[RFC PATCH 5/5] selinux: Add SCTP support
Paul Moore
paul at paul-moore.com
Tue Nov 7 00:09:08 UTC 2017
On Tue, Oct 17, 2017 at 9:59 AM, Richard Haines
<richard_c_haines at btinternet.com> wrote:
> The SELinux SCTP implementation is explained in:
> Documentation/security/SELinux-sctp.txt
>
> Signed-off-by: Richard Haines <richard_c_haines at btinternet.com>
> ---
> Documentation/security/SELinux-sctp.txt | 108 +++++++++++++
> security/selinux/hooks.c | 268 ++++++++++++++++++++++++++++++--
> security/selinux/include/classmap.h | 3 +-
> security/selinux/include/netlabel.h | 9 +-
> security/selinux/include/objsec.h | 5 +
> security/selinux/netlabel.c | 52 ++++++-
> 6 files changed, 427 insertions(+), 18 deletions(-)
> create mode 100644 Documentation/security/SELinux-sctp.txt
>
> diff --git a/Documentation/security/SELinux-sctp.txt b/Documentation/security/SELinux-sctp.txt
> new file mode 100644
> index 0000000..32e0255
> --- /dev/null
> +++ b/Documentation/security/SELinux-sctp.txt
> @@ -0,0 +1,108 @@
See my previous comments about moving to reStructuredText for these docs.
> + SCTP SELinux Support
> + ======================
> +
> +Security Hooks
> +===============
> +
> +The Documentation/security/LSM-sctp.txt document describes how the following
> +sctp security hooks are utilised:
> + security_sctp_assoc_request()
> + security_sctp_bind_connect()
> + security_sctp_sk_clone()
> +
> + security_inet_conn_established()
> +
> +
> +Policy Statements
> +==================
> +The following class and permissions to support SCTP are available within the
> +kernel:
> + class sctp_socket inherits socket { node_bind }
> +
> +whenever the following policy capability is enabled:
> + policycap extended_socket_class;
> +
> +The SELinux SCTP support adds the additional permissions that are explained
> +in the sections below:
> + association bindx connectx
Is the distinction between bind and bindx significant? The same
question applies to connect/connectx. I think we can probably just
reuse bind and connect in these cases.
See my question on sctp_socket:association below.
> +If userspace tools have been updated, SCTP will support the portcon
> +statement as shown in the following example:
> + portcon sctp 1024-1036 system_u:object_r:sctp_ports_t:s0
> +
> +
> +SCTP Bind, Connect and ASCONF Chunk Parameter Permission Checks
> +================================================================
> +The hook security_sctp_bind_connect() is called by SCTP to check permissions
> +required for ipv4/ipv6 addresses based on the @optname as follows:
> +
> + ------------------------------------------------------------------
> + | BINDX Permission Check |
> + | @optname | @address contains |
> + |----------------------------|-----------------------------------|
> + | SCTP_SOCKOPT_BINDX_ADD | One or more ipv4 / ipv6 addresses |
> + ------------------------------------------------------------------
> +
> + ------------------------------------------------------------------
> + | BIND Permission Checks |
> + | @optname | @address contains |
> + |----------------------------|-----------------------------------|
> + | SCTP_PRIMARY_ADDR | Single ipv4 or ipv6 address |
> + | SCTP_SET_PEER_PRIMARY_ADDR | Single ipv4 or ipv6 address |
> + ------------------------------------------------------------------
> +
> + ------------------------------------------------------------------
> + | CONNECTX Permission Check |
> + | @optname | @address contains |
> + |----------------------------|-----------------------------------|
> + | SCTP_SOCKOPT_CONNECTX | One or more ipv4 / ipv6 addresses |
> + ------------------------------------------------------------------
> +
> + ------------------------------------------------------------------
> + | CONNECT Permission Checks |
> + | @optname | @address contains |
> + |----------------------------|-----------------------------------|
> + | SCTP_SENDMSG_CONNECT | Single ipv4 or ipv6 address |
> + | SCTP_PARAM_ADD_IP | One or more ipv4 / ipv6 addresses |
> + | SCTP_PARAM_SET_PRIMARY | Single ipv4 or ipv6 address |
> + ------------------------------------------------------------------
> +
> +SCTP Peer Labeling
> +===================
> +An SCTP socket will only have one peer label assigned to it. This will be
> +assigned during the establishment of the first association. Once the peer
> +label has been assigned, any new associations will have the "association"
> +permission validated by checking the socket peer sid against the received
> +packets peer sid to determine whether the association should be allowed or
> +denied.
