[RFC PATCH 3/5] sctp: Add LSM hooks

[Richard Haines]

Add security hooks to allow security modules to exercise access control
over SCTP.

Signed-off-by: Richard Haines <***@btinternet.com>
---
include/net/sctp/structs.h | 10 ++++++++
include/uapi/linux/sctp.h | 1 +
net/sctp/sm_make_chunk.c | 12 +++++++++
net/sctp/sm_statefuns.c | 14 ++++++++++-
net/sctp/socket.c | 61 +++++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 96 insertions(+), 2 deletions(-)

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7767577..6e72e3e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1270,6 +1270,16 @@ struct sctp_endpoint {
reconf_enable:1;

__u8 strreset_enable;
+
+ /* Security identifiers from incoming (INIT). These are set by
+ * security_sctp_assoc_request(). These will only be used by
+ * SCTP TCP type sockets and peeled off connections as they
+ * cause a new socket to be generated. security_sctp_sk_clone()
+ * will then plug these into the new socket.
+ */
+
+ u32 secid;
+ u32 peer_secid;
};

/* Recover the outter endpoint structure. */
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 6217ff8..c04812f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
#define SCTP_RESET_ASSOC 120
#define SCTP_ADD_STREAMS 121
#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_SENDMSG_CONNECT 123

/* PR-SCTP policies */
#define SCTP_PR_SCTP_NONE 0x0000
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 6110447..ca4705b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3059,6 +3059,12 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr, &asconf->source, sizeof(addr));

+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_ADD_IP,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
* request and does not have the local resources to add this
* new address to the association, it MUST return an Error
@@ -3125,6 +3131,12 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));

+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_SET_PRIMARY,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_DNS_FAILED;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b2a74c3..4ba5805 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -314,6 +314,11 @@ sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
sctp_unrecognized_param_t *unk_param;
int len;

+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb, SCTP_CID_INIT))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
@@ -446,7 +451,6 @@ sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
}

sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
-
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));

/*
@@ -507,6 +511,11 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;

+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb, SCTP_CID_INIT_ACK))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);

@@ -899,6 +908,9 @@ sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
*/
sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());

+ /* Set peer label for connection. */
+ security_inet_conn_established(ep->base.sk, chunk->skb);
+
/* RFC 2960 5.1 Normal Establishment of an Association
*
* E) Upon reception of the COOKIE ACK, endpoint "A" will move
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 70355a0..e948163 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1014,6 +1014,12 @@ static int sctp_setsockopt_bindx(struct sock *sk,
/* Do the work. */
switch (op) {
case SCTP_BINDX_ADD_ADDR:
+ /* Allow security module to validate bindx addresses. */
+ err = security_sctp_bind_connect(sk, SCTP_SOCKOPT_BINDX_ADD,
+ (struct sockaddr *)kaddrs,
+ addrs_size);
+ if (err)
+ goto out;
err = sctp_bindx_add(sk, kaddrs, addrcnt);
if (err)
goto out;
@@ -1223,6 +1229,7 @@ static int __sctp_connect(struct sock *sk,

if (assoc_id)
*assoc_id = asoc->assoc_id;
+
err = sctp_wait_for_connect(asoc, &timeo);
/* Note: the asoc may be freed after the return of
* sctp_wait_for_connect.
@@ -1336,9 +1343,17 @@ static int __sctp_setsockopt_connectx(struct sock *sk,
if (__copy_from_user(kaddrs, addrs, addrs_size)) {
err = -EFAULT;
} else {
+ /* Allow security module to validate connectx addresses. */
+ err = security_sctp_bind_connect(sk, SCTP_SOCKOPT_CONNECTX,
+ (struct sockaddr *)kaddrs,
+ addrs_size);
+ if (err)
+ goto out_free;
+
err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
}

