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    Subject[PATCH 4.14 104/126] inet: frags: break the 2GB limit for frags storage
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Eric Dumazet <edumazet@google.com>

    Some users are willing to provision huge amounts of memory to be able
    to perform reassembly reasonnably well under pressure.

    Current memory tracking is using one atomic_t and integers.

    Switch to atomic_long_t so that 64bit arches can use more than 2GB,
    without any cost for 32bit arches.

    Note that this patch avoids an overflow error, if high_thresh was set
    to ~2GB, since this test in inet_frag_alloc() was never true :

    if (... || frag_mem_limit(nf) > nf->high_thresh)

    Tested:

    $ echo 16000000000 >/proc/sys/net/ipv4/ipfrag_high_thresh

    <frag DDOS>

    $ grep FRAG /proc/net/sockstat
    FRAG: inuse 14705885 memory 16000002880

    $ nstat -n ; sleep 1 ; nstat | grep Reas
    IpReasmReqds 3317150 0.0
    IpReasmFails 3317112 0.0

    Signed-off-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    (cherry picked from commit 3e67f106f619dcfaf6f4e2039599bdb69848c714)
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    Documentation/networking/ip-sysctl.txt | 4 ++--
    include/net/inet_frag.h | 20 ++++++++++----------
    net/ieee802154/6lowpan/reassembly.c | 10 +++++-----
    net/ipv4/ip_fragment.c | 10 +++++-----
    net/ipv4/proc.c | 2 +-
    net/ipv6/netfilter/nf_conntrack_reasm.c | 10 +++++-----
    net/ipv6/proc.c | 2 +-
    net/ipv6/reassembly.c | 6 +++---
    8 files changed, 32 insertions(+), 32 deletions(-)

    --- a/Documentation/networking/ip-sysctl.txt
    +++ b/Documentation/networking/ip-sysctl.txt
    @@ -133,10 +133,10 @@ min_adv_mss - INTEGER

    IP Fragmentation:

    -ipfrag_high_thresh - INTEGER
    +ipfrag_high_thresh - LONG INTEGER
    Maximum memory used to reassemble IP fragments.

    -ipfrag_low_thresh - INTEGER
    +ipfrag_low_thresh - LONG INTEGER
    (Obsolete since linux-4.17)
    Maximum memory used to reassemble IP fragments before the kernel
    begins to remove incomplete fragment queues to free up resources.
    --- a/include/net/inet_frag.h
    +++ b/include/net/inet_frag.h
    @@ -8,11 +8,11 @@ struct netns_frags {
    struct rhashtable rhashtable ____cacheline_aligned_in_smp;

    /* Keep atomic mem on separate cachelines in structs that include it */
    - atomic_t mem ____cacheline_aligned_in_smp;
    + atomic_long_t mem ____cacheline_aligned_in_smp;
    /* sysctls */
    + long high_thresh;
    + long low_thresh;
    int timeout;
    - int high_thresh;
    - int low_thresh;
    int max_dist;
    struct inet_frags *f;
    };
    @@ -102,7 +102,7 @@ void inet_frags_fini(struct inet_frags *

    static inline int inet_frags_init_net(struct netns_frags *nf)
    {
    - atomic_set(&nf->mem, 0);
    + atomic_long_set(&nf->mem, 0);
    return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);
    }
    void inet_frags_exit_net(struct netns_frags *nf);
    @@ -119,19 +119,19 @@ static inline void inet_frag_put(struct

    /* Memory Tracking Functions. */

    -static inline int frag_mem_limit(struct netns_frags *nf)
    +static inline long frag_mem_limit(const struct netns_frags *nf)
    {
    - return atomic_read(&nf->mem);
    + return atomic_long_read(&nf->mem);
    }

    -static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
    +static inline void sub_frag_mem_limit(struct netns_frags *nf, long val)
    {
    - atomic_sub(i, &nf->mem);
    + atomic_long_sub(val, &nf->mem);
    }

    -static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
    +static inline void add_frag_mem_limit(struct netns_frags *nf, long val)
    {
    - atomic_add(i, &nf->mem);
    + atomic_long_add(val, &nf->mem);
    }

    /* RFC 3168 support :
    --- a/net/ieee802154/6lowpan/reassembly.c
    +++ b/net/ieee802154/6lowpan/reassembly.c
    @@ -411,23 +411,23 @@ err:
    }

