[PATCH 05/11] netfilter: nf_tables: use nla_memdup to copy udata

[Pablo Neira Ayuso]

From: "Jose M. Guisado Gomez" <gui...@riseup.net>

When userdata support was added to tables and objects, user data coming
from user space was allocated and copied using kzalloc + nla_memcpy.

Use nla_memdup to copy userdata of tables and objects.

Signed-off-by: Jose M. Guisado Gomez <gui...@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index b3c3c3fc1969..0473316aa392 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -986,7 +986,6 @@ static int nf_tables_newtable(struct net *net, struct sock 
*nlsk,
        struct nft_table *table;
        struct nft_ctx ctx;
        u32 flags = 0;
-       u16 udlen = 0;
        int err;
 
        lockdep_assert_held(&net->nft.commit_mutex);
@@ -1023,13 +1022,11 @@ static int nf_tables_newtable(struct net *net, struct 
sock *nlsk,
                goto err_strdup;
 
        if (nla[NFTA_TABLE_USERDATA]) {
-               udlen = nla_len(nla[NFTA_TABLE_USERDATA]);
-               table->udata = kzalloc(udlen, GFP_KERNEL);
+               table->udata = nla_memdup(nla[NFTA_TABLE_USERDATA], GFP_KERNEL);
                if (table->udata == NULL)
                        goto err_table_udata;
 
-               nla_memcpy(table->udata, nla[NFTA_TABLE_USERDATA], udlen);
-               table->udlen = udlen;
+               table->udlen = nla_len(nla[NFTA_TABLE_USERDATA]);
        }
 
        err = rhltable_init(&table->chains_ht, &nft_chain_ht_params);
@@ -5900,7 +5897,6 @@ static int nf_tables_newobj(struct net *net, struct sock 
*nlsk,
        struct nft_object *obj;
        struct nft_ctx ctx;
        u32 objtype;
-       u16 udlen;
        int err;
 
        if (!nla[NFTA_OBJ_TYPE] ||
@@ -5957,13 +5953,11 @@ static int nf_tables_newobj(struct net *net, struct 
sock *nlsk,
        }
 
        if (nla[NFTA_OBJ_USERDATA]) {
-               udlen = nla_len(nla[NFTA_OBJ_USERDATA]);
-               obj->udata = kzalloc(udlen, GFP_KERNEL);
+               obj->udata = nla_memdup(nla[NFTA_OBJ_USERDATA], GFP_KERNEL);
                if (obj->udata == NULL)
                        goto err_userdata;
 
-               nla_memcpy(obj->udata, nla[NFTA_OBJ_USERDATA], udlen);
-               obj->udlen = udlen;
+               obj->udlen = nla_len(nla[NFTA_OBJ_USERDATA]);
        }
 
        err = nft_trans_obj_add(&ctx, NFT_MSG_NEWOBJ, obj);
-- 
2.20.1