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* l2tp: Avoid possible recursive deadlock in l2tp_tunnel_register()Shigeru Yoshida2023-02-201-58/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a file descriptor of pppol2tp socket is passed as file descriptor of UDP socket, a recursive deadlock occurs in l2tp_tunnel_register(). This situation is reproduced by the following program: int main(void) { int sock; struct sockaddr_pppol2tp addr; sock = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); if (sock < 0) { perror("socket"); return 1; } addr.sa_family = AF_PPPOX; addr.sa_protocol = PX_PROTO_OL2TP; addr.pppol2tp.pid = 0; addr.pppol2tp.fd = sock; addr.pppol2tp.addr.sin_family = PF_INET; addr.pppol2tp.addr.sin_port = htons(0); addr.pppol2tp.addr.sin_addr.s_addr = inet_addr("192.168.0.1"); addr.pppol2tp.s_tunnel = 1; addr.pppol2tp.s_session = 0; addr.pppol2tp.d_tunnel = 0; addr.pppol2tp.d_session = 0; if (connect(sock, (const struct sockaddr *)&addr, sizeof(addr)) < 0) { perror("connect"); return 1; } return 0; } This program causes the following lockdep warning: ============================================ WARNING: possible recursive locking detected 6.2.0-rc5-00205-gc96618275234 #56 Not tainted -------------------------------------------- repro/8607 is trying to acquire lock: ffff8880213c8130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: l2tp_tunnel_register+0x2b7/0x11c0 but task is already holding lock: ffff8880213c8130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0xa82/0x1a30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_PPPOX); lock(sk_lock-AF_PPPOX); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by repro/8607: #0: ffff8880213c8130 (sk_lock-AF_PPPOX){+.+.}-{0:0}, at: pppol2tp_connect+0xa82/0x1a30 stack backtrace: CPU: 0 PID: 8607 Comm: repro Not tainted 6.2.0-rc5-00205-gc96618275234 #56 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x100/0x178 __lock_acquire.cold+0x119/0x3b9 ? lockdep_hardirqs_on_prepare+0x410/0x410 lock_acquire+0x1e0/0x610 ? l2tp_tunnel_register+0x2b7/0x11c0 ? lock_downgrade+0x710/0x710 ? __fget_files+0x283/0x3e0 lock_sock_nested+0x3a/0xf0 ? l2tp_tunnel_register+0x2b7/0x11c0 l2tp_tunnel_register+0x2b7/0x11c0 ? sprintf+0xc4/0x100 ? l2tp_tunnel_del_work+0x6b0/0x6b0 ? debug_object_deactivate+0x320/0x320 ? lockdep_init_map_type+0x16d/0x7a0 ? lockdep_init_map_type+0x16d/0x7a0 ? l2tp_tunnel_create+0x2bf/0x4b0 ? l2tp_tunnel_create+0x3c6/0x4b0 pppol2tp_connect+0x14e1/0x1a30 ? pppol2tp_put_sk+0xd0/0xd0 ? aa_sk_perm+0x2b7/0xa80 ? aa_af_perm+0x260/0x260 ? bpf_lsm_socket_connect+0x9/0x10 ? pppol2tp_put_sk+0xd0/0xd0 __sys_connect_file+0x14f/0x190 __sys_connect+0x133/0x160 ? __sys_connect_file+0x190/0x190 ? lockdep_hardirqs_on+0x7d/0x100 ? ktime_get_coarse_real_ts64+0x1b7/0x200 ? ktime_get_coarse_real_ts64+0x147/0x200 ? __audit_syscall_entry+0x396/0x500 __x64_sys_connect+0x72/0xb0 do_syscall_64+0x38/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd This patch fixes the issue by getting/creating the tunnel before locking the pppol2tp socket. Fixes: 0b2c59720e65 ("l2tp: close all race conditions in l2tp_tunnel_register()") Cc: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: prevent lockdep issue in l2tp_tunnel_register()Eric Dumazet2023-01-181-3/+2
| | | | | | | | | | | | | | | | | | | | lockdep complains with the following lock/unlock sequence: lock_sock(sk); write_lock_bh(&sk->sk_callback_lock); [1] release_sock(sk); [2] write_unlock_bh(&sk->sk_callback_lock); We need to swap [1] and [2] to fix this issue. Fixes: 0b2c59720e65 ("l2tp: close all race conditions in l2tp_tunnel_register()") Reported-by: syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/netdev/20230114030137.672706-1-xiyou.wangcong@gmail.com/T/#m1164ff20628671b0f326a24cb106ab3239c70ce3 Cc: Cong Wang <cong.wang@bytedance.com> Cc: Guillaume Nault <gnault@redhat.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: close all race conditions in l2tp_tunnel_register()Cong Wang2023-01-161-14/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The code in l2tp_tunnel_register() is racy in several ways: 1. It modifies the tunnel socket _after_ publishing it. 2. It calls setup_udp_tunnel_sock() on an existing socket without locking. 3. It changes sock lock class on fly, which triggers many syzbot reports. This patch amends all of them by moving socket initialization code before publishing and under sock lock. As suggested by Jakub, the l2tp lockdep class is not necessary as we can just switch to bh_lock_sock_nested(). Fixes: 37159ef2c1ae ("l2tp: fix a lockdep splat") Fixes: 6b9f34239b00 ("l2tp: fix races in tunnel creation") Reported-by: syzbot+52866e24647f9a23403f@syzkaller.appspotmail.com Reported-by: syzbot+94cc2a66fc228b23f360@syzkaller.appspotmail.com Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Guillaume Nault <gnault@redhat.com> Cc: Jakub Sitnicki <jakub@cloudflare.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Parkin <tparkin@katalix.com> Signed-off-by: Cong Wang <cong.wang@bytedance.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: convert l2tp_tunnel_list to idrCong Wang2023-01-161-43/+42
