lkml.org 
[lkml]   [2019]   [Jun]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.14 13/45] ipvs: Fix use-after-free in ip_vs_in
    Date
    [ Upstream commit 719c7d563c17b150877cee03a4b812a424989dfa ]

    BUG: KASAN: use-after-free in ip_vs_in.part.29+0xe8/0xd20 [ip_vs]
    Read of size 4 at addr ffff8881e9b26e2c by task sshd/5603

    CPU: 0 PID: 5603 Comm: sshd Not tainted 4.19.39+ #30
    Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
    Call Trace:
    dump_stack+0x71/0xab
    print_address_description+0x6a/0x270
    kasan_report+0x179/0x2c0
    ip_vs_in.part.29+0xe8/0xd20 [ip_vs]
    ip_vs_in+0xd8/0x170 [ip_vs]
    nf_hook_slow+0x5f/0xe0
    __ip_local_out+0x1d5/0x250
    ip_local_out+0x19/0x60
    __tcp_transmit_skb+0xba1/0x14f0
    tcp_write_xmit+0x41f/0x1ed0
    ? _copy_from_iter_full+0xca/0x340
    __tcp_push_pending_frames+0x52/0x140
    tcp_sendmsg_locked+0x787/0x1600
    ? tcp_sendpage+0x60/0x60
    ? inet_sk_set_state+0xb0/0xb0
    tcp_sendmsg+0x27/0x40
    sock_sendmsg+0x6d/0x80
    sock_write_iter+0x121/0x1c0
    ? sock_sendmsg+0x80/0x80
    __vfs_write+0x23e/0x370
    vfs_write+0xe7/0x230
    ksys_write+0xa1/0x120
    ? __ia32_sys_read+0x50/0x50
    ? __audit_syscall_exit+0x3ce/0x450
    do_syscall_64+0x73/0x200
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
    RIP: 0033:0x7ff6f6147c60
    Code: 73 01 c3 48 8b 0d 28 12 2d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 5d 73 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83
    RSP: 002b:00007ffd772ead18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
    RAX: ffffffffffffffda RBX: 0000000000000034 RCX: 00007ff6f6147c60
    RDX: 0000000000000034 RSI: 000055df30a31270 RDI: 0000000000000003
    RBP: 000055df30a31270 R08: 0000000000000000 R09: 0000000000000000
    R10: 00007ffd772ead70 R11: 0000000000000246 R12: 00007ffd772ead74
    R13: 00007ffd772eae20 R14: 00007ffd772eae24 R15: 000055df2f12ddc0

    Allocated by task 6052:
    kasan_kmalloc+0xa0/0xd0
    __kmalloc+0x10a/0x220
    ops_init+0x97/0x190
    register_pernet_operations+0x1ac/0x360
    register_pernet_subsys+0x24/0x40
    0xffffffffc0ea016d
    do_one_initcall+0x8b/0x253
    do_init_module+0xe3/0x335
    load_module+0x2fc0/0x3890
    __do_sys_finit_module+0x192/0x1c0
    do_syscall_64+0x73/0x200
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

    Freed by task 6067:
    __kasan_slab_free+0x130/0x180
    kfree+0x90/0x1a0
    ops_free_list.part.7+0xa6/0xc0
    unregister_pernet_operations+0x18b/0x1f0
    unregister_pernet_subsys+0x1d/0x30
    ip_vs_cleanup+0x1d/0xd2f [ip_vs]
    __x64_sys_delete_module+0x20c/0x300
    do_syscall_64+0x73/0x200
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

    The buggy address belongs to the object at ffff8881e9b26600 which belongs to the cache kmalloc-4096 of size 4096
    The buggy address is located 2092 bytes inside of 4096-byte region [ffff8881e9b26600, ffff8881e9b27600)
    The buggy address belongs to the page:
    page:ffffea0007a6c800 count:1 mapcount:0 mapping:ffff888107c0e600 index:0x0 compound_mapcount: 0
    flags: 0x17ffffc0008100(slab|head)
    raw: 0017ffffc0008100 dead000000000100 dead000000000200 ffff888107c0e600
    raw: 0000000000000000 0000000080070007 00000001ffffffff 0000000000000000
    page dumped because: kasan: bad access detected

    while unregistering ipvs module, ops_free_list calls
    __ip_vs_cleanup, then nf_unregister_net_hooks be called to
    do remove nf hook entries. It need a RCU period to finish,
    however net->ipvs is set to NULL immediately, which will
    trigger NULL pointer dereference when a packet is hooked
    and handled by ip_vs_in where net->ipvs is dereferenced.

    Another scene is ops_free_list call ops_free to free the
    net_generic directly while __ip_vs_cleanup finished, then
    calling ip_vs_in will triggers use-after-free.

    This patch moves nf_unregister_net_hooks from __ip_vs_cleanup()
    to __ip_vs_dev_cleanup(), where rcu_barrier() is called by
    unregister_pernet_device -> unregister_pernet_operations,
    that will do the needed grace period.

    Reported-by: Hulk Robot <hulkci@huawei.com>
    Fixes: efe41606184e ("ipvs: convert to use pernet nf_hook api")
    Suggested-by: Julian Anastasov <ja@ssi.bg>
    Signed-off-by: YueHaibing <yuehaibing@huawei.com>
    Acked-by: Julian Anastasov <ja@ssi.bg>
    Signed-off-by: Simon Horman <horms@verge.net.au>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/netfilter/ipvs/ip_vs_core.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
    index d1c0378144f3..ee97ce176b9a 100644
    --- a/net/netfilter/ipvs/ip_vs_core.c
    +++ b/net/netfilter/ipvs/ip_vs_core.c
    @@ -2268,7 +2268,6 @@ static void __net_exit __ip_vs_cleanup(struct net *net)
    {
    struct netns_ipvs *ipvs = net_ipvs(net);

    - nf_unregister_net_hooks(net, ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
    ip_vs_service_net_cleanup(ipvs); /* ip_vs_flush() with locks */
    ip_vs_conn_net_cleanup(ipvs);
    ip_vs_app_net_cleanup(ipvs);
    @@ -2283,6 +2282,7 @@ static void __net_exit __ip_vs_dev_cleanup(struct net *net)
    {
    struct netns_ipvs *ipvs = net_ipvs(net);
    EnterFunction(2);
    + nf_unregister_net_hooks(net, ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
    ipvs->enable = 0; /* Disable packet reception */
    smp_wmb();
    ip_vs_sync_net_cleanup(ipvs);
    --
    2.20.1


    \
     
     \ /
      Last update: 2019-06-20 20:25    [W:4.453 / U:0.044 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site