From 89e1f6d2b956649fbe0704d543a90b8e0cf872b0 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 01:02:18 +0800 Subject: [PATCH 1/7] netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT After I add the nft rule "nft add rule filter prerouting reject with tcp reset", kernel panic happened on my system: NULL pointer dereference at ... IP: [] nf_send_reset+0xaf/0x400 Call Trace: [] ? nf_reject_ip_tcphdr_get+0x160/0x160 [] nft_reject_ipv4_eval+0x61/0xb0 [nft_reject_ipv4] [] nft_do_chain+0x1fa/0x890 [nf_tables] [] ? __nft_trace_packet+0x170/0x170 [nf_tables] [] ? nf_ct_invert_tuple+0xb0/0xc0 [nf_conntrack] [] ? nf_nat_setup_info+0x5d4/0x650 [nf_nat] [...] Because in the PREROUTING chain, routing information is not exist, then we will dereference the NULL pointer and oops happen. So we restrict reject expression to INPUT, FORWARD and OUTPUT chain. This is consistent with iptables REJECT target. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nft_reject.h | 4 ++++ net/ipv4/netfilter/nft_reject_ipv4.c | 1 + net/ipv6/netfilter/nft_reject_ipv6.c | 1 + net/netfilter/nft_reject.c | 16 ++++++++++++++++ net/netfilter/nft_reject_inet.c | 7 ++++++- 5 files changed, 28 insertions(+), 1 deletion(-) diff --git a/include/net/netfilter/nft_reject.h b/include/net/netfilter/nft_reject.h index 60fa1530006b..02e28c529b29 100644 --- a/include/net/netfilter/nft_reject.h +++ b/include/net/netfilter/nft_reject.h @@ -8,6 +8,10 @@ struct nft_reject { extern const struct nla_policy nft_reject_policy[]; +int nft_reject_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data); + int nft_reject_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]); diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c index c24f41c816b3..2c2553b9026c 100644 --- a/net/ipv4/netfilter/nft_reject_ipv4.c +++ b/net/ipv4/netfilter/nft_reject_ipv4.c @@ -46,6 +46,7 @@ static const struct nft_expr_ops nft_reject_ipv4_ops = { .eval = nft_reject_ipv4_eval, .init = nft_reject_init, .dump = nft_reject_dump, + .validate = nft_reject_validate, }; static struct nft_expr_type nft_reject_ipv4_type __read_mostly = { diff --git a/net/ipv6/netfilter/nft_reject_ipv6.c b/net/ipv6/netfilter/nft_reject_ipv6.c index 533cd5719c59..92bda9908bb9 100644 --- a/net/ipv6/netfilter/nft_reject_ipv6.c +++ b/net/ipv6/netfilter/nft_reject_ipv6.c @@ -47,6 +47,7 @@ static const struct nft_expr_ops nft_reject_ipv6_ops = { .eval = nft_reject_ipv6_eval, .init = nft_reject_init, .dump = nft_reject_dump, + .validate = nft_reject_validate, }; static struct nft_expr_type nft_reject_ipv6_type __read_mostly = { diff --git a/net/netfilter/nft_reject.c b/net/netfilter/nft_reject.c index 0522fc9bfb0a..c64de3f7379d 100644 --- a/net/netfilter/nft_reject.c +++ b/net/netfilter/nft_reject.c @@ -26,11 +26,27 @@ const struct nla_policy nft_reject_policy[NFTA_REJECT_MAX + 1] = { }; EXPORT_SYMBOL_GPL(nft_reject_policy); +int nft_reject_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) +{ + return nft_chain_validate_hooks(ctx->chain, + (1 << NF_INET_LOCAL_IN) | + (1 << NF_INET_FORWARD) | + (1 << NF_INET_LOCAL_OUT)); +} +EXPORT_SYMBOL_GPL(nft_reject_validate); + int nft_reject_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]) { struct nft_reject *priv = nft_expr_priv(expr); + int err; + + err = nft_reject_validate(ctx, expr, NULL); + if (err < 0) + return err; if (tb[NFTA_REJECT_TYPE] == NULL) return -EINVAL; diff --git a/net/netfilter/nft_reject_inet.c b/net/netfilter/nft_reject_inet.c index 759ca5248a3d..e79d9ca2ffee 100644 --- a/net/netfilter/nft_reject_inet.c +++ b/net/netfilter/nft_reject_inet.c @@ -66,7 +66,11 @@ static int nft_reject_inet_init(const struct nft_ctx *ctx, const struct nlattr * const tb[]) { struct nft_reject *priv = nft_expr_priv(expr); - int icmp_code; + int icmp_code, err; + + err = nft_reject_validate(ctx, expr, NULL); + if (err < 0) + return err; if (tb[NFTA_REJECT_TYPE] == NULL) return -EINVAL; @@ -124,6 +128,7 @@ static const struct nft_expr_ops nft_reject_inet_ops = { .eval = nft_reject_inet_eval, .init = nft_reject_inet_init, .dump = nft_reject_inet_dump, + .validate = nft_reject_validate, }; static struct nft_expr_type nft_reject_inet_type __read_mostly = { From 93fac10b99d78eb2c50a739cba2e590c7332d539 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 21:58:16 +0800 Subject: [PATCH 2/7] netfilter: nfnetlink: use list_for_each_entry_safe to delete all objects cttimeout and acct objects are deleted from the list while traversing it, so use list_for_each_entry is unsafe here. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_acct.c | 6 +++--- net/netfilter/nfnetlink_cttimeout.c | 5 +++-- 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c index 70eb2f6a3b01..d44d89b56127 100644 --- a/net/netfilter/nfnetlink_acct.c +++ b/net/netfilter/nfnetlink_acct.c @@ -343,12 +343,12 @@ static int nfnl_acct_del(struct net *net, struct sock *nfnl, struct sk_buff *skb, const struct nlmsghdr *nlh, const struct nlattr * const tb[]) { - char *acct_name; - struct nf_acct *cur; + struct nf_acct *cur, *tmp; int ret = -ENOENT; + char *acct_name; if (!tb[NFACCT_NAME]) { - list_for_each_entry(cur, &net->nfnl_acct_list, head) + list_for_each_entry_safe(cur, tmp, &net->nfnl_acct_list, head) nfnl_acct_try_del(cur); return 0; diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 68216cdc7083..f74fee1e2d0a 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -350,12 +350,13 @@ static int cttimeout_del_timeout(struct net *net, struct sock *ctnl, const struct nlmsghdr *nlh, const struct nlattr * const cda[]) { - struct ctnl_timeout *cur; + struct ctnl_timeout *cur, *tmp; int ret = -ENOENT; char *name; if (!cda[CTA_TIMEOUT_NAME]) { - list_for_each_entry(cur, &net->nfct_timeout_list, head) + list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list, + head) ctnl_timeout_try_del(net, cur); return 0; From 23aaba5ad55547db62bada5066c8fb6412d5b1c2 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 21:58:17 +0800 Subject: [PATCH 3/7] netfilter: cttimeout: put back l4proto when replacing timeout policy We forget to call nf_ct_l4proto_put when replacing the existing timeout policy. Acctually, there's no need to get ct l4proto before doing replace, so we can move it to a later position. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_cttimeout.c | 31 +++++++++++++---------------- 1 file changed, 14 insertions(+), 17 deletions(-) diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index f74fee1e2d0a..6844c7af0b8f 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -98,31 +98,28 @@ static int cttimeout_new_timeout(struct net *net, struct sock *ctnl, break; } - l4proto = nf_ct_l4proto_find_get(l3num, l4num); - - /* This protocol is not supportted, skip. */ - if (l4proto->l4proto != l4num) { - ret = -EOPNOTSUPP; - goto err_proto_put; - } - if (matching) { if (nlh->nlmsg_flags & NLM_F_REPLACE) { /* You cannot replace one timeout policy by another of * different kind, sorry. */ if (matching->l3num != l3num || - matching->l4proto->l4proto != l4num) { - ret = -EINVAL; - goto err_proto_put; - } + matching->l4proto->l4proto != l4num) + return -EINVAL; - ret = ctnl_timeout_parse_policy(&matching->data, - l4proto, net, - cda[CTA_TIMEOUT_DATA]); - return ret; + return ctnl_timeout_parse_policy(&matching->data, + matching->l4proto, net, + cda[CTA_TIMEOUT_DATA]); } - ret = -EBUSY; + + return -EBUSY; + } + + l4proto = nf_ct_l4proto_find_get(l3num, l4num); + + /* This protocol is not supportted, skip. */ + if (l4proto->l4proto != l4num) { + ret = -EOPNOTSUPP; goto err_proto_put; } From 533e33009897c7dd1b0424c0d4b3331b222d5681 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 21:58:18 +0800 Subject: [PATCH 4/7] netfilter: cttimeout: unlink timeout objs in the unconfirmed ct lists KASAN reported this bug: BUG: KASAN: use-after-free in icmp_packet+0x25/0x50 [nf_conntrack_ipv4] at addr ffff880002db08c8 Read of size 4 by task lt-nf-queue/19041 Call Trace: [] dump_stack+0x63/0x88 [] kasan_report_error+0x528/0x560 [] kasan_report+0x58/0x60 [] ? icmp_packet+0x25/0x50 [nf_conntrack_ipv4] [] __asan_load4+0x61/0x80 [] icmp_packet+0x25/0x50 [nf_conntrack_ipv4] [] nf_conntrack_in+0x550/0x980 [nf_conntrack] [] ? __nf_conntrack_confirm+0xb10/0xb10 [nf_conntrack] [ ... ] The main reason is that we missed to unlink the timeout objects in the unconfirmed ct lists, so we will access the timeout objects that have already been freed. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_cttimeout.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c index 6844c7af0b8f..139e0867e56e 100644 --- a/net/netfilter/nfnetlink_cttimeout.c +++ b/net/netfilter/nfnetlink_cttimeout.c @@ -302,7 +302,16 @@ static void ctnl_untimeout(struct net *net, struct ctnl_timeout *timeout) const struct hlist_nulls_node *nn; unsigned int last_hsize; spinlock_t *lock; - int i; + int i, cpu; + + for_each_possible_cpu(cpu) { + struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); + + spin_lock_bh(&pcpu->lock); + hlist_nulls_for_each_entry(h, nn, &pcpu->unconfirmed, hnnode) + untimeout(h, timeout); + spin_unlock_bh(&pcpu->lock); + } local_bh_disable(); restart: From 960fa72f67f1be6891d63a5518860d1ae4e14b88 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Mon, 22 Aug 2016 22:57:56 +0800 Subject: [PATCH 5/7] netfilter: nft_meta: improve the validity check of pkttype set expr "meta pkttype set" is only supported on prerouting chain with bridge family and ingress chain with netdev family. But the validate check is incomplete, and the user can add the nft rules on input chain with bridge family, for example: # nft add table bridge filter # nft add chain bridge filter input {type filter hook input \ priority 0 \;} # nft add chain bridge filter test # nft add rule bridge filter test meta pkttype set unicast # nft add rule bridge filter input jump test This patch fixes the problem. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nft_meta.h | 4 ++++ net/bridge/netfilter/nft_meta_bridge.c | 1 + net/netfilter/nft_meta.c | 17 +++++++++++++---- 3 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/net/netfilter/nft_meta.h b/include/net/netfilter/nft_meta.h index d27588c8dbd9..1139cde0fdc5 100644 --- a/include/net/netfilter/nft_meta.h +++ b/include/net/netfilter/nft_meta.h @@ -36,4 +36,8 @@ void nft_meta_set_eval(const struct nft_expr *expr, void nft_meta_set_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr); +int nft_meta_set_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data); + #endif diff --git a/net/bridge/netfilter/nft_meta_bridge.c b/net/bridge/netfilter/nft_meta_bridge.c index 4b901d9f2e7c..ad47a921b701 100644 --- a/net/bridge/netfilter/nft_meta_bridge.c +++ b/net/bridge/netfilter/nft_meta_bridge.c @@ -86,6 +86,7 @@ static const struct nft_expr_ops nft_meta_bridge_set_ops = { .init = nft_meta_set_init, .destroy = nft_meta_set_destroy, .dump = nft_meta_set_dump, + .validate = nft_meta_set_validate, }; static const struct nft_expr_ops * diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c index 2863f3493038..8a6bc7630912 100644 --- a/net/netfilter/nft_meta.c +++ b/net/netfilter/nft_meta.c @@ -291,10 +291,16 @@ int nft_meta_get_init(const struct nft_ctx *ctx, } EXPORT_SYMBOL_GPL(nft_meta_get_init); -static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx) +int nft_meta_set_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) { + struct nft_meta *priv = nft_expr_priv(expr); unsigned int hooks; + if (priv->key != NFT_META_PKTTYPE) + return 0; + switch (ctx->afi->family) { case NFPROTO_BRIDGE: hooks = 1 << NF_BR_PRE_ROUTING; @@ -308,6 +314,7 @@ static int nft_meta_set_init_pkttype(const struct nft_ctx *ctx) return nft_chain_validate_hooks(ctx->chain, hooks); } +EXPORT_SYMBOL_GPL(nft_meta_set_validate); int nft_meta_set_init(const struct nft_ctx *ctx, const struct nft_expr *expr, @@ -327,15 +334,16 @@ int nft_meta_set_init(const struct nft_ctx *ctx, len = sizeof(u8); break; case NFT_META_PKTTYPE: - err = nft_meta_set_init_pkttype(ctx); - if (err) - return err; len = sizeof(u8); break; default: return -EOPNOTSUPP; } + err = nft_meta_set_validate(ctx, expr, NULL); + if (err < 0) + return err; + priv->sreg = nft_parse_register(tb[NFTA_META_SREG]); err = nft_validate_register_load(priv->sreg, len); if (err < 0) @@ -407,6 +415,7 @@ static const struct nft_expr_ops nft_meta_set_ops = { .init = nft_meta_set_init, .destroy = nft_meta_set_destroy, .dump = nft_meta_set_dump, + .validate = nft_meta_set_validate, }; static const struct nft_expr_ops * From 4249fc1f023a2106170bbf715e2e1a0ebc2d5b1f Mon Sep 17 00:00:00 2001 From: Sabrina Dubroca Date: Tue, 23 Aug 2016 10:20:31 +0200 Subject: [PATCH 6/7] netfilter: ebtables: put module reference when an incorrect extension is found commit bcf493428840 ("netfilter: ebtables: Fix extension lookup with identical name") added a second lookup in case the extension that was found during the first lookup matched another extension with the same name, but didn't release the reference on the incorrect module. Fixes: bcf493428840 ("netfilter: ebtables: Fix extension lookup with identical name") Signed-off-by: Sabrina Dubroca Acked-by: Phil Sutter Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index cceac5bb658f..0833c251aef7 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -368,6 +368,8 @@ ebt_check_match(struct ebt_entry_match *m, struct xt_mtchk_param *par, match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); if (IS_ERR(match) || match->family != NFPROTO_BRIDGE) { + if (!IS_ERR(match)) + module_put(match->me); request_module("ebt_%s", m->u.name); match = xt_find_match(NFPROTO_BRIDGE, m->u.name, 0); } From c73c2484901139c28383b58eabcbf4d613e91518 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 28 Aug 2016 16:59:52 +0800 Subject: [PATCH 7/7] netfilter: nf_tables_netdev: remove redundant ip_hdr assignment We have already use skb_header_pointer to get the ip header pointer, so there's no need to use ip_hdr again. Moreover, in NETDEV INGRESS hook, ip header maybe not linear, so use ip_hdr is not appropriate, remove it. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_netdev.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c index 5eefe4a355c6..75d696f11045 100644 --- a/net/netfilter/nf_tables_netdev.c +++ b/net/netfilter/nf_tables_netdev.c @@ -30,7 +30,6 @@ nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt, if (!iph) return; - iph = ip_hdr(skb); if (iph->ihl < 5 || iph->version != 4) return;