| | | | | | | | | | | | | | | | | | | | l2tp uses l2tp_tunnel_list to track all registered tunnels and to allocate tunnel ID's. IDR can do the same job. More importantly, with IDR we can hold the ID before a successful registration so that we don't need to worry about late error handling, it is not easy to rollback socket changes. This is a preparation for the following fix. Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Guillaume Nault <gnault@redhat.com> Cc: Jakub Sitnicki <jakub@cloudflare.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Tom Parkin <tparkin@katalix.com> Signed-off-by: Cong Wang <cong.wang@bytedance.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski2022-11-291-8/+9
|\ | | | | | | | | | | | | | | | | tools/lib/bpf/ringbuf.c 927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap") b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c") https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| * l2tp: Don't sleep and disable BH under writer-side sk_callback_lockJakub Sitnicki2022-11-231-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When holding a reader-writer spin lock we cannot sleep. Calling setup_udp_tunnel_sock() with write lock held violates this rule, because we end up calling percpu_down_read(), which might sleep, as syzbot reports [1]: __might_resched.cold+0x222/0x26b kernel/sched/core.c:9890 percpu_down_read include/linux/percpu-rwsem.h:49 [inline] cpus_read_lock+0x1b/0x140 kernel/cpu.c:310 static_key_slow_inc+0x12/0x20 kernel/jump_label.c:158 udp_tunnel_encap_enable include/net/udp_tunnel.h:187 [inline] setup_udp_tunnel_sock+0x43d/0x550 net/ipv4/udp_tunnel_core.c:81 l2tp_tunnel_register+0xc51/0x1210 net/l2tp/l2tp_core.c:1509 pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723 Trim the writer-side critical section for sk_callback_lock down to the minimum, so that it covers only operations on sk_user_data. Also, when grabbing the sk_callback_lock, we always need to disable BH, as Eric points out. Failing to do so leads to deadlocks because we acquire sk_callback_lock in softirq context, which can get stuck waiting on us if: 1) it runs on the same CPU, or CPU0 ---- lock(clock-AF_INET6); <Interrupt> lock(clock-AF_INET6); 2) lock ordering leads to priority inversion CPU0 CPU1 ---- ---- lock(clock-AF_INET6); local_irq_disable(); lock(&tcp_hashinfo.bhash[i].lock); lock(clock-AF_INET6); <Interrupt> lock(&tcp_hashinfo.bhash[i].lock); ... as syzbot reports [2,3]. Use the _bh variants for write_(un)lock. [1] https://lore.kernel.org/netdev/0000000000004e78ec05eda79749@google.com/ [2] https://lore.kernel.org/netdev/000000000000e38b6605eda76f98@google.com/ [3] https://lore.kernel.org/netdev/000000000000dfa31e05eda76f75@google.com/ v2: - Check and set sk_user_data while holding sk_callback_lock for both L2TP encapsulation types (IP and UDP) (Tetsuo) Cc: Tom Parkin <tparkin@katalix.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Fixes: b68777d54fac ("l2tp: Serialize access to sk_user_data with sk_callback_lock") Reported-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot+703d9e154b3b58277261@syzkaller.appspotmail.com Reported-by: syzbot+50680ced9e98a61f7698@syzkaller.appspotmail.com Reported-by: syzbot+de987172bb74a381879b@syzkaller.appspotmail.com Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski2022-11-181-6/+13
|\| | | | | | | | | | | | | | | | | | | include/linux/bpf.h 1f6e04a1c7b8 ("bpf: Fix offset calculation error in __copy_map_value and zero_map_value") aa3496accc41 ("bpf: Refactor kptr_off_tab into btf_record") f71b2f64177a ("bpf: Refactor map->off_arr handling") https://lore.kernel.org/all/20221114095000.67a73239@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| * l2tp: Serialize access to sk_user_data with sk_callback_lockJakub Sitnicki2022-11-161-6/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sk->sk_user_data has multiple users, which are not compatible with each other. Writers must synchronize by grabbing the sk->sk_callback_lock. l2tp currently fails to grab the lock when modifying the underlying tunnel socket fields. Fix it by adding appropriate locking. We err on the side of safety and grab the sk_callback_lock also inside the sk_destruct callback overridden by l2tp, even though there should be no refs allowing access to the sock at the time when sk_destruct gets called. v4: - serialize write to sk_user_data in l2tp sk_destruct v3: - switch from sock lock to sk_callback_lock - document write-protection for sk_user_data v2: - update Fixes to point to origin of the bug - use real names in Reported/Tested-by tags Cc: Tom Parkin <tparkin@katalix.com> Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core") Reported-by: Haowei Yan <g1042620637@gmail.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | inet6: Remove inet6_destroy_sock() in sk->sk_prot->destroy().Kuniyuki Iwashima2022-10-241-2/+0
