From 2638fd0f92d4397884fd991d8f4925cb3f081901 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 3 Apr 2017 10:55:11 -0700 Subject: netfilter: xt_TCPMSS: add more sanity tests on tcph->doff Denys provided an awesome KASAN report pointing to an use after free in xt_TCPMSS I have provided three patches to fix this issue, either in xt_TCPMSS or in xt_tcpudp.c. It seems xt_TCPMSS patch has the smallest possible impact. Signed-off-by: Eric Dumazet Reported-by: Denys Fedoryshchenko Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_TCPMSS.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index 27241a767f17..c64aca611ac5 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -104,7 +104,7 @@ tcpmss_mangle_packet(struct sk_buff *skb, tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); tcp_hdrlen = tcph->doff * 4; - if (len < tcp_hdrlen) + if (len < tcp_hdrlen || tcp_hdrlen < sizeof(struct tcphdr)) return -1; if (info->mss == XT_TCPMSS_CLAMP_PMTU) { @@ -152,6 +152,10 @@ tcpmss_mangle_packet(struct sk_buff *skb, if (len > tcp_hdrlen) return 0; + /* tcph->doff has 4 bits, do not wrap it to 0 */ + if (tcp_hdrlen >= 15 * 4) + return 0; + /* * MSS Option not found ?! add it.. */ -- cgit v1.2.3-58-ga151 From 97aae0df1de4d7dd80905fb067e28b032a132995 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sat, 1 Apr 2017 20:31:32 +0800 Subject: netfilter: ctnetlink: using bit to represent the ct event Otherwise, creating a new conntrack via nfnetlink: # conntrack -I -p udp -s 1.1.1.1 -d 2.2.2.2 -t 10 --sport 10 --dport 20 will emit the wrong ct events(where UPDATE should be NEW): # conntrack -E [UPDATE] udp 17 10 src=1.1.1.1 dst=2.2.2.2 sport=10 dport=20 [UNREPLIED] src=2.2.2.2 dst=1.1.1.1 sport=20 dport=10 mark=0 Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 908d858034e4..59ee27deb9a0 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1929,9 +1929,9 @@ static int ctnetlink_new_conntrack(struct net *net, struct sock *ctnl, err = 0; if (test_bit(IPS_EXPECTED_BIT, &ct->status)) - events = IPCT_RELATED; + events = 1 << IPCT_RELATED; else - events = IPCT_NEW; + events = 1 << IPCT_NEW; if (cda[CTA_LABELS] && ctnetlink_attach_labels(ct, cda) == 0) -- cgit v1.2.3-58-ga151 From 8b5995d0633b04f9a0d321a7cc77e386440730cf Mon Sep 17 00:00:00 2001 From: Gao Feng Date: Wed, 29 Mar 2017 19:11:27 +0800 Subject: netfilter: helper: Add the rcu lock when call __nf_conntrack_helper_find When invoke __nf_conntrack_helper_find, it needs the rcu lock to protect the helper module which would not be unloaded. Now there are two caller nf_conntrack_helper_try_module_get and ctnetlink_create_expect which don't hold rcu lock. And the other callers left like ctnetlink_change_helper, ctnetlink_create_conntrack, and ctnetlink_glue_attach_expect, they already hold the rcu lock or spin_lock_bh. Remove the rcu lock in functions nf_ct_helper_expectfn_find_by_name and nf_ct_helper_expectfn_find_by_symbol. Because they return one pointer which needs rcu lock, so their caller should hold the rcu lock, not in these two functions. Signed-off-by: Gao Feng Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_helper.c | 17 ++++++++++++----- net/netfilter/nf_conntrack_netlink.c | 10 ++++++++-- 2 files changed, 20 insertions(+), 7 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index 6dc44d9b4190..4eeb3418366a 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -158,16 +158,25 @@ nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum) { struct nf_conntrack_helper *h; + rcu_read_lock(); + h = __nf_conntrack_helper_find(name, l3num, protonum); #ifdef CONFIG_MODULES if (h == NULL) { - if (request_module("nfct-helper-%s", name) == 0) + rcu_read_unlock(); + if (request_module("nfct-helper-%s", name) == 0) { + rcu_read_lock(); h = __nf_conntrack_helper_find(name, l3num, protonum); + } else { + return h; + } } #endif if (h != NULL && !try_module_get(h->me)) h = NULL; + rcu_read_unlock(); + return h; } EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get); @@ -311,38 +320,36 @@ void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n) } EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister); +/* Caller should hold the rcu lock */ struct nf_ct_helper_expectfn * nf_ct_helper_expectfn_find_by_name(const char *name) { struct nf_ct_helper_expectfn *cur; bool found = false; - rcu_read_lock(); list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { if (!strcmp(cur->name, name)) { found = true; break; } } - rcu_read_unlock(); return found ? cur : NULL; } EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name); +/* Caller should hold the rcu lock */ struct nf_ct_helper_expectfn * nf_ct_helper_expectfn_find_by_symbol(const void *symbol) { struct nf_ct_helper_expectfn *cur; bool found = false; - rcu_read_lock(); list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { if (cur->expectfn == symbol) { found = true; break; } } - rcu_read_unlock(); return found ? cur : NULL; } EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 59ee27deb9a0..06d28ac663df 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3133,23 +3133,27 @@ ctnetlink_create_expect(struct net *net, return -ENOENT; ct = nf_ct_tuplehash_to_ctrack(h); + rcu_read_lock(); if (cda[CTA_EXPECT_HELP_NAME]) { const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]); helper = __nf_conntrack_helper_find(helpname, u3, nf_ct_protonum(ct)); if (helper == NULL) { + rcu_read_unlock(); #ifdef CONFIG_MODULES if (request_module("nfct-helper-%s", helpname) < 0) { err = -EOPNOTSUPP; goto err_ct; } + rcu_read_lock(); helper = __nf_conntrack_helper_find(helpname, u3, nf_ct_protonum(ct)); if (helper) { err = -EAGAIN; - goto err_ct; + goto err_rcu; } + rcu_read_unlock(); #endif err = -EOPNOTSUPP; goto err_ct; @@ -3159,11 +3163,13 @@ ctnetlink_create_expect(struct net *net, exp = ctnetlink_alloc_expect(cda, ct, helper, &tuple, &mask); if (IS_ERR(exp)) { err = PTR_ERR(exp); - goto err_ct; + goto err_rcu; } err = nf_ct_expect_related_report(exp, portid, report); nf_ct_expect_put(exp); +err_rcu: + rcu_read_unlock(); err_ct: nf_ct_put(ct); return err; -- cgit v1.2.3-58-ga151 From 3173d5b8c89e67fa3176292ff9af06f09f365348 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sat, 1 Apr 2017 20:55:44 +0800 Subject: netfilter: ctnetlink: make it safer when checking the ct helper name One CPU is doing ctnetlink_change_helper(), while another CPU is doing unhelp() at the same time. So even if help->helper is not NULL at first, the later statement strcmp(help->helper->name, ...) may still access the NULL pointer. So we must use rcu_read_lock and rcu_dereference to avoid such _bad_ thing happen. Fixes: f95d7a46bc57 ("netfilter: ctnetlink: Fix regression in CTA_HELP processing") Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 06d28ac663df..f9c643bc1a8e 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1488,11 +1488,16 @@ static int ctnetlink_change_helper(struct nf_conn *ct, * treat the second attempt as a no-op instead of returning * an error. */ - if (help && help->helper && - !strcmp(help->helper->name, helpname)) - return 0; - else - return -EBUSY; + err = -EBUSY; + if (help) { + rcu_read_lock(); + helper = rcu_dereference(help->helper); + if (helper && !strcmp(helper->name, helpname)) + err = 0; + rcu_read_unlock(); + } + + return err; } if (!strcmp(helpname, "")) { -- cgit v1.2.3-58-ga151 From 0c7930e5763bdd189bd50035c025a9cbe5e82f23 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 2 Apr 2017 17:27:53 +0800 Subject: netfilter: make it safer during the inet6_dev->addr_list traversal inet6_dev->addr_list is protected by inet6_dev->lock, so only using rcu_read_lock is not enough, we should acquire read_lock_bh(&idev->lock) before the inet6_dev->addr_list traversal. