target/linux/generic/pending-4.14/610-netfilter_match_bypass_default_checks.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Subject: kernel: add a new version of my netfilter speedup patches for linux 2.6.39 and 3.0
   3
   4 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   5 ---
   6  include/uapi/linux/netfilter_ipv4/ip_tables.h |  1 +
   7  net/ipv4/netfilter/ip_tables.c                | 37 +++++++++++++++++++++++++++
   8  2 files changed, 38 insertions(+)
   9
  10 --- a/include/uapi/linux/netfilter_ipv4/ip_tables.h
  11 +++ b/include/uapi/linux/netfilter_ipv4/ip_tables.h
  12 @@ -89,6 +89,7 @@ struct ipt_ip {
  13  #define IPT_F_FRAG             0x01    /* Set if rule is a fragment rule */
  14  #define IPT_F_GOTO             0x02    /* Set if jump is a goto */
  15  #define IPT_F_MASK             0x03    /* All possible flag bits mask. */
  16 +#define IPT_F_NO_DEF_MATCH     0x80    /* Internal: no default match rules present */
  17
  18  /* Values for "inv" field in struct ipt_ip. */
  19  #define IPT_INV_VIA_IN         0x01    /* Invert the sense of IN IFACE. */
  20 --- a/net/ipv4/netfilter/ip_tables.c
  21 +++ b/net/ipv4/netfilter/ip_tables.c
  22 @@ -52,6 +52,9 @@ ip_packet_match(const struct iphdr *ip,
  23  {
  24         unsigned long ret;
  25
  26 +       if (ipinfo->flags & IPT_F_NO_DEF_MATCH)
  27 +               return true;
  28 +
  29         if (NF_INVF(ipinfo, IPT_INV_SRCIP,
  30                     (ip->saddr & ipinfo->smsk.s_addr) != ipinfo->src.s_addr) ||
  31             NF_INVF(ipinfo, IPT_INV_DSTIP,
  32 @@ -82,6 +85,29 @@ ip_packet_match(const struct iphdr *ip,
  33         return true;
  34  }
  35
  36 +static void
  37 +ip_checkdefault(struct ipt_ip *ip)
  38 +{
  39 +       static const char iface_mask[IFNAMSIZ] = {};
  40 +
  41 +       if (ip->invflags || ip->flags & IPT_F_FRAG)
  42 +               return;
  43 +
  44 +       if (memcmp(ip->iniface_mask, iface_mask, IFNAMSIZ) != 0)
  45 +               return;
  46 +
  47 +       if (memcmp(ip->outiface_mask, iface_mask, IFNAMSIZ) != 0)
  48 +               return;
  49 +
  50 +       if (ip->smsk.s_addr || ip->dmsk.s_addr)
  51 +               return;
  52 +
  53 +       if (ip->proto)
  54 +               return;
  55 +
  56 +       ip->flags |= IPT_F_NO_DEF_MATCH;
  57 +}
  58 +
  59  static bool
  60  ip_checkentry(const struct ipt_ip *ip)
  61  {
  62 @@ -537,6 +563,8 @@ find_check_entry(struct ipt_entry *e, st
  63         struct xt_mtchk_param mtpar;
  64         struct xt_entry_match *ematch;
  65
  66 +       ip_checkdefault(&e->ip);
  67 +
  68         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
  69                 return -ENOMEM;
  70
  71 @@ -818,6 +846,7 @@ copy_entries_to_user(unsigned int total_
  72         const struct xt_table_info *private = table->private;
  73         int ret = 0;
  74         const void *loc_cpu_entry;
  75 +       u8 flags;
  76
  77         counters = alloc_counters(table);
  78         if (IS_ERR(counters))
  79 @@ -845,6 +874,14 @@ copy_entries_to_user(unsigned int total_
  80                         goto free_counters;
  81                 }
  82
  83 +               flags = e->ip.flags & IPT_F_MASK;
  84 +               if (copy_to_user(userptr + off
  85 +                                + offsetof(struct ipt_entry, ip.flags),
  86 +                                &flags, sizeof(flags)) != 0) {
  87 +                       ret = -EFAULT;
  88 +                       goto free_counters;
  89 +               }
  90 +
  91                 for (i = sizeof(struct ipt_entry);
  92                      i < e->target_offset;
  93                      i += m->u.match_size) {
  94 @@ -1227,12 +1264,15 @@ compat_copy_entry_to_user(struct ipt_ent
  95         compat_uint_t origsize;
  96         const struct xt_entry_match *ematch;
  97         int ret = 0;
  98 +       u8 flags = e->ip.flags & IPT_F_MASK;
  99
 100         origsize = *size;
 101         ce = *dstptr;
 102         if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 ||
 103             copy_to_user(&ce->counters, &counters[i],
 104 -           sizeof(counters[i])) != 0)
 105 +           sizeof(counters[i])) != 0 ||
 106 +           copy_to_user(&ce->ip.flags, &flags,
 107 +           sizeof(flags)) != 0)
 108                 return -EFAULT;
 109
 110         *dstptr += sizeof(struct compat_ipt_entry);