On Tue, Mar 11, 2025 at 10:55:42AM +0800, Wang Liang wrote: > > 在 2025/3/10 18:14, Leon Romanovsky 写道: > > On Mon, Mar 10, 2025 at 02:45:16PM +0800, Wang Liang wrote: > > > Syzbot reported a slab-use-after-free with the following call trace: > > > > > > ================================================================== > > > BUG: KASAN: slab-use-after-free in nla_put+0xd3/0x150 lib/nlattr.c:1099 > > > Read of size 5 at addr ffff888140ea1c60 by task syz.0.988/10025 > > > > > > CPU: 0 UID: 0 PID: 10025 Comm: syz.0.988 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0 > > > Hardware name: Google Compute Engine, BIOS Google 02/12/2025 > > > Call Trace: > > > <TASK> > > > __dump_stack lib/dump_stack.c:94 [inline] > > > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 > > > print_address_description mm/kasan/report.c:408 [inline] > > > print_report+0x16e/0x5b0 mm/kasan/report.c:521 > > > kasan_report+0x143/0x180 mm/kasan/report.c:634 > > > kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 > > > __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105 > > > nla_put+0xd3/0x150 lib/nlattr.c:1099 > > > nla_put_string include/net/netlink.h:1621 [inline] > > > fill_nldev_handle+0x16e/0x200 drivers/infiniband/core/nldev.c:265 > > > rdma_nl_notify_event+0x561/0xef0 drivers/infiniband/core/nldev.c:2857 > > > ib_device_notify_register+0x22/0x230 drivers/infiniband/core/device.c:1344 > > > ib_register_device+0x1292/0x1460 drivers/infiniband/core/device.c:1460 > > > rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540 > > > rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550 > > > rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212 > > > nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795 > > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] > > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259 > > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] > > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 > > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883 > > > sock_sendmsg_nosec net/socket.c:709 [inline] > > > __sock_sendmsg+0x221/0x270 net/socket.c:724 > > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564 > > > ___sys_sendmsg net/socket.c:2618 [inline] > > > __sys_sendmsg+0x269/0x350 net/socket.c:2650 > > > 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: 0033:0x7f42d1b8d169 > > > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 ... > > > RSP: 002b:00007f42d2960038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > > > RAX: ffffffffffffffda RBX: 00007f42d1da6320 RCX: 00007f42d1b8d169 > > > RDX: 0000000000000000 RSI: 00004000000002c0 RDI: 000000000000000c > > > RBP: 00007f42d1c0e2a0 R08: 0000000000000000 R09: 0000000000000000 > > > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > > > R13: 0000000000000000 R14: 00007f42d1da6320 R15: 00007ffe399344a8 > > > </TASK> > > > > > > Allocated by task 10025: > > > kasan_save_stack mm/kasan/common.c:47 [inline] > > > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 > > > poison_kmalloc_redzone mm/kasan/common.c:377 [inline] > > > __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 > > > kasan_kmalloc include/linux/kasan.h:260 [inline] > > > __do_kmalloc_node mm/slub.c:4294 [inline] > > > __kmalloc_node_track_caller_noprof+0x28b/0x4c0 mm/slub.c:4313 > > > __kmemdup_nul mm/util.c:61 [inline] > > > kstrdup+0x42/0x100 mm/util.c:81 > > > kobject_set_name_vargs+0x61/0x120 lib/kobject.c:274 > > > dev_set_name+0xd5/0x120 drivers/base/core.c:3468 > > > assign_name drivers/infiniband/core/device.c:1202 [inline] > > > ib_register_device+0x178/0x1460 drivers/infiniband/core/device.c:1384 > > > rxe_register_device+0x233/0x350 drivers/infiniband/sw/rxe/rxe_verbs.c:1540 > > > rxe_net_add+0x74/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:550 > > > rxe_newlink+0xde/0x1a0 drivers/infiniband/sw/rxe/rxe.c:212 > > > nldev_newlink+0x5ea/0x680 drivers/infiniband/core/nldev.c:1795 > > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] > > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259 > > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] > > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 > > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883 > > > sock_sendmsg_nosec net/socket.c:709 [inline] > > > __sock_sendmsg+0x221/0x270 net/socket.c:724 > > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564 > > > ___sys_sendmsg net/socket.c:2618 [inline] > > > __sys_sendmsg+0x269/0x350 net/socket.c:2650 > > > 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 > > > > > > Freed by task 10035: > > > kasan_save_stack mm/kasan/common.c:47 [inline] > > > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 > > > kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 > > > poison_slab_object mm/kasan/common.c:247 [inline] > > > __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 > > > kasan_slab_free include/linux/kasan.h:233 [inline] > > > slab_free_hook mm/slub.c:2353 [inline] > > > slab_free mm/slub.c:4609 [inline] > > > kfree+0x196/0x430 mm/slub.c:4757 > > > kobject_rename+0x38f/0x410 lib/kobject.c:524 > > > device_rename+0x16a/0x200 drivers/base/core.c:4525 > > > ib_device_rename+0x270/0x710 drivers/infiniband/core/device.c:402 > > > nldev_set_doit+0x30e/0x4c0 drivers/infiniband/core/nldev.c:1146 > > > rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] > > > rdma_nl_rcv+0x6dd/0x9e0 drivers/infiniband/core/netlink.c:259 > > > netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] > > > netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1339 > > > netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1883 > > > sock_sendmsg_nosec net/socket.c:709 [inline] > > > __sock_sendmsg+0x221/0x270 net/socket.c:724 > > > ____sys_sendmsg+0x53a/0x860 net/socket.c:2564 > > > ___sys_sendmsg net/socket.c:2618 [inline] > > > __sys_sendmsg+0x269/0x350 net/socket.c:2650 > > > 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 > > > > > > This is because if rename device happens, the old name is freed in > > > ib_device_rename() with lock, but fill_nldev_handle() may visit the dev > > > name locklessly triggered by rxe_newlink(). > > > > > > Fix this by add lock around rdma_nl_notify_event() in > > > ib_device_notify_register(). > > > > > > Reported-by: syzbot+f60349ba1f9f08df349f@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Closes: https://syzkaller.appspot.com/bug?extid=25bc6f0ed2b88b9eb9b8 > > > Fixes: 9cbed5aab5ae ("RDMA/nldev: Add support for RDMA monitoring") > > > Signed-off-by: Wang Liang <wangliang74@xxxxxxxxxx> > > > --- > > > drivers/infiniband/core/device.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c > > > index 0ded91f056f3..4536621ada0d 100644 > > > --- a/drivers/infiniband/core/device.c > > > +++ b/drivers/infiniband/core/device.c > > > @@ -1341,7 +1341,9 @@ static void ib_device_notify_register(struct ib_device *device) > > > u32 port; > > > int ret; > > > + down_write(&devices_rwsem); > > The analysis looks correct to me, however this should be down_read(&devices_rwsem) > > together with comment about possible race with RDMA netlink, which can change > > internals of struct ib_device. > > > > I wonder if this read semaphore should be hold for whole > > ib_device_notify_register() function and not only for RDMA_REGISTER_EVENT event. > > > > Thanks > Yes, you are right! The RDMA_NETDEV_ATTACH_EVENT event in function > ib_device_notify_register() can also visit the dev name locklessly: > > rxe_newlink > ... > ib_device_notify_register > rdma_nl_notify_event(RDMA_NETDEV_ATTACH_EVENT) > fill_mon_netdev_association > // visit dev_name without devices_rwsem > > What's more, the following trace may also trigger the issue when function > nldev_set_doit() rename device: > > (1) > RDMA_NLDEV_CMD_GET > nldev_get_doit > fill_dev_info > fill_nldev_handle > // visit dev_name without devices_rwsem > > (2) > RDMA_NLDEV_CMD_PORT_GET > nldev_port_get_doit > fill_port_info > fill_nldev_handle > // visit dev_name without devices_rwsem > > (3) > RDMA_NLDEV_CMD_RES_GET > nldev_res_get_doit > fill_res_info > fill_nldev_handle > // visit dev_name without devices_rwsem > > And more... > > However, some scenarios hold devices_rwsem, like function > nldev_get_dumpit(), > which was modified by 921eab1143aa("RDMA/devices: Re-organize device.c > locking"): > > RDMA_NLDEV_CMD_GET > nldev_get_dumpit > ib_enum_all_devs > down_read(&devices_rwsem); // hold devices_rwsem read > _nldev_get_dumpit > fill_dev_info > fill_nldev_handle > // visit dev_name with devices_rwsem > up_read(&devices_rwsem); > > So only hold devices_rwsem for whole ib_device_notify_register() may be not > enough. > > How about add down_read(&devices_rwsem) around > fill_dev_info()/fill_port_info()/ > fill_res_info()/ib_device_notify_register(). I don't think so, as all flows in nldev.c except rdma_nl_notify_event() are single threaded and call to ib_device_rename() will make sure that no other RDMA_NLDEV_CMD_* commands are executed. In your case call to rdma_nl_notify_event() can happen in parallel to device_rename only. Thanks
