Christoph Hellwig wrote: > Of course that needs further changes! > > (a) actually implement that field, and > (b) change the prototype of the hook to int (*sysctl)(int op, enum sensitivity); No. If one were to add such a field, then it would be accessible through the ctl_table structure that is already passed to the hook. You would not replace the ctl_table parameter with the kernel's sensitivity hint, since the security module must be able to make its own determination as to the protection requirements based on its particular security model and attributes. If you only pass the kernel's view of the sensitivity, then you are hardcoding a specific policy into the kernel and severely limiting the flexibility of the security module. Since the kernel's hint is necessarily independent of any particular security model/attributes, it will only provide a coarse-grained partitioning, e.g. you are unlikely to be able to uniquely distinguish the modprobe variable if you want to specifically limit a particular process to modifying it. The existing hook interface does not need to change. Implementing a sensitivity hint field in the ctl_table structure would be trivial, but determining a set of policy-neutral hint values that capture important confidentiality, integrity, and functional characteristics and mapping the existing set of sysctl variables to those hint values is a longer term task. The hook provides useful functionality now, apart from such hints, and should not need to wait on them. In the short term, there may be a certain amount of duplication of information among security modules regarding sensitive sysctl variables, but that information can actually help to feed back into the process of determining the right general set of hint values necessary to support multiple security models and the mappings for the existing sysctl variables. -- Stephen Smalley, NSA sdsat_private _______________________________________________ linux-security-module mailing list linux-security-moduleat_private http://mail.wirex.com/mailman/listinfo/linux-security-module
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