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    Subject[PATCH 4.14 061/293] ipvs: defer hook registration to avoid leaks
    Date
    [ Upstream commit cf47a0b882a4e5f6b34c7949d7b293e9287f1972 ]

    syzkaller reports for memory leak when registering hooks [1]

    As we moved the nf_unregister_net_hooks() call into
    __ip_vs_dev_cleanup(), defer the nf_register_net_hooks()
    call, so that hooks are allocated and freed from same
    pernet_operations (ipvs_core_dev_ops).

    [1]
    BUG: memory leak
    unreferenced object 0xffff88810acd8a80 (size 96):
    comm "syz-executor073", pid 7254, jiffies 4294950560 (age 22.250s)
    hex dump (first 32 bytes):
    02 00 00 00 00 00 00 00 50 8b bb 82 ff ff ff ff ........P.......
    00 00 00 00 00 00 00 00 00 77 bb 82 ff ff ff ff .........w......
    backtrace:
    [<0000000013db61f1>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<0000000013db61f1>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000013db61f1>] slab_alloc_node mm/slab.c:3269 [inline]
    [<0000000013db61f1>] kmem_cache_alloc_node_trace+0x15b/0x2a0 mm/slab.c:3597
    [<000000001a27307d>] __do_kmalloc_node mm/slab.c:3619 [inline]
    [<000000001a27307d>] __kmalloc_node+0x38/0x50 mm/slab.c:3627
    [<0000000025054add>] kmalloc_node include/linux/slab.h:590 [inline]
    [<0000000025054add>] kvmalloc_node+0x4a/0xd0 mm/util.c:431
    [<0000000050d1bc00>] kvmalloc include/linux/mm.h:637 [inline]
    [<0000000050d1bc00>] kvzalloc include/linux/mm.h:645 [inline]
    [<0000000050d1bc00>] allocate_hook_entries_size+0x3b/0x60 net/netfilter/core.c:61
    [<00000000e8abe142>] nf_hook_entries_grow+0xae/0x270 net/netfilter/core.c:128
    [<000000004b94797c>] __nf_register_net_hook+0x9a/0x170 net/netfilter/core.c:337
    [<00000000d1545cbc>] nf_register_net_hook+0x34/0xc0 net/netfilter/core.c:464
    [<00000000876c9b55>] nf_register_net_hooks+0x53/0xc0 net/netfilter/core.c:480
    [<000000002ea868e0>] __ip_vs_init+0xe8/0x170 net/netfilter/ipvs/ip_vs_core.c:2280
    [<000000002eb2d451>] ops_init+0x4c/0x140 net/core/net_namespace.c:130
    [<000000000284ec48>] setup_net+0xde/0x230 net/core/net_namespace.c:316
    [<00000000a70600fa>] copy_net_ns+0xf0/0x1e0 net/core/net_namespace.c:439
    [<00000000ff26c15e>] create_new_namespaces+0x141/0x2a0 kernel/nsproxy.c:107
    [<00000000b103dc79>] copy_namespaces+0xa1/0xe0 kernel/nsproxy.c:165
    [<000000007cc008a2>] copy_process.part.0+0x11fd/0x2150 kernel/fork.c:2035
    [<00000000c344af7c>] copy_process kernel/fork.c:1800 [inline]
    [<00000000c344af7c>] _do_fork+0x121/0x4f0 kernel/fork.c:2369

    Reported-by: syzbot+722da59ccb264bc19910@syzkaller.appspotmail.com
    Fixes: 719c7d563c17 ("ipvs: Fix use-after-free in ip_vs_in")
    Signed-off-by: Julian Anastasov <ja@ssi.bg>
    Acked-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 | 21 ++++++++++++++-------
    1 file changed, 14 insertions(+), 7 deletions(-)

    diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
    index ee97ce176b9a..2156571455db 100644
    --- a/net/netfilter/ipvs/ip_vs_core.c
    +++ b/net/netfilter/ipvs/ip_vs_core.c
    @@ -2206,7 +2206,6 @@ static const struct nf_hook_ops ip_vs_ops[] = {
    static int __net_init __ip_vs_init(struct net *net)
    {
    struct netns_ipvs *ipvs;
    - int ret;

    ipvs = net_generic(net, ip_vs_net_id);
    if (ipvs == NULL)
    @@ -2238,17 +2237,11 @@ static int __net_init __ip_vs_init(struct net *net)
    if (ip_vs_sync_net_init(ipvs) < 0)
    goto sync_fail;

    - ret = nf_register_net_hooks(net, ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
    - if (ret < 0)
    - goto hook_fail;
    -
    return 0;
    /*
    * Error handling
    */

    -hook_fail:
    - ip_vs_sync_net_cleanup(ipvs);
    sync_fail:
    ip_vs_conn_net_cleanup(ipvs);
    conn_fail:
    @@ -2278,6 +2271,19 @@ static void __net_exit __ip_vs_cleanup(struct net *net)
    net->ipvs = NULL;
    }

    +static int __net_init __ip_vs_dev_init(struct net *net)
    +{
    + int ret;
    +
    + ret = nf_register_net_hooks(net, ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
    + if (ret < 0)
    + goto hook_fail;
    + return 0;
    +
    +hook_fail:
    + return ret;
    +}
    +
    static void __net_exit __ip_vs_dev_cleanup(struct net *net)
    {
    struct netns_ipvs *ipvs = net_ipvs(net);
    @@ -2297,6 +2303,7 @@ static struct pernet_operations ipvs_core_ops = {
    };

    static struct pernet_operations ipvs_core_dev_ops = {
    + .init = __ip_vs_dev_init,
    .exit = __ip_vs_dev_cleanup,
    };

    --
    2.20.1


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