The total size calculated for EPC can overflow u64 given the added up page for SECS. Further, the total size calculated for shmem can overflow even when the EPC size stays within limits of u64, given that it adds the extra space for 128 byte PCMD structures (one for each page).
Address this by pre-evaluating the micro-architectural requirement of SGX: the address space size must be power of two. This is eventually checked up by ECREATE but the pre-check has the additional benefit of making sure that there is some space for additional data.
Cc: stable@vger.kernel.org # v5.11+ Fixes: 888d24911787 ("x86/sgx: Add SGX_IOC_ENCLAVE_CREATE") Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/linux-sgx/c87e01a0-e7dd-4749-a348-0980d3444f04@stanl... Signed-off-by: Jarkko Sakkinen jarkko@kernel.org --- v3: Updated the commit message according to Dave's suggestion and added fixes tag. v2: Simply check the micro-architetural requirement in order to address Dave's comment: https://lore.kernel.org/linux-sgx/45e68dea-af6a-4b2a-8249-420f14de3424@intel... --- arch/x86/kernel/cpu/sgx/ioctl.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index b65ab214bdf5..776a20172867 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -64,6 +64,13 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs) struct file *backing; long ret;
+ /* + * ECREATE would detect this too, but checking here also ensures + * that the 'encl_size' calculations below can never overflow. + */ + if (!is_power_of_2(secs->size)) + return -EINVAL; + va_page = sgx_encl_grow(encl, true); if (IS_ERR(va_page)) return PTR_ERR(va_page);