> +
> +NOTES:
> + 1) If peer labeling is not enabled, then the peer context will always be
> + SECINITSID_UNLABELED (unlabeled_t in Reference Policy).
> +
> + 2) As SCTP supports multiple endpoints with multi-homing on a single socket
> + it is recommended that peer labels are consistent.
My apologies if I'm confused, but I thought it was multiple
associations per-endpoint, with the associations providing the
multi-homing functionality, no?
> + 3) getpeercon(3) may be used by userspace to retrieve the sockets peer
> + context.
> +
> + 4) If using NetLabel be aware that if a label is assigned to a specific
> + interface, and that interface 'goes down', then the NetLabel service
> + will remove the entry. Therefore ensure that the network startup scripts
> + call netlabelctl(8) to set the required label (see netlabel-config(8)
> + helper script for details).
Maybe this will be made clear as I work my way through this patch, but
how is point #4 SCTP specific?
> + 5) The NetLabel SCTP peer labeling rules apply as discussed in the following
> + set of posts tagged "netlabel" at: http://www.paul-moore.com/blog/t.
> +
> + 6) CIPSO is only supported for IPv4 addressing: socket(AF_INET, ...)
> + CALIPSO is only supported for IPv6 addressing: socket(AF_INET6, ...)
> +
> + Note the following when testing CIPSO/CALIPSO:
> + a) CIPSO will send an ICMP packet if an SCTP packet cannot be
> + delivered because of an invalid label.
> + b) CALIPSO does not send an ICMP packet, just silently discards it.
Okay, this answers one of my questions from earlier in the patchset.
> + 7) IPSEC is not supported as rfc3554 - sctp/ipsec support has not been
> + implemented in userspace (racoon(8) or ipsec_pluto(8)), although the
> + kernel supports SCTP/IPSEC.
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 33fd061..c3e9600 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -67,6 +67,8 @@
> #include <linux/tcp.h>
> #include <linux/udp.h>
> #include <linux/dccp.h>
> +#include <linux/sctp.h>
> +#include <net/sctp/structs.h>
> #include <linux/quota.h>
> #include <linux/un.h> /* for Unix socket types */
> #include <net/af_unix.h> /* for Unix socket types */
> @@ -4119,6 +4121,23 @@ static int selinux_parse_skb_ipv4(struct sk_buff *skb,
> break;
> }
>
> +#if IS_ENABLED(CONFIG_IP_SCTP)
> + case IPPROTO_SCTP: {
> + struct sctphdr _sctph, *sh;
> +
> + if (ntohs(ih->frag_off) & IP_OFFSET)
> + break;
> +
> + offset += ihlen;
> + sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
> + if (sh == NULL)
> + break;
> +
> + ad->u.net->sport = sh->source;
> + ad->u.net->dport = sh->dest;
> + break;
> + }
> +#endif
> default:
> break;
> }
> @@ -4192,6 +4211,19 @@ static int selinux_parse_skb_ipv6(struct sk_buff *skb,
> break;
> }
>
> +#if IS_ENABLED(CONFIG_IP_SCTP)
> + case IPPROTO_SCTP: {
> + struct sctphdr _sctph, *sh;
> +
> + sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph);
> + if (sh == NULL)
> + break;
> +
> + ad->u.net->sport = sh->source;
> + ad->u.net->dport = sh->dest;
> + break;
> + }
> +#endif
> /* includes fragments */
> default:
> break;
> @@ -4381,6 +4413,10 @@ static int selinux_socket_post_create(struct socket *sock, int family,
> sksec = sock->sk->sk_security;
> sksec->sclass = sclass;
> sksec->sid = sid;
> + /* Allows detection of the first association on this socket */
> + if (sksec->sclass == SECCLASS_SCTP_SOCKET)
> + sksec->sctp_assoc_state = SCTP_ASSOC_UNSET;
> +
> err = selinux_netlbl_socket_post_create(sock->sk, family);
> }
>
> @@ -4401,11 +4437,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
> if (err)
> goto out;
>
> - /*
> - * If PF_INET or PF_INET6, check name_bind permission for the port.
> - * Multiple address binding for SCTP is not supported yet: we just
> - * check the first address now.
> - */
> + /* If PF_INET or PF_INET6, check name_bind permission for the port. */
> family = sk->sk_family;
Instead of checking both family and address->sa_family multiple times
in this function, let's just set the correct family value once and
store it in the family variable as we do today; for example:
family = sk->sk_family;
if (family == PF_INET6 && address->sa_family == PF_INET)
family = PF_INET;
... or I wonder if it is just safe to ignore the address family in the
socket, and simply use the value provided in address? Perhaps that is
the better option?
