382,7 @@ struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 	int n;
 
 	n = atomic_inc_return(&peer->usage);
-	trace_rxrpc_peer(peer, rxrpc_peer_got, n, here);
+	trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n, here);
 	return peer;
 }
 
@@ -396,7 +396,7 @@ struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 	if (peer) {
 		int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
 		if (n > 0)
-			trace_rxrpc_peer(peer, rxrpc_peer_got, n + 1, here);
+			trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n + 1, here);
 		else
 			peer = NULL;
 	}
@@ -426,11 +426,13 @@ static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 void rxrpc_put_peer(struct rxrpc_peer *peer)
 {
 	const void *here = __builtin_return_address(0);
+	unsigned int debug_id;
 	int n;
 
 	if (peer) {
+		debug_id = peer->debug_id;
 		n = atomic_dec_return(&peer->usage);
-		trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
+		trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 		if (n == 0)
 			__rxrpc_put_peer(peer);
 	}
@@ -443,10 +445,11 @@ void rxrpc_put_peer(struct rxrpc_peer *peer)
 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 {
 	const void *here = __builtin_return_address(0);
+	unsigned int debug_id = peer->debug_id;
 	int n;
 
 	n = atomic_dec_return(&peer->usage);
-	trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
+	trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 	if (n == 0) {
 		hash_del_rcu(&peer->hash_link);
 		list_del_init(&peer->keepalive_link);

[PATCH net 3/6] rxrpc: Fix trace-after-put looking at the put connection record

[David Howells]

rxrpc_put_*conn() calls trace_rxrpc_conn() after they have done the
decrement of the refcount - which looks at the debug_id in the connection
record.  But unless the refcount was reduced to zero, we no longer have the
right to look in the record and, indeed, it may be deleted by some other
thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: 363deeab6d0f ("rxrpc: Add connection tracepoint and client conn state tracepoint")
Signed-off-by: David Howells <dhowells@redhat.com>
---

 include/trace/events/rxrpc.h |    6 +++---
 net/rxrpc/call_accept.c      |    2 +-
 net/rxrpc/conn_client.c      |    6 ++++--
 net/rxrpc/conn_object.c      |   13 +++++++------
 net/rxrpc/conn_service.c     |    2 +-
 5 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 45556fe771c3..38a97e890cb6 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -546,10 +546,10 @@ TRACE_EVENT(rxrpc_peer,
 	    );
 
 TRACE_EVENT(rxrpc_conn,
-	    TP_PROTO(struct rxrpc_connection *conn, enum rxrpc_conn_trace op,
+	    TP_PROTO(unsigned int conn_debug_id, enum rxrpc_conn_trace op,
 		     int usage, const void *where),
 
-	    TP_ARGS(conn, op, usage, where),
+	    TP_ARGS(conn_debug_id, op, usage, where),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,	conn		)
@@ -559,7 +559,7 @@ TRACE_EVENT(rxrpc_conn,
 			     ),
 
 	    TP_fast_assign(
-		    __entry->conn = conn->debug_id;
+		    __entry->conn = conn_debug_id;
 		    __entry->op = op;
 		    __entry->usage = usage;
 		    __entry->where = where;
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 00c095d74145..c1b1b7dd2924 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -84,7 +84,7 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
 		smp_store_release(&b->conn_backlog_head,
 				  (head + 1) & (size - 1));
 
-		trace_rxrpc_conn(conn, rxrpc_conn_new_service,
+		trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_service,
 				 atomic_read(&conn->usage), here);
 	}
 
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index 3f1da1b49f69..700eb77173fc 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -212,7 +212,8 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 	rxrpc_get_local(conn->params.local);
 	key_get(conn->params.key);
 
