kernel/linux.git/net/can/bcm.c, branch v6.12.91

can: bcm: fix locking for bcm_op runtime updates

2026-03-13T16:20:40+00:00

[ Upstream commit c35636e91e392e1540949bbc67932167cb48bc3a ] Commit c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") added a locking for some variables that can be modified at runtime when updating the sending bcm_op with a new TX_SETUP command in bcm_tx_setup(). Usually the RX_SETUP only handles and filters incoming traffic with one exception: When the RX_RTR_FRAME flag is set a predefined CAN frame is sent when a specific RTR frame is received. Therefore the rx bcm_op uses bcm_can_tx() which uses the bcm_tx_lock that was only initialized in bcm_tx_setup(). Add the missing spin_lock_init() when allocating the bcm_op in bcm_rx_setup() to handle the RTR case properly. Fixes: c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") Reported-by: syzbot+5b11eccc403dd1cea9f8@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-can/699466e4.a70a0220.2c38d7.00ff.GAE@google.com/ Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260218-bcm_spin_lock_init-v1-1-592634c8a5b5@hartkopp.net Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

can: bcm: add missing rcu read protection for procfs content

2025-05-29T09:03:19+00:00

commit dac5e6249159ac255dad9781793dbe5908ac9ddb upstream. When the procfs content is generated for a bcm_op which is in the process to be removed the procfs output might show unreliable data (UAF). As the removal of bcm_op's is already implemented with rcu handling this patch adds the missing rcu_read_lock() and makes sure the list entries are properly removed under rcu protection. Fixes: f1b4e32aca08 ("can: bcm: use call_rcu() instead of costly synchronize_rcu()") Reported-by: Anderson Nascimento Suggested-by: Anderson Nascimento Tested-by: Anderson Nascimento Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20250519125027.11900-2-socketcan@hartkopp.net Cc: stable@vger.kernel.org # >= 5.4 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: bcm: add locking for bcm_op runtime updates

2025-05-29T09:03:19+00:00

commit c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7 upstream. The CAN broadcast manager (CAN BCM) can send a sequence of CAN frames via hrtimer. The content and also the length of the sequence can be changed resp reduced at runtime where the 'currframe' counter is then set to zero. Although this appeared to be a safe operation the updates of 'currframe' can be triggered from user space and hrtimer context in bcm_can_tx(). Anderson Nascimento created a proof of concept that triggered a KASAN slab-out-of-bounds read access which can be prevented with a spin_lock_bh. At the rework of bcm_can_tx() the 'count' variable has been moved into the protected section as this variable can be modified from both contexts too. Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Reported-by: Anderson Nascimento Tested-by: Anderson Nascimento Reviewed-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20250519125027.11900-1-socketcan@hartkopp.net Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: bcm: Clear bo->bcm_proc_read after remove_proc_entry().

2024-09-12T07:40:08+00:00

syzbot reported a warning in bcm_release(). [0] The blamed change fixed another warning that is triggered when connect() is issued again for a socket whose connect()ed device has been unregistered. However, if the socket is just close()d without the 2nd connect(), the remaining bo->bcm_proc_read triggers unnecessary remove_proc_entry() in bcm_release(). Let's clear bo->bcm_proc_read after remove_proc_entry() in bcm_notify(). [0] name '4986' WARNING: CPU: 0 PID: 5234 at fs/proc/generic.c:711 remove_proc_entry+0x2e7/0x5d0 fs/proc/generic.c:711 Modules linked in: CPU: 0 UID: 0 PID: 5234 Comm: syz-executor606 Not tainted 6.11.0-rc5-syzkaller-00178-g5517ae241919 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:remove_proc_entry+0x2e7/0x5d0 fs/proc/generic.c:711 Code: ff eb 05 e8 cb 1e 5e ff 48 8b 5c 24 10 48 c7 c7 e0 f7 aa 8e e8 2a 38 8e 09 90 48 c7 c7 60 3a 1b 8c 48 89 de e8 da 42 20 ff 90 <0f> 0b 90 90 48 8b 44 24 18 48 c7 44 24 40 0e 36 e0 45 49 c7 04 07 RSP: 0018:ffffc9000345fa20 EFLAGS: 00010246 RAX: 2a2d0aee2eb64600 RBX: ffff888032f1f548 RCX: ffff888029431e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000345fb08 R08: ffffffff8155b2f2 R09: 1ffff1101710519a R10: dffffc0000000000 R11: ffffed101710519b R12: ffff888011d38640 R13: 0000000000000004 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcfb52722f0 CR3: 000000000e734000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bcm_release+0x250/0x880 net/can/bcm.c:1578 __sock_release net/socket.c:659 [inline] sock_close+0xbc/0x240 net/socket.c:1421 __fput+0x24a/0x8a0 fs/file_table.c:422 task_work_run+0x24f/0x310 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2f/0x27f0 kernel/exit.c:882 do_group_exit+0x207/0x2c0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcfb51ee969 Code: Unable to access opcode bytes at 0x7fcfb51ee93f. RSP: 002b:00007ffce0109ca8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fcfb51ee969 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000001 RBP: 00007fcfb526f3b0 R08: ffffffffffffffb8 R09: 0000555500000000 R10: 0000555500000000 R11: 0000000000000246 R12: 00007fcfb526f3b0 R13: 0000000000000000 R14: 00007fcfb5271ee0 R15: 00007fcfb51bf160 Fixes: 76fe372ccb81 ("can: bcm: Remove proc entry when dev is unregistered.") Reported-by: syzbot+0532ac7a06fb1a03187e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0532ac7a06fb1a03187e Tested-by: syzbot+0532ac7a06fb1a03187e@syzkaller.appspotmail.com Signed-off-by: Kuniyuki Iwashima Reviewed-by: Vincent Mailhol Link: https://patch.msgid.link/20240905012237.79683-1-kuniyu@amazon.com Signed-off-by: Marc Kleine-Budde

