From mboxrd@z Thu Jan 1 00:00:00 1970 From: casey@schaufler-ca.com (Casey Schaufler) Date: Tue, 10 Jul 2018 08:21:21 -0700 Subject: [PATCH RFC] Smack: Fix handling of IPv4 traffic received by PF_INET6 sockets In-Reply-To: <20180710070515eucas1p1dddc12cc44c820971809a242e8cee106~-8AfqiO9s0149301493eucas1p1h@eucas1p1.samsung.com> References: <20180710070515eucas1p1dddc12cc44c820971809a242e8cee106~-8AfqiO9s0149301493eucas1p1h@eucas1p1.samsung.com> Message-ID: <7e7b9c3e-1fa4-d0fa-fbba-10493af52c4d@schaufler-ca.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On 7/10/2018 12:05 AM, Piotr Sawicki wrote: > 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 Looks fine from here. Do you have a simple test case? > --- > security/smack/smack_lsm.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 19de675..1315de4 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -3924,15 +3924,19 @@ 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 > /* > @@ -3950,7 +3954,7 @@ 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 > @@ -3963,7 +3967,7 @@ 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 > @@ -3977,7 +3981,7 @@ 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: -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html