[PATCH 5.4 194/203] rxrpc: Fix missing security check on incoming calls

Greg Kroah-Hartman
2020-01-16T23:42:06Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit 063c60d39180cec7c9317f5acfc3071f8fecd705 ]

Fix rxrpc_new_incoming_call() to check that we have a suitable service key
available for the combination of service ID and security class of a new
incoming call - and to reject calls for which we don't.

This causes an assertion like the following to appear:

rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false
kernel BUG at net/rxrpc/call_object.c:456!

Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than
RXRPC_CALL_COMPLETE (12).

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/rxrpc/ar-internal.h | 10 ++++--
net/rxrpc/call_accept.c | 14 ++++++--
net/rxrpc/conn_event.c | 16 +--------
net/rxrpc/conn_service.c | 4 +++
net/rxrpc/rxkad.c | 5 +--
net/rxrpc/security.c | 70 +++++++++++++++++++---------------------
6 files changed, 59 insertions(+), 60 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 7c7d10f2e0c1..5e99df80e80a 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -209,6 +209,7 @@ struct rxrpc_skb_priv {
struct rxrpc_security {
const char *name; /* name of this service */
u8 security_index; /* security type provided */
+ u32 no_key_abort; /* Abort code indicating no key */

/* Initialise a security service */
int (*init)(void);
@@ -977,8 +978,9 @@ static inline void rxrpc_reduce_conn_timer(struct rxrpc_connection *conn,
struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
struct sk_buff *);
struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *, gfp_t);
-void rxrpc_new_incoming_connection(struct rxrpc_sock *,
- struct rxrpc_connection *, struct sk_buff *);
+void rxrpc_new_incoming_connection(struct rxrpc_sock *, struct rxrpc_connection *,
+ const struct rxrpc_security *, struct key *,
+ struct sk_buff *);
void rxrpc_unpublish_service_conn(struct rxrpc_connection *);

/*
@@ -1103,7 +1105,9 @@ extern const struct rxrpc_security rxkad;
int __init rxrpc_init_security(void);
void rxrpc_exit_security(void);
int rxrpc_init_client_conn_security(struct rxrpc_connection *);
-int rxrpc_init_server_conn_security(struct rxrpc_connection *);
+bool rxrpc_look_up_server_security(struct rxrpc_local *, struct rxrpc_sock *,
+ const struct rxrpc_security **, struct key **,
+ struct sk_buff *);

/*
* sendmsg.c
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index 44fa22b020ef..70e44abf106c 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -263,6 +263,8 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
struct rxrpc_local *local,
struct rxrpc_peer *peer,
struct rxrpc_connection *conn,
+ const struct rxrpc_security *sec,
+ struct key *key,
struct sk_buff *skb)
{
struct rxrpc_backlog *b = rx->backlog;
@@ -310,7 +312,7 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
conn->params.local = rxrpc_get_local(local);
conn->params.peer = peer;
rxrpc_see_connection(conn);
- rxrpc_new_incoming_connection(rx, conn, skb);
+ rxrpc_new_incoming_connection(rx, conn, sec, key, skb);
} else {
rxrpc_get_connection(conn);
}
@@ -349,9 +351,11 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ const struct rxrpc_security *sec = NULL;
struct rxrpc_connection *conn;
struct rxrpc_peer *peer = NULL;
- struct rxrpc_call *call;
+ struct rxrpc_call *call = NULL;
+ struct key *key = NULL;

_enter("");

@@ -372,7 +376,11 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
*/
conn = rxrpc_find_connection_rcu(local, skb, &peer);

- call = rxrpc_alloc_incoming_call(rx, local, peer, conn, skb);
+ if (!conn && !rxrpc_look_up_server_security(local, rx, &sec, &key, skb))
+ goto no_call;
+
+ call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, key, skb);
+ key_put(key);
if (!call) {
skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
goto no_call;
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index a1ceef4f5cd0..808a4723f868 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -376,21 +376,7 @@ static void rxrpc_secure_connection(struct rxrpc_connection *conn)
_enter("{%d}", conn->debug_id);