-	trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage),
+	trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client,
+			 atomic_read(&conn->usage),
 			 __builtin_return_address(0));
 	trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
 	_leave(" = %p", conn);
@@ -985,11 +986,12 @@ rxrpc_put_one_client_conn(struct rxrpc_connection *conn)
 void rxrpc_put_client_conn(struct rxrpc_connection *conn)
 {
 	const void *here = __builtin_return_address(0);
+	unsigned int debug_id = conn->debug_id;
 	int n;
 
 	do {
 		n = atomic_dec_return(&conn->usage);
-		trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here);
+		trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, n, here);
 		if (n > 0)
 			return;
 		ASSERTCMP(n, >=, 0);
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index ed05b6922132..38d718e90dc6 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -269,7 +269,7 @@ bool rxrpc_queue_conn(struct rxrpc_connection *conn)
 	if (n == 0)
 		return false;
 	if (rxrpc_queue_work(&conn->processor))
-		trace_rxrpc_conn(conn, rxrpc_conn_queued, n + 1, here);
+		trace_rxrpc_conn(conn->debug_id, rxrpc_conn_queued, n + 1, here);
 	else
 		rxrpc_put_connection(conn);
 	return true;
@@ -284,7 +284,7 @@ void rxrpc_see_connection(struct rxrpc_connection *conn)
 	if (conn) {
 		int n = atomic_read(&conn->usage);
 
-		trace_rxrpc_conn(conn, rxrpc_conn_seen, n, here);
+		trace_rxrpc_conn(conn->debug_id, rxrpc_conn_seen, n, here);
 	}
 }
 
@@ -296,7 +296,7 @@ void rxrpc_get_connection(struct rxrpc_connection *conn)
 	const void *here = __builtin_return_address(0);
 	int n = atomic_inc_return(&conn->usage);
 
-	trace_rxrpc_conn(conn, rxrpc_conn_got, n, here);
+	trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n, here);
 }
 
 /*
@@ -310,7 +310,7 @@ rxrpc_get_connection_maybe(struct rxrpc_connection *conn)
 	if (conn) {
 		int n = atomic_fetch_add_unless(&conn->usage, 1, 0);
 		if (n > 0)
-			trace_rxrpc_conn(conn, rxrpc_conn_got, n + 1, here);
+			trace_rxrpc_conn(conn->debug_id, rxrpc_conn_got, n + 1, here);
 		else
 			conn = NULL;
 	}
@@ -333,10 +333,11 @@ static void rxrpc_set_service_reap_timer(struct rxrpc_net *rxnet,
 void rxrpc_put_service_conn(struct rxrpc_connection *conn)
 {
 	const void *here = __builtin_return_address(0);
+	unsigned int debug_id = conn->debug_id;
 	int n;
 
 	n = atomic_dec_return(&conn->usage);
-	trace_rxrpc_conn(conn, rxrpc_conn_put_service, n, here);
+	trace_rxrpc_conn(debug_id, rxrpc_conn_put_service, n, here);
 	ASSERTCMP(n, >=, 0);
 	if (n == 1)
 		rxrpc_set_service_reap_timer(conn->params.local->rxnet,
@@ -420,7 +421,7 @@ void rxrpc_service_connection_reaper(struct work_struct *work)
 		 */
 		if (atomic_cmpxchg(&conn->usage, 1, 0) != 1)
 			continue;
-		trace_rxrpc_conn(conn, rxrpc_conn_reap_service, 0, NULL);
+		trace_rxrpc_conn(conn->debug_id, rxrpc_conn_reap_service, 0, NULL);
 
 		if (rxrpc_conn_is_client(conn))
 			BUG();
diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c
index b30e13f6d95f..123d6ceab15c 100644
--- a/net/rxrpc/conn_service.c
+++ b/net/rxrpc/conn_service.c
@@ -134,7 +134,7 @@ struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxn
 		list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
 		write_unlock(&rxnet->conn_lock);
 
-		trace_rxrpc_conn(conn, rxrpc_conn_new_service,
+		trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_service,
 				 atomic_read(&conn->usage),
 				 __builtin_return_address(0));
 	}

[PATCH net 4/6] rxrpc: Fix trace-after-put looking at the put call record

[David Howells]

rxrpc_put_call() calls trace_rxrpc_call() after it has done the decrement
of the refcount - which looks at the debug_id in the call record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: e34d4234b0b7 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: David Howells <dhowells@redhat.com>
---

 include/trace/events/rxrpc.h |    6 +++---
 net/rxrpc/call_accept.c      |    2 +-
 net/rxrpc/call_object.c      |   28 +++++++++++++++++-----------
 3 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 38a97e890cb6..191fe447f990 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -606,10 +606,10 @@ TRACE_EVENT(rxrpc_client,
 	    );
 
