Hi Pablo,
On Thu, Jan 12, 2017 at 7:21 PM, Pablo Neira Ayuso <[email protected]> wrote:
> On Wed, Jan 11, 2017 at 09:32:15AM +0800, [email protected] wrote:
>> From: Gao Feng <[email protected]>
>>
>> The return value of nf_tables_table_lookup is valid pointer or one
>> pointer error. There are two cases totally.
>> case1: IS_ERR(table) is true, it would return the error or reset the
>> table as NULL, it is unnecessary to perform the latter check
>> "table != NULL".
>> case2: IS_ERR(obj) is false, the table is one valid pointer. It is also
>> unnecessary to perform that check.
>> The nf_tables_newset and nf_tables_newobj have same logic codes.
>>
>> In summary, we could move the block of condition check "table != NULL"
>> in the else block to eliminate the original condition checks.
>>
>> Signed-off-by: Gao Feng <[email protected]>
>> ---
>> net/netfilter/nf_tables_api.c | 12 +++---------
>> 1 file changed, 3 insertions(+), 9 deletions(-)
>>
>> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
>> index a019a87..3d7267f 100644
>> --- a/net/netfilter/nf_tables_api.c
>> +++ b/net/netfilter/nf_tables_api.c
>> @@ -697,9 +697,7 @@ static int nf_tables_newtable(struct net *net, struct
>> sock *nlsk,
>> if (PTR_ERR(table) != -ENOENT)
>> return PTR_ERR(table);
>> table = NULL;
>
> We follow up with table = NULL down the code, I think this breaks.
Look at the following nf_tables_table_lookup codes, it won't return NULL.
It returns one valid table pointer or one error.
static struct nft_table *nf_tables_table_lookup(const struct nft_af_info *afi,
const struct nlattr *nla,
u8 genmask)
{
struct nft_table *table;
if (nla == NULL)
return ERR_PTR(-EINVAL);
table = nft_table_lookup(afi, nla, genmask);
if (table != NULL)
return table;
return ERR_PTR(-ENOENT);
}
When returns one error, IS_ERR(table) is true, it then returns error
or reset table as NULL.
Wehn returns a valid table pointer, IS_ERR(table) is false, we could
perform the latter codes like "if (nlh->nlmsg_flags & NLM_F_EXCL)"
directly.
Regards
Feng
>
>> - }
>> -
>> - if (table != NULL) {
>> + } else {
>> if (nlh->nlmsg_flags & NLM_F_EXCL)
>> return -EEXIST;
>> if (nlh->nlmsg_flags & NLM_F_REPLACE)
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