diff options
Diffstat (limited to '0008-x86-sgx-x86-sgx-Add-sgx_encl_page-vm_run_prot_bits-f.patch')
| -rw-r--r-- | 0008-x86-sgx-x86-sgx-Add-sgx_encl_page-vm_run_prot_bits-f.patch | 168 |
1 files changed, 0 insertions, 168 deletions
diff --git a/0008-x86-sgx-x86-sgx-Add-sgx_encl_page-vm_run_prot_bits-f.patch b/0008-x86-sgx-x86-sgx-Add-sgx_encl_page-vm_run_prot_bits-f.patch deleted file mode 100644 index e05dcbd7cdc2..000000000000 --- a/0008-x86-sgx-x86-sgx-Add-sgx_encl_page-vm_run_prot_bits-f.patch +++ /dev/null @@ -1,168 +0,0 @@ -From f2bdca656a164126d3a89893828d334ae008c93a Mon Sep 17 00:00:00 2001 -From: Reinette Chatre <reinette.chatre@intel.com> -Date: Mon, 7 Feb 2022 16:45:30 -0800 -Subject: [PATCH 08/34] x86/sgx: x86/sgx: Add sgx_encl_page->vm_run_prot_bits - for dynamic permission changes - -Enclave creators declare their enclave page permissions (EPCM -permissions) at the time the pages are added to the enclave. These -page permissions are the vetted permissible accesses of the enclave -pages and stashed off (in struct sgx_encl_page->vm_max_prot_bits) -for later comparison with enclave PTEs and VMAs. - -Current permission support assume that EPCM permissions remain static -for the lifetime of the enclave. This is about to change with the -addition of support for SGX2 where the EPCM permissions of enclave -pages belonging to an initialized enclave may change during the -enclave's lifetime. - -Support for changing of EPCM permissions should continue to respect -the vetted maximum protection bits maintained in -sgx_encl_page->vm_max_prot_bits. Towards this end, add -sgx_encl_page->vm_run_prot_bits in preparation for support of -enclave page permission changes. sgx_encl_page->vm_run_prot_bits -reflect the active EPCM permissions of an enclave page and are not to -exceed sgx_encl_page->vm_max_prot_bits. - -Two permission fields are used: sgx_encl_page->vm_run_prot_bits -reflects the current EPCM permissions and is used to manage the page -table entries while sgx_encl_page->vm_max_prot_bits contains the vetted -maximum protection bits and is used to guide which EPCM permissions -are allowed in the upcoming SGX2 permission changing support (it guides -what values sgx_encl_page->vm_run_prot_bits may have). - -Consider this example how sgx_encl_page->vm_max_prot_bits and -sgx_encl_page->vm_run_prot_bits are used: - -(1) Add an enclave page with secinfo of RW to an uninitialized enclave: - sgx_encl_page->vm_max_prot_bits = RW - sgx_encl_page->vm_run_prot_bits = RW - - At this point RW VMAs would be allowed to access this page and PTEs - would allow write access as guided by - sgx_encl_page->vm_run_prot_bits. - -(2) User space invokes SGX2 to change the EPCM permissions to read-only. - This is allowed because sgx_encl_page->vm_max_prot_bits = RW: - sgx_encl_page->vm_max_prot_bits = RW - sgx_encl_page->vm_run_prot_bits = R - - At this point only new read-only VMAs would be allowed to access - this page and PTEs would not allow write access as guided - by sgx_encl_page->vm_run_prot_bits. - -(3) User space invokes SGX2 to change the EPCM permissions to RX. - This will not be supported by the kernel because - sgx_encl_page->vm_max_prot_bits = RW: - sgx_encl_page->vm_max_prot_bits = RW - sgx_encl_page->vm_run_prot_bits = R - -(3) User space invokes SGX2 to change the EPCM permissions to RW. - This will be allowed because sgx_encl_page->vm_max_prot_bits = RW: - sgx_encl_page->vm_max_prot_bits = RW - sgx_encl_page->vm_run_prot_bits = RW - - At this point RW VMAs would again be allowed to access this page - and PTEs would allow write access as guided by - sgx_encl_page->vm_run_prot_bits. - -struct sgx_encl_page hosting this information is maintained for each -enclave page so the space consumed by the struct is important. -The