|/ | | | | | | | | | | | | | | | | After commit d38afeec26ed ("tcp/udp: Call inet6_destroy_sock() in IPv6 sk->sk_destruct()."), we call inet6_destroy_sock() in sk->sk_destruct() by setting inet6_sock_destruct() to it to make sure we do not leak inet6-specific resources. Now we can remove unnecessary inet6_destroy_sock() calls in sk->sk_prot->destroy(). DCCP and SCTP have their own sk->sk_destruct() function, so we change them separately in the following patches. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* genetlink: start to validate reserved header bytesJakub Kicinski2022-08-291-0/+1
| | | | | | | | | | | | | | | | | We had historically not checked that genlmsghdr.reserved is 0 on input which prevents us from using those precious bytes in the future. One use case would be to extend the cmd field, which is currently just 8 bits wide and 256 is not a lot of commands for some core families. To make sure that new families do the right thing by default put the onus of opting out of validation on existing families. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel) Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: move from strlcpy with unused retval to strscpyWolfram Sang2022-08-231-2/+2
| | | | | | | | | | | Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Link: https://lore.kernel.org/r/20220818210222.8515-1-wsa+renesas@sang-engineering.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
* l2tp: l2tp_debugfs: fix Clang -Wformat warningsJustin Stitt2022-07-081-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When building with Clang we encounter the following warnings: | net/l2tp/l2tp_debugfs.c:187:40: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] seq_printf(m, " nr %hu, ns %hu\n", session->nr, | session->ns); - | net/l2tp/l2tp_debugfs.c:196:32: error: format specifies type 'unsigned | short' but the argument has type 'int' [-Werror,-Wformat] | session->l2specific_type, l2tp_get_l2specific_len(session)); - | net/l2tp/l2tp_debugfs.c:219:6: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] session->nr, session->ns, Both session->nr and ->nc are of type `u32`. The currently used format specifier is `%hu` which describes a `u16`. My proposed fix is to listen to Clang and use the correct format specifier `%u`. For the warning at line 196, l2tp_get_l2specific_len() returns an int and should therefore be using the `%d` format specifier. Link: https://github.com/ClangBuiltLinux/linux/issues/378 Signed-off-by: Justin Stitt <justinstitt@google.com> Acked-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: l2tp: fix clang -Wformat warningJustin Stitt2022-07-081-1/+1
| | | | | | | | | | | | | | | | | | | | | When building with clang we encounter this warning: | net/l2tp/l2tp_ppp.c:1557:6: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] session->nr, session->ns, Both session->nr and session->ns are of type u32. The format specifier previously used is `%hu` which would truncate our unsigned integer from 32 to 16 bits. This doesn't seem like intended behavior, if it is then perhaps we need to consider suppressing the warning with pragma clauses. This patch should get us closer to the goal of enabling the -Wformat flag for Clang builds. Link: https://github.com/ClangBuiltLinux/linux/issues/378 Signed-off-by: Justin Stitt <justinstitt@google.com> Acked-by: Guillaume Nault <gnault@redhat.com> Link: https://lore.kernel.org/r/20220706230833.535238-1-justinstitt@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
* ipv6: Fix signed integer overflow in l2tp_ip6_sendmsgWang Yufen2022-06-081-2/+3
| | | | | | | | | | When len >= INT_MAX - transhdrlen, ulen = len + transhdrlen will be overflow. To fix, we can follow what udpv6 does and subtract the transhdrlen from the max. Signed-off-by: Wang Yufen <wangyufen@huawei.com> Link: https://lore.kernel.org/r/20220607120028.845916-2-wangyufen@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
* l2tp: use add READ_ONCE() to fetch sk->sk_bound_dev_ifEric Dumazet2022-05-162-4/+8
| | | | | | | Use READ_ONCE() in paths not holding the socket lock. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: remove noblock parameter from recvmsg() entitiesOliver Hartkopp2022-04-122-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | 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 <socketcan@hartkopp.net> Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net Signed-off-by: Paolo Abeni <pabeni@redhat.com>
