mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-13 01:26:43 +07:00
72e89f5008
The SCTP security hooks are explained in: Documentation/security/LSM-sctp.rst Signed-off-by: Richard Haines <richard_c_haines@btinternet.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
176 lines
7.5 KiB
ReStructuredText
176 lines
7.5 KiB
ReStructuredText
SCTP LSM Support
|
|
================
|
|
|
|
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()
|
|
|
|
The usage of these hooks are described below with the SELinux implementation
|
|
described in ``Documentation/security/SELinux-sctp.rst``
|
|
|
|
|
|
security_sctp_assoc_request()
|
|
-----------------------------
|
|
Passes the ``@ep`` and ``@chunk->skb`` of the association INIT packet to the
|
|
security module. Returns 0 on success, error on failure.
|
|
::
|
|
|
|
@ep - pointer to sctp endpoint structure.
|
|
@skb - pointer to skbuff of association packet.
|
|
|
|
|
|
security_sctp_bind_connect()
|
|
-----------------------------
|
|
Passes one or more ipv4/ipv6 addresses to the security module for validation
|
|
based on the ``@optname`` that will result in either a bind or connect
|
|
service as shown in the permission check tables below.
|
|
Returns 0 on success, error on failure.
|
|
::
|
|
|
|
@sk - Pointer to sock structure.
|
|
@optname - Name of the option to validate.
|
|
@address - One or more ipv4 / ipv6 addresses.
|
|
@addrlen - The total length of address(s). This is calculated on each
|
|
ipv4 or ipv6 address using sizeof(struct sockaddr_in) or
|
|
sizeof(struct sockaddr_in6).
|
|
|
|
------------------------------------------------------------------
|
|
| BIND Type Checks |
|
|
| @optname | @address contains |
|
|
|----------------------------|-----------------------------------|
|
|
| SCTP_SOCKOPT_BINDX_ADD | One or more ipv4 / ipv6 addresses |
|
|
| SCTP_PRIMARY_ADDR | Single ipv4 or ipv6 address |
|
|
| SCTP_SET_PEER_PRIMARY_ADDR | Single ipv4 or ipv6 address |
|
|
------------------------------------------------------------------
|
|
|
|
------------------------------------------------------------------
|
|
| CONNECT Type Checks |
|
|
| @optname | @address contains |
|
|
|----------------------------|-----------------------------------|
|
|
| SCTP_SOCKOPT_CONNECTX | One or more ipv4 / ipv6 addresses |
|
|
| SCTP_PARAM_ADD_IP | One or more ipv4 / ipv6 addresses |
|
|
| SCTP_SENDMSG_CONNECT | Single ipv4 or ipv6 address |
|
|
| SCTP_PARAM_SET_PRIMARY | Single ipv4 or ipv6 address |
|
|
------------------------------------------------------------------
|
|
|
|
A summary of the ``@optname`` entries is as follows::
|
|
|
|
SCTP_SOCKOPT_BINDX_ADD - Allows additional bind addresses to be
|
|
associated after (optionally) calling
|
|
bind(3).
|
|
sctp_bindx(3) adds a set of bind
|
|
addresses on a socket.
|
|
|
|
SCTP_SOCKOPT_CONNECTX - Allows the allocation of multiple
|
|
addresses for reaching a peer
|
|
(multi-homed).
|
|
sctp_connectx(3) initiates a connection
|
|
on an SCTP socket using multiple
|
|
destination addresses.
|
|
|
|
SCTP_SENDMSG_CONNECT - Initiate a connection that is generated by a
|
|
sendmsg(2) or sctp_sendmsg(3) on a new asociation.
|
|
|
|
SCTP_PRIMARY_ADDR - Set local primary address.
|
|
|
|
SCTP_SET_PEER_PRIMARY_ADDR - Request peer sets address as
|
|
association primary.
|
|
|
|
SCTP_PARAM_ADD_IP - These are used when Dynamic Address
|
|
SCTP_PARAM_SET_PRIMARY - Reconfiguration is enabled as explained below.
|
|
|
|
|
|
To support Dynamic Address Reconfiguration the following parameters must be
|
|
enabled on both endpoints (or use the appropriate **setsockopt**\(2))::
|
|
|
|
/proc/sys/net/sctp/addip_enable
|
|
/proc/sys/net/sctp/addip_noauth_enable
|
|
|
|
then the following *_PARAM_*'s are sent to the peer in an
|
|
ASCONF chunk when the corresponding ``@optname``'s are present::
|
|
|
|
@optname ASCONF Parameter
|
|
---------- ------------------
|
|
SCTP_SOCKOPT_BINDX_ADD -> SCTP_PARAM_ADD_IP
|
|
SCTP_SET_PEER_PRIMARY_ADDR -> SCTP_PARAM_SET_PRIMARY
|
|
|
|
|
|
security_sctp_sk_clone()
|
|
-------------------------
|
|
Called whenever a new socket is created by **accept**\(2)
|
|
(i.e. a TCP style socket) or when a socket is 'peeled off' e.g userspace
|
|
calls **sctp_peeloff**\(3).
|
|
::
|
|
|
|
@ep - pointer to current sctp endpoint structure.
|
|
@sk - pointer to current sock structure.
|
|
@sk - pointer to new sock structure.
|
|
|
|
|
|
security_inet_conn_established()
|
|
---------------------------------
|
|
Called when a COOKIE ACK is received::
|
|
|
|
@sk - pointer to sock structure.
|
|
@skb - pointer to skbuff of the COOKIE ACK packet.
|
|
|
|
|
|
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
|
|
establishing an association.
|
|
::
|
|
|
|
SCTP endpoint "A" SCTP endpoint "Z"
|
|
================= =================
|
|
sctp_sf_do_prm_asoc()
|
|
Association setup can be initiated
|
|
by a connect(2), sctp_connectx(3),
|
|
sendmsg(2) or sctp_sendmsg(3).
|
|
These will result in a call to
|
|
security_sctp_bind_connect() to
|
|
initiate an association to
|
|
SCTP peer endpoint "Z".
|
|
INIT --------------------------------------------->
|
|
sctp_sf_do_5_1B_init()
|
|
Respond to an INIT chunk.
|
|
SCTP peer endpoint "A" is
|
|
asking for an association. Call
|
|
security_sctp_assoc_request()
|
|
to set the peer label if first
|
|
association.
|
|
If not first association, check
|
|
whether allowed, IF so send:
|
|
<----------------------------------------------- INIT ACK
|
|
| ELSE audit event and silently
|
|
| discard the packet.
|
|
|
|
|
COOKIE ECHO ------------------------------------------>
|
|
|
|
|
|
|
|
|
|
|
<------------------------------------------- COOKIE ACK
|
|
| |
|
|
sctp_sf_do_5_1E_ca |
|
|
Call security_inet_conn_established() |
|
|
to set the peer label. |
|
|
| |
|
|
| If SCTP_SOCKET_TCP or peeled off
|
|
| socket security_sctp_sk_clone() is
|
|
| called to clone the new socket.
|
|
| |
|
|
ESTABLISHED ESTABLISHED
|
|
| |
|
|
------------------------------------------------------------------
|
|
| Association Established |
|
|
------------------------------------------------------------------
|
|
|
|
|