    #ifdef CONFIG_SYSCTL
    -static int zero;
    +static long zero;

    static struct ctl_table lowpan_frags_ns_ctl_table[] = {
    {
    .procname = "6lowpanfrag_high_thresh",
    .data = &init_net.ieee802154_lowpan.frags.high_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &init_net.ieee802154_lowpan.frags.low_thresh
    },
    {
    .procname = "6lowpanfrag_low_thresh",
    .data = &init_net.ieee802154_lowpan.frags.low_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &zero,
    .extra2 = &init_net.ieee802154_lowpan.frags.high_thresh
    },
    --- a/net/ipv4/ip_fragment.c
    +++ b/net/ipv4/ip_fragment.c
    @@ -683,23 +683,23 @@ struct sk_buff *ip_check_defrag(struct n
    EXPORT_SYMBOL(ip_check_defrag);

    #ifdef CONFIG_SYSCTL
    -static int zero;
    +static long zero;

    static struct ctl_table ip4_frags_ns_ctl_table[] = {
    {
    .procname = "ipfrag_high_thresh",
    .data = &init_net.ipv4.frags.high_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &init_net.ipv4.frags.low_thresh
    },
    {
    .procname = "ipfrag_low_thresh",
    .data = &init_net.ipv4.frags.low_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &zero,
    .extra2 = &init_net.ipv4.frags.high_thresh
    },
    --- a/net/ipv4/proc.c
    +++ b/net/ipv4/proc.c
    @@ -71,7 +71,7 @@ static int sockstat_seq_show(struct seq_
    sock_prot_inuse_get(net, &udplite_prot));
    seq_printf(seq, "RAW: inuse %d\n",
    sock_prot_inuse_get(net, &raw_prot));
    - seq_printf(seq, "FRAG: inuse %u memory %u\n",
    + seq_printf(seq, "FRAG: inuse %u memory %lu\n",
    atomic_read(&net->ipv4.frags.rhashtable.nelems),
    frag_mem_limit(&net->ipv4.frags));
    return 0;
    --- a/net/ipv6/netfilter/nf_conntrack_reasm.c
    +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
    @@ -63,7 +63,7 @@ struct nf_ct_frag6_skb_cb
    static struct inet_frags nf_frags;

    #ifdef CONFIG_SYSCTL
    -static int zero;
    +static long zero;

    static struct ctl_table nf_ct_frag6_sysctl_table[] = {
    {
    @@ -76,18 +76,18 @@ static struct ctl_table nf_ct_frag6_sysc
    {
    .procname = "nf_conntrack_frag6_low_thresh",
    .data = &init_net.nf_frag.frags.low_thresh,
    - .maxlen = sizeof(unsigned int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &zero,
    .extra2 = &init_net.nf_frag.frags.high_thresh
    },
    {
    .procname = "nf_conntrack_frag6_high_thresh",
    .data = &init_net.nf_frag.frags.high_thresh,
    - .maxlen = sizeof(unsigned int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &init_net.nf_frag.frags.low_thresh
    },
    { }
    --- a/net/ipv6/proc.c
    +++ b/net/ipv6/proc.c
    @@ -47,7 +47,7 @@ static int sockstat6_seq_show(struct seq
    sock_prot_inuse_get(net, &udplitev6_prot));
    seq_printf(seq, "RAW6: inuse %d\n",
    sock_prot_inuse_get(net, &rawv6_prot));
    - seq_printf(seq, "FRAG6: inuse %u memory %u\n",
    + seq_printf(seq, "FRAG6: inuse %u memory %lu\n",
    atomic_read(&net->ipv6.frags.rhashtable.nelems),
    frag_mem_limit(&net->ipv6.frags));
    return 0;
    --- a/net/ipv6/reassembly.c
    +++ b/net/ipv6/reassembly.c
    @@ -552,15 +552,15 @@ static struct ctl_table ip6_frags_ns_ctl
    {
    .procname = "ip6frag_high_thresh",
    .data = &init_net.ipv6.frags.high_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    - .proc_handler = proc_dointvec_minmax,
    + .proc_handler = proc_doulongvec_minmax,
    .extra1 = &init_net.ipv6.frags.low_thresh
    },
    {
    .procname = "ip6frag_low_thresh",
    .data = &init_net.ipv6.frags.low_thresh,
    - .maxlen = sizeof(int),
    + .maxlen = sizeof(unsigned long),
    .mode = 0644,
    .proc_handler = proc_dointvec_minmax,
    .extra1 = &zero,

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