+out_free:
kfree(kaddrs);

return err;
@@ -1604,6 +1619,7 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
struct sctp_transport *transport, *chunk_tp;
struct sctp_chunk *chunk;
union sctp_addr to;
+ struct sctp_af *af;
struct sockaddr *msg_name = NULL;
struct sctp_sndrcvinfo default_sinfo;
struct sctp_sndrcvinfo *sinfo;
@@ -1833,6 +1849,24 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
}

scope = sctp_scope(&to);
+
+ /* Label connection socket for first association 1-to-many
+ * style for client sequence socket()->sendmsg(). This
+ * needs to be done before sctp_assoc_add_peer() as that will
+ * set up the initial packet that needs to account for any
+ * security ip options (CIPSO/CALIPSO) added to the packet.
+ */
+ af = sctp_get_af_specific(to.sa.sa_family);
+ if (!af) {
+ err = -EINVAL;
+ goto out_unlock;
+ }
+ err = security_sctp_bind_connect(sk, SCTP_SENDMSG_CONNECT,
+ (struct sockaddr *)&to,
+ af->sockaddr_len);
+ if (err < 0)
+ goto out_unlock;
+
new_asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
if (!new_asoc) {
err = -ENOMEM;
@@ -2865,6 +2899,8 @@ static int sctp_setsockopt_primary_addr(struct sock *sk, char __user *optval,
{
struct sctp_prim prim;
struct sctp_transport *trans;
+ struct sctp_af *af;
+ int err;

if (optlen != sizeof(struct sctp_prim))
return -EINVAL;
@@ -2872,6 +2908,17 @@ static int sctp_setsockopt_primary_addr(struct sock *sk, char __user *optval,
if (copy_from_user(&prim, optval, sizeof(struct sctp_prim)))
return -EFAULT;

+ /* Allow security module to validate address but need address len. */
+ af = sctp_get_af_specific(prim.ssp_addr.ss_family);
+ if (!af)
+ return -EINVAL;
+
+ err = security_sctp_bind_connect(sk, SCTP_PRIMARY_ADDR,
+ (struct sockaddr *)&prim.ssp_addr,
+ af->sockaddr_len);
+ if (err)
+ return err;
+
trans = sctp_addr_id2transport(sk, &prim.ssp_addr, prim.ssp_assoc_id);
if (!trans)
return -EINVAL;
@@ -3192,6 +3239,13 @@ static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optva
if (!sctp_assoc_lookup_laddr(asoc, (union sctp_addr *)&prim.sspp_addr))
return -EADDRNOTAVAIL;

+ /* Allow security module to validate address. */
+ err = security_sctp_bind_connect(sk, SCTP_SET_PEER_PRIMARY_ADDR,
+ (struct sockaddr *)&prim.sspp_addr,
+ af->sockaddr_len);
+ if (err)
+ return err;
+
/* Create an ASCONF chunk with SET_PRIMARY parameter */
chunk = sctp_make_asconf_set_prim(asoc,
(union sctp_addr *)&prim.sspp_addr);
@@ -8024,6 +8078,8 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
{
struct inet_sock *inet = inet_sk(sk);
struct inet_sock *newinet;
+ struct sctp_sock *sp = sctp_sk(sk);
+ struct sctp_endpoint *ep = sp->ep;

newsk->sk_type = sk->sk_type;
newsk->sk_bound_dev_if = sk->sk_bound_dev_if;
@@ -8066,7 +8122,10 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
net_enable_timestamp();

- security_sk_clone(sk, newsk);
+ /* Set newsk security attributes from orginal sk and connection
+ * security attribute from ep.
+ */
+ security_sctp_sk_clone(ep, sk, newsk);
}

static inline void sctp_copy_descendant(struct sock *sk_to,

[Xin Long]

On Tue, Oct 17, 2017 at 9:58 PM, Richard Haines

Post by Richard Haines
Add security hooks to allow security modules to exercise access control
over SCTP.
---
include/net/sctp/structs.h | 10 ++++++++
include/uapi/linux/sctp.h | 1 +
net/sctp/sm_make_chunk.c | 12 +++++++++
net/sctp/sm_statefuns.c | 14 ++++++++++-
net/sctp/socket.c | 61 +++++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 96 insertions(+), 2 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7767577..6e72e3e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1270,6 +1270,16 @@ struct sctp_endpoint {
reconf_enable:1;
__u8 strreset_enable;
+
+ /* Security identifiers from incoming (INIT). These are set by
+ * security_sctp_assoc_request(). These will only be used by
+ * SCTP TCP type sockets and peeled off connections as they
+ * cause a new socket to be generated. security_sctp_sk_clone()
+ * will then plug these into the new socket.
+ */
+
+ u32 secid;
+ u32 peer_secid;
};
/* Recover the outter endpoint structure. */
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 6217ff8..c04812f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
#define SCTP_RESET_ASSOC 120
#define SCTP_ADD_STREAMS 121
#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_SENDMSG_CONNECT 123
/* PR-SCTP policies */
#define SCTP_PR_SCTP_NONE 0x0000
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 6110447..ca4705b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3059,6 +3059,12 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr, &asconf->source, sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_ADD_IP,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
* request and does not have the local resources to add this
* new address to the association, it MUST return an Error
@@ -3125,6 +3131,12 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_SET_PRIMARY,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_DNS_FAILED;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b2a74c3..4ba5805 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -314,6 +314,11 @@ sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
sctp_unrecognized_param_t *unk_param;
int len;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb, SCTP_CID_INIT))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
@@ -446,7 +451,6 @@ sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
-
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
/*
@@ -507,6 +511,11 @@ sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb, SCTP_CID_INIT_ACK))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+

