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 3e92331d8c9a02519ea7839e796b943d3b7a4793..e2c786af2fc68ffd36cb6eac60e19d70a17ae235 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -283,9 +283,22 @@ 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 8ded61a3f93e8e8db90c2985b9835ce377e8dd9e..df10a2047bb0ec77b23d5b88b5462b50f3623c0d 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,
        };
 
@@ -5073,6 +5074,7 @@ 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;
@@ -5148,6 +5150,7 @@ 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,
        };
 
@@ -5504,6 +5507,7 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
        args.cb                 = cb;
        args.skb                = skb;
        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;
@@ -6833,6 +6837,7 @@ 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 d9c1c467ea6848df6e1cb31e524427651497bd1f..8cce39411619ad0ea98309904fd6375a64a93df3 100644 (file)
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -2042,13 +2042,14 @@ 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;