net/netfilter/nf_conntrack_extend.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Structure dynamic extension infrastructure
   3  * Copyright (C) 2004 Rusty Russell IBM Corporation
   4  * Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
   5  * Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/kmemleak.h>
   9 #include <linux/module.h>
  10 #include <linux/mutex.h>
  11 #include <linux/rcupdate.h>
  12 #include <linux/slab.h>
  13 #include <linux/skbuff.h>
  14 #include <net/netfilter/nf_conntrack_extend.h>
  15
  16 #include <net/netfilter/nf_conntrack_helper.h>
  17 #include <net/netfilter/nf_conntrack_acct.h>
  18 #include <net/netfilter/nf_conntrack_seqadj.h>
  19 #include <net/netfilter/nf_conntrack_ecache.h>
  20 #include <net/netfilter/nf_conntrack_zones.h>
  21 #include <net/netfilter/nf_conntrack_timestamp.h>
  22 #include <net/netfilter/nf_conntrack_timeout.h>
  23 #include <net/netfilter/nf_conntrack_labels.h>
  24 #include <net/netfilter/nf_conntrack_synproxy.h>
  25 #include <net/netfilter/nf_conntrack_act_ct.h>
  26 #include <net/netfilter/nf_nat.h>
  27
  28 #define NF_CT_EXT_PREALLOC      128u /* conntrack events are on by default */
  29
  30 static const u8 nf_ct_ext_type_len[NF_CT_EXT_NUM] = {
  31         [NF_CT_EXT_HELPER] = sizeof(struct nf_conn_help),
  32 #if IS_ENABLED(CONFIG_NF_NAT)
  33         [NF_CT_EXT_NAT] = sizeof(struct nf_conn_nat),
  34 #endif
  35         [NF_CT_EXT_SEQADJ] = sizeof(struct nf_conn_seqadj),
  36         [NF_CT_EXT_ACCT] = sizeof(struct nf_conn_acct),
  37 #ifdef CONFIG_NF_CONNTRACK_EVENTS
  38         [NF_CT_EXT_ECACHE] = sizeof(struct nf_conntrack_ecache),
  39 #endif
  40 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
  41         [NF_CT_EXT_TSTAMP] = sizeof(struct nf_conn_acct),
  42 #endif
  43 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
  44         [NF_CT_EXT_TIMEOUT] = sizeof(struct nf_conn_tstamp),
  45 #endif
  46 #ifdef CONFIG_NF_CONNTRACK_LABELS
  47         [NF_CT_EXT_LABELS] = sizeof(struct nf_conn_labels),
  48 #endif
  49 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
  50         [NF_CT_EXT_SYNPROXY] = sizeof(struct nf_conn_synproxy),
  51 #endif
  52 #if IS_ENABLED(CONFIG_NET_ACT_CT)
  53         [NF_CT_EXT_ACT_CT] = sizeof(struct nf_conn_act_ct_ext),
  54 #endif
  55 };
  56
  57 static __always_inline unsigned int total_extension_size(void)
  58 {
  59         /* remember to add new extensions below */
  60         BUILD_BUG_ON(NF_CT_EXT_NUM > 10);
  61
  62         return sizeof(struct nf_ct_ext) +
  63                sizeof(struct nf_conn_help)
  64 #if IS_ENABLED(CONFIG_NF_NAT)
  65                 + sizeof(struct nf_conn_nat)
  66 #endif
  67                 + sizeof(struct nf_conn_seqadj)
  68                 + sizeof(struct nf_conn_acct)
  69 #ifdef CONFIG_NF_CONNTRACK_EVENTS
  70                 + sizeof(struct nf_conntrack_ecache)
  71 #endif
  72 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
  73                 + sizeof(struct nf_conn_tstamp)
  74 #endif
  75 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
  76                 + sizeof(struct nf_conn_timeout)
  77 #endif
  78 #ifdef CONFIG_NF_CONNTRACK_LABELS
  79                 + sizeof(struct nf_conn_labels)
  80 #endif
  81 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
  82                 + sizeof(struct nf_conn_synproxy)
  83 #endif
  84 #if IS_ENABLED(CONFIG_NET_ACT_CT)
  85                 + sizeof(struct nf_conn_act_ct_ext)
  86 #endif
  87         ;
  88 }
  89
  90 void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
  91 {
  92         unsigned int newlen, newoff, oldlen, alloc;
  93         struct nf_ct_ext *new;
  94
  95         /* Conntrack must not be confirmed to avoid races on reallocation. */
  96         WARN_ON(nf_ct_is_confirmed(ct));
  97
  98         /* struct nf_ct_ext uses u8 to store offsets/size */
  99         BUILD_BUG_ON(total_extension_size() > 255u);
 100
 101         if (ct->ext) {
 102                 const struct nf_ct_ext *old = ct->ext;
 103
 104                 if (__nf_ct_ext_exist(old, id))
 105                         return NULL;
 106                 oldlen = old->len;
 107         } else {
 108                 oldlen = sizeof(*new);
 109         }
 110
 111         newoff = ALIGN(oldlen, __alignof__(struct nf_ct_ext));
 112         newlen = newoff + nf_ct_ext_type_len[id];
 113
 114         alloc = max(newlen, NF_CT_EXT_PREALLOC);
 115         new = krealloc(ct->ext, alloc, gfp);
 116         if (!new)
 117                 return NULL;
 118
 119         if (!ct->ext)
 120                 memset(new->offset, 0, sizeof(new->offset));
 121
 122         new->offset[id] = newoff;
 123         new->len = newlen;
 124         memset((void *)new + newoff, 0, newlen - newoff);
 125
 126         ct->ext = new;
 127         return (void *)new + newoff;
 128 }
 129 EXPORT_SYMBOL(nf_ct_ext_add);