netfilter: nf_tables: add nft_setelem_parse_key()

Add helper function to parse the set element key netlink attribute.

v4: No changes
v3: New patch

[sbrivio: refactor error paths and labels; use NFT_DATA_VALUE_MAXLEN
  instead of sizeof(*key) in helper, value can be longer than that;
  rebase]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7e63b481cc86be8d95e92eae750c091036238f87..58e3b285a3d1e49e9d9a58f991422c22482be174 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4524,11 +4524,28 @@ static int nft_setelem_parse_flags(const struct nft_set *set,
        return 0;
 }
 
+static int nft_setelem_parse_key(struct nft_ctx *ctx, struct nft_set *set,
+                                struct nft_data *key, struct nlattr *attr)
+{
+       struct nft_data_desc desc;
+       int err;
+
+       err = nft_data_init(ctx, key, NFT_DATA_VALUE_MAXLEN, &desc, attr);
+       if (err < 0)
+               return err;
+
+       if (desc.type != NFT_DATA_VALUE || desc.len != set->klen) {
+               nft_data_release(key, desc.type);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
 static int nft_get_set_elem(struct nft_ctx *ctx, struct nft_set *set,
                            const struct nlattr *attr)
 {
        struct nlattr *nla[NFTA_SET_ELEM_MAX + 1];
-       struct nft_data_desc desc;
        struct nft_set_elem elem;
        struct sk_buff *skb;
        uint32_t flags = 0;
@@ -4547,17 +4564,11 @@ static int nft_get_set_elem(struct nft_ctx *ctx, struct nft_set *set,
        if (err < 0)
                return err;
 
-       err = nft_data_init(ctx, &elem.key.val, sizeof(elem.key), &desc,
-                           nla[NFTA_SET_ELEM_KEY]);
+       err = nft_setelem_parse_key(ctx, set, &elem.key.val,
+                                   nla[NFTA_SET_ELEM_KEY]);
        if (err < 0)
                return err;
 
-       err = -EINVAL;
-       if (desc.type != NFT_DATA_VALUE || desc.len != set->klen) {
-               nft_data_release(&elem.key.val, desc.type);
-               return err;
-       }
-
        priv = set->ops->get(ctx->net, set, &elem, flags);
        if (IS_ERR(priv))
                return PTR_ERR(priv);
@@ -4756,13 +4767,13 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 {
        struct nlattr *nla[NFTA_SET_ELEM_MAX + 1];
        u8 genmask = nft_genmask_next(ctx->net);
-       struct nft_data_desc d1, d2;
        struct nft_set_ext_tmpl tmpl;
        struct nft_set_ext *ext, *ext2;
        struct nft_set_elem elem;
        struct nft_set_binding *binding;
        struct nft_object *obj = NULL;
        struct nft_userdata *udata;
+       struct nft_data_desc desc;
        struct nft_data data;
        enum nft_registers dreg;
        struct nft_trans *trans;
@@ -4828,15 +4839,12 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
                        return err;
        }
 
-       err = nft_data_init(ctx, &elem.key.val, sizeof(elem.key), &d1,
-                           nla[NFTA_SET_ELEM_KEY]);
+       err = nft_setelem_parse_key(ctx, set, &elem.key.val,
+                                   nla[NFTA_SET_ELEM_KEY]);
        if (err < 0)
                goto err1;
-       err = -EINVAL;
-       if (d1.type != NFT_DATA_VALUE || d1.len != set->klen)
-               goto err2;
 
-       nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, d1.len);
+       nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, set->klen);
        if (timeout > 0) {
                nft_set_ext_add(&tmpl, NFT_SET_EXT_EXPIRATION);
                if (timeout != set->timeout)
@@ -4859,13 +4867,13 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
        }
 
        if (nla[NFTA_SET_ELEM_DATA] != NULL) {
-               err = nft_data_init(ctx, &data, sizeof(data), &d2,
+               err = nft_data_init(ctx, &data, sizeof(data), &desc,
                                    nla[NFTA_SET_ELEM_DATA]);
                if (err < 0)
                        goto err2;
 
                err = -EINVAL;
-               if (set->dtype != NFT_DATA_VERDICT && d2.len != set->dlen)
+               if (set->dtype != NFT_DATA_VERDICT && desc.len != set->dlen)
                        goto err3;
 
                dreg = nft_type_to_reg(set->dtype);
@@ -4882,18 +4890,18 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 
                        err = nft_validate_register_store(&bind_ctx, dreg,
                                                          &data,
-                                                         d2.type, d2.len);
+                                                         desc.type, desc.len);
                        if (err < 0)
                                goto err3;
 
