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Sat, 7 Dec 2019 22:51:52 +0000 (UTC) Received: from elisabeth (ovpn-200-27.brq.redhat.com [10.40.200.27]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2ED08A4B8F; Sat, 7 Dec 2019 22:51:50 +0000 (UTC) Date: Sat, 7 Dec 2019 23:51:38 +0100 From: Stefano Brivio To: Pablo Neira Ayuso Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH,nf-next RFC 1/2] netfilter: nf_tables: add nft_setelem_parse_key() Message-ID: <20191207235138.393d306c@elisabeth> In-Reply-To: <20191206194517.gg6e34uekje647sn@salvia> References: <20191202131407.500999-1-pablo@netfilter.org> <20191202131407.500999-2-pablo@netfilter.org> <20191205234350.3dd81c1c@elisabeth> <20191206194517.gg6e34uekje647sn@salvia> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: wImlMClvMamKE_k1nz6djg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Fri, 6 Dec 2019 20:45:17 +0100 Pablo Neira Ayuso wrote: > On Thu, Dec 05, 2019 at 11:43:50PM +0100, Stefano Brivio wrote: > > Hi Pablo, > > > > Just two nits: > > > > On Mon, 2 Dec 2019 14:14:06 +0100 > > Pablo Neira Ayuso wrote: > > > > > Add helper function to parse the set element key netlink attribute. > > > > > > Signed-off-by: Pablo Neira Ayuso > > > --- > > > net/netfilter/nf_tables_api.c | 56 ++++++++++++++++++++++++------------------- > > > 1 file changed, 32 insertions(+), 24 deletions(-) > > > > > > diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c > > > index 0db2784fee9a..13e291fac26f 100644 > > > --- a/net/netfilter/nf_tables_api.c > > > +++ b/net/netfilter/nf_tables_api.c > > > @@ -4490,11 +4490,31 @@ 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, sizeof(*key), &desc, attr); > > > + if (err < 0) > > > + goto err1; > > > + > > > + err = -EINVAL; > > > + if (desc.type != NFT_DATA_VALUE || desc.len != set->klen) > > > + goto err2; > > > + > > > + return 0; > > > +err2: > > > + nft_data_release(key, desc.type); > > > +err1: > > > + return err; > > > +} > > > + > > > 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; > > > @@ -4513,15 +4533,11 @@ 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) > > > - return err; > > > - > > > priv = set->ops->get(ctx->net, set, &elem, flags); > > > if (IS_ERR(priv)) > > > return PTR_ERR(priv); > > > @@ -4720,13 +4736,13 @@ 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 d2; > > > > At this point, this could simply be desc, or data_desc. > > > > > struct nft_data data; > > > enum nft_registers dreg; > > > struct nft_trans *trans; > > > @@ -4792,15 +4808,12 @@ 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) > > > @@ -4942,7 +4955,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, > > > if (nla[NFTA_SET_ELEM_DATA] != NULL) > > > nft_data_release(&data, d2.type); > > > err2: > > > - nft_data_release(&elem.key.val, d1.type); > > > + nft_data_release(&elem.key.val, NFT_DATA_VALUE); > > > err1: > > > return err; > > > } > > > @@ -5038,7 +5051,6 @@ 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; > > > @@ -5063,16 +5075,12 @@ 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; > > > - > > > - 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, > > > @@ -5109,7 +5117,7 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set, > > > err3: > > > kfree(elem.priv); > > > err2: > > > - nft_data_release(&elem.key.val, desc.type); > > > + nft_data_release(&elem.key.val, NFT_DATA_VALUE); > > > > I'm not sure if this can actually happen, but in > > nft_setelem_parse_key() you are checking that the type is > > NFT_DATA_VALUE, and returning error if it's not. > > Exactly. > > > If the type is not NFT_DATA_VALUE, I guess we shouldn't pass > > NFT_DATA_VALUE to nft_data_release() here. > > The new nft_setelem_parse_key() function makes sure that the key is > NFT_DATA_VALUE, otherwise bails out and calls nft_data_release() with > desc.type. > > Then, moving forward in nft_add_set_elem() after the > nft_setelem_parse_key(), if an error occurs, nft_data_release() can be > called with NFT_DATA_VALUE, because that was already validated by > nft_setelem_parse_key(). > > > Maybe nft_setelem_parse_key() could clean up after itself on error. > > It's doing so already, right? See err2: label. Right you are, my bad, I mixed up err2: and err1: in nft_set_delelem() and then forgot about err2: in nft_setelem_parse_key(). Well, on the other hand, 'return err;" and 'goto fail_elem;" would have been easier to follow, but maybe it's just my taste. :) -- Stefano