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authorFlorian Westphal <fw@strlen.de>2018-04-10 09:30:27 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2018-04-16 17:47:26 +0200
commit569ccae68b38654f04b6842b034aa33857f605fe (patch)
tree4223504432e7e88caa9f8b4275c06259794720a6 /net
parenta6615743704fdc179e227f84b7903edd1f0b4241 (diff)
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netfilter: nf_tables: can't fail after linking rule into active rule list
rules in nftables a free'd using kfree, but protected by rcu, i.e. we must wait for a grace period to elapse. Normal removal patch does this, but nf_tables_newrule() doesn't obey this rule during error handling. It calls nft_trans_rule_add() *after* linking rule, and, if that fails to allocate memory, it unlinks the rule and then kfree() it -- this is unsafe. Switch order -- first add rule to transaction list, THEN link it to public list. Note: nft_trans_rule_add() uses GFP_KERNEL; it will not fail so this is not a problem in practice (spotted only during code review). Fixes: 0628b123c96d12 ("netfilter: nfnetlink: add batch support and use it from nf_tables") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_tables_api.c59
1 files changed, 32 insertions, 27 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 9134cc429ad4..b1984f8f7253 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2361,41 +2361,46 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
}
if (nlh->nlmsg_flags & NLM_F_REPLACE) {
- if (nft_is_active_next(net, old_rule)) {
- trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE,
- old_rule);
- if (trans == NULL) {
- err = -ENOMEM;
- goto err2;
- }
- nft_deactivate_next(net, old_rule);
- chain->use--;
- list_add_tail_rcu(&rule->list, &old_rule->list);
- } else {
+ if (!nft_is_active_next(net, old_rule)) {
err = -ENOENT;
goto err2;
}
- } else if (nlh->nlmsg_flags & NLM_F_APPEND)
- if (old_rule)
- list_add_rcu(&rule->list, &old_rule->list);
- else
- list_add_tail_rcu(&rule->list, &chain->rules);
- else {
- if (old_rule)
- list_add_tail_rcu(&rule->list, &old_rule->list);
- else
- list_add_rcu(&rule->list, &chain->rules);
- }
+ trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE,
+ old_rule);
+ if (trans == NULL) {
+ err = -ENOMEM;
+ goto err2;
+ }
+ nft_deactivate_next(net, old_rule);
+ chain->use--;
- if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
- err = -ENOMEM;
- goto err3;
+ if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
+ err = -ENOMEM;
+ goto err2;
+ }
+
+ list_add_tail_rcu(&rule->list, &old_rule->list);
+ } else {
+ if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
+ err = -ENOMEM;
+ goto err2;
+ }
+
+ if (nlh->nlmsg_flags & NLM_F_APPEND) {
+ if (old_rule)
+ list_add_rcu(&rule->list, &old_rule->list);
+ else
+ list_add_tail_rcu(&rule->list, &chain->rules);
+ } else {
+ if (old_rule)
+ list_add_tail_rcu(&rule->list, &old_rule->list);
+ else
+ list_add_rcu(&rule->list, &chain->rules);
+ }
}
chain->use++;
return 0;
-err3:
- list_del_rcu(&rule->list);
err2:
nf_tables_rule_destroy(&ctx, rule);
err1: