netfilter: nf_tables: memleak in hw offload abort path
Release flow from the abort path, this is easy to reproduce sinceb72920f6e4("netfilter: nftables: counter hardware offload support"). If the preparation phase fails, then the abort path is exercised without releasing the flow rule object. unreferenced object 0xffff8881f0fa7700 (size 128): comm "nft", pid 1335, jiffies 4294931120 (age 4163.740s) hex dump (first 32 bytes): 08 e4 de 13 82 88 ff ff 98 e4 de 13 82 88 ff ff ................ 48 e4 de 13 82 88 ff ff 01 00 00 00 00 00 00 00 H............... backtrace: [<00000000634547e7>] flow_rule_alloc+0x26/0x80 [<00000000c8426156>] nft_flow_rule_create+0xc9/0x3f0 [nf_tables] [<0000000075ff8e46>] nf_tables_newrule+0xc79/0x10a0 [nf_tables] [<00000000ba65e40e>] nfnetlink_rcv_batch+0xaac/0xf90 [nfnetlink] [<00000000505c614a>] nfnetlink_rcv+0x1bb/0x1f0 [nfnetlink] [<00000000eb78e1fe>] netlink_unicast+0x34b/0x480 [<00000000a8f72c94>] netlink_sendmsg+0x3af/0x690 [<000000009cb1ddf4>] sock_sendmsg+0x96/0xa0 [<0000000039d06e44>] ____sys_sendmsg+0x3fe/0x440 [<00000000137e82ca>] ___sys_sendmsg+0xd8/0x140 [<000000000c6bf6a6>] __sys_sendmsg+0xb3/0x130 [<0000000043bd6268>] do_syscall_64+0x40/0xb0 [<00000000afdebc2d>] entry_SYSCALL_64_after_hwframe+0x44/0xae Remove flow rule release from the offload commit path, otherwise error from the offload commit phase might trigger a double-free due to the execution of the abort_offload -> abort. After this patch, the abort path takes care of releasing the flow rule. This fix also needs to move the nft_flow_rule_create() call before the transaction object is added otherwise the abort path might find a NULL pointer to the flow rule object for the NFT_CHAIN_HW_OFFLOAD case. While at it, rename BASIC-like goto tags to slightly more meaningful names rather than adding a new "err3" tag. Fixes:63b48c73ff("netfilter: nf_tables_offload: undo updates if transaction fails") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso
parent
52f0f4e178
commit
3c5e446220
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@ -3243,9 +3243,9 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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u8 genmask = nft_genmask_next(info->net);
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struct nft_rule *rule, *old_rule = NULL;
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struct nft_expr_info *expr_info = NULL;
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struct nft_flow_rule *flow = NULL;
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int family = nfmsg->nfgen_family;
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struct net *net = info->net;
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struct nft_flow_rule *flow;
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struct nft_userdata *udata;
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struct nft_table *table;
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struct nft_chain *chain;
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@ -3340,13 +3340,13 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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nla_for_each_nested(tmp, nla[NFTA_RULE_EXPRESSIONS], rem) {
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err = -EINVAL;
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if (nla_type(tmp) != NFTA_LIST_ELEM)
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goto err1;
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goto err_release_expr;
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if (n == NFT_RULE_MAXEXPRS)
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goto err1;
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goto err_release_expr;
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err = nf_tables_expr_parse(&ctx, tmp, &expr_info[n]);
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if (err < 0) {
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NL_SET_BAD_ATTR(extack, tmp);
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goto err1;
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goto err_release_expr;
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}
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size += expr_info[n].ops->size;
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n++;
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@ -3355,7 +3355,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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/* Check for overflow of dlen field */
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err = -EFBIG;
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if (size >= 1 << 12)
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goto err1;
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goto err_release_expr;
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if (nla[NFTA_RULE_USERDATA]) {
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ulen = nla_len(nla[NFTA_RULE_USERDATA]);
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@ -3366,7 +3366,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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err = -ENOMEM;
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rule = kzalloc(sizeof(*rule) + size + usize, GFP_KERNEL);
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if (rule == NULL)
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goto err1;
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goto err_release_expr;
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nft_activate_next(net, rule);
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@ -3385,7 +3385,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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err = nf_tables_newexpr(&ctx, &expr_info[i], expr);
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if (err < 0) {
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NL_SET_BAD_ATTR(extack, expr_info[i].attr);
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goto err2;
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goto err_release_rule;
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}
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if (expr_info[i].ops->validate)
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@ -3395,16 +3395,24 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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expr = nft_expr_next(expr);
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}
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if (chain->flags & NFT_CHAIN_HW_OFFLOAD) {
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flow = nft_flow_rule_create(net, rule);
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if (IS_ERR(flow)) {
