Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull usercopy protection from Kees Cook:
 "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and
  copy_from_user bounds checking for most architectures on SLAB and
  SLUB"

* tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm: SLUB hardened usercopy support
  mm: SLAB hardened usercopy support
  s390/uaccess: Enable hardened usercopy
  sparc/uaccess: Enable hardened usercopy
  powerpc/uaccess: Enable hardened usercopy
  ia64/uaccess: Enable hardened usercopy
  arm64/uaccess: Enable hardened usercopy
  ARM: uaccess: Enable hardened usercopy
  x86/uaccess: Enable hardened usercopy
  mm: Hardened usercopy
  mm: Implement stack frame object validation
  mm: Add is_migrate_cma_page

1 files changed, 28 insertions, 0 deletions

diff --git a/security/Kconfig b/security/Kconfig
index 176758cdfa57..df28f2b6f3e1 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -118,6 +118,34 @@ config LSM_MMAP_MIN_ADDR
           this low address space will need the permission specific to the
           systems running LSM.
 
+config HAVE_HARDENED_USERCOPY_ALLOCATOR
+        bool
+        help
+          The heap allocator implements __check_heap_object() for
+          validating memory ranges against heap object sizes in
+          support of CONFIG_HARDENED_USERCOPY.
+
+config HAVE_ARCH_HARDENED_USERCOPY
+        bool
+        help
+          The architecture supports CONFIG_HARDENED_USERCOPY by
+          calling check_object_size() just before performing the
+          userspace copies in the low level implementation of
+          copy_to_user() and copy_from_user().
+
+config HARDENED_USERCOPY
+        bool "Harden memory copies between kernel and userspace"
+        depends on HAVE_ARCH_HARDENED_USERCOPY
+        select BUG
+        help
+          This option checks for obviously wrong memory regions when
+          copying memory to/from the kernel (via copy_to_user() and
+          copy_from_user() functions) by rejecting memory ranges that
+          are larger than the specified heap object, span multiple
+          separately allocates pages, are not on the process stack,
+          or are part of the kernel text. This kills entire classes
+          of heap overflow exploits and similar kernel memory exposures.
+
 source security/selinux/Kconfig
 source security/smack/Kconfig
 source security/tomoyo/Kconfig