> if (family == PF_INET || family == PF_INET6) {
> char *addrp;
> @@ -4417,7 +4449,13 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
> unsigned short snum;
> u32 sid, node_perm;
>
> - if (family == PF_INET) {
> + /*
> + * sctp_bindx(3) calls via selinux_sctp_bind_connect()
> + * that validates multiple binding addresses. Because of this
> + * need to check address->sa_family as it is possible to have
> + * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
> + */
> + if (family == PF_INET || address->sa_family == AF_INET) {
> if (addrlen < sizeof(struct sockaddr_in)) {
> err = -EINVAL;
> goto out;
> @@ -4471,6 +4509,10 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
> node_perm = DCCP_SOCKET__NODE_BIND;
> break;
>
> + case SECCLASS_SCTP_SOCKET:
> + node_perm = SCTP_SOCKET__NODE_BIND;
> + break;
> +
> default:
> node_perm = RAWIP_SOCKET__NODE_BIND;
> break;
> @@ -4485,7 +4527,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
> ad.u.net->sport = htons(snum);
> ad.u.net->family = family;
>
> - if (family == PF_INET)
> + if (family == PF_INET || address->sa_family == AF_INET)
> ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
> else
> ad.u.net->v6info.saddr = addr6->sin6_addr;
> @@ -4510,10 +4552,12 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
> return err;
>
> /*
> - * If a TCP or DCCP socket, check name_connect permission for the port.
> + * If a TCP, DCCP or SCTP socket, check name_connect permission
> + * for the port.
> */
> if (sksec->sclass == SECCLASS_TCP_SOCKET ||
> - sksec->sclass == SECCLASS_DCCP_SOCKET) {
> + sksec->sclass == SECCLASS_DCCP_SOCKET ||
> + sksec->sclass == SECCLASS_SCTP_SOCKET) {
> struct common_audit_data ad;
> struct lsm_network_audit net = {0,};
> struct sockaddr_in *addr4 = NULL;
> @@ -4521,7 +4565,14 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
> unsigned short snum;
> u32 sid, perm;
>
> - if (sk->sk_family == PF_INET) {
> + /* sctp_connectx(3) calls via
> + *selinux_sctp_bind_connect() that validates multiple
Typo. A space is needed after the "*" in the comment line above.
> + * connect addresses. Because of this need to check
> + * address->sa_family as it is possible to have
> + * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
> + */
> + if (sk->sk_family == PF_INET ||
> + address->sa_family == AF_INET) {
Once again, I wonder if we just check sa_family and skip the sk_family?
> addr4 = (struct sockaddr_in *)address;
> if (addrlen < sizeof(struct sockaddr_in))
> return -EINVAL;
> @@ -4534,11 +4585,21 @@ static int selinux_socket_connect(struct socket *sock, struct sockaddr *address,
> }
>
> err = sel_netport_sid(sk->sk_protocol, snum, &sid);
> +
No added vertical whitespace here please.
> if (err)
> goto out;
>
> - perm = (sksec->sclass == SECCLASS_TCP_SOCKET) ?
> - TCP_SOCKET__NAME_CONNECT : DCCP_SOCKET__NAME_CONNECT;
> + switch (sksec->sclass) {
> + case SECCLASS_TCP_SOCKET:
> + perm = TCP_SOCKET__NAME_CONNECT;
> + break;
> + case SECCLASS_DCCP_SOCKET:
> + perm = DCCP_SOCKET__NAME_CONNECT;
> + break;
> + case SECCLASS_SCTP_SOCKET:
> + perm = SCTP_SOCKET__NAME_CONNECT;
> + break;
> + }
>
> ad.type = LSM_AUDIT_DATA_NET;
> ad.u.net = &net;
> @@ -4815,7 +4876,8 @@ static int selinux_socket_getpeersec_stream(struct socket *sock, char __user *op
> u32 peer_sid = SECSID_NULL;
>
> if (sksec->sclass == SECCLASS_UNIX_STREAM_SOCKET ||
> - sksec->sclass == SECCLASS_TCP_SOCKET)
> + sksec->sclass == SECCLASS_TCP_SOCKET ||
> + sksec->sclass == SECCLASS_SCTP_SOCKET)
> peer_sid = sksec->peer_sid;
> if (peer_sid == SECSID_NULL)
> return -ENOPROTOOPT;
> @@ -4928,6 +4990,183 @@ static void selinux_sock_graft(struct sock *sk, struct socket *parent)
> sksec->sclass = isec->sclass;
> }
>
> +/* Called whenever SCTP receives an INIT or INIT_ACK chunk */
> +static int selinux_sctp_assoc_request(struct sctp_endpoint *ep,
> + struct sk_buff *skb,
> + int sctp_cid)
> +{
> + struct sk_security_struct *sksec = ep->base.sk->sk_security;
> + struct common_audit_data ad;
> + struct lsm_network_audit net = {0,};
> + u8 peerlbl_active;
> + u32 peer_sid = SECINITSID_UNLABELED;
> + u32 conn_sid;
> + int err;
> +
> + if (!selinux_policycap_extsockclass)
> + return 0;
We *may* need to protect a lot of the new SCTP code with a new policy
capability, I think reusing extsockclass here could be problematic.
> + peerlbl_active = selinux_peerlbl_enabled();
> +
> + if (peerlbl_active) {
> + /* This will return peer_sid = SECSID_NULL if there are
> + * no peer labels, see security_net_peersid_resolve().
> + */
> + err = selinux_skb_peerlbl_sid(skb, ep->base.sk->sk_family,
> + &peer_sid);
> +
Drop the extra vertical whitespace between the function call and the
return code check please.
> + if (err)
> + return err;
> +
> + if (peer_sid == SECSID_NULL)
> + peer_sid = SECINITSID_UNLABELED;
> + }
> +
> + if (sksec->sctp_assoc_state == SCTP_ASSOC_UNSET) {
> + sksec->sctp_assoc_state = SCTP_ASSOC_SET;
> +
> + /* Here as first association on socket. As the peer SID
> + * was allowed by peer recv (and the netif/node checks),
> + * then it is approved by policy and used as the primary
> + * peer SID for getpeercon(3).
> + */
> + sksec->peer_sid = peer_sid;
> + } else if (sksec->peer_sid != peer_sid) {
> + /* Other association peer SIDs are checked to enforce
> + * consistency among the peer SIDs.
> + */
> + ad.type = LSM_AUDIT_DATA_NET;
> + ad.u.net = &net;
> + ad.u.net->sk = ep->base.sk;
> + err = avc_has_perm(sksec->peer_sid, peer_sid, sksec->sclass,
> + SCTP_SOCKET__ASSOCIATION, &ad);
Can anyone think of any reason why we would ever want to allow an
association that doesn't have the same label as the existing
associations? Maybe I'm thinking about this wrong, but I can't
imagine this being a good idea ...
> + if (err)
> + return err;
> + }
> +
> + if (sctp_cid == SCTP_CID_INIT) {
> + /* Have INIT when incoming connect(2), sctp_connectx(3)
> + * or sctp_sendmsg(3) (with no association already present),
> + * so compute the MLS component for the connection and store
> + * the information in ep. This will be used by SCTP TCP type
> + * sockets and peeled off connections as they cause a new
> + * socket to be generated. selinux_sctp_sk_clone() will then
> + * plug this into the new socket.
> + */
> + err = selinux_conn_sid(sksec->sid, peer_sid, &conn_sid);
> + if (err)
> + return err;
> +
> + ep->secid = conn_sid;
> + ep->peer_secid = peer_sid;
> +
> + /* Set any NetLabel labels including CIPSO/CALIPSO options. */
> + return selinux_netlbl_sctp_assoc_request(ep, skb);
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Check if sctp IPv4/IPv6 addresses are valid for binding or connecting
> + * based on their @optname.
> + */
> +static int selinux_sctp_bind_connect(struct sock *sk, int optname,
> + struct sockaddr *address,
> + int addrlen)
> +{
> + int len, err = 0, walk_size = 0;
> + void *addr_buf;
> + struct sockaddr *addr;
> + struct socket *sock;
> +
> + if (!selinux_policycap_extsockclass)
> + return 0;
> +
> + switch (optname) {
> + case SCTP_SOCKOPT_BINDX_ADD:
> + err = sock_has_perm(sk, SCTP_SOCKET__BINDX);
> + break;
> + case SCTP_SOCKOPT_CONNECTX:
> + err = sock_has_perm(sk, SCTP_SOCKET__CONNECTX);
> + break;
> + /* These need SOCKET__BIND or SOCKET__CONNECT permissions that will
> + * be checked later.