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err = PTR_ERR(flow);
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goto err_release_rule;
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}
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}
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if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
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trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
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if (trans == NULL) {
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err = -ENOMEM;
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goto err2;
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goto err_destroy_flow_rule;
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}
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err = nft_delrule(&ctx, old_rule);
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if (err < 0) {
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nft_trans_destroy(trans);
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goto err2;
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goto err_destroy_flow_rule;
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}
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list_add_tail_rcu(&rule->list, &old_rule->list);
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@ -3412,7 +3420,7 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule);
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if (!trans) {
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err = -ENOMEM;
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goto err2;
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goto err_destroy_flow_rule;
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}
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if (info->nlh->nlmsg_flags & NLM_F_APPEND) {
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@ -3430,21 +3438,19 @@ static int nf_tables_newrule(struct sk_buff *skb, const struct nfnl_info *info,
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kvfree(expr_info);
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chain->use++;
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if (flow)
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nft_trans_flow_rule(trans) = flow;
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if (nft_net->validate_state == NFT_VALIDATE_DO)
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return nft_table_validate(net, table);
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if (chain->flags & NFT_CHAIN_HW_OFFLOAD) {
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flow = nft_flow_rule_create(net, rule);
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if (IS_ERR(flow))
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return PTR_ERR(flow);
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nft_trans_flow_rule(trans) = flow;
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}
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return 0;
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err2:
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err_destroy_flow_rule:
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nft_flow_rule_destroy(flow);
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err_release_rule:
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nf_tables_rule_release(&ctx, rule);
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err1:
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err_release_expr:
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for (i = 0; i < n; i++) {
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if (expr_info[i].ops) {
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module_put(expr_info[i].ops->type->owner);
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@ -8839,11 +8845,16 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
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nft_rule_expr_deactivate(&trans->ctx,
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nft_trans_rule(trans),
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NFT_TRANS_ABORT);
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if (trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD)
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nft_flow_rule_destroy(nft_trans_flow_rule(trans));
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break;
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case NFT_MSG_DELRULE:
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trans->ctx.chain->use++;
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nft_clear(trans->ctx.net, nft_trans_rule(trans));
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nft_rule_expr_activate(&trans->ctx, nft_trans_rule(trans));
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if (trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD)
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nft_flow_rule_destroy(nft_trans_flow_rule(trans));
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nft_trans_destroy(trans);
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break;
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case NFT_MSG_NEWSET:
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@ -594,23 +594,6 @@ int nft_flow_rule_offload_commit(struct net *net)
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}
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}
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list_for_each_entry(trans, &nft_net->commit_list, list) {
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if (trans->ctx.family != NFPROTO_NETDEV)
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continue;
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switch (trans->msg_type) {
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case NFT_MSG_NEWRULE:
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case NFT_MSG_DELRULE:
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if (!(trans->ctx.chain->flags & NFT_CHAIN_HW_OFFLOAD))
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continue;
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nft_flow_rule_destroy(nft_trans_flow_rule(trans));
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break;
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default:
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break;
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}
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}
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return err;
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}
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