Just thinking security_sctp_assoc_request hook should also be in
sctp_sf_do_unexpected_init() and sctp_sf_do_5_2_4_dupcook() ?

[Richard Haines]

Post by Xin Long
On Tue, Oct 17, 2017 at 9:58 PM, Richard Haines

Post by Richard Haines
Add security hooks to allow security modules to exercise access control
over SCTP.
---
include/net/sctp/structs.h | 10 ++++++++
include/uapi/linux/sctp.h | 1 +
net/sctp/sm_make_chunk.c | 12 +++++++++
net/sctp/sm_statefuns.c | 14 ++++++++++-
net/sctp/socket.c | 61
+++++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 96 insertions(+), 2 deletions(-)
diff --git a/include/net/sctp/structs.h
b/include/net/sctp/structs.h
index 7767577..6e72e3e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1270,6 +1270,16 @@ struct sctp_endpoint {
reconf_enable:1;
__u8 strreset_enable;
+
+ /* Security identifiers from incoming (INIT). These are set by
+ * security_sctp_assoc_request(). These will only be used by
+ * SCTP TCP type sockets and peeled off connections as they
+ * cause a new socket to be generated.
security_sctp_sk_clone()
+ * will then plug these into the new socket.
+ */
+
+ u32 secid;
+ u32 peer_secid;
};
/* Recover the outter endpoint structure. */
diff --git a/include/uapi/linux/sctp.h
b/include/uapi/linux/sctp.h
index 6217ff8..c04812f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
#define SCTP_RESET_ASSOC 120
#define SCTP_ADD_STREAMS 121
#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_SENDMSG_CONNECT 123
/* PR-SCTP policies */
#define SCTP_PR_SCTP_NONE 0x0000
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 6110447..ca4705b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3059,6 +3059,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr, &asconf->source,
sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_ADD_IP,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
* request and does not have the local resources to add this
* new address to the association, it MUST return an Error
@@ -3125,6 +3131,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_SET_PRI
MARY,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_DNS_FAILED;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b2a74c3..4ba5805 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -314,6 +314,11 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
sctp_unrecognized_param_t *unk_param;
int len;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
@@ -446,7 +451,6 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC,
SCTP_ASOC(new_asoc));
-
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(repl));
/*
@@ -507,6 +511,11 @@ sctp_disposition_t
sctp_sf_do_5_1C_ack(struct net *net,
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT_ACK))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+

Just thinking security_sctp_assoc_request hook should also be in
sctp_sf_do_unexpected_init() and sctp_sf_do_5_2_4_dupcook() ?

I agree, i think if this hook is gating on the creation of a new
association,
they should be in all the locations where that happens
Neil

Thanks for the comments. I've just added the hook as requested for my
next update, however I have not managed to trigger these areas using
the lksctp-tools tests. Can you suggest any suitable tools for testing
these scenarios.

