diff options
| author | Rick Edgecombe <rick.p.edgecombe@intel.com> | 2023-06-12 17:10:47 -0700 |
|---|---|---|
| committer | Rick Edgecombe <rick.p.edgecombe@intel.com> | 2023-07-11 14:12:19 -0700 |
| commit | b497e52ddb2ab750b00d8cc78209613558fc503b (patch) | |
| tree | 50a6375a6c6b7f0cf81c08081bec6831b1adf841 | |
| parent | 29f890d1050fc099fd578d9db844d6c0375902b6 (diff) | |
x86/mm: Teach pte_mkwrite() about stack memory
If a VMA has the VM_SHADOW_STACK flag, it is shadow stack memory. So
when it is made writable with pte_mkwrite(), it should create shadow
stack memory, not conventionally writable memory. Now that all the places
where shadow stack memory might be created pass a VMA into pte_mkwrite(),
it can know when it should do this.
So make pte_mkwrite() create shadow stack memory when the VMA has the
VM_SHADOW_STACK flag. Do the same thing for pmd_mkwrite().
This requires referencing VM_SHADOW_STACK in these functions, which are
currently defined in pgtable.h, however mm.h (where VM_SHADOW_STACK is
located) can't be pulled in without causing problems for files that
reference pgtable.h. So also move pte/pmd_mkwrite() into pgtable.c, where
they can safely reference VM_SHADOW_STACK.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Deepak Gupta <debug@rivosinc.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-22-rick.p.edgecombe%40intel.com
| -rw-r--r-- | arch/x86/mm/pgtable.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 4bfbe4cb6978..0d66aeb703a1 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -875,6 +875,9 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) { + if (vma->vm_flags & VM_SHADOW_STACK) + return pte_mkwrite_shstk(pte); + pte = pte_mkwrite_novma(pte); return pte_clear_saveddirty(pte); @@ -882,6 +885,9 @@ pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma) pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) { + if (vma->vm_flags & VM_SHADOW_STACK) + return pmd_mkwrite_shstk(pmd); + pmd = pmd_mkwrite_novma(pmd); return pmd_clear_saveddirty(pmd); |