path: root/security/selinux/ss
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authorVenkat Yekkirala <vyekkirala@TrustedCS.com>2006-07-24 23:26:30 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2006-09-22 14:53:20 -0700
commit51bd39860ff829475aef611a3234309e37e090d9 (patch)
tree2ff1569f44f54ecad1d1d232bacfa4c76b9502a6 /security/selinux/ss
parente6e5fee1426bef07f4e6c3c76f48343c14207938 (diff)
[MLSXFRM]: Granular IPSec associations for use in MLS environments
The current approach to labeling Security Associations for SELinux purposes uses a one-to-one mapping between xfrm policy rules and security associations. This doesn't address the needs of real world MLS (Multi-level System, traditional Bell-LaPadula) environments where a single xfrm policy rule (pertaining to a range, classified to secret for example) might need to map to multiple Security Associations (one each for classified, secret, top secret and all the compartments applicable to these security levels). This patch set addresses the above problem by allowing for the mapping of a single xfrm policy rule to multiple security associations, with each association used in the security context it is defined for. It also includes the security context to be used in IKE negotiation in the acquire messages sent to the IKE daemon so that a unique SA can be negotiated for each unique security context. A couple of bug fixes are also included; checks to make sure the SAs used by a packet match policy (security context-wise) on the inbound and also that the bundle used for the outbound matches the security context of the flow. This patch set also makes the use of the SELinux sid in flow cache lookups seemless by including the sid in the flow key itself. Also, open requests as well as connection-oriented child sockets are labeled automatically to be at the same level as the peer to allow for use of appropriately labeled IPSec associations. Description of changes: A "sid" member has been added to the flow cache key resulting in the sid being available at all needed locations and the flow cache lookups automatically using the sid. The flow sid is derived from the socket on the outbound and the SAs (unlabeled where an SA was not used) on the inbound. Outbound case: 1. Find policy for the socket. 2. OLD: Find an SA that matches the policy. NEW: Find an SA that matches BOTH the policy and the flow/socket. This is necessary since not every SA that matches the policy can be used for the flow/socket. Consider policy range Secret-TS, and SAs each for Secret and TS. We don't want a TS socket to use the Secret SA. Hence the additional check for the SA Vs. flow/socket. 3. NEW: When looking thru bundles for a policy, make sure the flow/socket can use the bundle. If a bundle is not found, create one, calling for IKE if necessary. If using IKE, include the security context in the acquire message to the IKE daemon. Inbound case: 1. OLD: Find policy for the socket. NEW: Find policy for the incoming packet based on the sid of the SA(s) it used or the unlabeled sid if no SAs were used. (Consider a case where a socket is "authorized" for two policies (unclassified-confidential, secret-top_secret). If the packet has come in using a secret SA, we really ought to be using the latter policy (secret-top_secret).) 2. OLD: BUG: No check to see if the SAs used by the packet agree with the policy sec_ctx-wise. (It was indicated in selinux_xfrm_sock_rcv_skb() that this was being accomplished by (x->id.spi == tmpl->id.spi || !tmpl->id.spi) in xfrm_state_ok, but it turns out tmpl->id.spi would normally be zero (unless xfrm policy rules specify one at the template level, which they usually don't). NEW: The socket is checked for access to the SAs used (based on the sid of the SAs) in selinux_xfrm_sock_rcv_skb(). Forward case: This would be Step 1 from the Inbound case, followed by Steps 2 and 3 from the Outbound case. Outstanding items/issues: - Timewait acknowledgements and such are generated in the current/upstream implementation using a NULL socket resulting in the any_socket sid (SYSTEM_HIGH) to be used. This problem is not addressed by this patch set. This patch: Add new flask definitions to SELinux Adds a new avperm "polmatch" to arbitrate flow/state access to a xfrm policy rule. Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'security/selinux/ss')
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