x86/sgx: Return -EINVAL on a zero length buffer in sgx_ioc_enclave_add_pages()

mainline inclusion
from mainline-v5.11-rc1
commit a4b9c48b
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SIGI


CVE: NA

--------------------------------

The sgx_enclave_add_pages.length field is documented as

 * @length:     length of the data (multiple of the page size)

Fail with -EINVAL, when the caller gives a zero length buffer of data
to be added as pages to an enclave. Right now 'ret' is returned as
uninitialized in that case.

 [ bp: Flesh out commit message. ]

Intel-SIG: commit a4b9c48b x86/sgx: Return -EINVAL on a zero length buffer in sgx_ioc_enclave_add_pages()
Backport for SGX Foundations support

Fixes: c6d26d37 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/linux-sgx/X8ehQssnslm194ld@mwanda/
Link: https://lkml.kernel.org/r/20201203183527.139317-1-jarkko@kernel.org


Signed-off-by: Fan Du <fan.du@intel.com> #openEuler_contributor
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Reviewed-by: Bamvor Zhang <bamvor.zhang@suse.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>