Thanks
Richard

Post by Xin Long
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[Xin Long]

On Fri, Oct 20, 2017 at 8:04 PM, Richard Haines

Post by Richard Haines

Post by Xin Long
On Tue, Oct 17, 2017 at 9:58 PM, Richard Haines

Post by Richard Haines
Add security hooks to allow security modules to exercise access control
over SCTP.
---
include/net/sctp/structs.h | 10 ++++++++
include/uapi/linux/sctp.h | 1 +
net/sctp/sm_make_chunk.c | 12 +++++++++
net/sctp/sm_statefuns.c | 14 ++++++++++-
net/sctp/socket.c | 61
+++++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 96 insertions(+), 2 deletions(-)
diff --git a/include/net/sctp/structs.h
b/include/net/sctp/structs.h
index 7767577..6e72e3e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1270,6 +1270,16 @@ struct sctp_endpoint {
reconf_enable:1;
__u8 strreset_enable;
+
+ /* Security identifiers from incoming (INIT). These are set by
+ * security_sctp_assoc_request(). These will only be used by
+ * SCTP TCP type sockets and peeled off connections as they
+ * cause a new socket to be generated.
security_sctp_sk_clone()
+ * will then plug these into the new socket.
+ */
+
+ u32 secid;
+ u32 peer_secid;
};
/* Recover the outter endpoint structure. */
diff --git a/include/uapi/linux/sctp.h
b/include/uapi/linux/sctp.h
index 6217ff8..c04812f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
#define SCTP_RESET_ASSOC 120
#define SCTP_ADD_STREAMS 121
#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_SENDMSG_CONNECT 123
/* PR-SCTP policies */
#define SCTP_PR_SCTP_NONE 0x0000
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 6110447..ca4705b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3059,6 +3059,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr, &asconf->source,
sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_ADD_IP,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
/* ADDIP 4.3 D9) If an endpoint receives an ADD IP address
* request and does not have the local resources to add this
* new address to the association, it MUST return an Error
@@ -3125,6 +3131,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep->base.sk,
+ SCTP_PARAM_SET_PRI
MARY,
+ (struct sockaddr *)&addr,
+ af->sockaddr_len))
+ return SCTP_ERROR_REQ_REFUSED;
+
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_DNS_FAILED;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index b2a74c3..4ba5805 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -314,6 +314,11 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
sctp_unrecognized_param_t *unk_param;
int len;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
@@ -446,7 +451,6 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC,
SCTP_ASOC(new_asoc));
-
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(repl));
/*
@@ -507,6 +511,11 @@ sctp_disposition_t
sctp_sf_do_5_1C_ack(struct net *net,
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT_ACK))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+

Just thinking security_sctp_assoc_request hook should also be in
sctp_sf_do_unexpected_init() and sctp_sf_do_5_2_4_dupcook() ?

I agree, i think if this hook is gating on the creation of a new
association,
they should be in all the locations where that happens
Neil

Thanks for the comments. I've just added the hook as requested for my
next update, however I have not managed to trigger these areas using
the lksctp-tools tests. Can you suggest any suitable tools for testing
these scenarios.

It's all a matter of timing:

sctp_sf_do_5_2_2_dupinit():
Case A:

Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)

INIT ----------------->

<----------------- INIT-ACK

COOKIE-ECHO ----------------->

<----------------- COOKIE-ACK
Communication Up ---------->
INIT ----------------->
(Different INIT-TAG)
<----------------- INIT-ACK

COOKIE-ECHO ----------------->

<----------------- COOKIE-ACK

DATA ----------------->

<----------------- SACK


sctp_sf_do_5_2_1_siminit():
Case B:

Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)

<----- Associate
<----------------- INIT

INIT ----------------->

<----------------- INIT-ACK

COOKIE-ECHO ----------------->

<----------------- COOKIE-ACK
Communication Up ---------->


sctp_sf_do_5_2_4_dupcook():
Case D:

Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)

<----- Associate
INIT ----------------->

<----------------- INIT-ACK

COOKIE-ECHO ----------------->

<----------------- COOKIE-ACK
Communication Up ---------->
COOKIE-ECHO ----------------->

<----------------- COOKIE-ACK

I think scapy could help with 4-shake stuff:
# iptables -A OUTPUT -p sctp -d 192.0.0.2 --chunk-type only abort -o
eth1 -j DROP
and
something like:
def start_assoc(self, target, local):
target_host, target_port = target
local_host, local_port = local

# init snd
self._tsn = 2017
self._cnt = 15

SCTP_HEADER = (IP(dst=target_host, flags="DF") /
SCTP(sport=local_port, dport=target_port, tag=0))
INIT = (SCTP_HEADER / SCTPChunkInit(init_tag=1,
a_rwnd=106496, n_out_streams=self._cnt, n_in_streams=self._cnt,
init_tsn=self._tsn,

params=[SCTPParamSupport(types=[64])]))
INIT_ACK = sr1(INIT, timeout=3, verbose=0)
if INIT_ACK == None or not INIT_ACK.haslayer(SCTPChunkInitAck):
return False

