x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES

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SGX enclave pages are inaccessible to normal software. They must be
populated with data by copying from normal memory with the help of the
EADD and EEXTEND functions of the ENCLS instruction.

Add an ioctl() which performs EADD that adds new data to an enclave, and
optionally EEXTEND functions that hash the page contents and use the
hash as part of enclave “measurement” to ensure enclave integrity.

The enclave author gets to decide which pages will be included in the
enclave measurement with EEXTEND. Measurement is very slow and has
sometimes has very little value. For instance, an enclave _could_
measure every page of data and code, but would be slow to initialize.
Or, it might just measure its code and then trust that code to
initialize the bulk of its data after it starts running.

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Jethro Beekman <jethro@fortanix.com>
Link: https://lkml.kernel.org/r/20201112220135.165028-14-jarkko@kernel.org

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This commit is contained in:

Jarkko Sakkinen 2020-11-13 00:01:24 +02:00 • committed by Borislav Petkov

parent 888d249117

commit c6d26d3707

3 changed files with 315 additions and 0 deletions

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30

arch/x86/include/uapi/asm/sgx.h

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284

arch/x86/kernel/cpu/sgx/ioctl.c

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1

arch/x86/kernel/cpu/sgx/sgx.h

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