From 129a99890936766f4b69b9da7ed88366313a9210 Mon Sep 17 00:00:00 2001 From: Piotr Sawicki Date: Thu, 19 Jul 2018 11:42:58 +0200 Subject: [PATCH 1/3] Smack: Fix handling of IPv4 traffic received by PF_INET6 sockets A socket which has sk_family set to PF_INET6 is able to receive not only IPv6 but also IPv4 traffic (IPv4-mapped IPv6 addresses). Prior to this patch, the smk_skb_to_addr_ipv6() could have been called for socket buffers containing IPv4 packets, in result such traffic was allowed. Signed-off-by: Piotr Sawicki Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 7ad226018f51..c4feb954d53f 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3923,15 +3923,19 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) struct smack_known *skp = NULL; int rc = 0; struct smk_audit_info ad; + u16 family = sk->sk_family; #ifdef CONFIG_AUDIT struct lsm_network_audit net; #endif #if IS_ENABLED(CONFIG_IPV6) struct sockaddr_in6 sadd; int proto; + + if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP)) + family = PF_INET; #endif /* CONFIG_IPV6 */ - switch (sk->sk_family) { + switch (family) { case PF_INET: #ifdef CONFIG_SECURITY_SMACK_NETFILTER /* @@ -3949,7 +3953,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) */ netlbl_secattr_init(&secattr); - rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr); + rc = netlbl_skbuff_getattr(skb, family, &secattr); if (rc == 0) skp = smack_from_secattr(&secattr, ssp); else @@ -3962,7 +3966,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) #endif #ifdef CONFIG_AUDIT smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); - ad.a.u.net->family = sk->sk_family; + ad.a.u.net->family = family; ad.a.u.net->netif = skb->skb_iif; ipv4_skb_to_auditdata(skb, &ad.a, NULL); #endif @@ -3976,7 +3980,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in, MAY_WRITE, rc); if (rc != 0) - netlbl_skbuff_err(skb, sk->sk_family, rc, 0); + netlbl_skbuff_err(skb, family, rc, 0); break; #if IS_ENABLED(CONFIG_IPV6) case PF_INET6: @@ -3992,7 +3996,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) skp = smack_net_ambient; #ifdef CONFIG_AUDIT smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); - ad.a.u.net->family = sk->sk_family; + ad.a.u.net->family = family; ad.a.u.net->netif = skb->skb_iif; ipv6_skb_to_auditdata(skb, &ad.a, NULL); #endif /* CONFIG_AUDIT */ From a07ef9516477aef2d052d75129a48f9f94d3b3f3 Mon Sep 17 00:00:00 2001 From: Piotr Sawicki Date: Thu, 19 Jul 2018 11:45:16 +0200 Subject: [PATCH 2/3] Smack: Check UDP-Lite and DCCP protocols during IPv6 handling The smack_socket_sock_rcv_skb() function is checking smack labels only for UDP and TCP frames carried in IPv6 packets. From now on, it is able also to handle UDP-Lite and DCCP protocols. Signed-off-by: Piotr Sawicki Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index c4feb954d53f..aff8397e8c7e 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3895,6 +3895,7 @@ static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip) sip->sin6_port = th->source; break; case IPPROTO_UDP: + case IPPROTO_UDPLITE: uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); if (uh != NULL) sip->sin6_port = uh->source; @@ -3985,7 +3986,8 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) #if IS_ENABLED(CONFIG_IPV6) case PF_INET6: proto = smk_skb_to_addr_ipv6(skb, &sadd); - if (proto != IPPROTO_UDP && proto != IPPROTO_TCP) + if (proto != IPPROTO_UDP && proto != IPPROTO_UDPLITE && + proto != IPPROTO_TCP && proto != IPPROTO_DCCP) break; #ifdef SMACK_IPV6_SECMARK_LABELING if (skb && skb->secmark != 0) From d66a8acbda926fa2398ae930f50787e8663bce96 Mon Sep 17 00:00:00 2001 From: Piotr Sawicki Date: Thu, 19 Jul 2018 11:47:31 +0200 Subject: [PATCH 3/3] Smack: Inform peer that IPv6 traffic has been blocked In this patch we're sending an ICMPv6 message to a peer to immediately inform it that making a connection is not possible. In case of TCP connections, without this change, the peer will be waiting until a connection timeout is exceeded. Signed-off-by: Piotr Sawicki Signed-off-by: Casey Schaufler --- security/smack/smack_lsm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index aff8397e8c7e..91750205a5de 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -4009,6 +4010,9 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) #ifdef SMACK_IPV6_PORT_LABELING rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING); #endif /* SMACK_IPV6_PORT_LABELING */ + if (rc != 0) + icmpv6_send(skb, ICMPV6_DEST_UNREACH, + ICMPV6_ADM_PROHIBITED, 0); break; #endif /* CONFIG_IPV6 */ }