-                       if (d2.type == NFT_DATA_VERDICT &&
+                       if (desc.type == NFT_DATA_VERDICT &&
                            (data.verdict.code == NFT_GOTO ||
                             data.verdict.code == NFT_JUMP))
                                nft_validate_state_update(ctx->net,
                                                          NFT_VALIDATE_NEED);
                }
 
-               nft_set_ext_add_length(&tmpl, NFT_SET_EXT_DATA, d2.len);
+               nft_set_ext_add_length(&tmpl, NFT_SET_EXT_DATA, desc.len);
        }
 
        /* The full maximum length of userdata can exceed the maximum
@@ -4976,9 +4984,9 @@ err4:
        kfree(elem.priv);
 err3:
        if (nla[NFTA_SET_ELEM_DATA] != NULL)
-               nft_data_release(&data, d2.type);
+               nft_data_release(&data, desc.type);
 err2:
-       nft_data_release(&elem.key.val, d1.type);
+       nft_data_release(&elem.key.val, NFT_DATA_VALUE);
 err1:
        return err;
 }
@@ -5074,7 +5082,6 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
 {
        struct nlattr *nla[NFTA_SET_ELEM_MAX + 1];
        struct nft_set_ext_tmpl tmpl;
-       struct nft_data_desc desc;
        struct nft_set_elem elem;
        struct nft_set_ext *ext;
        struct nft_trans *trans;
@@ -5085,11 +5092,10 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
        err = nla_parse_nested_deprecated(nla, NFTA_SET_ELEM_MAX, attr,
                                          nft_set_elem_policy, NULL);
        if (err < 0)
-               goto err1;
+               return err;
 
-       err = -EINVAL;
        if (nla[NFTA_SET_ELEM_KEY] == NULL)
-               goto err1;
+               return -EINVAL;
 
        nft_set_ext_prepare(&tmpl);
 
@@ -5099,37 +5105,31 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
        if (flags != 0)
                nft_set_ext_add(&tmpl, NFT_SET_EXT_FLAGS);
 
-       err = nft_data_init(ctx, &elem.key.val, sizeof(elem.key), &desc,
-                           nla[NFTA_SET_ELEM_KEY]);
+       err = nft_setelem_parse_key(ctx, set, &elem.key.val,
+                                   nla[NFTA_SET_ELEM_KEY]);
        if (err < 0)
-               goto err1;
-
-       err = -EINVAL;
-       if (desc.type != NFT_DATA_VALUE || desc.len != set->klen)
-               goto err2;
+               return err;
 
-       nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, desc.len);
+       nft_set_ext_add_length(&tmpl, NFT_SET_EXT_KEY, set->klen);
 
        err = -ENOMEM;
        elem.priv = nft_set_elem_init(set, &tmpl, elem.key.val.data, NULL, 0,
                                      0, GFP_KERNEL);
        if (elem.priv == NULL)
-               goto err2;
+               goto fail_elem;
 
        ext = nft_set_elem_ext(set, elem.priv);
        if (flags)
                *nft_set_ext_flags(ext) = flags;
 
        trans = nft_trans_elem_alloc(ctx, NFT_MSG_DELSETELEM, set);
-       if (trans == NULL) {
-               err = -ENOMEM;
-               goto err3;
-       }
+       if (trans == NULL)
+               goto fail_trans;
 
        priv = set->ops->deactivate(ctx->net, set, &elem);
        if (priv == NULL) {
                err = -ENOENT;
-               goto err4;
+               goto fail_ops;
        }
        kfree(elem.priv);
        elem.priv = priv;
@@ -5140,13 +5140,12 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
        list_add_tail(&trans->list, &ctx->net->nft.commit_list);
        return 0;
 
-err4:
+fail_ops:
        kfree(trans);
-err3:
+fail_trans:
        kfree(elem.priv);
-err2:
-       nft_data_release(&elem.key.val, desc.type);
-err1:
+fail_elem:
+       nft_data_release(&elem.key.val, NFT_DATA_VALUE);
        return err;
 }