x86/sgx: Add overflow check in sgx_validate_offset_length()

mainline inclusion
from mainline-v6.1-rc6
commit f0861f49
category: bugfix
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I6X1FF
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f0861f49bd946ff94fce4f82509c45e167f63690



Intel-SIG: commit f0861f49 x86/sgx: Add overflow check in
sgx_validate_offset_length()
Incremental backporting patches for SGX on Intel Xeon platform.

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

sgx_validate_offset_length() function verifies "offset" and "length"
arguments provided by userspace, but was missing an overflow check on
their addition. Add it.

Fixes: c6d26d37 ("x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES")
Signed-off-by: Borys Popławski <borysp@invisiblethingslab.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Cc: stable@vger.kernel.org # v5.11+
Link: https://lore.kernel.org/r/0d91ac79-6d84-abed-5821-4dbe59fa1a38@invisiblethingslab.com


[ Zhiquan: amend commit log ]
Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com>