| Message ID | 20230319001535.23210-19-rick.p.edgecombe@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Shadow stacks for userspace | expand |
On 19.03.23 01:15, Rick Edgecombe wrote: > From: Yu-cheng Yu <yu-cheng.yu@intel.com> > > New hardware extensions implement support for shadow stack memory, such > as x86 Control-flow Enforcement Technology (CET). Add a new VM flag to > identify these areas, for example, to be used to properly indicate shadow > stack PTEs to the hardware. > > Shadow stack VMA creation will be tightly controlled and limited to > anonymous memory to make the implementation simpler and since that is all > that is required. The solution will rely on pte_mkwrite() to create the > shadow stack PTEs, so it will not be required for vm_get_page_prot() to > learn how to create shadow stack memory. For this reason document that > VM_SHADOW_STACK should not be mixed with VM_SHARED. > > Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> > Tested-by: Pengfei Xu <pengfei.xu@intel.com> > Tested-by: John Allen <john.allen@amd.com> > Tested-by: Kees Cook <keescook@chromium.org> > --- Acked-by: David Hildenbrand <david@redhat.com>
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index 9d5fd9424e8b..8b314df7ccdf 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -564,6 +564,7 @@ encoded manner. The codes are the following: mt arm64 MTE allocation tags are enabled um userfaultfd missing tracking uw userfaultfd wr-protect tracking + ss shadow stack page == ======================================= Note that there is no guarantee that every flag and associated mnemonic will diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 6a96e1713fd5..324b092c2ac9 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -711,6 +711,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR [ilog2(VM_UFFD_MINOR)] = "ui", #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ +#ifdef CONFIG_X86_USER_SHADOW_STACK + [ilog2(VM_SHADOW_STACK)] = "ss", +#endif }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index a1b31caae013..097544afb1aa 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -326,11 +326,13 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) +#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ #ifdef CONFIG_ARCH_HAS_PKEYS @@ -346,6 +348,12 @@ extern unsigned int kobjsize(const void *objp); #endif #endif /* CONFIG_ARCH_HAS_PKEYS */ +#ifdef CONFIG_X86_USER_SHADOW_STACK +# define VM_SHADOW_STACK VM_HIGH_ARCH_5 /* Should not be set with VM_SHARED */ +#else +# define VM_SHADOW_STACK VM_NONE +#endif + #if defined(CONFIG_X86) # define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC)