From b45193cb4df556fe6251b285a5ce44046dd36b4a Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Tue, 4 Apr 2023 09:31:28 +0200 Subject: can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access In the j1939_tp_tx_dat_new() function, an out-of-bounds memory access could occur during the memcpy() operation if the size of skb->cb is larger than the size of struct j1939_sk_buff_cb. This is because the memcpy() operation uses the size of skb->cb, leading to a read beyond the struct j1939_sk_buff_cb. Updated the memcpy() operation to use the size of struct j1939_sk_buff_cb instead of the size of skb->cb. This ensures that the memcpy() operation only reads the memory within the bounds of struct j1939_sk_buff_cb, preventing out-of-bounds memory access. Additionally, add a BUILD_BUG_ON() to check that the size of skb->cb is greater than or equal to the size of struct j1939_sk_buff_cb. This ensures that the skb->cb buffer is large enough to hold the j1939_sk_buff_cb structure. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Reported-by: Shuangpeng Bai Tested-by: Shuangpeng Bai Signed-off-by: Oleksij Rempel Link: https://groups.google.com/g/syzkaller/c/G_LL-C3plRs/m/-8xCi6dCAgAJ Link: https://lore.kernel.org/all/20230404073128.3173900-1-o.rempel@pengutronix.de Cc: stable@vger.kernel.org [mkl: rephrase commit message] Signed-off-by: Marc Kleine-Budde --- net/can/j1939/transport.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/can') diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index fb92c3609e17..fe3df23a2595 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -604,7 +604,10 @@ sk_buff *j1939_tp_tx_dat_new(struct j1939_priv *priv, /* reserve CAN header */ skb_reserve(skb, offsetof(struct can_frame, data)); - memcpy(skb->cb, re_skcb, sizeof(skb->cb)); + /* skb->cb must be large enough to hold a j1939_sk_buff_cb structure */ + BUILD_BUG_ON(sizeof(skb->cb) < sizeof(*re_skcb)); + + memcpy(skb->cb, re_skcb, sizeof(*re_skcb)); skcb = j1939_skb_to_cb(skb); if (swap_src_dst) j1939_skbcb_swap(skcb); -- cgit v1.2.3 From 0145462fc802cd447ef5d029758043c7f15b4b1e Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Thu, 30 Mar 2023 19:02:48 +0200 Subject: can: isotp: isotp_recvmsg(): use sock_recv_cmsgs() to get SOCK_RXQ_OVFL infos isotp.c was still using sock_recv_timestamp() which does not provide control messages to detect dropped PDUs in the receive path. Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20230330170248.62342-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/can') diff --git a/net/can/isotp.c b/net/can/isotp.c index 9bc344851704..47c2ebad10ed 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1120,7 +1120,7 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, if (ret < 0) goto out_err; - sock_recv_timestamp(msg, sk, skb); + sock_recv_cmsgs(msg, sk, skb); if (msg->msg_name) { __sockaddr_check_size(ISOTP_MIN_NAMELEN); -- cgit v1.2.3 From 79e19fa79cb5d5f1b3bf3e3ae24989ccb93c7b7b Mon Sep 17 00:00:00 2001 From: Michal Sojka Date: Fri, 31 Mar 2023 14:55:11 +0200 Subject: can: isotp: isotp_ops: fix poll() to not report false EPOLLOUT events When using select()/poll()/epoll() with a non-blocking ISOTP socket to wait for when non-blocking write is possible, a false EPOLLOUT event is sometimes returned. This can happen at least after sending a message which must be split to multiple CAN frames. The reason is that isotp_sendmsg() returns -EAGAIN when tx.state is not equal to ISOTP_IDLE and this behavior is not reflected in datagram_poll(), which is used in isotp_ops. This is fixed by introducing ISOTP-specific poll function, which suppresses the EPOLLOUT events in that case. v2: https://lore.kernel.org/all/20230302092812.320643-1-michal.sojka@cvut.cz v1: https://lore.kernel.org/all/20230224010659.48420-1-michal.sojka@cvut.cz https://lore.kernel.org/all/b53a04a2-ba1f-3858-84c1-d3eb3301ae15@hartkopp.net Signed-off-by: Michal Sojka Reported-by: Jakub Jira Tested-by: Oliver Hartkopp Acked-by: Oliver Hartkopp Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol") Link: https://lore.kernel.org/all/20230331125511.372783-1-michal.sojka@cvut.cz Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'net/can') diff --git a/net/can/isotp.c b/net/can/isotp.c index 47c2ebad10ed..281b7766c54e 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1608,6 +1608,21 @@ static int isotp_init(struct sock *sk) return 0; } +static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait) +{ + struct sock *sk = sock->sk; + struct isotp_sock *so = isotp_sk(sk); + + __poll_t mask = datagram_poll(file, sock, wait); + poll_wait(file, &so->wait, wait); + + /* Check for false positives due to TX state */ + if ((mask & EPOLLWRNORM) && (so->tx.state != ISOTP_IDLE)) + mask &= ~(EPOLLOUT | EPOLLWRNORM); + + return mask; +} + static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd, unsigned long arg) { @@ -1623,7 +1638,7 @@ static const struct proto_ops isotp_ops = { .socketpair = sock_no_socketpair, .accept = sock_no_accept, .getname = isotp_getname, - .poll = datagram_poll, + .poll = isotp_poll, .ioctl = isotp_sock_no_ioctlcmd, .gettstamp = sock_gettstamp, .listen = sock_no_listen, -- cgit v1.2.3 From 051737439eaee5bdd03d3c2ef5510d54a478fd05 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Fri, 31 Mar 2023 15:19:35 +0200 Subject: can: isotp: fix race between isotp_sendsmg() and isotp_release() As discussed with Dae R. Jeong and Hillf Danton here [1] the sendmsg() function in isotp.c might get into a race condition when restoring the former tx.state from the old_state. Remove the old_state concept and implement proper locking for the ISOTP_IDLE transitions in isotp_sendmsg(), inspired by a simplification idea from Hillf Danton. Introduce a new tx.state ISOTP_SHUTDOWN and use the same locking mechanism from isotp_release() which resolves a potential race between isotp_sendsmg() and isotp_release(). [1] https://lore.kernel.org/linux-can/ZB%2F93xJxq%2FBUqAgG@dragonet v1: https://lore.kernel.org/all/20230331102114.15164-1-socketcan@hartkopp.net v2: https://lore.kernel.org/all/20230331123600.3550-1-socketcan@hartkopp.net take care of signal interrupts for wait_event_interruptible() in isotp_release() v3: https://lore.kernel.org/all/20230331130654.9886-1-socketcan@hartkopp.net take care of signal interrupts for wait_event_interruptible() in isotp_sendmsg() in the wait_tx_done case v4: https://lore.kernel.org/all/20230331131935.21465-1-socketcan@hartkopp.net take care of signal interrupts for wait_event_interruptible() in isotp_sendmsg() in ALL cases Cc: Dae R. Jeong Cc: Hillf Danton Signed-off-by: Oliver Hartkopp Fixes: 4f027cba8216 ("can: isotp: split tx timer into transmission and timeout") Link: https://lore.kernel.org/all/20230331131935.21465-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org [mkl: rephrase commit message] Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 55 +++++++++++++++++++++++++++++++------------------------ 1 file changed, 31 insertions(+), 24 deletions(-) (limited to 'net/can') diff --git a/net/can/isotp.c b/net/can/isotp.c index 281b7766c54e..5761d4ab839d 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -119,7 +119,8 @@ enum { ISOTP_WAIT_FIRST_FC, ISOTP_WAIT_FC, ISOTP_WAIT_DATA, - ISOTP_SENDING + ISOTP_SENDING, + ISOTP_SHUTDOWN, }; struct tpcon { @@ -880,8 +881,8 @@ static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer) txtimer); struct sock *sk = &so->sk; - /* don't handle timeouts in IDLE state */ - if (so->tx.state == ISOTP_IDLE) + /* don't handle timeouts in IDLE or SHUTDOWN state */ + if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN) return HRTIMER_NORESTART; /* we did not get any flow control or echo frame in time */ @@ -918,7 +919,6 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) { struct sock *sk = sock->sk; struct isotp_sock *so = isotp_sk(sk); - u32 old_state = so->tx.state; struct sk_buff *skb; struct net_device *dev; struct canfd_frame *cf; @@ -928,23 +928,24 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) int off; int err; - if (!so->bound) + if (!so->bound || so->tx.state == ISOTP_SHUTDOWN) return -EADDRNOTAVAIL; +wait_free_buffer: /* we do not support multiple buffers - for now */ - if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE || - wq_has_sleeper(&so->wait)) { - if (msg->msg_flags & MSG_DONTWAIT) { - err = -EAGAIN; - goto err_out; - } + if (wq_has_sleeper(&so->wait) && (msg->msg_flags & MSG_DONTWAIT)) + return -EAGAIN; - /* wait for complete transmission of current pdu */ - err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); - if (err) - goto err_out; + /* wait for complete transmission of current pdu */ + err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + if (err) + goto err_event_drop; - so->tx.state = ISOTP_SENDING; + if (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) { + if (so->tx.state == ISOTP_SHUTDOWN) + return -EADDRNOTAVAIL; + + goto wait_free_buffer; } if (!size || size > MAX_MSG_LENGTH) { @@ -1074,7 +1075,9 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) if (wait_tx_done) { /* wait for complete transmission of current pdu */ - wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + if (err) + goto err_event_drop; if (sk->sk_err) return -sk->sk_err; @@ -1082,13 +1085,15 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) return size; +err_event_drop: + /* got signal: force tx state machine to be idle */ + so->tx.state = ISOTP_IDLE; + hrtimer_cancel(&so->txfrtimer); + hrtimer_cancel(&so->txtimer); err_out_drop: /* drop this PDU and unlock a potential wait queue */ - old_state = ISOTP_IDLE; -err_out: - so->tx.state = old_state; - if (so->tx.state == ISOTP_IDLE) - wake_up_interruptible(&so->wait); + so->tx.state = ISOTP_IDLE; + wake_up_interruptible(&so->wait); return err; } @@ -1150,10 +1155,12 @@ static int isotp_release(struct socket *sock) net = sock_net(sk); /* wait for complete transmission of current pdu */ - wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE); + while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 && + cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE) + ; /* force state machines to be idle also when a signal occurred */ - so->tx.state = ISOTP_IDLE; + so->tx.state = ISOTP_SHUTDOWN; so->rx.state = ISOTP_IDLE; spin_lock(&isotp_notifier_lock); -- cgit v1.2.3