Commit 447750f2 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso

netfilter: nf_tables: don't use position attribute on rule replacement

Its possible to set both HANDLE and POSITION when replacing a rule.
In this case, the rule at POSITION gets replaced using the
userspace-provided handle.  Rule handles are supposed to be generated
by the kernel only.

Duplicate handles should be harmless, however better disable this "feature"
by only checking for the POSITION attribute on insert operations.

Fixes: 5e948466 ("netfilter: nf_tables: add insert operation")
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 25d8bced
...@@ -2589,17 +2589,14 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk, ...@@ -2589,17 +2589,14 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
if (chain->use == UINT_MAX) if (chain->use == UINT_MAX)
return -EOVERFLOW; return -EOVERFLOW;
}
if (nla[NFTA_RULE_POSITION]) {
if (!(nlh->nlmsg_flags & NLM_F_CREATE))
return -EOPNOTSUPP;
pos_handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_POSITION])); if (nla[NFTA_RULE_POSITION]) {
old_rule = __nft_rule_lookup(chain, pos_handle); pos_handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_POSITION]));
if (IS_ERR(old_rule)) { old_rule = __nft_rule_lookup(chain, pos_handle);
NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_POSITION]); if (IS_ERR(old_rule)) {
return PTR_ERR(old_rule); NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_POSITION]);
return PTR_ERR(old_rule);
}
} }
} }
......
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