kernel/linux.git/net/phonet, branch v6.1.175

phonet/pep: disable BH around forwarded sk_receive_skb()

2026-06-01T15:39:34+00:00

commit dbc81608e3a653dea6cf403f20cae35468b8ab9c upstream. The networking receive path is usually run from softirq context, but protocols that take the socket lock may have packets stored in the backlog and processed later from process context. In that case release_sock() -> __release_sock() drops the slock with spin_unlock_bh() and then calls sk->sk_backlog_rcv() with bottom halves enabled. Typical sk_backlog_rcv handlers process the socket whose backlog is being drained, so the BH state at entry is irrelevant for the slocks they touch. pep_do_rcv() is different: when the inbound skb targets an existing PEP pipe, it forwards the skb to a different *child* socket via sk_receive_skb(). That helper takes the child slock with bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH is already off. The same child slock therefore ends up acquired with BH on (process path) and with BH off (softirq path): process context softirq context --------------- --------------- release_sock(listener) __netif_receive_skb() __release_sock() phonet_rcv() spin_unlock_bh() __sk_receive_skb(listener) [BH now ENABLED] [BH already disabled] sk_backlog_rcv: sk_backlog_rcv: pep_do_rcv() pep_do_rcv() sk_receive_skb(child) sk_receive_skb(child) bh_lock_sock_nested(child) bh_lock_sock_nested(child) => SOFTIRQ-ON-W => IN-SOFTIRQ-W Lockdep flags this as inconsistent lock state, and it can become a real self-deadlock if a softirq on the same CPU tries to receive to the same child socket while its slock is held in the BH-enabled path: WARNING: inconsistent lock state inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. (slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900 __sk_receive_skb net/core/sock.c:563 sk_receive_skb include/net/sock.h:2022 [inline] pep_do_rcv net/phonet/pep.c:675 sk_backlog_rcv include/net/sock.h:1190 __release_sock net/core/sock.c:3216 release_sock net/core/sock.c:3815 pep_sock_accept net/phonet/pep.c:879 Wrap the forwarded sk_receive_skb() in local_bh_disable() / local_bh_enable() so the child slock is always acquired with BH off. local_bh_disable() nests safely on the softirq path. Discovered via in-house syzkaller fuzzing; the same root cause also on the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c. Reproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer: https://pastebin.com/A3t8xzCR Fixes: 9641458d3ec4 ("Phonet: Pipe End Point for Phonet Pipes protocol") Link: https://syzkaller.appspot.com/bug?extid=44f0626dd6284f02663c Cc: stable@vger.kernel.org Signed-off-by: Zijing Yin Acked-by: Rémi Denis-Courmont Reported-by: syzbot+9f4a135646b66c509935@syzkaller.appspotmail.com Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260519172635.86304-1-yzjaurora@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

phonet/pep: Move call to pn_skb_get_dst_sockaddr() earlier in pep_sock_accept()

2025-07-24T06:51:48+00:00

commit 17ba793f381eb813596d6de1cc6820bcbda5ed8b upstream. A new warning in clang [1] points out a place in pep_sock_accept() where dst is uninitialized then passed as a const pointer to pep_find_pipe(): net/phonet/pep.c:829:37: error: variable 'dst' is uninitialized when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer] 829 | newsk = pep_find_pipe(&pn->hlist, &dst, pipe_handle); | ^~~: Move the call to pn_skb_get_dst_sockaddr(), which initializes dst, to before the call to pep_find_pipe(), so that dst is consistently used initialized throughout the function. Cc: stable@vger.kernel.org Fixes: f7ae8d59f661 ("Phonet: allocate sock from accept syscall rather than soft IRQ") Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d441f19b319e [1] Closes: https://github.com/ClangBuiltLinux/linux/issues/2101 Signed-off-by: Nathan Chancellor Link: https://patch.msgid.link/20250715-net-phonet-fix-uninit-const-pointer-v1-1-8efd1bd188b3@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

