El 04/03/15 a las 20:20, Pablo Neira Ayuso escribió:
On Wed, Mar 04, 2015 at 08:03:18PM +0100, Pablo Neira Ayuso wrote:
On Tue, Mar 03, 2015 at 02:45:34PM +0100, Álvaro Neira Ayuso wrote:
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.
OK, so this bug can be triggered by malformed input.
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.
I think we have to make robust checks on the input, if what we get is
not "sane" then it's not worth going further.
So I'd suggest you modify this lines a bit below:
if (tree->value.opaque == NULL) {
err->error = NFT_PARSE_EBADINPUT;
goto err;
}
to look like:
if (tree == NULL || tree->value.opaque == NULL) {
err->error = NFT_PARSE_EBADINPUT;
goto err;
}
---
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;
Actually your patch looks correct because you're returning "missing
node" which is triggering the crash, right?
Yes, the first node of the tree is missing and we have a crash.
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