> + */
> + case SCTP_PRIMARY_ADDR:
> + case SCTP_SET_PEER_PRIMARY_ADDR:
> + case SCTP_PARAM_SET_PRIMARY:
> + case SCTP_PARAM_ADD_IP:
> + case SCTP_SENDMSG_CONNECT:
> + break;
> + default:
> + err = -EINVAL;
> + }
> + if (err)
> + return err;
> +
> + /* Process one or more addresses that may be IPv4 or IPv6 */
> + sock = sk->sk_socket;
> + addr_buf = address;
> +
> + while (walk_size < addrlen) {
> + addr = addr_buf;
> + switch (addr->sa_family) {
> + case AF_INET:
> + len = sizeof(struct sockaddr_in);
> + break;
> + case AF_INET6:
> + len = sizeof(struct sockaddr_in6);
> + break;
> + default:
> + return -EAFNOSUPPORT;
> + }
> +
> + err = -EINVAL;
> + switch (optname) {
> + /* Bind checks */
> + case SCTP_PRIMARY_ADDR:
> + case SCTP_SET_PEER_PRIMARY_ADDR:
> + case SCTP_SOCKOPT_BINDX_ADD:
> + err = selinux_socket_bind(sock, addr, len);
> + break;
> + /* Connect checks */
> + case SCTP_SOCKOPT_CONNECTX:
> + case SCTP_PARAM_SET_PRIMARY:
> + case SCTP_PARAM_ADD_IP:
> + case SCTP_SENDMSG_CONNECT:
> + err = selinux_socket_connect(sock, addr, len);
> + break;
> + }
> +
> + if (err)
> + return err;
> +
> + addr_buf += len;
> + walk_size += len;
> + }
> + return 0;
> +}
> +
> +/* Called whenever a new socket is created by accept(2) or sctp_peeloff(3). */
> +static void selinux_sctp_sk_clone(struct sctp_endpoint *ep, struct sock *sk,
> + struct sock *newsk)
> +{
> + struct sk_security_struct *sksec = sk->sk_security;
> + struct sk_security_struct *newsksec = newsk->sk_security;
> +
> + /* If policy does not support SECCLASS_SCTP_SOCKET then call
> + * the non-sctp clone version.
> + */
> + if (!selinux_policycap_extsockclass)
> + return selinux_sk_clone_security(sk, newsk);
> +
> + newsksec->sid = ep->secid;
> + newsksec->peer_sid = ep->peer_secid;
> + newsksec->sclass = sksec->sclass;
> + newsksec->nlbl_state = sksec->nlbl_state;
> +}
> +
> static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb,
> struct request_sock *req)
> {
> @@ -6416,6 +6655,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
> LSM_HOOK_INIT(sk_clone_security, selinux_sk_clone_security),
> LSM_HOOK_INIT(sk_getsecid, selinux_sk_getsecid),
> LSM_HOOK_INIT(sock_graft, selinux_sock_graft),
> + LSM_HOOK_INIT(sctp_assoc_request, selinux_sctp_assoc_request),
> + LSM_HOOK_INIT(sctp_sk_clone, selinux_sctp_sk_clone),
> + LSM_HOOK_INIT(sctp_bind_connect, selinux_sctp_bind_connect),
> LSM_HOOK_INIT(inet_conn_request, selinux_inet_conn_request),
> LSM_HOOK_INIT(inet_csk_clone, selinux_inet_csk_clone),
> LSM_HOOK_INIT(inet_conn_established, selinux_inet_conn_established),
> diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
> index b9fe343..b4b10da 100644
> --- a/security/selinux/include/classmap.h
> +++ b/security/selinux/include/classmap.h
> @@ -173,7 +173,8 @@ struct security_class_mapping secclass_map[] = {
> { COMMON_CAP2_PERMS, NULL } },
> { "sctp_socket",
> { COMMON_SOCK_PERMS,
> - "node_bind", NULL } },
> + "node_bind", "name_connect", "association", "bindx",
> + "connectx", NULL } },
> { "icmp_socket",
> { COMMON_SOCK_PERMS,
> "node_bind", NULL } },
> diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h
> index 75686d5..835a0d6 100644
> --- a/security/selinux/include/netlabel.h
> +++ b/security/selinux/include/netlabel.h
> @@ -33,6 +33,7 @@
> #include <linux/skbuff.h>
> #include <net/sock.h>
> #include <net/request_sock.h>
> +#include <net/sctp/structs.h>
>
> #include "avc.h"
> #include "objsec.h"
> @@ -53,7 +54,8 @@ int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
> int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
> u16 family,
> u32 sid);
> -
> +int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
> + struct sk_buff *skb);
> int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family);
> void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family);
> int selinux_netlbl_socket_post_create(struct sock *sk, u16 family);
> @@ -114,6 +116,11 @@ static inline int selinux_netlbl_conn_setsid(struct sock *sk,
> return 0;
> }
>
> +static inline int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
> + struct sk_buff *skb)
> +{
> + return 0;
> +}
> static inline int selinux_netlbl_inet_conn_request(struct request_sock *req,
> u16 family)
> {
> diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
> index 6ebc61e..660f270 100644
> --- a/security/selinux/include/objsec.h
> +++ b/security/selinux/include/objsec.h
> @@ -130,6 +130,11 @@ struct sk_security_struct {
> u32 sid; /* SID of this object */
> u32 peer_sid; /* SID of peer */
> u16 sclass; /* sock security class */
> +
Extra vertical whitespace is not needed.
