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EPCM permission changes could be made from within (to relax permissions) or out (to restrict permissions) the enclave. Kernel support is needed when permissions are restricted to be able to call the privileged ENCLS[EMODPR] instruction. EPCM permissions can be relaxed via ENCLU[EMODPE] from within the enclave but the enclave still depends on the kernel to install PTEs with the needed permissions. Add a test that exercises a few of the enclave page permission flows: 1) Test starts with a RW (from enclave and kernel perspective) enclave page that is mapped via a RW VMA. 2) Use the SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS ioctl() to restrict the enclave (EPCM) page permissions to read-only. 3) Run ENCLU[EACCEPT] from within the enclave to accept the new page permissions. 4) Attempt to write to the enclave page from within the enclave - this should fail with a page fault on the EPCM permissions since the page table entry continues to allow RW access. 5) Restore EPCM permissions to RW by running ENCLU[EMODPE] from within the enclave. 6) Attempt to write to the enclave page from within the enclave - this should succeed since both EPCM and PTE permissions allow this access. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lkml.kernel.org/r/2617bf2b2d1e27ca1d0096e1192ae5896baf3f80.1652137848.git.reinette.chatre@intel.com |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.