From 6cdedc18ba7b9dacc36466e27e3267d201948c8d Mon Sep 17 00:00:00 2001 From: Ziqi Zhao Date: Fri, 21 Jul 2023 09:22:26 -0700 Subject: [PATCH 1/3] can: j1939: prevent deadlock by changing j1939_socks_lock to rwlock The following 3 locks would race against each other, causing the deadlock situation in the Syzbot bug report: - j1939_socks_lock - active_session_list_lock - sk_session_queue_lock A reasonable fix is to change j1939_socks_lock to an rwlock, since in the rare situations where a write lock is required for the linked list that j1939_socks_lock is protecting, the code does not attempt to acquire any more locks. This would break the circular lock dependency, where, for example, the current thread already locks j1939_socks_lock and attempts to acquire sk_session_queue_lock, and at the same time, another thread attempts to acquire j1939_socks_lock while holding sk_session_queue_lock. NOTE: This patch along does not fix the unregister_netdevice bug reported by Syzbot; instead, it solves a deadlock situation to prepare for one or more further patches to actually fix the Syzbot bug, which appears to be a reference counting problem within the j1939 codebase. Reported-by: Signed-off-by: Ziqi Zhao Reviewed-by: Oleksij Rempel Acked-by: Oleksij Rempel Link: https://lore.kernel.org/all/20230721162226.8639-1-astrajoan@yahoo.com [mkl: remove unrelated newline change] Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde --- net/can/j1939/j1939-priv.h | 2 +- net/can/j1939/main.c | 2 +- net/can/j1939/socket.c | 24 ++++++++++++------------ 3 files changed, 14 insertions(+), 14 deletions(-) diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h index 16af1a7f80f60..74f15592d1708 100644 --- a/net/can/j1939/j1939-priv.h +++ b/net/can/j1939/j1939-priv.h @@ -86,7 +86,7 @@ struct j1939_priv { unsigned int tp_max_packet_size; /* lock for j1939_socks list */ - spinlock_t j1939_socks_lock; + rwlock_t j1939_socks_lock; struct list_head j1939_socks; struct kref rx_kref; diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index ecff1c947d683..a6fb89fa62785 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -274,7 +274,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) return ERR_PTR(-ENOMEM); j1939_tp_init(priv); - spin_lock_init(&priv->j1939_socks_lock); + rwlock_init(&priv->j1939_socks_lock); INIT_LIST_HEAD(&priv->j1939_socks); mutex_lock(&j1939_netdev_lock); diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 14c4316632339..94cfc2315e546 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -80,16 +80,16 @@ static void j1939_jsk_add(struct j1939_priv *priv, struct j1939_sock *jsk) jsk->state |= J1939_SOCK_BOUND; j1939_priv_get(priv); - spin_lock_bh(&priv->j1939_socks_lock); + write_lock_bh(&priv->j1939_socks_lock); list_add_tail(&jsk->list, &priv->j1939_socks); - spin_unlock_bh(&priv->j1939_socks_lock); + write_unlock_bh(&priv->j1939_socks_lock); } static void j1939_jsk_del(struct j1939_priv *priv, struct j1939_sock *jsk) { - spin_lock_bh(&priv->j1939_socks_lock); + write_lock_bh(&priv->j1939_socks_lock); list_del_init(&jsk->list); - spin_unlock_bh(&priv->j1939_socks_lock); + write_unlock_bh(&priv->j1939_socks_lock); j1939_priv_put(priv); jsk->state &= ~J1939_SOCK_BOUND; @@ -329,13 +329,13 @@ bool j1939_sk_recv_match(struct j1939_priv *priv, struct j1939_sk_buff_cb *skcb) struct j1939_sock *jsk; bool match = false; - spin_lock_bh(&priv->j1939_socks_lock); + read_lock_bh(&priv->j1939_socks_lock); list_for_each_entry(jsk, &priv->j1939_socks, list) { match = j1939_sk_recv_match_one(jsk, skcb); if (match) break; } - spin_unlock_bh(&priv->j1939_socks_lock); + read_unlock_bh(&priv->j1939_socks_lock); return match; } @@ -344,11 +344,11 @@ void j1939_sk_recv(struct j1939_priv *priv, struct sk_buff *skb) { struct j1939_sock *jsk; - spin_lock_bh(&priv->j1939_socks_lock); + read_lock_bh(&priv->j1939_socks_lock); list_for_each_entry(jsk, &priv->j1939_socks, list) { j1939_sk_recv_one(jsk, skb); } - spin_unlock_bh(&priv->j1939_socks_lock); + read_unlock_bh(&priv->j1939_socks_lock); } static void j1939_sk_sock_destruct(struct sock *sk) @@ -1080,12 +1080,12 @@ void j1939_sk_errqueue(struct j1939_session *session, } /* spread RX notifications to all sockets subscribed to this session */ - spin_lock_bh(&priv->j1939_socks_lock); + read_lock_bh(&priv->j1939_socks_lock); list_for_each_entry(jsk, &priv->j1939_socks, list) { if (j1939_sk_recv_match_one(jsk, &session->skcb)) __j1939_sk_errqueue(session, &jsk->sk, type); } - spin_unlock_bh(&priv->j1939_socks_lock); + read_unlock_bh(&priv->j1939_socks_lock); }; void j1939_sk_send_loop_abort(struct sock *sk, int err) @@ -1273,7 +1273,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv) struct j1939_sock *jsk; int error_code = ENETDOWN; - spin_lock_bh(&priv->j1939_socks_lock); + read_lock_bh(&priv->j1939_socks_lock); list_for_each_entry(jsk, &priv->j1939_socks, list) { jsk->sk.sk_err = error_code; if (!sock_flag(&jsk->sk, SOCK_DEAD)) @@ -1281,7 +1281,7 @@ void j1939_sk_netdev_event_netdown(struct j1939_priv *priv) j1939_sk_queue_drop_all(priv, jsk, error_code); } - spin_unlock_bh(&priv->j1939_socks_lock); + read_unlock_bh(&priv->j1939_socks_lock); } static int j1939_sk_no_ioctlcmd(struct socket *sock, unsigned int cmd, From efe7cf828039aedb297c1f9920b638fffee6aabc Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Fri, 20 Oct 2023 15:38:14 +0200 Subject: [PATCH 2/3] can: j1939: Fix UAF in j1939_sk_match_filter during setsockopt(SO_J1939_FILTER) Lock jsk->sk to prevent UAF when setsockopt(..., SO_J1939_FILTER, ...) modifies jsk->filters while receiving packets. Following trace was seen on affected system: ================================================================== BUG: KASAN: slab-use-after-free in j1939_sk_recv_match_one+0x1af/0x2d0 [can_j1939] Read of size 4 at addr ffff888012144014 by task j1939/350 CPU: 0 PID: 350 Comm: j1939 Tainted: G W OE 6.5.0-rc5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: print_report+0xd3/0x620 ? kasan_complete_mode_report_info+0x7d/0x200 ? j1939_sk_recv_match_one+0x1af/0x2d0 [can_j1939] kasan_report+0xc2/0x100 ? j1939_sk_recv_match_one+0x1af/0x2d0 [can_j1939] __asan_load4+0x84/0xb0 j1939_sk_recv_match_one+0x1af/0x2d0 [can_j1939] j1939_sk_recv+0x20b/0x320 [can_j1939] ? __kasan_check_write+0x18/0x20 ? __pfx_j1939_sk_recv+0x10/0x10 [can_j1939] ? j1939_simple_recv+0x69/0x280 [can_j1939] ? j1939_ac_recv+0x5e/0x310 [can_j1939] j1939_can_recv+0x43f/0x580 [can_j1939] ? __pfx_j1939_can_recv+0x10/0x10 [can_j1939] ? raw_rcv+0x42/0x3c0 [can_raw] ? __pfx_j1939_can_recv+0x10/0x10 [can_j1939] can_rcv_filter+0x11f/0x350 [can] can_receive+0x12f/0x190 [can] ? __pfx_can_rcv+0x10/0x10 [can] can_rcv+0xdd/0x130 [can] ? __pfx_can_rcv+0x10/0x10 [can] __netif_receive_skb_one_core+0x13d/0x150 ? __pfx___netif_receive_skb_one_core+0x10/0x10 ? __kasan_check_write+0x18/0x20 ? _raw_spin_lock_irq+0x8c/0xe0 __netif_receive_skb+0x23/0xb0 process_backlog+0x107/0x260 __napi_poll+0x69/0x310 net_rx_action+0x2a1/0x580 ? __pfx_net_rx_action+0x10/0x10 ? __pfx__raw_spin_lock+0x10/0x10 ? handle_irq_event+0x7d/0xa0 __do_softirq+0xf3/0x3f8 do_softirq+0x53/0x80 __local_bh_enable_ip+0x6e/0x70 netif_rx+0x16b/0x180 can_send+0x32b/0x520 [can] ? __pfx_can_send+0x10/0x10 [can] ? __check_object_size+0x299/0x410 raw_sendmsg+0x572/0x6d0 [can_raw] ? __pfx_raw_sendmsg+0x10/0x10 [can_raw] ? apparmor_socket_sendmsg+0x2f/0x40 ? __pfx_raw_sendmsg+0x10/0x10 [can_raw] sock_sendmsg+0xef/0x100 sock_write_iter+0x162/0x220 ? __pfx_sock_write_iter+0x10/0x10 ? __rtnl_unlock+0x47/0x80 ? security_file_permission+0x54/0x320 vfs_write+0x6ba/0x750 ? __pfx_vfs_write+0x10/0x10 ? __fget_light+0x1ca/0x1f0 ? __rcu_read_unlock+0x5b/0x280 ksys_write+0x143/0x170 ? __pfx_ksys_write+0x10/0x10 ? __kasan_check_read+0x15/0x20 ? fpregs_assert_state_consistent+0x62/0x70 __x64_sys_write+0x47/0x60 do_syscall_64+0x60/0x90 ? do_syscall_64+0x6d/0x90 ? irqentry_exit+0x3f/0x50 ? exc_page_fault+0x79/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Allocated by task 348: kasan_save_stack+0x2a/0x50 kasan_set_track+0x29/0x40 kasan_save_alloc_info+0x1f/0x30 __kasan_kmalloc+0xb5/0xc0 __kmalloc_node_track_caller+0x67/0x160 j1939_sk_setsockopt+0x284/0x450 [can_j1939] __sys_setsockopt+0x15c/0x2f0 __x64_sys_setsockopt+0x6b/0x80 do_syscall_64+0x60/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Freed by task 349: kasan_save_stack+0x2a/0x50 kasan_set_track+0x29/0x40 kasan_save_free_info+0x2f/0x50 __kasan_slab_free+0x12e/0x1c0 __kmem_cache_free+0x1b9/0x380 kfree+0x7a/0x120 j1939_sk_setsockopt+0x3b2/0x450 [can_j1939] __sys_setsockopt+0x15c/0x2f0 __x64_sys_setsockopt+0x6b/0x80 do_syscall_64+0x60/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") Reported-by: Sili Luo Suggested-by: Sili Luo Acked-by: Oleksij Rempel Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel Link: https://lore.kernel.org/all/20231020133814.383996-1-o.rempel@pengutronix.de Signed-off-by: Marc Kleine-Budde --- net/can/j1939/j1939-priv.h | 1 + net/can/j1939/socket.c | 22 ++++++++++++++++++---- 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h index 74f15592d1708..31a93cae5111b 100644 --- a/net/can/j1939/j1939-priv.h +++ b/net/can/j1939/j1939-priv.h @@ -301,6 +301,7 @@ struct j1939_sock { int ifindex; struct j1939_addr addr; + spinlock_t filters_lock; struct j1939_filter *filters; int nfilters; pgn_t pgn_rx_filter; diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 94cfc2315e546..305dd72c844c7 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -262,12 +262,17 @@ static bool j1939_sk_match_dst(struct j1939_sock *jsk, static bool j1939_sk_match_filter(struct j1939_sock *jsk, const struct j1939_sk_buff_cb *skcb) { - const struct j1939_filter *f = jsk->filters; - int nfilter = jsk->nfilters; + const struct j1939_filter *f; + int nfilter; + + spin_lock_bh(&jsk->filters_lock); + + f = jsk->filters; + nfilter = jsk->nfilters; if (!nfilter) /* receive all when no filters are assigned */ - return true; + goto filter_match_found; for (; nfilter; ++f, --nfilter) { if ((skcb->addr.pgn & f->pgn_mask) != f->pgn) @@ -276,9 +281,15 @@ static bool j1939_sk_match_filter(struct j1939_sock *jsk, continue; if ((skcb->addr.src_name & f->name_mask) != f->name) continue; - return true; + goto filter_match_found; } + + spin_unlock_bh(&jsk->filters_lock); return false; + +filter_match_found: + spin_unlock_bh(&jsk->filters_lock); + return true; } static bool j1939_sk_recv_match_one(struct j1939_sock *jsk, @@ -401,6 +412,7 @@ static int j1939_sk_init(struct sock *sk) atomic_set(&jsk->skb_pending, 0); spin_lock_init(&jsk->sk_session_queue_lock); INIT_LIST_HEAD(&jsk->sk_session_queue); + spin_lock_init(&jsk->filters_lock); /* j1939_sk_sock_destruct() depends on SOCK_RCU_FREE flag */ sock_set_flag(sk, SOCK_RCU_FREE); @@ -703,9 +715,11 @@ static int j1939_sk_setsockopt(struct socket *sock, int level, int optname, } lock_sock(&jsk->sk); + spin_lock_bh(&jsk->filters_lock); ofilters = jsk->filters; jsk->filters = filters; jsk->nfilters = count; + spin_unlock_bh(&jsk->filters_lock); release_sock(&jsk->sk); kfree(ofilters); return 0; From 2aa0a5e65eae27dbd96faca92c84ecbf6f492d42 Mon Sep 17 00:00:00 2001 From: Maxime Jayat Date: Mon, 6 Nov 2023 19:01:58 +0100 Subject: [PATCH 3/3] can: netlink: Fix TDCO calculation using the old data bittiming The TDCO calculation was done using the currently applied data bittiming, instead of the newly computed data bittiming, which means that the TDCO had an invalid value unless setting the same data bittiming twice. Fixes: d99755f71a80 ("can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)") Signed-off-by: Maxime Jayat Reviewed-by: Vincent Mailhol Link: https://lore.kernel.org/all/40579c18-63c0-43a4-8d4c-f3a6c1c0b417@munic.io Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index 036d85ef07f5b..dfdc039d92a6c 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -346,7 +346,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], /* Neither of TDC parameters nor TDC flags are * provided: do calculation */ - can_calc_tdco(&priv->tdc, priv->tdc_const, &priv->data_bittiming, + can_calc_tdco(&priv->tdc, priv->tdc_const, &dbt, &priv->ctrlmode, priv->ctrlmode_supported); } /* else: both CAN_CTRLMODE_TDC_{AUTO,MANUAL} are explicitly * turned off. TDC is disabled: do nothing