> + enum { /* SCTP association state */
> + SCTP_ASSOC_UNSET = 0,
> + SCTP_ASSOC_SET,
> + } sctp_assoc_state;
> };
>
> struct tun_security_struct {
> diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
> index aaba667..7d5aa15 100644
> --- a/security/selinux/netlabel.c
> +++ b/security/selinux/netlabel.c
> @@ -250,6 +250,7 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
> sk = skb_to_full_sk(skb);
> if (sk != NULL) {
> struct sk_security_struct *sksec = sk->sk_security;
> +
> if (sksec->nlbl_state != NLBL_REQSKB)
> return 0;
> secattr = selinux_netlbl_sock_getattr(sk, sid);
> @@ -271,6 +272,41 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
> }
>
> /**
> + * selinux_netlbl_sctp_assoc_request - Label an incoming sctp association.
> + * @ep: incoming association endpoint.
> + * @skb: the packet.
> + *
> + * Description:
> + * A new incoming connection is represented by @ep, ......
> + * Returns zero on success, negative values on failure.
> + *
> + */
> +int selinux_netlbl_sctp_assoc_request(struct sctp_endpoint *ep,
> + struct sk_buff *skb)
> +{
> + int rc;
> + struct netlbl_lsm_secattr secattr;
> + struct sk_security_struct *sksec = ep->base.sk->sk_security;
> +
> + if (ep->base.sk->sk_family != PF_INET &&
> + ep->base.sk->sk_family != PF_INET6)
> + return 0;
> +
> + netlbl_secattr_init(&secattr);
> + rc = security_netlbl_sid_to_secattr(ep->secid, &secattr);
> + if (rc != 0)
> + goto assoc_request_return;
> +
> + rc = netlbl_sctp_setattr(ep->base.sk, skb, &secattr);
> + if (rc == 0)
> + sksec->nlbl_state = NLBL_LABELED;
> +
> +assoc_request_return:
> + netlbl_secattr_destroy(&secattr);
> + return rc;
> +}
> +
> +/**
> * selinux_netlbl_inet_conn_request - Label an incoming stream connection
> * @req: incoming connection request socket
> *
> @@ -481,7 +517,7 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock,
> */
> int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
> {
> - int rc;
> + int rc, already_owned_by_user = 0;
> struct sk_security_struct *sksec = sk->sk_security;
> struct netlbl_lsm_secattr *secattr;
>
> @@ -489,7 +525,16 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
> sksec->nlbl_state != NLBL_CONNLABELED)
> return 0;
>
> - lock_sock(sk);
> + /* Note: When called via connect(2) this happens before the socket
> + * protocol layer connect operation and @sk is not locked, HOWEVER,
> + * when called by the SCTP protocol layer via sctp_connectx(3),
> + * sctp_sendmsg(3) or sendmsg(2), @sk is locked. Therefore check if
> + * @sk owned already.
> + */
> + if (sock_owned_by_user(sk) && sksec->sclass == SECCLASS_SCTP_SOCKET)
> + already_owned_by_user = 1;
> + else
> + lock_sock(sk);
>
> /* connected sockets are allowed to disconnect when the address family
> * is set to AF_UNSPEC, if that is what is happening we want to reset
> @@ -510,6 +555,7 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
> sksec->nlbl_state = NLBL_CONNLABELED;
>
> socket_connect_return:
> - release_sock(sk);
> + if (!already_owned_by_user)
> + release_sock(sk);
> return rc;
> }
> --
> 2.13.6
>
--
paul moore
www.paul-moore.com
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