lkml.org 
[lkml]   [2022]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 153/320] fs: dlm: filter user dlm messages for kernel locks
    Date
    From: Alexander Aring <aahringo@redhat.com>

    [ Upstream commit 6c2e3bf68f3e5e5a647aa52be246d5f552d7496d ]

    This patch fixes the following crash by receiving a invalid message:

    [ 160.672220] ==================================================================
    [ 160.676206] BUG: KASAN: user-memory-access in dlm_user_add_ast+0xc3/0x370
    [ 160.679659] Read of size 8 at addr 00000000deadbeef by task kworker/u32:13/319
    [ 160.681447]
    [ 160.681824] CPU: 10 PID: 319 Comm: kworker/u32:13 Not tainted 5.14.0-rc2+ #399
    [ 160.683472] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.14.0-1.module+el8.6.0+12648+6ede71a5 04/01/2014
    [ 160.685574] Workqueue: dlm_recv process_recv_sockets
    [ 160.686721] Call Trace:
    [ 160.687310] dump_stack_lvl+0x56/0x6f
    [ 160.688169] ? dlm_user_add_ast+0xc3/0x370
    [ 160.689116] kasan_report.cold.14+0x116/0x11b
    [ 160.690138] ? dlm_user_add_ast+0xc3/0x370
    [ 160.690832] dlm_user_add_ast+0xc3/0x370
    [ 160.691502] _receive_unlock_reply+0x103/0x170
    [ 160.692241] _receive_message+0x11df/0x1ec0
    [ 160.692926] ? rcu_read_lock_sched_held+0xa1/0xd0
    [ 160.693700] ? rcu_read_lock_bh_held+0xb0/0xb0
    [ 160.694427] ? lock_acquire+0x175/0x400
    [ 160.695058] ? do_purge.isra.51+0x200/0x200
    [ 160.695744] ? lock_acquired+0x360/0x5d0
    [ 160.696400] ? lock_contended+0x6a0/0x6a0
    [ 160.697055] ? lock_release+0x21d/0x5e0
    [ 160.697686] ? lock_is_held_type+0xe0/0x110
    [ 160.698352] ? lock_is_held_type+0xe0/0x110
    [ 160.699026] ? ___might_sleep+0x1cc/0x1e0
    [ 160.699698] ? dlm_wait_requestqueue+0x94/0x140
    [ 160.700451] ? dlm_process_requestqueue+0x240/0x240
    [ 160.701249] ? down_write_killable+0x2b0/0x2b0
    [ 160.701988] ? do_raw_spin_unlock+0xa2/0x130
    [ 160.702690] dlm_receive_buffer+0x1a5/0x210
    [ 160.703385] dlm_process_incoming_buffer+0x726/0x9f0
    [ 160.704210] receive_from_sock+0x1c0/0x3b0
    [ 160.704886] ? dlm_tcp_shutdown+0x30/0x30
    [ 160.705561] ? lock_acquire+0x175/0x400
    [ 160.706197] ? rcu_read_lock_sched_held+0xa1/0xd0
    [ 160.706941] ? rcu_read_lock_bh_held+0xb0/0xb0
    [ 160.707681] process_recv_sockets+0x32/0x40
    [ 160.708366] process_one_work+0x55e/0xad0
    [ 160.709045] ? pwq_dec_nr_in_flight+0x110/0x110
    [ 160.709820] worker_thread+0x65/0x5e0
    [ 160.710423] ? process_one_work+0xad0/0xad0
    [ 160.711087] kthread+0x1ed/0x220
    [ 160.711628] ? set_kthread_struct+0x80/0x80
    [ 160.712314] ret_from_fork+0x22/0x30

    The issue is that we received a DLM message for a user lock but the
    destination lock is a kernel lock. Note that the address which is trying
    to derefence is 00000000deadbeef, which is in a kernel lock
    lkb->lkb_astparam, this field should never be derefenced by the DLM
    kernel stack. In case of a user lock lkb->lkb_astparam is lkb->lkb_ua
    (memory is shared by a union field). The struct lkb_ua will be handled
    by the DLM kernel stack but on a kernel lock it will contain invalid
    data and ends in most likely crashing the kernel.

    It can be reproduced with two cluster nodes.

    node 2:
    dlm_tool join test
    echo "862 fooobaar 1 2 1" > /sys/kernel/debug/dlm/test_locks
    echo "862 3 1" > /sys/kernel/debug/dlm/test_waiters

    node 1:
    dlm_tool join test

    python:
    foo = DLM(h_cmd=3, o_nextcmd=1, h_nodeid=1, h_lockspace=0x77222027, \
    m_type=7, m_flags=0x1, m_remid=0x862, m_result=0xFFFEFFFE)
    newFile = open("/sys/kernel/debug/dlm/comms/2/rawmsg", "wb")
    newFile.write(bytes(foo))

    Signed-off-by: Alexander Aring <aahringo@redhat.com>
    Signed-off-by: David Teigland <teigland@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/dlm/lock.c | 9 +++++++++
    1 file changed, 9 insertions(+)

    diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
    index 18d81599522f3..53500b555bfa8 100644
    --- a/fs/dlm/lock.c
    +++ b/fs/dlm/lock.c
    @@ -3975,6 +3975,14 @@ static int validate_message(struct dlm_lkb *lkb, struct dlm_message *ms)
    int from = ms->m_header.h_nodeid;
    int error = 0;

    + /* currently mixing of user/kernel locks are not supported */
    + if (ms->m_flags & DLM_IFL_USER && ~lkb->lkb_flags & DLM_IFL_USER) {
    + log_error(lkb->lkb_resource->res_ls,
    + "got user dlm message for a kernel lock");
    + error = -EINVAL;
    + goto out;
    + }
    +
    switch (ms->m_type) {
    case DLM_MSG_CONVERT:
    case DLM_MSG_UNLOCK:
    @@ -4003,6 +4011,7 @@ static int validate_message(struct dlm_lkb *lkb, struct dlm_message *ms)
    error = -EINVAL;
    }

    +out:
    if (error)
    log_error(lkb->lkb_resource->res_ls,
    "ignore invalid message %d from %d %x %x %x %d",
    --
    2.34.1


    \
     
     \ /
      Last update: 2022-01-24 21:40    [W:4.289 / U:0.044 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site