# cookie echo snd
SCTP_HEADER[SCTP].tag = INIT_ACK[SCTPChunkInitAck].init_tag
COOKIE_ECHO = (SCTP_HEADER /
SCTPChunkCookieEcho(cookie=INIT_ACK[SCTPChunkParamStateCookie].cookie))
COOKIE_ACK = sr1(COOKIE_ECHO, timeout=3, verbose=0)
if COOKIE_ACK == None or not
COOKIE_ACK.haslayer(SCTPChunkCookieAck):
return False

[Richard Haines]

Post by Xin Long
On Fri, Oct 20, 2017 at 8:04 PM, Richard Haines

Post by Richard Haines

Post by Xin Long
On Tue, Oct 17, 2017 at 9:58 PM, Richard Haines

Post by Richard Haines
Add security hooks to allow security modules to exercise
access
control
over SCTP.
m>
---
include/net/sctp/structs.h | 10 ++++++++
include/uapi/linux/sctp.h | 1 +
net/sctp/sm_make_chunk.c | 12 +++++++++
net/sctp/sm_statefuns.c | 14 ++++++++++-
net/sctp/socket.c | 61
+++++++++++++++++++++++++++++++++++++++++++++-
5 files changed, 96 insertions(+), 2 deletions(-)
diff --git a/include/net/sctp/structs.h
b/include/net/sctp/structs.h
index 7767577..6e72e3e 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -1270,6 +1270,16 @@ struct sctp_endpoint {
reconf_enable:1;
__u8 strreset_enable;
+
+ /* Security identifiers from incoming (INIT). These
are
set by
+ * security_sctp_assoc_request(). These will only be
used
by
+ * SCTP TCP type sockets and peeled off connections
as
they
+ * cause a new socket to be generated.
security_sctp_sk_clone()
+ * will then plug these into the new socket.
+ */
+
+ u32 secid;
+ u32 peer_secid;
};
/* Recover the outter endpoint structure. */
diff --git a/include/uapi/linux/sctp.h
b/include/uapi/linux/sctp.h
index 6217ff8..c04812f 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
#define SCTP_RESET_ASSOC 120
#define SCTP_ADD_STREAMS 121
#define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_SENDMSG_CONNECT 123
/* PR-SCTP policies */
#define SCTP_PR_SCTP_NONE 0x0000
diff --git a/net/sctp/sm_make_chunk.c
b/net/sctp/sm_make_chunk.c
index 6110447..ca4705b 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3059,6 +3059,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr, &asconf->source,
sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep-

Post by Richard Haines
base.sk,

+ SCTP_PARAM_ADD
_IP,
+ (struct
sockaddr
*)&addr,
+ af-

Post by Richard Haines
sockaddr_len))

+ return SCTP_ERROR_REQ_REFUSED;
+
/* ADDIP 4.3 D9) If an endpoint receives an
ADD
IP address
* request and does not have the local
resources
to add this
* new address to the association, it MUST
return
an Error
@@ -3125,6 +3131,12 @@ static __be16
sctp_process_asconf_param(struct sctp_association *asoc,
if (af->is_any(&addr))
memcpy(&addr.v4, sctp_source(asconf),
sizeof(addr));
+ if (security_sctp_bind_connect(asoc->ep-

Post by Richard Haines
base.sk,

+ SCTP_PARAM_SET
_PRI
MARY,
+ (struct
sockaddr
*)&addr,
+ af-

Post by Richard Haines
sockaddr_len))

