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SubjectRe: [PATCH] ipv4: fib_rules: Fix possible infinite loop in fib_empty_table
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On 2018/12/29 13:15, David Miller wrote:
> From: YueHaibing <yuehaibing@huawei.com>
> Date: Wed, 26 Dec 2018 16:34:20 +0800
>
>> diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
>> index f8eb78d..1567e12 100644
>> --- a/net/ipv4/fib_rules.c
>> +++ b/net/ipv4/fib_rules.c
>> @@ -200,9 +200,13 @@ static struct fib_table *fib_empty_table(struct net *net)
>> {
>> u32 id;
>>
>> - for (id = 1; id <= RT_TABLE_MAX; id++)
>> + for (id = 1; id <= RT_TABLE_MAX; id++) {
>> if (!fib_get_table(net, id))
>> return fib_new_table(net, id);
>> +
>> + if (id == RT_TABLE_MAX)
>> + break;
>> + }
>> return NULL;
>> }
>
> The loop now has two exit conditions, one of which (by your analysis
> is completely impossible).
>

Thanks, will do it in v2.

> Please clean this up into a loop with better structure and no
> impossible tests. One approach could be simply:
>
> id = 1;
> while (1) {
> ...
> if (id++ == RT_TABLE_MAX)
> break;
> }
>
> Or even:
>
> id = 0;
> while (++id) {
> ...
> }
>
> .
>

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