diff options
Diffstat (limited to 'Documentation/security')
| -rw-r--r-- | Documentation/security/LSM.rst | 5 | ||||
| -rw-r--r-- | Documentation/security/SCTP.rst (renamed from Documentation/security/LSM-sctp.rst) | 180 | ||||
| -rw-r--r-- | Documentation/security/SELinux-sctp.rst | 158 | ||||
| -rw-r--r-- | Documentation/security/index.rst | 3 |
4 files changed, 179 insertions, 167 deletions
diff --git a/Documentation/security/LSM.rst b/Documentation/security/LSM.rst index 8b9ee597e9d0..31d92bc5fdd2 100644 --- a/Documentation/security/LSM.rst +++ b/Documentation/security/LSM.rst @@ -11,4 +11,7 @@ that end users and distros can make a more informed decision about which LSMs suit their requirements. For extensive documentation on the available LSM hook interfaces, please -see ``include/linux/lsm_hooks.h``. +see ``include/linux/lsm_hooks.h`` and associated structures: + +.. kernel-doc:: include/linux/lsm_hooks.h + :internal: diff --git a/Documentation/security/LSM-sctp.rst b/Documentation/security/SCTP.rst index 6e5a3925a860..d903eb97fcf3 100644 --- a/Documentation/security/LSM-sctp.rst +++ b/Documentation/security/SCTP.rst @@ -1,6 +1,15 @@ +.. SPDX-License-Identifier: GPL-2.0 + +==== +SCTP +==== + SCTP LSM Support ================ +Security Hooks +-------------- + For security module support, three SCTP specific hooks have been implemented:: security_sctp_assoc_request() @@ -12,11 +21,11 @@ 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`` +described in the `SCTP SELinux Support`_ chapter. 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. :: @@ -26,7 +35,7 @@ security module. Returns 0 on success, error on failure. 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. @@ -102,7 +111,7 @@ ASCONF chunk when the corresponding ``@optname``'s are present:: 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). @@ -114,7 +123,7 @@ calls **sctp_peeloff**\(3). security_inet_conn_established() ---------------------------------- +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Called when a COOKIE ACK is received:: @sk - pointer to sock structure. @@ -122,7 +131,8 @@ Called when a COOKIE ACK is received:: 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. @@ -173,3 +183,161 @@ establishing an association. ------------------------------------------------------------------ +SCTP SELinux Support +==================== + +Security Hooks +-------------- + +The `SCTP LSM Support`_ chapter above describes the following SCTP security +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_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. + +The security module performs the following operations: + IF this is the first association on ``@ep->base.sk``, then set the peer + sid to that in ``@skb``. This will ensure there is only one peer sid + assigned to ``@ep->base.sk`` that may support multiple associations. + + ELSE validate the ``@ep->base.sk peer_sid`` against the ``@skb peer sid`` + to determine whether the association should be allowed or denied. + + Set the sctp ``@ep sid`` to socket's sid (from ``ep->base.sk``) with + MLS portion taken from ``@skb peer sid``. This will be used by SCTP + TCP style sockets and peeled off connections as they cause a new socket + to be generated. + + If IP security options are configured (CIPSO/CALIPSO), then the ip + options are set on the socket. + + +security_sctp_bind_connect() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Checks permissions required for ipv4/ipv6 addresses based on the ``@optname`` +as follows:: + + ------------------------------------------------------------------ + | BIND Permission 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 Permission 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 | + ------------------------------------------------------------------ + + +`SCTP LSM Support`_ gives a summary of the ``@optname`` +entries and also describes ASCONF chunk processing when Dynamic Address +Reconfiguration is enabled. + + +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). ``security_sctp_sk_clone()`` will set the new +sockets sid and peer sid to that contained in the ``@ep sid`` and +``@ep peer sid`` respectively. +:: + + @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 where it sets the connection's peer sid +to that in ``@skb``:: + + @sk - pointer to sock structure. + @skb - pointer to skbuff of the COOKIE ACK packet. + + +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; + +SELinux SCTP support adds the ``name_connect`` permission for connecting +to a specific port type and the ``association`` permission that is explained +in the section 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 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. Any further +associations on this socket will have their packet peer label compared to +the sockets peer label, and only if they are different will the +``association`` permission be validated. This is 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 can support more than one transport address per endpoint + (multi-homing) on a single socket, it is possible to configure policy + and NetLabel to provide different peer labels for each of these. As the + socket peer label is determined by the first associations transport + address, it is recommended that all peer labels are consistent. + + 3) **getpeercon**\(3) may be used by userspace to retrieve the sockets peer + context. + + 4) While not SCTP specific, be aware when using NetLabel 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). + + 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. + + 7) IPSEC is not supported as RFC 3554 - sctp/ipsec support has not been + implemented in userspace (**racoon**\(8) or **ipsec_pluto**\(8)), + although the kernel supports SCTP/IPSEC. diff --git a/Documentation/security/SELinux-sctp.rst b/Documentation/security/SELinux-sctp.rst deleted file mode 100644 index a332cb1c5334..000000000000 --- a/Documentation/security/SELinux-sctp.rst +++ /dev/null @@ -1,158 +0,0 @@ -SCTP SELinux Support -===================== - -Security Hooks -=============== - -``Documentation/security/LSM-sctp.rst`` describes the following SCTP security -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_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. - -The security module performs the following operations: - IF this is the first association on ``@ep->base.sk``, then set the peer - sid to that in ``@skb``. This will ensure there is only one peer sid - assigned to ``@ep->base.sk`` that may support multiple associations. - - ELSE validate the ``@ep->base.sk peer_sid`` against the ``@skb peer sid`` - to determine whether the association should be allowed or denied. - - Set the sctp ``@ep sid`` to socket's sid (from ``ep->base.sk``) with - MLS portion taken from ``@skb peer sid``. This will be used by SCTP - TCP style sockets and peeled off connections as they cause a new socket - to be generated. - - If IP security options are configured (CIPSO/CALIPSO), then the ip - options are set on the socket. - - -security_sctp_bind_connect() ------------------------------ -Checks permissions required for ipv4/ipv6 addresses based on the ``@optname`` -as follows:: - - ------------------------------------------------------------------ - | BIND Permission 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 Permission 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 | - ------------------------------------------------------------------ - - -``Documentation/security/LSM-sctp.rst`` gives a summary of the ``@optname`` -entries and also describes ASCONF chunk processing when Dynamic Address -Reconfiguration is enabled. - - -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). ``security_sctp_sk_clone()`` will set the new -sockets sid and peer sid to that contained in the ``@ep sid`` and -``@ep peer sid`` respectively. -:: - - @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 where it sets the connection's peer sid -to that in ``@skb``:: - - @sk - pointer to sock structure. - @skb - pointer to skbuff of the COOKIE ACK packet. - - -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; - -SELinux SCTP support adds the ``name_connect`` permission for connecting -to a specific port type and the ``association`` permission that is explained -in the section 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 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. Any further -associations on this socket will have their packet peer label compared to -the sockets peer label, and only if they are different will the -``association`` permission be validated. This is 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 can support more than one transport address per endpoint - (multi-homing) on a single socket, it is possible to configure policy - and NetLabel to provide different peer labels for each of these. As the - socket peer label is determined by the first associations transport - address, it is recommended that all peer labels are consistent. - - 3) **getpeercon**\(3) may be used by userspace to retrieve the sockets peer - context. - - 4) While not SCTP specific, be aware when using NetLabel 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). - - 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. - - 7) IPSEC is not supported as RFC 3554 - sctp/ipsec support has not been - implemented in userspace (**racoon**\(8) or **ipsec_pluto**\(8)), - although the kernel supports SCTP/IPSEC. diff --git a/Documentation/security/index.rst b/Documentation/security/index.rst index 85492bfca530..aad6d92ffe31 100644 --- a/Documentation/security/index.rst +++ b/Documentation/security/index.rst @@ -9,7 +9,6 @@ Security Documentation IMA-templates keys/index LSM - LSM-sctp - SELinux-sctp + SCTP self-protection tpm/index |