* net: remove noblock parameter from skb_recv_datagram()Oliver Hartkopp2022-04-063-4/+5
| | | | | | | | | | | | | | | | | | | | | | 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 <lkp@intel.com> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: add netns refcount tracker to l2tp_dfs_seq_dataEric Dumazet2021-12-101-4/+5
| | | | | Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
* net/l2tp: convert tunnel rwlock_t to rcuTom Parkin2021-11-293-36/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously commit e02d494d2c60 ("l2tp: Convert rwlock to RCU") converted most, but not all, rwlock instances in the l2tp subsystem to RCU. The remaining rwlock protects the per-tunnel hashlist of sessions which is used for session lookups in the UDP-encap data path. Convert the remaining rwlock to rcu to improve performance of UDP-encap tunnels. Note that the tunnel and session, which both live on RCU-protected lists, use slightly different approaches to incrementing their refcounts in the various getter functions. The tunnel has to use refcount_inc_not_zero because the tunnel shutdown process involves dropping the refcount to zero prior to synchronizing RCU readers (via. kfree_rcu). By contrast, the session shutdown removes the session from the list(s) it is on, synchronizes with readers, and then decrements the session refcount. Since the getter functions increment the session refcount with the RCU read lock held we prevent getters seeing a zero session refcount, and therefore don't need to use refcount_inc_not_zero. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net/l2tp: Fix reference count leak in l2tp_udp_recv_coreXiyu Yang2021-09-091-1/+3
| | | | | | | | | | | | | | | | | | The reference count leak issue may take place in an error handling path. If both conditions of tunnel->version == L2TP_HDR_VER_3 and the return value of l2tp_v3_ensure_opt_in_linear is nonzero, the function would directly jump to label invalid, without decrementing the reference count of the l2tp_session object session increased earlier by l2tp_tunnel_get_session(). This may result in refcount leaks. Fix this issue by decrease the reference count before jumping to the label invalid. Fixes: 4522a70db7aa ("l2tp: fix reading optional fields of L2TPv3") Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: Fix spelling mistakesZheng Yongjun2021-06-072-2/+2
| | | | | | | | | Fix some spelling mistakes in comments: negociated ==> negotiated dont ==> don't Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Remove the member netns_okYejune Deng2021-05-181-1/+0
| | | | | | | | Every protocol has the 'netns_ok' member and it is euqal to 1. The 'if (!prot->netns_ok)' always false in inet_add_protocol(). Signed-off-by: Yejune Deng <yejunedeng@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix a concurrency bug in l2tp_tunnel_register()Gong, Sishuai2021-04-271-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | l2tp_tunnel_register() registers a tunnel without fully initializing its attribute. This can allow another kernel thread running l2tp_xmit_core() to access the uninitialized data and then cause a kernel NULL pointer dereference error, as shown below. Thread 1 Thread 2 //l2tp_tunnel_register() list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list); //pppol2tp_connect() tunnel = l2tp_tunnel_get(sock_net(sk), info.tunnel_id); // Fetch the new tunnel ... //l2tp_xmit_core() struct sock *sk = tunnel->sock; ... bh_lock_sock(sk); //Null pointer error happens tunnel->sock = sk; Fix this bug by initializing tunnel->sock before adding the tunnel into l2tp_tunnel_list. Reviewed-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: Sishuai Gong <sishuai@purdue.edu> Reported-by: Sishuai Gong <sishuai@purdue.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: l2tp: Fix a typoBhaskar Chowdhury2021-03-221-1/+1
| | | | | | | | s/verifed/verified/ Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: l2tp: reduce log level of messages in receive path, add counter insteadMatthias Schiffer2021-03-043-19/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 5ee759cda51b ("l2tp: use standard API for warning log messages") changed a number of warnings about invalid packets in the receive path so that they are always shown, instead of only when a special L2TP debug flag is set. Even with rate limiting these warnings can easily cause significant log spam - potentially triggered by a malicious party sending invalid packets on purpose. In addition these warnings were noticed by projects like Tunneldigger [1], which uses L2TP for its data path, but implements its own control protocol (which is sufficiently different from L2TP data packets that it would always be passed up to userspace even with future extensions of L2TP). Some of the warnings were already redundant, as l2tp_stats has a counter for these packets. This commit adds one additional counter for invalid packets that are passed up to userspace. Packets with unknown session are not counted as invalid, as there is nothing wrong with the format of these packets. With the additional counter, all of these messages are either redundant or benign, so we reduce them to pr_debug_ratelimited(). [1] https://github.com/wlanslovenija/tunneldigger/issues/160 Fixes: 5ee759cda51b ("l2tp: use standard API for warning log messages") Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* lsm,selinux: pass flowi_common instead of flowi to the LSM hooksPaul Moore2020-11-241-1/+1
| | | | | | | | | | | | As pointed out by Herbert in a recent related patch, the LSM hooks do not have the necessary address family information to use the flowi struct safely. As none of the LSMs currently use any of the protocol specific flowi information, replace the flowi pointers with pointers to the address family independent flowi_common struct. Reported-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
* genetlink: move to smaller ops wherever possibleJakub Kicinski2020-10-031-3/+3
| | | | | | | | Bulk of the genetlink users can use smaller ops, move them. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: report rx cookie discards in netlink getTom Parkin2020-09-291-0/+6
| | | | | | | | | | | | | | When an L2TPv3 session receives a data frame with an incorrect cookie l2tp_core logs a warning message and bumps a stats counter to reflect the fact that the packet has been dropped. However, the stats counter in question is missing from the l2tp_netlink get message for tunnel and session instances. Include the statistic in the netlink get response. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: fix up inconsistent rx/tx statisticsTom Parkin2020-09-181-3/+8
| | | | | | | | | | | | | Historically L2TP core statistics count the L2TP header in the per-session and per-tunnel byte counts tracked for transmission and receipt. Now that l2tp_xmit_skb updates tx stats, it is necessary for l2tp_xmit_core to pass out the length of the transmitted packet so that the statistics can be updated correctly. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: avoid duplicated code in l2tp_tunnel_closeallTom Parkin2020-09-031-13/+1
| | | | | | | | | | | | | | | | | | | | | | | | l2tp_tunnel_closeall is called as a part of tunnel shutdown in order to close all the sessions held by the tunnel. The code it uses to close a session duplicates what l2tp_session_delete does. Rather than duplicating the code, have l2tp_tunnel_closeall call l2tp_session_delete instead. This involves a very minor change to locking in l2tp_tunnel_closeall. Previously, l2tp_tunnel_closeall checked the session "dead" flag while holding tunnel->hlist_lock. This allowed for the code to step to the next session in the list without releasing the lock if the current session happened to be in the process of closing already. By calling l2tp_session_delete instead, l2tp_tunnel_closeall must now drop and regain the hlist lock for each session in the tunnel list. Given that the likelihood of a session being in the process of closing when the tunnel is closed, it seems worth this very minor potential loss of efficiency to avoid duplication of the session delete code. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: make magic feather checks more usefulTom Parkin2020-09-035-20/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The l2tp tunnel and session structures contain a "magic feather" field which was originally intended to help trace lifetime bugs in the code. Since the introduction of the shared kernel refcount code in refcount.h, and l2tp's porting to those APIs, we are covered by the refcount code's checks and warnings. Duplicating those checks in the l2tp code isn't useful. However, magic feather checks are still useful to help to detect bugs stemming from misuse/trampling of the sk_user_data pointer in struct sock. The l2tp code makes extensive use of sk_user_data to stash pointers to the tunnel and session structures, and if another subsystem overwrites sk_user_data it's important to detect this. As such, rework l2tp's magic feather checks to focus on validating the tunnel and session data structures when they're extracted from sk_user_data. * Add a new accessor function l2tp_sk_to_tunnel which contains a magic feather check, and is used by l2tp_core and l2tp_ip[6] * Comment l2tp_udp_encap_recv which doesn't use this new accessor function because of the specific nature of the codepath it is called in * Drop l2tp_session_queue_purge's check on the session magic feather: it is called from code which is walking the tunnel session list, and hence doesn't need validation * Drop l2tp_session_free's check on the tunnel magic feather: the intention of this check is covered by refcount.h's reference count sanity checking * Add session magic validation in pppol2tp_ioctl. On failure return -EBADF, which mirrors the approach in pppol2tp_[sg]etsockopt. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: capture more tx errors in data plane statsTom Parkin2020-09-031-34/+37