+ return SCTP_ERROR_REQ_REFUSED;
+
peer = sctp_assoc_lookup_paddr(asoc, &addr);
if (!peer)
return SCTP_ERROR_DNS_FAILED;
diff --git a/net/sctp/sm_statefuns.c
b/net/sctp/sm_statefuns.c
index b2a74c3..4ba5805 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -314,6 +314,11 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
sctp_unrecognized_param_t *unk_param;
int len;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT))
+ return sctp_sf_pdiscard(net, ep, asoc, type,
arg,
commands);
+
/* 6.10 Bundling
* An endpoint MUST NOT bundle INIT, INIT ACK or
* SHUTDOWN COMPLETE with any other chunks.
@@ -446,7 +451,6 @@ sctp_disposition_t
sctp_sf_do_5_1B_init(struct net *net,
}
sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC,
SCTP_ASOC(new_asoc));
-
sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
SCTP_CHUNK(repl));
/*
@@ -507,6 +511,11 @@ sctp_disposition_t
sctp_sf_do_5_1C_ack(struct net *net,
struct sctp_chunk *err_chunk;
struct sctp_packet *packet;
+ /* Update socket peer label if first association. */
+ if (security_sctp_assoc_request((struct sctp_endpoint *)ep,
+ chunk->skb,
SCTP_CID_INIT_ACK))
+ return sctp_sf_pdiscard(net, ep, asoc, type,
arg,
commands);
+

Just thinking security_sctp_assoc_request hook should also be in
sctp_sf_do_unexpected_init() and sctp_sf_do_5_2_4_dupcook() ?

I agree, i think if this hook is gating on the creation of a new
association,
they should be in all the locations where that happens
Neil

Thanks for the comments. I've just added the hook as requested for my
next update, however I have not managed to trigger these areas using
the lksctp-tools tests. Can you suggest any suitable tools for testing
these scenarios.

Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)
INIT ----------------->
<----------------- INIT-ACK
COOKIE-ECHO ----------------->
<----------------- COOKIE-ACK
Communication Up ---------->
INIT ----------------->
(Different INIT-TAG)
<----------------- INIT-ACK
COOKIE-ECHO ----------------->
<----------------- COOKIE-ACK
DATA ----------------->
<----------------- SACK
Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)
<--
--- Associate
<----------------- INIT
INIT ----------------->
<----------------- INIT-ACK
COOKIE-ECHO ----------------->
<----------------- COOKIE-ACK
Communication Up ---------->
Endpoint A Endpoint B ULP
(CLOSED) (CLOSED)
<--
--- Associate
INIT ----------------->
<----------------- INIT-ACK
COOKIE-ECHO ----------------->
<----------------- COOKIE-ACK
Communication Up ---------->
COOKIE-ECHO ----------------->
<----------------- COOKIE-ACK
# iptables -A OUTPUT -p sctp -d 192.0.0.2 --chunk-type only abort -o
eth1 -j DROP
and
target_host, target_port = target
local_host, local_port = local
# init snd
self._tsn = 2017
self._cnt = 15
SCTP_HEADER = (IP(dst=target_host, flags="DF") /
SCTP(sport=local_port, dport=target_port, tag=0))
INIT = (SCTP_HEADER / SCTPChunkInit(init_tag=1,
a_rwnd=106496, n_out_streams=self._cnt, n_in_streams=self._cnt,
init_tsn=self._tsn,
params=[SCTPParamSupport(types=[64])]))
INIT_ACK = sr1(INIT, timeout=3, verbose=0)
if INIT_ACK == None or not
return False
# cookie echo snd
SCTP_HEADER[SCTP].tag =
INIT_ACK[SCTPChunkInitAck].init_tag
COOKIE_ECHO = (SCTP_HEADER /
SCTPChunkCookieEcho(cookie=INIT_ACK[SCTPChunkParamStateCookie].cookie
))
COOKIE_ACK = sr1(COOKIE_ECHO, timeout=3, verbose=0)
if COOKIE_ACK == None or not
return False

That looks a bit complicated for me so I found some SCTP Conformance
Test Tools at: https://github.com/nplab

I added the required hooks as suggested above and then built and ran
"ETSI-SCTP-Conformance-Testsuite" and "sctp-tests" with the following
specific tests for the above scenarios according to RFC2960 sections
5.2.2 and 5.2.4:
sctp-dm-o-4-8
sctp-as-o-1-9-1
sctp-as-o-1-9-2
sctp-dm-o-4-2-1

They all passed except when running:
"sctp-tests" runsctptest sctp-as-o-1-9-2 - TIMEOUT
This is because the SUT needs to reply with a new IP address that
required a modified test server (I just used a simple sctp server),
however the ETSI-SCTP-Conformance-Testsuite did pass as I guess that
provided the required IP address.

Are these tests okay ??
Does anyone on the list use these conformance tools ???

Post by Xin Long
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