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 > ret = rdma_nl_notify_event(device, 0, RDMA_REGISTER_EVENT); > + up_write(&devices_rwsem); > if (ret) > return; > > -- > 2.34.1 > >