can: bcm: Remove proc entry when dev is unregistered.

2024-08-06T07:25:12+00:00

syzkaller reported a warning in bcm_connect() below. [0] The repro calls connect() to vxcan1, removes vxcan1, and calls connect() with ifindex == 0. Calling connect() for a BCM socket allocates a proc entry. Then, bcm_sk(sk)->bound is set to 1 to prevent further connect(). However, removing the bound device resets bcm_sk(sk)->bound to 0 in bcm_notify(). The 2nd connect() tries to allocate a proc entry with the same name and sets NULL to bcm_sk(sk)->bcm_proc_read, leaking the original proc entry. Since the proc entry is available only for connect()ed sockets, let's clean up the entry when the bound netdev is unregistered. [0]: proc_dir_entry 'can-bcm/2456' already registered WARNING: CPU: 1 PID: 394 at fs/proc/generic.c:376 proc_register+0x645/0x8f0 fs/proc/generic.c:375 Modules linked in: CPU: 1 PID: 394 Comm: syz-executor403 Not tainted 6.10.0-rc7-g852e42cc2dd4 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:proc_register+0x645/0x8f0 fs/proc/generic.c:375 Code: 00 00 00 00 00 48 85 ed 0f 85 97 02 00 00 4d 85 f6 0f 85 9f 02 00 00 48 c7 c7 9b cb cf 87 48 89 de 4c 89 fa e8 1c 6f eb fe 90 <0f> 0b 90 90 48 c7 c7 98 37 99 89 e8 cb 7e 22 05 bb 00 00 00 10 48 RSP: 0018:ffa0000000cd7c30 EFLAGS: 00010246 RAX: 9e129be1950f0200 RBX: ff1100011b51582c RCX: ff1100011857cd80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 RBP: 0000000000000000 R08: ffd400000000000f R09: ff1100013e78cac0 R10: ffac800000cd7980 R11: ff1100013e12b1f0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ff1100011a99a2ec FS: 00007fbd7086f740(0000) GS:ff1100013fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200071c0 CR3: 0000000118556004 CR4: 0000000000771ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: proc_create_net_single+0x144/0x210 fs/proc/proc_net.c:220 bcm_connect+0x472/0x840 net/can/bcm.c:1673 __sys_connect_file net/socket.c:2049 [inline] __sys_connect+0x5d2/0x690 net/socket.c:2066 __do_sys_connect net/socket.c:2076 [inline] __se_sys_connect net/socket.c:2073 [inline] __x64_sys_connect+0x8f/0x100 net/socket.c:2073 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7fbd708b0e5d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48 RSP: 002b:00007fff8cd33f08 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbd708b0e5d RDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000040 R09: 0000000000000040 R10: 0000000000000040 R11: 0000000000000246 R12: 00007fff8cd34098 R13: 0000000000401280 R14: 0000000000406de8 R15: 00007fbd70ab9000 remove_proc_entry: removing non-empty directory 'net/can-bcm', leaking at least '2456' Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Reported-by: syzkaller Signed-off-by: Kuniyuki Iwashima Reviewed-by: Simon Horman Link: https://lore.kernel.org/all/20240722192842.37421-1-kuniyu@amazon.com Signed-off-by: Marc Kleine-Budde

can: bcm: add recvmsg flags for own, local and remote traffic

2024-02-12T15:55:17+00:00

CAN RAW sockets allow userspace to tell if a received CAN frame comes from the same socket, another socket on the same host, or another host. See commit 1e55659ce6dd ("can-raw: add msg_flags to distinguish local traffic"). However, this feature is missing in CAN BCM sockets. Add the same feature to CAN BCM sockets. When reading a received frame (opcode RX_CHANGED) using recvmsg, two flags in msg->msg_flags may be set following the previous convention (from CAN RAW), to distinguish between 'own', 'local' and 'remote' CAN traffic. Update the documentation to reflect this change. Signed-off-by: Nicolas Maier Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20240120081018.2319-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde

can: bcm: Fix UAF in bcm_proc_show()

