On Mon, Oct 26, 2020 at 02:26:13PM -0700, Dave Hansen wrote: > On 6/26/20 8:34 AM, Borislav Petkov wrote: > >> + if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED)) > >> + return -EINVAL; > >> + > >> + if (copy_from_user(&addp, arg, sizeof(addp))) > >> + return -EFAULT; > >> + > >> + if (!IS_ALIGNED(addp.offset, PAGE_SIZE) || > >> + !IS_ALIGNED(addp.src, PAGE_SIZE)) > >> + return -EINVAL; > >> + > >> + if (!(access_ok(addp.src, PAGE_SIZE))) > >> + return -EFAULT; > >> + > >> + if (addp.length & (PAGE_SIZE - 1)) > >> + return -EINVAL; > > How many pages are allowed? Unlimited? I'm hoping some limits are > > checked somewhere... > > What were you concerned about here? Was it how long the syscall could > take, or that one user could exhaust all the enclave memory in one call? > > Some later versions of this patch have a 1MB limit per to reduce how > long each SGX_IOC_ENCLAVE_ADD_PAGES call spends in the kernel. But, I'm > not _sure_ that's what you were intending. The loop does check for pending signals, i.e. it is possible to interrupt it. /Jarkko