existing sgx_encl_page->vm_max_prot_bits is already unsigned long -while only using three bits. Transition to a bitfield for the two -members containing protection bits. - -Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> ---- - Documentation/x86/sgx.rst | 10 ++++++++++ - arch/x86/kernel/cpu/sgx/encl.c | 6 +++--- - arch/x86/kernel/cpu/sgx/encl.h | 3 ++- - arch/x86/kernel/cpu/sgx/ioctl.c | 6 ++++++ - 4 files changed, 21 insertions(+), 4 deletions(-) - -diff --git a/Documentation/x86/sgx.rst b/Documentation/x86/sgx.rst -index 5659932728a5..9df620b59f83 100644 ---- a/Documentation/x86/sgx.rst -+++ b/Documentation/x86/sgx.rst -@@ -99,6 +99,16 @@ The relationships between the different permission masks are: - * PTEs are installed to match the EPCM permissions, but not be more - relaxed than the VMA permissions. - -+During runtime the EPCM permissions of enclave pages belonging to an -+initialized enclave can change on systems supporting SGX2. In support -+of these runtime changes the kernel maintains (for each enclave page) -+the most permissive EPCM permission mask allowed by policy as -+the ``vm_max_prot_bits`` of that page. EPCM permissions are not allowed -+to be relaxed beyond ``vm_max_prot_bits``. The kernel also maintains -+the currently active EPCM permissions of an enclave page as its -+``vm_run_prot_bits`` to ensure PTEs and new VMAs respect the active -+EPCM permission values. -+ - On systems supporting SGX2 EPCM permissions may change while the - enclave page belongs to a VMA without impacting the VMA permissions. - This means that a running VMA may appear to allow access to an enclave -diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c -index acedccf8c4ef..85429db8c8b5 100644 ---- a/arch/x86/kernel/cpu/sgx/encl.c -+++ b/arch/x86/kernel/cpu/sgx/encl.c -@@ -205,7 +205,7 @@ static vm_fault_t sgx_vma_fault(struct vm_fault *vmf) - * exceed the VMA permissions. - */ - vm_prot_bits = vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC); -- page_prot_bits = entry->vm_max_prot_bits & vm_prot_bits; -+ page_prot_bits = entry->vm_run_prot_bits & vm_prot_bits; - /* - * Add VM_SHARED so that PTE is made writable right away if VMA - * and EPCM are writable (no COW in SGX). -@@ -258,7 +258,7 @@ static vm_fault_t sgx_vma_pfn_mkwrite(struct vm_fault *vmf) - goto out; - } - -- if (!(entry->vm_max_prot_bits & VM_WRITE)) -+ if (!(entry->vm_run_prot_bits & VM_WRITE)) - ret = VM_FAULT_SIGBUS; - - out: -@@ -321,7 +321,7 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, - mutex_lock(&encl->lock); - xas_lock(&xas); - xas_for_each(&xas, page, PFN_DOWN(end - 1)) { -- if (~page->vm_max_prot_bits & vm_prot_bits) { -+ if (~page->vm_run_prot_bits & vm_prot_bits) { - ret = -EACCES; - break; - } -diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h -index fec43ca65065..dc262d843411 100644 ---- a/arch/x86/kernel/cpu/sgx/encl.h -+++ b/arch/x86/kernel/cpu/sgx/encl.h -@@ -27,7 +27,8 @@ - - struct sgx_encl_page { - unsigned long desc; -- unsigned long vm_max_prot_bits; -+ unsigned long vm_max_prot_bits:8; -+ unsigned long vm_run_prot_bits:8; - struct sgx_epc_page *epc_page; - struct sgx_encl *encl; - struct sgx_va_page *va_page; -diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c -index 83df20e3e633..7e0819a89532 100644 ---- a/arch/x86/kernel/cpu/sgx/ioctl.c -+++ b/arch/x86/kernel/cpu/sgx/ioctl.c -@@ -197,6 +197,12 @@ static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl, - /* Calculate maximum of the VM flags for the page. */ - encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0); - -+ /* -+ * At time of allocation, the runtime protection bits are the same -+ * as the maximum protection bits. -+ */ -+ encl_page->vm_run_prot_bits = encl_page->vm_max_prot_bits; -+ - return encl_page; - } - --- -2.35.1 - |