netfilter: nft_set_pipapo: walk over current view on netlink dump

commit 29b359cf6d95fd60730533f7f10464e95bd17c73 upstream.

The generation mask can be updated while netlink dump is in progress.
The pipapo set backend walk iterator cannot rely on it to infer what
view of the datastructure is to be used. Add notation to specify if user
wants to read/update the set.

Based on patch from Florian Westphal.

Fixes: 2b84e215f874 ("netfilter: nft_set_pipapo: .walk does not deal with generations")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 8af2543520b999a92698fef7b4e6f06910a81a5f..1b95c34a4e3d11d41b43a3b8c29bd4934846cbed 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -297,9 +297,22 @@ struct nft_set_elem {
        void                    *priv;
 };
 
+/**
+ * enum nft_iter_type - nftables set iterator type
+ *
+ * @NFT_ITER_READ: read-only iteration over set elements
+ * @NFT_ITER_UPDATE: iteration under mutex to update set element state
+ */
+enum nft_iter_type {
+       NFT_ITER_UNSPEC,
+       NFT_ITER_READ,
+       NFT_ITER_UPDATE,
+};
+
 struct nft_set;
 struct nft_set_iter {
        u8              genmask;
+       enum nft_iter_type type:8;
        unsigned int    count;
        unsigned int    skip;
        int             err;

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index fc99a5e91829dd4809fe69baf7e76fd9dfce4959..da5684e3fd08c82fd828f6e2af8658b635488caa 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -628,6 +628,7 @@ static void nft_map_deactivate(const struct nft_ctx *ctx, struct nft_set *set)
 {
        struct nft_set_iter iter = {
                .genmask        = nft_genmask_next(ctx->net),
+               .type           = NFT_ITER_UPDATE,
                .fn             = nft_mapelem_deactivate,
        };
 
@@ -5392,6 +5393,7 @@ int nf_tables_bind_set(const struct nft_ctx *ctx, struct nft_set *set,
                }
 
                iter.genmask    = nft_genmask_next(ctx->net);
+               iter.type       = NFT_ITER_UPDATE;
                iter.skip       = 0;
                iter.count      = 0;
                iter.err        = 0;
@@ -5467,6 +5469,7 @@ static void nft_map_activate(const struct nft_ctx *ctx, struct nft_set *set)
 {
        struct nft_set_iter iter = {
                .genmask        = nft_genmask_next(ctx->net),
+               .type           = NFT_ITER_UPDATE,
                .fn             = nft_mapelem_activate,
        };
 
@@ -5845,6 +5848,7 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
        args.skb                = skb;
        args.reset              = reset;
        args.iter.genmask       = nft_genmask_cur(net);
+       args.iter.type          = NFT_ITER_READ;
        args.iter.skip          = cb->args[0];
        args.iter.count         = 0;
        args.iter.err           = 0;
@@ -7246,6 +7250,7 @@ static int nft_set_flush(struct nft_ctx *ctx, struct nft_set *set, u8 genmask)
 {
        struct nft_set_iter iter = {
                .genmask        = genmask,
+               .type           = NFT_ITER_UPDATE,
                .fn             = nft_setelem_flush,
        };
 

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index e4dd7309304840cbc12e36bc7cf4c1268f993a57..90f129f1a136a42589d5aefafc3511ffa899bce2 100644 (file)
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -2037,13 +2037,14 @@ static void nft_pipapo_walk(const struct nft_ctx *ctx, struct nft_set *set,
                            struct nft_set_iter *iter)
 {
        struct nft_pipapo *priv = nft_set_priv(set);
-       struct net *net = read_pnet(&set->net);
        const struct nft_pipapo_match *m;
        const struct nft_pipapo_field *f;
        int i, r;
 
+       WARN_ON_ONCE(iter->type == NFT_ITER_UNSPEC);
+
        rcu_read_lock();
-       if (iter->genmask == nft_genmask_cur(net))
+       if (iter->type == NFT_ITER_READ)
                m = rcu_dereference(priv->match);
        else
                m = priv->clone;