On Thu, 7 Feb 2002, Emily Ratliff wrote: > I don't think that this is unique to SECURE_SHM, but I am not sure if it > is due to the fact that SECURE_SHM is not access control functionality, or > whether it is just because it touches a part of the kernel that exports > very few of its symbols. I can see other module writers having this > problem and I'd like to know what the LSM community's opinion is. The LSM kernel patch already moves some of the private data structure definitions for System V IPC into public headers in order to allow LSM to hook operations on these kernel objects. Hence, there is a precedent for such changes; however, an apparent difference is that you are seeking access to not only private data structure definitions but to the actual private data and functions of the IPC subsystem. Of course, if such access were exported, a security module that uses it would need to be configurable to reflect the fact that the IPC subsystem may not be present in the kernel depending on the kernel configuration. The SELinux security module had a similar issue in implementing some of its new System V IPC system calls. However, these new calls could be implemented by calling the entrypoint function for the IPC calls and using the hook functions to perform any additional processing, passing information between the new call and the hook using fields in the task security object. See selinux/syscalls.c:sys_shmsid for an example; this call retrieves the security identifier for a shared memory object by calling the entrypoint function with the shmctl call and IPC_STAT command, and the selinux_shm_shmctl hook then saves the security identifier in a field of the task security object for return. However, this approach doesn't seem especially well-suited to your need. My concern with exporting the private IPC data and functions would be the potential reaction by the kernel IPC maintainer. It might be wise to interact with that maintainer to see whether such a change would be strongly resisted or if another approach might be better. -- Stephen D. Smalley, NAI Labs ssmalleyat_private _______________________________________________ linux-security-module mailing list linux-security-moduleat_private http://mail.wirex.com/mailman/listinfo/linux-security-module
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