From f55ce7b024090a51382ccab2730b96e2f7b4e9cf Mon Sep 17 00:00:00 2001 From: Mateusz Jurczyk Date: Wed, 7 Jun 2017 15:50:38 +0200 Subject: [PATCH 1/5] netfilter: nfnetlink: Improve input length sanitization in nfnetlink_rcv Verify that the length of the socket buffer is sufficient to cover the nlmsghdr structure before accessing the nlh->nlmsg_len field for further input sanitization. If the client only supplies 1-3 bytes of data in sk_buff, then nlh->nlmsg_len remains partially uninitialized and contains leftover memory from the corresponding kernel allocation. Operating on such data may result in indeterminate evaluation of the nlmsg_len < NLMSG_HDRLEN expression. The bug was discovered by a runtime instrumentation designed to detect use of uninitialized memory in the kernel. The patch prevents this and other similar tools (e.g. KMSAN) from flagging this behavior in the future. Signed-off-by: Mateusz Jurczyk Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 92b05e188fd1..733d3e4a30d8 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -472,8 +472,7 @@ static void nfnetlink_rcv_skb_batch(struct sk_buff *skb, struct nlmsghdr *nlh) if (msglen > skb->len) msglen = skb->len; - if (nlh->nlmsg_len < NLMSG_HDRLEN || - skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) + if (skb->len < NLMSG_HDRLEN + sizeof(struct nfgenmsg)) return; err = nla_parse(cda, NFNL_BATCH_MAX, attr, attrlen, nfnl_batch_policy, @@ -500,7 +499,8 @@ static void nfnetlink_rcv(struct sk_buff *skb) { struct nlmsghdr *nlh = nlmsg_hdr(skb); - if (nlh->nlmsg_len < NLMSG_HDRLEN || + if (skb->len < NLMSG_HDRLEN || + nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) return; From cf56c2f892a8a1870a8358114ad896772da7543a Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 6 Jul 2017 23:17:44 +0200 Subject: [PATCH 2/5] netfilter: remove old pre-netns era hook api no more users in the tree, remove this. The old api is racy wrt. module removal, all users have been converted to the netns-aware api. The old api pretended we still have global hooks but that has not been true for a long time. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter.h | 9 --- net/netfilter/core.c | 143 -------------------------------------- 2 files changed, 152 deletions(-) diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index a4b97be30b28..22f081065d49 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -61,8 +61,6 @@ typedef unsigned int nf_hookfn(void *priv, struct sk_buff *skb, const struct nf_hook_state *state); struct nf_hook_ops { - struct list_head list; - /* User fills in from here down. */ nf_hookfn *hook; struct net_device *dev; @@ -160,13 +158,6 @@ int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, unsigned int n); -int nf_register_hook(struct nf_hook_ops *reg); -void nf_unregister_hook(struct nf_hook_ops *reg); -int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); -void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); -int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); -void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); - /* Functions to register get/setsockopt ranges (non-inclusive). You need to check permissions yourself! */ int nf_register_sockopt(struct nf_sockopt_ops *reg); diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 552d606e57ca..368610dbc3c0 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -227,114 +227,6 @@ void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, } EXPORT_SYMBOL(nf_unregister_net_hooks); -static LIST_HEAD(nf_hook_list); - -static int _nf_register_hook(struct nf_hook_ops *reg) -{ - struct net *net, *last; - int ret; - - for_each_net(net) { - ret = nf_register_net_hook(net, reg); - if (ret && ret != -ENOENT) - goto rollback; - } - list_add_tail(®->list, &nf_hook_list); - - return 0; -rollback: - last = net; - for_each_net(net) { - if (net == last) - break; - nf_unregister_net_hook(net, reg); - } - return ret; -} - -int nf_register_hook(struct nf_hook_ops *reg) -{ - int ret; - - rtnl_lock(); - ret = _nf_register_hook(reg); - rtnl_unlock(); - - return ret; -} -EXPORT_SYMBOL(nf_register_hook); - -static void _nf_unregister_hook(struct nf_hook_ops *reg) -{ - struct net *net; - - list_del(®->list); - for_each_net(net) - nf_unregister_net_hook(net, reg); -} - -void nf_unregister_hook(struct nf_hook_ops *reg) -{ - rtnl_lock(); - _nf_unregister_hook(reg); - rtnl_unlock(); -} -EXPORT_SYMBOL(nf_unregister_hook); - -int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) -{ - unsigned int i; - int err = 0; - - for (i = 0; i < n; i++) { - err = nf_register_hook(®[i]); - if (err) - goto err; - } - return err; - -err: - if (i > 0) - nf_unregister_hooks(reg, i); - return err; -} -EXPORT_SYMBOL(nf_register_hooks); - -/* Caller MUST take rtnl_lock() */ -int _nf_register_hooks(struct nf_hook_ops *reg, unsigned int n) -{ - unsigned int i; - int err = 0; - - for (i = 0; i < n; i++) { - err = _nf_register_hook(®[i]); - if (err) - goto err; - } - return err; - -err: - if (i > 0) - _nf_unregister_hooks(reg, i); - return err; -} -EXPORT_SYMBOL(_nf_register_hooks); - -void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) -{ - while (n-- > 0) - nf_unregister_hook(®[n]); -} -EXPORT_SYMBOL(nf_unregister_hooks); - -/* Caller MUST take rtnl_lock */ -void _nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n) -{ - while (n-- > 0) - _nf_unregister_hook(®[n]); -} -EXPORT_SYMBOL(_nf_unregister_hooks); - /* Returns 