| | | | | | | | | | | | | | | | l2tp_xmit_skb has a number of failure paths which are not reflected in the tunnel and session statistics because the stats are updated by l2tp_xmit_core. Hence any errors occurring before l2tp_xmit_core is called are missed from the statistics. Refactor the transmit path slightly to capture all error paths. l2tp_xmit_skb now leaves all the actual work of transmission to l2tp_xmit_core, and updates the statistics based on l2tp_xmit_core's return code. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: drop net argument from l2tp_tunnel_createTom Parkin2020-09-034-4/+4
| | | | | | | The argument is unused, so remove it. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: drop data_len argument from l2tp_xmit_coreTom Parkin2020-09-031-3/+2
| | | | | | | | The data_len argument passed to l2tp_xmit_core is no longer used, so remove it. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: remove header length param from l2tp_xmit_skbTom Parkin2020-09-034-10/+9
| | | | | | | | | | | | All callers pass the session structure's hdr_len field as the header length parameter to l2tp_xmit_skb. Since we're passing a pointer to the session structure to l2tp_xmit_skb anyway, there's not much point breaking the header length out as a separate argument. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: remove tunnel and session debug flags fieldTom Parkin2020-08-225-35/+12
| | | | | | | | | | | | | | | | | The l2tp subsystem now uses standard kernel logging APIs for informational and warning messages, and tracepoints for debug information. Now that the tunnel and session debug flags are unused, remove the field from the core structures. Various system calls (in the case of l2tp_ppp) and netlink messages handle the getting and setting of debug flags. To avoid userspace breakage don't modify the API of these calls; simply ignore set requests, and send dummy data for get requests. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: remove custom logging macrosTom Parkin2020-08-221-13/+0
| | | | | | | | | | | | | All l2tp's informational and warning logging is now carried out using standard kernel APIs. Debugging information is now handled using tracepoints. Now that no code is using the custom logging macros, remove them from l2tp_core.h. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: add tracepoints to l2tp_core.cTom Parkin2020-08-221-52/+31
| | | | | | | | | | | Add lifetime event tracing for tunnel and session instances, tracking tunnel and session registration, deletion, and eventual freeing. Port the data path sequence number debug logging to use trace points rather than custom debug macros. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: add tracepoint definitions in trace.hTom Parkin2020-08-222-2/+200
| | | | | | | | | | | | | | l2tp can provide a better debug experience using tracepoints rather than printk-style logging. Add tracepoint definitions in trace.h for use in the l2tp subsystem code. Add preprocessor definitions for the length of session and tunnel names in l2tp_core.h so we can reuse these in trace.h. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: add tracepoint infrastructure to coreTom Parkin2020-08-223-0/+20
| | | | | | | | | | | The l2tp subsystem doesn't currently make use of tracepoints. As a starting point for adding tracepoints, add skeleton infrastructure for defining tracepoints for the subsystem, and for having them build appropriately whether compiled into the kernel or built as a module. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: use standard API for warning log messagesTom Parkin2020-08-222-20/+14
| | | | | | | | | | | | | | | | | The l2tp_* log wrappers only emit messages of a given category if the tunnel or session structure has the appropriate flag set in its debug field. Flags default to being unset. For warning messages, this doesn't make a lot of sense since an administrator is likely to want to know about datapath warnings without needing to tweak the debug flags setting for a given tunnel or session instance. Modify l2tp_warn callsites to use pr_warn_ratelimited instead for unconditional output of warning messages. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: remove noisy logging, use appropriate log levelsTom Parkin2020-08-222-43/+5
