Re: [libnftnl PATCH] mxml: test if the root node name is initialized before to compare it.

["Álvaro Neira Ayuso" <alvaroneay@gmail.com>]

El 03/03/15 a las 00:35, Pablo Neira Ayuso escribió:
> On Mon, Mar 02, 2015 at 08:58:38PM +0100, Alvaro Neira Ayuso wrote:
>> If the root node name is not correctly initialized, we have a crash.
>
> Under what circunstances may tree->value.opaque be NULL?

The function mxmlLoadFile doesn't work correctly. With my patch to 
import ruleset in json and xml. I have seen that if we use a ruleset in 
json and use the command nft import xml. The function mxmlLoadFile 
returns a tree without any information inside. Therefore, when we try to 
verify that the name of the first node is the same of the parameter, we 
have a crash.

We have two ways to solve it. Test if the node is NULL and:
  1- show an error that the node is not found.
  2- show an error that the input is not correctly.

I have thought that the best is the first. But I can change it.

>
>> ---
>>   src/mxml.c |    3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/mxml.c b/src/mxml.c
>> index 0001ba0..b68f86f 100644
>> --- a/src/mxml.c
>> +++ b/src/mxml.c
>> @@ -43,7 +43,8 @@ mxml_node_t *nft_mxml_build_tree(const void *data, const char *treename,
>>   		goto err;
>>   	}
>>
>> -	if (strcmp(tree->value.opaque, treename) == 0)
>> +	if (tree->value.opaque != NULL &&
>> +	    strcmp(tree->value.opaque, treename) == 0)
>>   		return tree;
>>
>>   	err->error = NFT_PARSE_EMISSINGNODE;
>> --
>> 1.7.10.4
>>
>> --
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