git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 7930377d1b249b4365c04a410c4ec520375ea7a2 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Thu, 29 Oct 2020 13:50:03 +0100
   4 Subject: netfilter: nf_tables: missing validation from the abort path
   5
   6 From: Pablo Neira Ayuso <pablo@netfilter.org>
   7
   8 [ Upstream commit c0391b6ab810381df632677a1dcbbbbd63d05b6d ]
   9
  10 If userspace does not include the trailing end of batch message, then
  11 nfnetlink aborts the transaction. This allows to check that ruleset
  12 updates trigger no errors.
  13
  14 After this patch, invoking this command from the prerouting chain:
  15
  16  # nft -c add rule x y fib saddr . oif type local
  17
  18 fails since oif is not supported there.
  19
  20 This patch fixes the lack of rule validation from the abort/check path
  21 to catch configuration errors such as the one above.
  22
  23 Fixes: a654de8fdc18 ("netfilter: nf_tables: fix chain dependency validation")
  24 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  25 Signed-off-by: Sasha Levin <sashal@kernel.org>
  26 ---
  27  include/linux/netfilter/nfnetlink.h |  9 ++++++++-
  28  net/netfilter/nf_tables_api.c       | 15 ++++++++++-----
  29  net/netfilter/nfnetlink.c           | 22 ++++++++++++++++++----
  30  3 files changed, 36 insertions(+), 10 deletions(-)
  31
  32 diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
  33 index 89016d08f6a27..f6267e2883f26 100644
  34 --- a/include/linux/netfilter/nfnetlink.h
  35 +++ b/include/linux/netfilter/nfnetlink.h
  36 @@ -24,6 +24,12 @@ struct nfnl_callback {
  37         const u_int16_t attr_count;             /* number of nlattr's */
  38  };
  39
  40 +enum nfnl_abort_action {
  41 +       NFNL_ABORT_NONE         = 0,
  42 +       NFNL_ABORT_AUTOLOAD,
  43 +       NFNL_ABORT_VALIDATE,
  44 +};
  45 +
  46  struct nfnetlink_subsystem {
  47         const char *name;
  48         __u8 subsys_id;                 /* nfnetlink subsystem ID */
  49 @@ -31,7 +37,8 @@ struct nfnetlink_subsystem {
  50         const struct nfnl_callback *cb; /* callback for individual types */
  51         struct module *owner;
  52         int (*commit)(struct net *net, struct sk_buff *skb);
  53 -       int (*abort)(struct net *net, struct sk_buff *skb, bool autoload);
  54 +       int (*abort)(struct net *net, struct sk_buff *skb,
  55 +                    enum nfnl_abort_action action);
  56         void (*cleanup)(struct net *net);
  57         bool (*valid_genid)(struct net *net, u32 genid);
  58  };
  59 diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
  60 index 5a77b7a177229..51391d5d22656 100644
  61 --- a/net/netfilter/nf_tables_api.c
  62 +++ b/net/netfilter/nf_tables_api.c
  63 @@ -7010,11 +7010,15 @@ static void nf_tables_abort_release(struct nft_trans *trans)
  64         kfree(trans);
  65  }
  66
  67 -static int __nf_tables_abort(struct net *net, bool autoload)
  68 +static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
  69  {
  70         struct nft_trans *trans, *next;
  71         struct nft_trans_elem *te;
  72
  73 +       if (action == NFNL_ABORT_VALIDATE &&
  74 +           nf_tables_validate(net) < 0)
  75 +               return -EAGAIN;
  76 +
  77         list_for_each_entry_safe_reverse(trans, next, &net->nft.commit_list,
  78                                          list) {
  79                 switch (trans->msg_type) {
  80 @@ -7132,7 +7136,7 @@ static int __nf_tables_abort(struct net *net, bool autoload)
  81                 nf_tables_abort_release(trans);
  82         }
  83
  84 -       if (autoload)
  85 +       if (action == NFNL_ABORT_AUTOLOAD)
  86                 nf_tables_module_autoload(net);
  87         else
  88                 nf_tables_module_autoload_cleanup(net);
  89 @@ -7145,9 +7149,10 @@ static void nf_tables_cleanup(struct net *net)
  90         nft_validate_state_update(net, NFT_VALIDATE_SKIP);
  91  }
  92
  93 -static int nf_tables_abort(struct net *net, struct sk_buff *skb, bool autoload)
  94 +static int nf_tables_abort(struct net *net, struct sk_buff *skb,
  95 +                          enum nfnl_abort_action action)
  96  {
  97 -       int ret = __nf_tables_abort(net, autoload);
  98 +       int ret = __nf_tables_abort(net, action);
  99
 100         mutex_unlock(&net->nft.commit_mutex);
 101
 102 @@ -7754,7 +7759,7 @@ static void __net_exit nf_tables_exit_net(struct net *net)
 103  {
 104         mutex_lock(&net->nft.commit_mutex);
 105         if (!list_empty(&net->nft.commit_list))
 106 -               __nf_tables_abort(net, false);
 107 +               __nf_tables_abort(net, NFNL_ABORT_NONE);
 108         __nft_release_tables(net);
 109         mutex_unlock(&net->nft.commit_mutex);
 110         WARN_ON_ONCE(!list_empty(&net->nft.tables));
 111 diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
 112 index 6d03b09096210..81c86a156c6c0 100644
 113 --- a/net/netfilter/nfnetlink.c
 114 +++ b/net/netfilter/nfnetlink.c
 115 @@ -315,7 +315,7 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 116                 return netlink_ack(skb, nlh, -EINVAL, NULL);
 117  replay:
 118         status = 0;
 119 -
 120 +replay_abort:
 121         skb = netlink_skb_clone(oskb, GFP_KERNEL);
 122         if (!skb)
 123                 return netlink_ack(oskb, nlh, -ENOMEM, NULL);
 124 @@ -481,7 +481,7 @@ ack:
 125         }
 126  done:
 127         if (status & NFNL_BATCH_REPLAY) {
 128 -               ss->abort(net, oskb, true);
 129 +               ss->abort(net, oskb, NFNL_ABORT_AUTOLOAD);
 130                 nfnl_err_reset(&err_list);
 131                 kfree_skb(skb);
 132                 module_put(ss->owner);
 133 @@ -492,11 +492,25 @@ done:
 134                         status |= NFNL_BATCH_REPLAY;
 135                         goto done;
 136                 } else if (err) {
 137 -                       ss->abort(net, oskb, false);
 138 +                       ss->abort(net, oskb, NFNL_ABORT_NONE);
 139                         netlink_ack(oskb, nlmsg_hdr(oskb), err, NULL);
 140                 }
 141         } else {
 142 -               ss->abort(net, oskb, false);
 143 +               enum nfnl_abort_action abort_action;
 144 +
 145 +               if (status & NFNL_BATCH_FAILURE)
 146 +                       abort_action = NFNL_ABORT_NONE;
 147 +               else
 148 +                       abort_action = NFNL_ABORT_VALIDATE;
 149 +
 150 +               err = ss->abort(net, oskb, abort_action);
 151 +               if (err == -EAGAIN) {
 152 +                       nfnl_err_reset(&err_list);
 153 +                       kfree_skb(skb);
 154 +                       module_put(ss->owner);
 155 +                       status |= NFNL_BATCH_FAILURE;
 156 +                       goto replay_abort;
 157 +               }
 158         }
 159         if (ss->cleanup)
 160                 ss->cleanup(net);
 161 --
 162 2.27.0
 163