 TRACE_EVENT(rxrpc_call,
-	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_call_trace op,
+	    TP_PROTO(unsigned int call_debug_id, enum rxrpc_call_trace op,
 		     int usage, const void *where, const void *aux),
 
-	    TP_ARGS(call, op, usage, where, aux),
+	    TP_ARGS(call_debug_id, op, usage, where, aux),
 
 	    TP_STRUCT__entry(
 		    __field(unsigned int,		call		)
@@ -620,7 +620,7 @@ TRACE_EVENT(rxrpc_call,
 			     ),
 
 	    TP_fast_assign(
-		    __entry->call = call->debug_id;
+		    __entry->call = call_debug_id;
 		    __entry->op = op;
 		    __entry->usage = usage;
 		    __entry->where = where;
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index c1b1b7dd2924..1f778102ed8d 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -97,7 +97,7 @@ static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
 	call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
 	call->state = RXRPC_CALL_SERVER_PREALLOC;
 
-	trace_rxrpc_call(call, rxrpc_call_new_service,
+	trace_rxrpc_call(call->debug_id, rxrpc_call_new_service,
 			 atomic_read(&call->usage),
 			 here, (const void *)user_call_ID);
 
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 32d8dc677142..6dace078971a 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -240,7 +240,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 	if (p->intr)
 		__set_bit(RXRPC_CALL_IS_INTR, &call->flags);
 	call->tx_total_len = p->tx_total_len;
-	trace_rxrpc_call(call, rxrpc_call_new_client, atomic_read(&call->usage),
+	trace_rxrpc_call(call->debug_id, rxrpc_call_new_client,
+			 atomic_read(&call->usage),
 			 here, (const void *)p->user_call_ID);
 
 	/* We need to protect a partially set up call against the user as we
@@ -290,8 +291,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 	if (ret < 0)
 		goto error;
 
-	trace_rxrpc_call(call, rxrpc_call_connected, atomic_read(&call->usage),
-			 here, NULL);
+	trace_rxrpc_call(call->debug_id, rxrpc_call_connected,
+			 atomic_read(&call->usage), here, NULL);
 
 	rxrpc_start_call_timer(call);
 
@@ -313,8 +314,8 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
 error:
 	__rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR,
 				    RX_CALL_DEAD, ret);
-	trace_rxrpc_call(call, rxrpc_call_error, atomic_read(&call->usage),
-			 here, ERR_PTR(ret));
+	trace_rxrpc_call(call->debug_id, rxrpc_call_error,
+			 atomic_read(&call->usage), here, ERR_PTR(ret));
 	rxrpc_release_call(rx, call);
 	mutex_unlock(&call->user_mutex);
 	rxrpc_put_call(call, rxrpc_call_put);
@@ -376,7 +377,8 @@ bool rxrpc_queue_call(struct rxrpc_call *call)
 	if (n == 0)
 		return false;
 	if (rxrpc_queue_work(&call->processor))
-		trace_rxrpc_call(call, rxrpc_call_queued, n + 1, here, NULL);
+		trace_rxrpc_call(call->debug_id, rxrpc_call_queued, n + 1,
+				 here, NULL);
 	else
 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
 	return true;
@@ -391,7 +393,8 @@ bool __rxrpc_queue_call(struct rxrpc_call *call)
 	int n = atomic_read(&call->usage);
 	ASSERTCMP(n, >=, 1);
 	if (rxrpc_queue_work(&call->processor))
-		trace_rxrpc_call(call, rxrpc_call_queued_ref, n, here, NULL);
+		trace_rxrpc_call(call->debug_id, rxrpc_call_queued_ref, n,
+				 here, NULL);
 	else
 		rxrpc_put_call(call, rxrpc_call_put_noqueue);
 	return true;
@@ -406,7 +409,8 @@ void rxrpc_see_call(struct rxrpc_call *call)
 	if (call) {
 		int n = atomic_read(&call->usage);
 
-		trace_rxrpc_call(call, rxrpc_call_seen, n, here, NULL);
+		trace_rxrpc_call(call->debug_id, rxrpc_call_seen, n,
+				 here, NULL);
 	}
 }
 
@@ -418,7 +422,7 @@ void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 	const void *here = __builtin_return_address(0);
 	int n = atomic_inc_return(&call->usage);
 
