diff mbox series

[06/16] netfilter: nf_tables: don't use position attribute on rule replacement

Message ID 20181128101741.20924-7-pablo@netfilter.org
State Accepted
Delegated to: Pablo Neira
Headers show
Series [01/16] netfilter: nf_conncount: use spin_lock_bh instead of spin_lock | expand

Commit Message

Pablo Neira Ayuso Nov. 28, 2018, 10:17 a.m. UTC 
From: Florian Westphal <fw@strlen.de>

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: 5e94846686d0 ("netfilter: nf_tables: add insert operation")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index dd577e7d100c..e496030fdc3b 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2589,17 +2589,14 @@  static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 
 		if (chain->use == UINT_MAX)
 			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]));
-		old_rule = __nft_rule_lookup(chain, pos_handle);
-		if (IS_ERR(old_rule)) {
-			NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_POSITION]);
-			return PTR_ERR(old_rule);
+		if (nla[NFTA_RULE_POSITION]) {
+			pos_handle = be64_to_cpu(nla_get_be64(nla[NFTA_RULE_POSITION]));
+			old_rule = __nft_rule_lookup(chain, pos_handle);
+			if (IS_ERR(old_rule)) {
+				NL_SET_BAD_ATTR(extack, nla[NFTA_RULE_POSITION]);
+				return PTR_ERR(old_rule);
+			}
 		}
 	}