phonet: fix rtm_phonet_notify() skb allocation

2024-05-17T09:56:12+00:00

[ Upstream commit d8cac8568618dcb8a51af3db1103e8d4cc4aeea7 ] fill_route() stores three components in the skb: - struct rtmsg - RTA_DST (u8) - RTA_OIF (u32) Therefore, rtm_phonet_notify() should use NLMSG_ALIGN(sizeof(struct rtmsg)) + nla_total_size(1) + nla_total_size(4) Fixes: f062f41d0657 ("Phonet: routing table Netlink interface") Signed-off-by: Eric Dumazet Acked-by: Rémi Denis-Courmont Link: https://lore.kernel.org/r/20240502161700.1804476-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

phonet/pep: fix racy skb_queue_empty() use

2024-03-01T12:26:38+00:00

[ Upstream commit 7d2a894d7f487dcb894df023e9d3014cf5b93fe5 ] The receive queues are protected by their respective spin-lock, not the socket lock. This could lead to skb_peek() unexpectedly returning NULL or a pointer to an already dequeued socket buffer. Fixes: 9641458d3ec4 ("Phonet: Pipe End Point for Phonet Pipes protocol") Signed-off-by: Rémi Denis-Courmont Link: https://lore.kernel.org/r/20240218081214.4806-2-remi@remlab.net Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

phonet: take correct lock to peek at the RX queue

2024-03-01T12:26:38+00:00

[ Upstream commit 3b2d9bc4d4acdf15a876eae2c0d83149250e85ba ] The receive queue is protected by its embedded spin-lock, not the socket lock, so we need the former lock here (and only that one). Fixes: 107d0d9b8d9a ("Phonet: Phonet datagram transport protocol") Reported-by: Luosili Signed-off-by: Rémi Denis-Courmont Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240218081214.4806-1-remi@remlab.net Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net: remove noblock parameter from recvmsg() entities

2022-04-12T13:00:25+00:00

The internal recvmsg() functions have two parameters 'flags' and 'noblock' that were merged inside skb_recv_datagram(). As a follow up patch to commit f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()") this patch removes the separate 'noblock' parameter for recvmsg(). Analogue to the referenced patch for skb_recv_datagram() the 'flags' and 'noblock' parameters are unnecessarily split up with e.g. err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); or in err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg, sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); instead of simply using only flags all the time and check for MSG_DONTWAIT where needed (to preserve for the formerly separated no(n)block condition). Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net Signed-off-by: Paolo Abeni

net: remove noblock parameter from skb_recv_datagram()

2022-04-06T12:45:26+00:00

skb_recv_datagram() has two parameters 'flags' and 'noblock' that are merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)' As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags' into 'flags' and 'noblock' with finally obsolete bit operations like this: skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc); And this is not even done consistently with the 'flags' parameter. This patch removes the obsolete and costly splitting into two parameters and only performs bit operations when really needed on the caller side. One missing conversion thankfully reported by kernel test robot. I missed to enable kunit tests to build the mctp code. Reported-by: kernel test robot Signed-off-by: Oliver Hartkopp Signed-off-by: David S. Miller

phonet: Use netif_rx().

2022-03-07T11:40:41+00:00

Since commit baebdf48c3600 ("net: dev: Makes sure netif_rx() can be invoked in any context.") the function netif_rx() can be used in preemptible/thread context as well as in interrupt context. Use netif_rx(). Cc: Remi Denis-Courmont Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: David S. Miller

phonet/pep: refuse to enable an unbound pipe

2021-12-20T11:49:51+00:00

This ioctl() implicitly assumed that the socket was already bound to a valid local socket name, i.e. Phonet object. If the socket was not bound, two separate problems would occur: 1) We'd send an pipe enablement request with an invalid source object. 2) Later socket calls could BUG on the socket unexpectedly being connected yet not bound to a valid object. Reported-by: syzbot+2dc91e7fc3dea88b1e8a@syzkaller.appspotmail.com Signed-off-by: Rémi Denis-Courmont Signed-off-by: David S. Miller

phonet: refcount leak in pep_sock_accep

2021-12-11T03:53:52+00:00

sock_hold(sk) is invoked in pep_sock_accept(), but __sock_put(sk) is not invoked in subsequent failure branches(pep_accept_conn() != 0). Signed-off-by: Hangyu Hua Link: https://lore.kernel.org/r/20211209082839.33985-1-hbh25y@gmail.com Signed-off-by: Jakub Kicinski