-	trace_rxrpc_call(call, op, n, here, NULL);
+	trace_rxrpc_call(call->debug_id, op, n, here, NULL);
 }
 
 /*
@@ -445,7 +449,8 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
 
 	_enter("{%d,%d}", call->debug_id, atomic_read(&call->usage));
 
-	trace_rxrpc_call(call, rxrpc_call_release, atomic_read(&call->usage),
+	trace_rxrpc_call(call->debug_id, rxrpc_call_release,
+			 atomic_read(&call->usage),
 			 here, (const void *)call->flags);
 
 	ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
@@ -534,12 +539,13 @@ void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
 {
 	struct rxrpc_net *rxnet = call->rxnet;
 	const void *here = __builtin_return_address(0);
+	unsigned int debug_id = call->debug_id;
 	int n;
 
 	ASSERT(call != NULL);
 
 	n = atomic_dec_return(&call->usage);
-	trace_rxrpc_call(call, op, n, here, NULL);
+	trace_rxrpc_call(debug_id, op, n, here, NULL);
 	ASSERTCMP(n, >=, 0);
 	if (n == 0) {
 		_debug("call %d dead", call->debug_id);

[PATCH net 5/6] rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record

[David Howells]

The rxrpc_peer record needs to hold a reference on the rxrpc_local record
it points as the peer is used as a base to access information in the
rxrpc_local record.

This can cause problems in __rxrpc_put_peer(), where we need the network
namespace pointer, and in rxrpc_send_keepalive(), where we need to access
the UDP socket, leading to symptoms like:

    BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
    [inline]
    BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
    net/rxrpc/peer_object.c:435
    Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216

Fix this by taking a ref on the local record for the peer record.

Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive")
Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing")
Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
---

 net/rxrpc/peer_object.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index b700b7ecaa3d..64830d8c1fdb 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -216,7 +216,7 @@ struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
 	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
 	if (peer) {
 		atomic_set(&peer->usage, 1);
-		peer->local = local;
+		peer->local = rxrpc_get_local(local);
 		INIT_HLIST_HEAD(&peer->error_targets);
 		peer->service_conns = RB_ROOT;
 		seqlock_init(&peer->service_conn_lock);
@@ -307,7 +307,6 @@ void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
 	unsigned long hash_key;
 
 	hash_key = rxrpc_peer_hash_key(local, &peer->srx);
-	peer->local = local;
 	rxrpc_init_peer(rx, peer, hash_key);
 
 	spin_lock(&rxnet->peer_hash_lock);
@@ -417,6 +416,7 @@ static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 	list_del_init(&peer->keepalive_link);
 	spin_unlock_bh(&rxnet->peer_hash_lock);
 
+	rxrpc_put_local(peer->local);
 	kfree_rcu(peer, rcu);
 }
 
@@ -453,6 +453,7 @@ void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 	if (n == 0) {
 		hash_del_rcu(&peer->hash_link);
 		list_del_init(&peer->keepalive_link);
+		rxrpc_put_local(peer->local);
 		kfree_rcu(peer, rcu);
 	}
 }

[PATCH net 6/6] rxrpc: Fix call crypto state cleanup

[David Howells]

Fix the cleanup of the crypto state on a call after the call has been
disconnected.  As the call has been disconnected, its connection ref has
been discarded and so we can't go through that to get to the security ops
table.

Fix this by caching the security ops pointer in the rxrpc_call struct and
using that when freeing the call security state.  Also use this in other
places we're dealing with call-specific security.

The symptoms look like:

    BUG: KASAN: use-after-free in rxrpc_release_call+0xb2d/0xb60
    net/rxrpc/call_object.c:481
    Read of size 8 at addr ffff888062ffeb50 by task syz-executor.5/4764

