target/linux/generic/patches-2.6.39/610-netfilter_match_bypass_default_checks.patch

   1 --- a/include/linux/netfilter_ipv4/ip_tables.h
   2 +++ b/include/linux/netfilter_ipv4/ip_tables.h
   3 @@ -93,6 +93,7 @@ struct ipt_ip {
   4  #define IPT_F_FRAG             0x01    /* Set if rule is a fragment rule */
   5  #define IPT_F_GOTO             0x02    /* Set if jump is a goto */
   6  #define IPT_F_MASK             0x03    /* All possible flag bits mask. */
   7 +#define IPT_F_NO_DEF_MATCH     0x80    /* Internal: no default match rules present */
   8
   9  /* Values for "inv" field in struct ipt_ip. */
  10  #define IPT_INV_VIA_IN         0x01    /* Invert the sense of IN IFACE. */
  11 --- a/net/ipv4/netfilter/ip_tables.c
  12 +++ b/net/ipv4/netfilter/ip_tables.c
  13 @@ -90,6 +90,9 @@ ip_packet_match(const struct iphdr *ip,
  14
  15  #define FWINV(bool, invflg) ((bool) ^ !!(ipinfo->invflags & (invflg)))
  16
  17 +       if (ipinfo->flags & IPT_F_NO_DEF_MATCH)
  18 +               return true;
  19 +
  20         if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
  21                   IPT_INV_SRCIP) ||
  22             FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
  23 @@ -143,6 +146,26 @@ ip_packet_match(const struct iphdr *ip,
  24         return true;
  25  }
  26
  27 +static void
  28 +ip_checkdefault(struct ipt_ip *ip)
  29 +{
  30 +       static const char iface_mask[IFNAMSIZ] = {};
  31 +
  32 +       if (ip->invflags || ip->flags & IPT_F_FRAG)
  33 +               return;
  34 +
  35 +       if (memcmp(ip->iniface_mask, iface_mask, IFNAMSIZ) != 0)
  36 +               return;
  37 +
  38 +       if (memcmp(ip->outiface_mask, iface_mask, IFNAMSIZ) != 0)
  39 +               return;
  40 +
  41 +       if (ip->proto)
  42 +               return;
  43 +
  44 +       ip->flags |= IPT_F_NO_DEF_MATCH;
  45 +}
  46 +
  47  static bool
  48  ip_checkentry(const struct ipt_ip *ip)
  49  {
  50 @@ -566,7 +589,7 @@ static void cleanup_match(struct xt_entr
  51  }
  52
  53  static int
  54 -check_entry(const struct ipt_entry *e, const char *name)
  55 +check_entry(struct ipt_entry *e, const char *name)
  56  {
  57         const struct xt_entry_target *t;
  58
  59 @@ -575,6 +598,8 @@ check_entry(const struct ipt_entry *e, c
  60                 return -EINVAL;
  61         }
  62
  63 +       ip_checkdefault(&e->ip);
  64 +
  65         if (e->target_offset + sizeof(struct xt_entry_target) >
  66             e->next_offset)
  67                 return -EINVAL;
  68 @@ -936,6 +961,7 @@ copy_entries_to_user(unsigned int total_
  69         const struct xt_table_info *private = table->private;
  70         int ret = 0;
  71         const void *loc_cpu_entry;
  72 +       u8 flags;
  73
  74         counters = alloc_counters(table);
  75         if (IS_ERR(counters))
  76 @@ -967,6 +993,14 @@ copy_entries_to_user(unsigned int total_
  77                         goto free_counters;
  78                 }
  79
  80 +               flags = e->ip.flags & IPT_F_MASK;
  81 +               if (copy_to_user(userptr + off
  82 +                                + offsetof(struct ipt_entry, ip.flags),
  83 +                                &flags, sizeof(flags)) != 0) {
  84 +                       ret = -EFAULT;
  85 +                       goto free_counters;
  86 +               }
  87 +
  88                 for (i = sizeof(struct ipt_entry);
  89                      i < e->target_offset;
  90                      i += m->u.match_size) {