1 if okfn() needs to be executed by the caller, * -EPERM for NF_DROP, 0 otherwise. Caller must hold rcu_read_lock. */ int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state, @@ -450,37 +342,6 @@ void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *); EXPORT_SYMBOL(nf_nat_decode_session_hook); #endif -static int nf_register_hook_list(struct net *net) -{ - struct nf_hook_ops *elem; - int ret; - - rtnl_lock(); - list_for_each_entry(elem, &nf_hook_list, list) { - ret = nf_register_net_hook(net, elem); - if (ret && ret != -ENOENT) - goto out_undo; - } - rtnl_unlock(); - return 0; - -out_undo: - list_for_each_entry_continue_reverse(elem, &nf_hook_list, list) - nf_unregister_net_hook(net, elem); - rtnl_unlock(); - return ret; -} - -static void nf_unregister_hook_list(struct net *net) -{ - struct nf_hook_ops *elem; - - rtnl_lock(); - list_for_each_entry(elem, &nf_hook_list, list) - nf_unregister_net_hook(net, elem); - rtnl_unlock(); -} - static int __net_init netfilter_net_init(struct net *net) { int i, h, ret; @@ -500,16 +361,12 @@ static int __net_init netfilter_net_init(struct net *net) return -ENOMEM; } #endif - ret = nf_register_hook_list(net); - if (ret) - remove_proc_entry("netfilter", net->proc_net); return ret; } static void __net_exit netfilter_net_exit(struct net *net) { - nf_unregister_hook_list(net); remove_proc_entry("netfilter", net->proc_net); } From 97772bcd56efa21d9d8976db6f205574ea602f51 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 7 Jul 2017 13:07:17 +0200 Subject: [PATCH 3/5] netfilter: nat: fix src map lookup When doing initial conversion to rhashtable I replaced the bucket walk with a single rhashtable_lookup_fast(). When moving to rhlist I failed to properly walk the list of identical tuples, but that is what is needed for this to work correctly. The table contains the original tuples, so the reply tuples are all distinct. We currently decide that mapping is (not) in range only based on the first entry, but in case its not we need to try the reply tuple of the next entry until we either find an in-range mapping or we checked all the entries. This bug makes nat core attempt collision resolution while it might be able to use the mapping as-is. Fixes: 870190a9ec90 ("netfilter: nat: convert nat bysrc hash to rhashtable") Reported-by: Jaco Kroon Tested-by: Jaco Kroon Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_nat_core.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 832c5a08d9a5..eb541786ccb7 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -222,20 +222,21 @@ find_appropriate_src(struct net *net, .tuple = tuple, .zone = zone }; - struct rhlist_head *hl; + struct rhlist_head *hl, *h; hl = rhltable_lookup(&nf_nat_bysource_table, &key, nf_nat_bysource_params); - if (!hl) - return 0; - ct = container_of(hl, typeof(*ct), nat_bysource); + rhl_for_each_entry_rcu(ct, h, hl, nat_bysource) { + nf_ct_invert_tuplepr(result, + &ct->tuplehash[IP_CT_DIR_REPLY].tuple); + result->dst = tuple->dst; - nf_ct_invert_tuplepr(result, - &ct->tuplehash[IP_CT_DIR_REPLY].tuple); - result->dst = tuple->dst; + if (in_range(l3proto, l4proto, result, range)) + return 1; + } - return in_range(l3proto, l4proto, result, range); + return 0; } /* For [FUTURE] fragmentation handling, we want the least-used From 974292defee033bc43ccfcb2fcefc3eba3905340 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 7 Jul 2017 13:29:03 +0200 Subject: [PATCH 4/5] netfilter: nf_tables: only allow in/output for arp packets arp packets cannot be forwarded. They can be bridged, but then they can be filtered using either ebtables or nftables bridge family. The bridge netfilter exposes a "call-arptables" switch which pushes packets into arptables, but lets not expose this for nftables, so better close this asap. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_tables_arp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv4/netfilter/nf_tables_arp.c b/net/ipv4/netfilter/nf_tables_arp.c index 805c8ddfe860..4bbc273b45e8 100644 --- a/net/ipv4/netfilter/nf_tables_arp.c +++ b/net/ipv4/netfilter/nf_tables_arp.c @@ -72,8 +72,7 @@ static const struct nf_chain_type filter_arp = { .family = NFPROTO_ARP, .owner = THIS_MODULE, .hook_mask = (1 << NF_ARP_IN) | - (1 << NF_ARP_OUT) | - (1 << NF_ARP_FORWARD), + (1 << NF_ARP_OUT), }; static int __init nf_tables_arp_init(void) From 36ac344e16e04e3e55e8fed7446095a6458c64e6 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 10 Jul 2017 13:53:53 +0200 Subject: [PATCH 5/5] netfilter: expect: fix crash when putting uninited expectation We crash in __nf_ct_expect_check, it calls nf_ct_remove_expect on the uninitialised expectation instead of existing one, so del_timer chokes on random memory address. Fixes: ec0e3f01114ad32711243 ("netfilter: nf_ct_expect: Add nf_ct_remove_expect()") Reported-by: Sergey Kvachonok Tested-by: Sergey Kvachonok Cc: Gao Feng Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_expect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index e03d16ed550d..899c2c36da13 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -422,7 +422,7 @@ static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect) h = nf_ct_expect_dst_hash(net, &expect->tuple); hlist_for_each_entry_safe(i, next, &nf_ct_expect_hash[h], hnode) { if (expect_matches(i, expect)) { - if (nf_ct_remove_expect(expect)) + if (nf_ct_remove_expect(i)) break; } else if (expect_clash(i, expect)) { ret = -EBUSY;