• Jonathon Reinhart's avatar
    netfilter: conntrack: Make global sysctls readonly in non-init netns · 2671fa4d
    Jonathon Reinhart authored
    These sysctls point to global variables:
    - NF_SYSCTL_CT_MAX (&nf_conntrack_max)
    - NF_SYSCTL_CT_EXPECT_MAX (&nf_ct_expect_max)
    - NF_SYSCTL_CT_BUCKETS (&nf_conntrack_htable_size_user)
    Because their data pointers are not updated to point to per-netns
    structures, they must be marked read-only in a non-init_net ns.
    Otherwise, changes in any net namespace are reflected in (leaked into)
    all other net namespaces. This problem has existed since the
    introduction of net namespaces.
    The current logic marks them read-only only if the net namespace is
    owned by an unprivileged user (other than init_user_ns).
    Commit d0febd81 ("netfilter: conntrack: re-visit sysctls in
    unprivileged namespaces") "exposes all sysctls even if the namespace is
    unpriviliged." Since we need to mark them readonly in any case, we can
    forego the unprivileged user check altogether.
    Fixes: d0febd81
     ("netfilter: conntrack: re-visit sysctls in unprivileged namespaces")
    Signed-off-by: default avatarJonathon Reinhart <Jonathon.Reinhart@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
nf_conntrack_standalone.c 31.2 KB