Fixes: 1db88c534371 ("rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto")
Reported-by: syzbot+eed305768ece6682bb7f@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
---

 net/rxrpc/ar-internal.h |    1 +
 net/rxrpc/call_accept.c |    1 +
 net/rxrpc/call_object.c |    6 +++---
 net/rxrpc/conn_client.c |    3 +++
 net/rxrpc/recvmsg.c     |    6 +++---
 net/rxrpc/sendmsg.c     |    2 +-
 6 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 1091bf35a199..ecc17dabec8f 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -556,6 +556,7 @@ struct rxrpc_call {
 	struct rxrpc_peer	*peer;		/* Peer record for remote address */
 	struct rxrpc_sock __rcu	*socket;	/* socket responsible */
 	struct rxrpc_net	*rxnet;		/* Network namespace to which call belongs */
+	const struct rxrpc_security *security;	/* applied security module */
 	struct mutex		user_mutex;	/* User access mutex */
 	unsigned long		ack_at;		/* When deferred ACK needs to happen */
 	unsigned long		ack_lost_at;	/* When ACK is figured as lost */
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 1f778102ed8d..135bf5cd8dd5 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -307,6 +307,7 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 
 	rxrpc_see_call(call);
 	call->conn = conn;
+	call->security = conn->security;
 	call->peer = rxrpc_get_peer(conn->params.peer);
 	call->cong_cwnd = call->peer->cong_cwnd;
 	return call;
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 6dace078971a..a31c18c09894 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -493,10 +493,10 @@ void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call)
 
 	_debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn);
 
-	if (conn) {
+	if (conn)
 		rxrpc_disconnect_call(call);
-		conn->security->free_call_crypto(call);
-	}
+	if (call->security)
+		call->security->free_call_crypto(call);
 
 	rxrpc_cleanup_ring(call);
 	_leave("");
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index 700eb77173fc..376370cd9285 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -353,6 +353,7 @@ static int rxrpc_get_client_conn(struct rxrpc_sock *rx,
 
 	if (cp->exclusive) {
 		call->conn = candidate;
+		call->security = candidate->security;
 		call->security_ix = candidate->security_ix;
 		call->service_id = candidate->service_id;
 		_leave(" = 0 [exclusive %d]", candidate->debug_id);
@@ -404,6 +405,7 @@ static int rxrpc_get_client_conn(struct rxrpc_sock *rx,
 candidate_published:
 	set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
 	call->conn = candidate;
+	call->security = candidate->security;
 	call->security_ix = candidate->security_ix;
 	call->service_id = candidate->service_id;
 	spin_unlock(&local->client_conns_lock);
@@ -426,6 +428,7 @@ static int rxrpc_get_client_conn(struct rxrpc_sock *rx,
 
 	spin_lock(&conn->channel_lock);
 	call->conn = conn;
+	call->security = conn->security;
 	call->security_ix = conn->security_ix;
 	call->service_id = conn->service_id;
 	list_add_tail(&call->chan_wait_link, &conn->waiting_calls);
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index 3b0becb12041..a4090797c9b2 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -251,8 +251,8 @@ static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
 		seq += subpacket;
 	}
 
-	return call->conn->security->verify_packet(call, skb, offset, len,
-						   seq, cksum);
+	return call->security->verify_packet(call, skb, offset, len,
+					     seq, cksum);
 }
 
 /*
@@ -291,7 +291,7 @@ static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
 
 	*_offset = offset;
 	*_len = len;
-	call->conn->security->locate_data(call, skb, _offset, _len);
+	call->security->locate_data(call, skb, _offset, _len);
 	return 0;
 }
 
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 22f51a7e356e..813fd6888142 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -419,7 +419,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 				 call->tx_winsize)
 				sp->hdr.flags |= RXRPC_MORE_PACKETS;
 
-			ret = conn->security->secure_packet(
+			ret = call->security->secure_packet(
 				call, skb, skb->mark, skb->head);
 			if (ret < 0)
 				goto out;

Re: [PATCH net 0/6] rxrpc: Syzbot-inspired fixes

[David Miller]

From: David Howells <dhowells@redhat.com>
Date: Mon, 07 Oct 2019 11:15:35 +0100

> 
> Here's a series of patches that fix a number of issues found by syzbot:
> 
>  (1) A reference leak on rxrpc_call structs in a sendmsg error path.
> 
>  (2) A tracepoint that looked in the rxrpc_peer record after putting it.
> 
>      Analogous with this, though not presently detected, the same bug is
>      also fixed in relation to rxrpc_connection and rxrpc_call records.
> 
>  (3) Peer records don't pin local endpoint records, despite accessing them.
> 
>  (4) Access to connection crypto ops to clean up a call after the call's
>      ref on that connection has been put.
> 
> The patches are tagged here:
> 
> 	git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
> 	rxrpc-fixes-20191007

Pulled, thanks David.