| | | | | | | | | | | | l2tp_ppp in particular had a lot of log messages for tracing [get|set]sockopt calls. These aren't especially useful, so remove these messages. Several log messages flagging error conditions were logged using l2tp_info: they're better off as l2tp_warn. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: don't log data framesTom Parkin2020-08-225-101/+6
| | | | | | | | | | l2tp had logging to trace data frame receipt and transmission, including code to dump packet contents. This was originally intended to aid debugging of core l2tp packet handling, but is of limited use now that code is stable. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: improve API documentation in l2tp_core.hTom Parkin2020-07-311-14/+72
| | | | | | | | | | | * Improve the description of the key l2tp subsystem data structures. * Add high-level description of the main APIs for interacting with l2tp core. * Add documentation for the l2tp netlink session command callbacks. * Document the session pseudowire callbacks. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: tweak exports for l2tp_recv_common and l2tp_ioctlTom Parkin2020-07-312-2/+2
| | | | | | | | | | | | | | | All of the l2tp subsystem's exported symbols are exported using EXPORT_SYMBOL_GPL, except for l2tp_recv_common and l2tp_ioctl. These functions alone are not useful without the rest of the l2tp infrastructure, so there's no practical benefit to these symbols using a different export policy. Change these exports to use EXPORT_SYMBOL_GPL for consistency with the rest of l2tp. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: remove build_header callback in struct l2tp_sessionTom Parkin2020-07-312-7/+4
| | | | | | | | | | | | | | | | | The structure of an L2TP data packet header varies depending on the version of the L2TP protocol being used. struct l2tp_session used to have a build_header callback to abstract this difference away. It's clearer to simply choose the correct function to use when building the data packet (and we save on the function pointer in the session structure). This approach does mean dereferencing the parent tunnel structure in order to determine the tunnel version, but we're doing that in the transmit path in any case. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: return void from l2tp_session_deleteTom Parkin2020-07-313-10/+5
| | | | | | | | | | | | | l2tp_session_delete is used to schedule a session instance for deletion. The function itself always returns zero, and none of its direct callers check its return value, so have the function return void. This change de-facto changes the l2tp netlink session_delete callback prototype since all pseudowires currently use l2tp_session_delete for their implementation of that operation. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: don't export tunnel and session free functionsTom Parkin2020-07-312-47/+46
| | | | | | | | | | | | | | | | Tunnel and session instances are reference counted, and shouldn't be directly freed by pseudowire code. Rather than exporting l2tp_tunnel_free and l2tp_session_free, make them private to l2tp_core.c, and export the refcount functions instead. In order to do this, the refcount functions cannot be declared as inline. Since the codepaths which take and drop tunnel and session references are not directly in the datapath this shouldn't cause performance issues. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: don't export __l2tp_session_unhashTom Parkin2020-07-312-32/+26
| | | | | | | | | | | | | | | | When __l2tp_session_unhash was first added it was used outside of l2tp_core.c, but that's no longer the case. As such, there's no longer a need to export the function. Make it private inside l2tp_core.c, and relocate it to avoid having to declare the function prototype in l2tp_core.h. Since the function is no longer used outside l2tp_core.c, remove the "__" prefix since we don't need to indicate anything special about its expected use to callers. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* l2tp: WARN_ON rather than BUG_ON in l2tp_session_freeTom Parkin2020-07-251-1/+3
| | | | | | | | | | | | | | | l2tp_session_free called BUG_ON if the tunnel magic feather value wasn't correct. The intent of this was to catch lifetime bugs; for example early tunnel free due to incorrect use of reference counts. Since the tunnel magic feather being wrong indicates either early free or structure corruption, we can avoid doing more damage by simply leaving the tunnel structure alone. If the tunnel refcount isn't dropped when it should be, the tunnel instance will remain in the kernel, resulting in the tunnel structure and socket leaking. Signed-off-by: Tom Parkin <tparkin@katalix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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