2023-07-17T07:46:26+00:00

BUG: KASAN: slab-use-after-free in bcm_proc_show+0x969/0xa80 Read of size 8 at addr ffff888155846230 by task cat/7862 CPU: 1 PID: 7862 Comm: cat Not tainted 6.5.0-rc1-00153-gc8746099c197 #230 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: dump_stack_lvl+0xd5/0x150 print_report+0xc1/0x5e0 kasan_report+0xba/0xf0 bcm_proc_show+0x969/0xa80 seq_read_iter+0x4f6/0x1260 seq_read+0x165/0x210 proc_reg_read+0x227/0x300 vfs_read+0x1d5/0x8d0 ksys_read+0x11e/0x240 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Allocated by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x9e/0xa0 bcm_sendmsg+0x264b/0x44e0 sock_sendmsg+0xda/0x180 ____sys_sendmsg+0x735/0x920 ___sys_sendmsg+0x11d/0x1b0 __sys_sendmsg+0xfa/0x1d0 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x27/0x40 ____kasan_slab_free+0x161/0x1c0 slab_free_freelist_hook+0x119/0x220 __kmem_cache_free+0xb4/0x2e0 rcu_core+0x809/0x1bd0 bcm_op is freed before procfs entry be removed in bcm_release(), this lead to bcm_proc_show() may read the freed bcm_op. Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Signed-off-by: YueHaibing Reviewed-by: Oliver Hartkopp Acked-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20230715092543.15548-1-yuehaibing@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde

sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES)

2023-06-24T22:50:13+00:00

Remove ->sendpage() and ->sendpage_locked(). sendmsg() with MSG_SPLICE_PAGES should be used instead. This allows multiple pages and multipage folios to be passed through. Signed-off-by: David Howells Acked-by: Marc Kleine-Budde # for net/can cc: Jens Axboe cc: Matthew Wilcox cc: linux-afs@lists.infradead.org cc: mptcp@lists.linux.dev cc: rds-devel@oss.oracle.com cc: tipc-discussion@lists.sourceforge.net cc: virtualization@lists.linux-foundation.org Link: https://lore.kernel.org/r/20230623225513.2732256-16-dhowells@redhat.com Signed-off-by: Jakub Kicinski

can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write

2023-03-27T12:40:45+00:00

Syzkaller reported the following issue: ===================================================== BUG: KMSAN: uninit-value in aio_rw_done fs/aio.c:1520 [inline] BUG: KMSAN: uninit-value in aio_write+0x899/0x950 fs/aio.c:1600 aio_rw_done fs/aio.c:1520 [inline] aio_write+0x899/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook mm/slab.h:766 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc+0x11d/0x3b0 mm/slab_common.c:981 kmalloc_array include/linux/slab.h:636 [inline] bcm_tx_setup+0x80e/0x29d0 net/can/bcm.c:930 bcm_sendmsg+0x3a2/0xce0 net/can/bcm.c:1351 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] sock_write_iter+0x495/0x5e0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd CPU: 1 PID: 5034 Comm: syz-executor350 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 ===================================================== We can follow the call chain and find that 'bcm_tx_setup' function calls 'memcpy_from_msg' to copy some content to the newly allocated frame of 'op->frames'. After that the 'len' field of copied structure being compared with some constant value (64 or 8). However, if 'memcpy_from_msg' returns an error, we will compare some uninitialized memory. This triggers 'uninit-value' issue. This patch will add 'memcpy_from_msg' possible errors processing to avoid uninit-value issue. Tested via syzkaller Reported-by: syzbot+c9bfd85eca611ebf5db1@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=47f897f8ad958bbde5790ebf389b5e7e0a345089 Signed-off-by: Ivan Orlov Fixes: 6f3b911d5f29b ("can: bcm: add support for CAN FD frames") Acked-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20230314120445.12407-1-ivan.orlov0322@gmail.com Signed-off-by: Marc Kleine-Budde

can: bcm: check the result of can_send() in bcm_can_tx()

2022-09-23T11:53:10+00:00

If can_send() fail, it should not update frames_abs counter in bcm_can_tx(). Add the result check for can_send() in bcm_can_tx(). Suggested-by: Marc Kleine-Budde Suggested-by: Oliver Hartkopp Signed-off-by: Ziyang Xuan Link: https://lore.kernel.org/all/9851878e74d6d37aee2f1ee76d68361a46f89458.1663206163.git.william.xuanziyang@huawei.com Acked-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde