For a heap makes sense to leave its contents "unmeasured" in the SGX
enclave build process, meaning that they won't contribute to the
cryptographic signature (a RSA-3072 signed SHA56 hash) of the enclave.
Enclaves are signed blobs where the signature is calculated both from
page data and also from "structural properties" of the pages. For
instance a page offset of *every* page added to the enclave is hashed.
For data, this is optional, not least because hashing a page has a
significant contribution to the enclave load time. Thus, where there is
no reason to hash, do not. The SGX ioctl interface supports this with
SGX_PAGE_MEASURE flag. Only when the flag is *set*, data is measured.
Add seg->measure boolean flag to struct encl_segment. Only when the
flag is set, include the segment data to the signature (represented
by SIGSTRUCT architectural structure).
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/625b6fe28fed76275e9238ec4e15ec3c0d87de81.1636997631.git.reinette.chatre@intel.com
Define source per segment so that enclave pages can be added from different
sources, e.g. anonymous VMA for zero pages. In other words, add 'src' field
to struct encl_segment, and assign it to 'encl->src' for pages inherited
from the enclave binary.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/7850709c3089fe20e4bcecb8295ba87c54cc2b4a.1636997631.git.reinette.chatre@intel.com
Q1 and Q2 are numbers with *maximum* length of 384 bytes. If the
calculated length of Q1 and Q2 is less than 384 bytes, things will
go wrong.
E.g. if Q2 is 383 bytes, then
1. The bytes of q2 are copied to sigstruct->q2 in calc_q1q2().
2. The entire sigstruct->q2 is reversed, which results it being
256 * Q2, given that the last byte of sigstruct->q2 is added
to before the bytes given by calc_q1q2().
Either change in key or measurement can trigger the bug. E.g. an
unmeasured heap could cause a devastating change in Q1 or Q2.
Reverse exactly the bytes of Q1 and Q2 in calc_q1q2() before returning
to the caller.
Fixes: 2adcba79e6 ("selftests/x86: Add a selftest for SGX")
Link: https://lore.kernel.org/linux-sgx/20210301051836.30738-1-tianjia.zhang@linux.alibaba.com/
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Use a statically generated key for signing the enclave, because
generating keys on the fly can eat the kernel entropy pool. Another
good reason for doing this is predictable builds. The RSA has been
arbitrarily selected. It's contents do not matter.
This also makes the selftest execute a lot quicker instead of the delay
that it had before (because of slow key generation).
[ bp: Disambiguate "static key" which means something else in the
kernel, fix typos. ]
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: linux-kselftest@vger.kernel.org
Link: https://lkml.kernel.org/r/20201118170640.39629-1-jarkko@kernel.org
Add a selftest for SGX. It is a trivial test where a simple enclave
copies one 64-bit word of memory between two memory locations,
but ensures that all SGX hardware and software infrastructure is
functioning.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Cc: linux-kselftest@vger.kernel.org
Link: https://lkml.kernel.org/r/20201112220135.165028-21-jarkko@kernel.org