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_redirect.c | 2 ++ net/netfilter/xt_TPROXY.c | 5 ++++- 2 files changed, 6 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/netfilter/nf_nat_redirect.c b/net/netfilter/nf_nat_redirect.c index d43869879fcf..86067560a318 100644 --- a/net/netfilter/nf_nat_redirect.c +++ b/net/netfilter/nf_nat_redirect.c @@ -101,11 +101,13 @@ nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range *range, rcu_read_lock(); idev = __in6_dev_get(skb->dev); if (idev != NULL) { + read_lock_bh(&idev->lock); list_for_each_entry(ifa, &idev->addr_list, if_list) { newdst = ifa->addr; addr = true; break; } + read_unlock_bh(&idev->lock); } rcu_read_unlock(); diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c index 80cb7babeb64..df7f1df00330 100644 --- a/net/netfilter/xt_TPROXY.c +++ b/net/netfilter/xt_TPROXY.c @@ -393,7 +393,8 @@ tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr, rcu_read_lock(); indev = __in6_dev_get(skb->dev); - if (indev) + if (indev) { + read_lock_bh(&indev->lock); list_for_each_entry(ifa, &indev->addr_list, if_list) { if (ifa->flags & (IFA_F_TENTATIVE | IFA_F_DEPRECATED)) continue; @@ -401,6 +402,8 @@ tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr, laddr = &ifa->addr; break; } + read_unlock_bh(&indev->lock); + } rcu_read_unlock(); return laddr ? laddr : daddr; -- cgit v1.2.3-58-ga151 From 207df81501021f6d1a935cebf8e1f34d6d25564b Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 2 Apr 2017 18:01:33 +0800 Subject: netfilter: ctnetlink: skip dumping expect when nfct_help(ct) is NULL For IPCTNL_MSG_EXP_GET, if the CTA_EXPECT_MASTER attr is specified, then the NLM_F_DUMP request will dump the expectations related to this connection tracking. But we forget to check whether the conntrack has nf_conn_help or not, so if nfct_help(ct) is NULL, oops will happen: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: ctnetlink_exp_ct_dump_table+0xf9/0x1e0 [nf_conntrack_netlink] Call Trace: ? ctnetlink_exp_ct_dump_table+0x75/0x1e0 [nf_conntrack_netlink] netlink_dump+0x124/0x2a0 __netlink_dump_start+0x161/0x190 ctnetlink_dump_exp_ct+0x16c/0x1bc [nf_conntrack_netlink] ? ctnetlink_exp_fill_info.constprop.33+0xf0/0xf0 [nf_conntrack_netlink] ? ctnetlink_glue_seqadj+0x20/0x20 [nf_conntrack_netlink] ctnetlink_get_expect+0x32e/0x370 [nf_conntrack_netlink] ? debug_lockdep_rcu_enabled+0x1d/0x20 nfnetlink_rcv_msg+0x60a/0x6a9 [nfnetlink] ? nfnetlink_rcv_msg+0x1b9/0x6a9 [nfnetlink] [...] Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index f9c643bc1a8e..f78eadba343d 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -2794,6 +2794,12 @@ static int ctnetlink_dump_exp_ct(struct net *net, struct sock *ctnl, return -ENOENT; ct = nf_ct_tuplehash_to_ctrack(h); + /* No expectation linked to this connection tracking. */ + if (!nfct_help(ct)) { + nf_ct_put(ct); + return 0; + } + c.data = ct; err = netlink_dump_start(ctnl, skb, nlh, &c); -- cgit v1.2.3-58-ga151 From 7cddd967bfc2e4fc6b3218c2ddc67fbeed433ad3 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 2 Apr 2017 18:25:37 +0800 Subject: netfilter: nf_ct_expect: use proper RCU list traversal/update APIs We should use proper RCU list APIs to manipulate help->expectations, as we can dump the conntrack's expectations via nfnetlink, i.e. in ctnetlink_exp_ct_dump_table(), where only rcu_read_lock is acquired. So for list traversal, use hlist_for_each_entry_rcu; for list add/del, use hlist_add_head_rcu and hlist_del_rcu. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_expect.c | 4 ++-- net/netfilter/nf_conntrack_netlink.c | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'net') diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index 4b2e1fb28bb4..d80073037856 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -57,7 +57,7 @@ void nf_ct_unlink_expect_report(struct nf_conntrack_expect *exp, hlist_del_rcu(&exp->hnode); net->ct.expect_count--; - hlist_del(&exp->lnode); + hlist_del_rcu(&exp->lnode); master_help->expecting[exp->class]--; nf_ct_expect_event_report(IPEXP_DESTROY, exp, portid, report); @@ -363,7 +363,7 @@ static void nf_ct_expect_insert(struct nf_conntrack_expect *exp) /* two references : one for hash insert, one for the timer */ atomic_add(2, &exp->use); - hlist_add_head(&exp->lnode, &master_help->expectations); + hlist_add_head_rcu(&exp->lnode, &master_help->expectations); master_help->expecting[exp->class]++; hlist_add_head_rcu(&exp->hnode, &nf_ct_expect_hash[h]); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index f78eadba343d..dc7dfd68fafe 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -2680,8 +2680,8 @@ ctnetlink_exp_dump_table(struct sk_buff *skb, struct netlink_callback *cb) last = (struct nf_conntrack_expect *)cb->args[1]; for (; cb->args[0] < nf_ct_expect_hsize; cb->args[0]++) { restart: - hlist_for_each_entry(exp, &nf_ct_expect_hash[cb->args[0]], - hnode) { + hlist_for_each_entry_rcu(exp, &nf_ct_expect_hash[cb->args[0]], + hnode) { if (l3proto && exp->tuple.src.l3num != l3proto) continue; @@ -2732,7 +2732,7 @@ ctnetlink_exp_ct_dump_table(struct sk_buff *skb, struct netlink_callback *cb) rcu_read_lock(); last = (struct nf_conntrack_expect *)cb->args[1]; restart: - hlist_for_each_entry(exp, &help->expectations, lnode) { + hlist_for_each_entry_rcu(exp, &help->expectations, lnode) { if (l3proto && exp->tuple.src.l3num != l3proto) continue; if (cb->args[1]) { -- cgit v1.2.3-58-ga151 From 79e09ef96b6a5fb888f5241f3aa707e9ad0b1cce Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 3 Apr 2017 16:34:38 +0800 Subject: netfilter: nft_hash: do not dump the auto generated seed This can prevent the nft utility from printing out the auto generated seed to the user, which is unnecessary and confusing. Fixes: cb1b69b0b15b ("netfilter: nf_tables: add hash expression") Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_hash.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index eb2721af898d..c4dad1254ead 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -21,6 +21,7 @@ struct nft_hash { enum nft_registers sreg:8; enum nft_registers dreg:8; u8 len; + bool autogen_seed:1; u32 modulus; u32 seed; u32 offset; @@ -82,10 +83,12 @@ static int nft_hash_init(const struct nft_ctx *ctx, if (priv->offset + priv->modulus - 1 < priv->offset) return -EOVERFLOW; - if (tb[NFTA_HASH_SEED]) + if (tb[NFTA_HASH_SEED]) { priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED])); - else + } else { + priv->autogen_seed = true; get_random_bytes(&priv->seed, sizeof(priv->seed)); + } return nft_validate_register_load(priv->sreg, len) && nft_validate_register_store(ctx, priv->dreg, NULL, @@ -105,7 +108,8 @@ static int nft_hash_dump(struct sk_buff *skb, goto nla_put_failure; if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus))) goto nla_put_failure; - if (nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed))) + if (!priv->autogen_seed && + nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed))) goto nla_put_failure; if (priv->offset != 0) if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset))) -- cgit v1.2.3-58-ga151 From fe50543c194e2e1aee2f3eba41fcafd187b3dbde Mon Sep 17 00:00:00 2001 From: Gao Feng Date: Thu, 6 Apr 2017 09:45:22 +0800 Subject: netfilter: ipt_CLUSTERIP: Fix wrong conntrack netns refcnt usage Current codes invoke wrongly nf_ct_netns_get in the destroy routine, it should use nf_ct_netns_put, not nf_ct_netns_get. It could cause some modules could not be unloaded. Fixes: ecb2421b5ddf ("netfilter: add and use nf_ct_netns_get/put") Signed-off-by: Gao Feng Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_CLUSTERIP.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 52f26459efc3..9b8841316e7b 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -461,7 +461,7 @@ static void clusterip_tg_destroy(const struct xt_tgdtor_param *par) clusterip_config_put(cipinfo->config); - nf_ct_netns_get(par->net, par->family); + nf_ct_netns_put(par->net, par->family); } #ifdef CONFIG_COMPAT -- cgit v1.2.3-58-ga151