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security: add sctp_assoc_established hook

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security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.

Fixes: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Based-on-patch-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Ondrej Mosnacek 2022-02-12 18:59:21 +01:00 committed by Paul Moore
parent 70f4169ab4
commit 5e50f5d4ff
6 changed files with 37 additions and 15 deletions
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22
Documentation/security/SCTP.rst
View File

@ -15,10 +15,7 @@ For security module support, three SCTP specific hooks have been implemented::
security_sctp_assoc_request()
security_sctp_bind_connect()
security_sctp_sk_clone()
Also the following security hook has been utilised::
security_inet_conn_established()
security_sctp_assoc_established()
The usage of these hooks are described below with the SELinux implementation
described in the `SCTP SELinux Support`_ chapter.
@ -122,11 +119,12 @@ calls **sctp_peeloff**\(3).
@newsk - pointer to new sock structure.
security_inet_conn_established()
security_sctp_assoc_established()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Called when a COOKIE ACK is received::
Called when a COOKIE ACK is received, and the peer secid will be
saved into ``@asoc->peer_secid`` for client::
@sk - pointer to sock structure.
@asoc - pointer to sctp association structure.
@skb - pointer to skbuff of the COOKIE ACK packet.
@ -134,7 +132,7 @@ Security Hooks used for Association Establishment
-------------------------------------------------
The following diagram shows the use of ``security_sctp_bind_connect()``,
``security_sctp_assoc_request()``, ``security_inet_conn_established()`` when
``security_sctp_assoc_request()``, ``security_sctp_assoc_established()`` when
establishing an association.
::
@ -172,7 +170,7 @@ establishing an association.
<------------------------------------------- COOKIE ACK
| |
sctp_sf_do_5_1E_ca |
Call security_inet_conn_established() |
Call security_sctp_assoc_established() |
to set the peer label. |
| |
| If SCTP_SOCKET_TCP or peeled off
@ -198,7 +196,7 @@ hooks with the SELinux specifics expanded below::
security_sctp_assoc_request()
security_sctp_bind_connect()
security_sctp_sk_clone()
security_inet_conn_established()
security_sctp_assoc_established()
security_sctp_assoc_request()
@ -271,12 +269,12 @@ sockets sid and peer sid to that contained in the ``@asoc sid`` and
@newsk - pointer to new sock structure.
security_inet_conn_established()
security_sctp_assoc_established()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Called when a COOKIE ACK is received where it sets the connection's peer sid
to that in ``@skb``::
@sk - pointer to sock structure.
@asoc - pointer to sctp association structure.
@skb - pointer to skbuff of the COOKIE ACK packet.

2
include/linux/lsm_hook_defs.h
View File

@ -332,6 +332,8 @@ LSM_HOOK(int, 0, sctp_bind_connect, struct sock *sk, int optname,
struct sockaddr *address, int addrlen)
LSM_HOOK(void, LSM_RET_VOID, sctp_sk_clone, struct sctp_association *asoc,
struct sock *sk, struct sock *newsk)
LSM_HOOK(int, 0, sctp_assoc_established, struct sctp_association *asoc,
struct sk_buff *skb)
#endif /* CONFIG_SECURITY_NETWORK */
#ifdef CONFIG_SECURITY_INFINIBAND

5
include/linux/lsm_hooks.h
View File

@ -1046,6 +1046,11 @@
* @asoc pointer to current sctp association structure.
* @sk pointer to current sock structure.
* @newsk pointer to new sock structure.
* @sctp_assoc_established:
* Passes the @asoc and @chunk->skb of the association COOKIE_ACK packet
* to the security module.
* @asoc pointer to sctp association structure.
* @skb pointer to skbuff of association packet.
*
* Security hooks for Infiniband
*

8
include/linux/security.h
View File

@ -1422,6 +1422,8 @@ int security_sctp_bind_connect(struct sock *sk, int optname,
struct sockaddr *address, int addrlen);
void security_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
struct sock *newsk);
int security_sctp_assoc_established(struct sctp_association *asoc,
struct sk_buff *skb);
#else /* CONFIG_SECURITY_NETWORK */
static inline int security_unix_stream_connect(struct sock *sock,
@ -1641,6 +1643,12 @@ static inline void security_sctp_sk_clone(struct sctp_association *asoc,
struct sock *newsk)
{
}
static inline int security_sctp_assoc_established(struct sctp_association *asoc,
struct sk_buff *skb)
{
return 0;
}
#endif /* CONFIG_SECURITY_NETWORK */
#ifdef CONFIG_SECURITY_INFINIBAND

8
net/sctp/sm_statefuns.c
View File

@ -930,6 +930,11 @@ enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
if (!sctp_vtag_verify(chunk, asoc))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Set peer label for connection. */
if (security_sctp_assoc_established((struct sctp_association *)asoc,
chunk->skb))
return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
/* Verify that the chunk length for the COOKIE-ACK is OK.
* If we don't do this, any bundled chunks may be junked.
*/
@ -945,9 +950,6 @@ enum sctp_disposition 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

7
security/security.c
View File

@ -2393,6 +2393,13 @@ void security_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk,
}
EXPORT_SYMBOL(security_sctp_sk_clone);
int security_sctp_assoc_established(struct sctp_association *asoc,
struct sk_buff *skb)
{
return call_int_hook(sctp_assoc_established, 0, asoc, skb);
}
EXPORT_SYMBOL(security_sctp_assoc_established);
#endif /* CONFIG_SECURITY_NETWORK */
#ifdef CONFIG_SECURITY_INFINIBAND