ASSERT(conn->security_ix != 0);
-
- if (!conn->params.key) {
- _debug("set up security");
- ret = rxrpc_init_server_conn_security(conn);
- switch (ret) {
- case 0:
- break;
- case -ENOENT:
- abort_code = RX_CALL_DEAD;
- goto abort;
- default:
- abort_code = RXKADNOAUTH;
- goto abort;
- }
- }
+ ASSERT(conn->server_key);

if (conn->security->issue_challenge(conn) < 0) {
abort_code = RX_CALL_DEAD;
diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c
index 123d6ceab15c..21da48e3d2e5 100644
--- a/net/rxrpc/conn_service.c
+++ b/net/rxrpc/conn_service.c
@@ -148,6 +148,8 @@ struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxn
*/
void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
struct rxrpc_connection *conn,
+ const struct rxrpc_security *sec,
+ struct key *key,
struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
@@ -160,6 +162,8 @@ void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
conn->service_id = sp->hdr.serviceId;
conn->security_ix = sp->hdr.securityIndex;
conn->out_clientflag = 0;
+ conn->security = sec;
+ conn->server_key = key_get(key);
if (conn->security_ix)
conn->state = RXRPC_CONN_SERVICE_UNSECURED;
else
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 8d8aa3c230b5..098f1f9ec53b 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -648,9 +648,9 @@ static int rxkad_issue_challenge(struct rxrpc_connection *conn)
u32 serial;
int ret;

- _enter("{%d,%x}", conn->debug_id, key_serial(conn->params.key));
+ _enter("{%d,%x}", conn->debug_id, key_serial(conn->server_key));

- ret = key_validate(conn->params.key);
+ ret = key_validate(conn->server_key);
if (ret < 0)
return ret;

@@ -1293,6 +1293,7 @@ static void rxkad_exit(void)
const struct rxrpc_security rxkad = {
.name = "rxkad",
.security_index = RXRPC_SECURITY_RXKAD,
+ .no_key_abort = RXKADUNKNOWNKEY,
.init = rxkad_init,
.exit = rxkad_exit,
.init_connection_security = rxkad_init_connection_security,
diff --git a/net/rxrpc/security.c b/net/rxrpc/security.c
index a4c47d2b7054..9b1fb9ed0717 100644
--- a/net/rxrpc/security.c
+++ b/net/rxrpc/security.c
@@ -101,62 +101,58 @@ int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
}

/*
- * initialise the security on a server connection
+ * Find the security key for a server connection.
*/
-int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
+bool rxrpc_look_up_server_security(struct rxrpc_local *local, struct rxrpc_sock *rx,
+ const struct rxrpc_security **_sec,
+ struct key **_key,
+ struct sk_buff *skb)
{
const struct rxrpc_security *sec;
- struct rxrpc_local *local = conn->params.local;
- struct rxrpc_sock *rx;
- struct key *key;
- key_ref_t kref;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ key_ref_t kref = NULL;
char kdesc[5 + 1 + 3 + 1];

_enter("");

- sprintf(kdesc, "%u:%u", conn->service_id, conn->security_ix);
+ sprintf(kdesc, "%u:%u", sp->hdr.serviceId, sp->hdr.securityIndex);

- sec = rxrpc_security_lookup(conn->security_ix);
+ sec = rxrpc_security_lookup(sp->hdr.securityIndex);
if (!sec) {
- _leave(" = -ENOKEY [lookup]");
- return -ENOKEY;
+ trace_rxrpc_abort(0, "SVS",
+ sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+ RX_INVALID_OPERATION, EKEYREJECTED);
+ skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+ skb->priority = RX_INVALID_OPERATION;
+ return false;
}

- /* find the service */
- read_lock(&local->services_lock);
- rx = rcu_dereference_protected(local->service,
- lockdep_is_held(&local->services_lock));
- if (rx && (rx->srx.srx_service == conn->service_id ||
- rx->second_service == conn->service_id))
- goto found_service;
+ if (sp->hdr.securityIndex == RXRPC_SECURITY_NONE)
+ goto out;

- /* the service appears to have died */
- read_unlock(&local->services_lock);
- _leave(" = -ENOENT");
- return -ENOENT;
-
-found_service:
if (!rx->securities) {
- read_unlock(&local->services_lock);
- _leave(" = -ENOKEY");
- return -ENOKEY;
+ trace_rxrpc_abort(0, "SVR",
+ sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+ RX_INVALID_OPERATION, EKEYREJECTED);
+ skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+ skb->priority = RX_INVALID_OPERATION;
+ return false;
}

/* look through the service's keyring */
kref = keyring_search(make_key_ref(rx->securities, 1UL),
&key_type_rxrpc_s, kdesc, true);
if (IS_ERR(kref)) {
- read_unlock(&local->services_lock);
- _leave(" = %ld [search]", PTR_ERR(kref));
- return PTR_ERR(kref);
+ trace_rxrpc_abort(0, "SVK",
+ sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+ sec->no_key_abort, EKEYREJECTED);
+ skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
+ skb->priority = sec->no_key_abort;
+ return false;
}

- key = key_ref_to_ptr(kref);
- read_unlock(&local->services_lock);
-
- conn->server_key = key;
- conn->security = sec;
-
- _leave(" = 0");
- return 0;
+out:
+ *_sec = sec;
+ *_key = key_ref_to_ptr(kref);
+ return true;
}
--
2.20.1