Merge tag 'hardening-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "As usual, it's scattered changes all over. Patches touching things
  outside of our traditional areas in the tree have been Acked by
  maintainers or were trivial changes:

   - loadpin: remove unsupported MODULE_COMPRESS_NONE (Arulpandiyan
     Vadivel)

   - samples/check-exec: Fix script name (Mickaël Salaün)

   - yama: remove needless locking in yama_task_prctl() (Oleg Nesterov)

   - lib/string_choices: Sort by function name (R Sundar)

   - hardening: Allow default HARDENED_USERCOPY to be set at compile
     time (Mel Gorman)

   - uaccess: Split out compile-time checks into ucopysize.h

   - kbuild: clang: Support building UM with SUBARCH=i386

   - x86: Enable i386 FORTIFY_SOURCE on Clang 16+

   - ubsan/overflow: Rework integer overflow sanitizer option

   - Add missing __nonstring annotations for callers of
     memtostr*()/strtomem*()

   - Add __must_be_noncstr() and have memtostr*()/strtomem*() check for
     it

   - Introduce __nonstring_array for silencing future GCC 15 warnings"

* tag 'hardening-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits)
  compiler_types: Introduce __nonstring_array
  hardening: Enable i386 FORTIFY_SOURCE on Clang 16+
  x86/build: Remove -ffreestanding on i386 with GCC
  ubsan/overflow: Enable ignorelist parsing and add type filter
  ubsan/overflow: Enable pattern exclusions
  ubsan/overflow: Rework integer overflow sanitizer option to turn on everything
  samples/check-exec: Fix script name
  yama: don't abuse rcu_read_lock/get_task_struct in yama_task_prctl()
  kbuild: clang: Support building UM with SUBARCH=i386
  loadpin: remove MODULE_COMPRESS_NONE as it is no longer supported
  lib/string_choices: Rearrange functions in sorted order
  string.h: Validate memtostr*()/strtomem*() arguments more carefully
  compiler.h: Introduce __must_be_noncstr()
  nilfs2: Mark on-disk strings as nonstring
  uapi: stddef.h: Introduce __kernel_nonstring
  x86/tdx: Mark message.bytes as nonstring
  string: kunit: Mark nonstring test strings as __nonstring
  scsi: qla2xxx: Mark device strings as nonstring
  scsi: mpt3sas: Mark device strings as nonstring
  scsi: mpi3mr: Mark device strings as nonstring
  ...

1 files changed, 10 insertions, 8 deletions

diff --git a/mm/usercopy.c b/mm/usercopy.c
index 83c164aba6e0..dbdcc43964fb 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -17,7 +17,7 @@
 #include <linux/sched.h>
 #include <linux/sched/task.h>
 #include <linux/sched/task_stack.h>
-#include <linux/thread_info.h>
+#include <linux/ucopysize.h>
 #include <linux/vmalloc.h>
 #include <linux/atomic.h>
 #include <linux/jump_label.h>
@@ -201,7 +201,9 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 	}
 }
 
-static DEFINE_STATIC_KEY_FALSE_RO(bypass_usercopy_checks);
+DEFINE_STATIC_KEY_MAYBE_RO(CONFIG_HARDENED_USERCOPY_DEFAULT_ON,
+			   validate_usercopy_range);
+EXPORT_SYMBOL(validate_usercopy_range);
 
 /*
  * Validates that the given object is:
@@ -212,9 +214,6 @@ static DEFINE_STATIC_KEY_FALSE_RO(bypass_usercopy_checks);
  */
 void __check_object_size(const void *ptr, unsigned long n, bool to_user)
 {
-	if (static_branch_unlikely(&bypass_usercopy_checks))
-		return;
-
 	/* Skip all tests if size is zero. */
 	if (!n)
 		return;
@@ -255,7 +254,8 @@ void __check_object_size(const void *ptr, unsigned long n, bool to_user)
 }
 EXPORT_SYMBOL(__check_object_size);
 
-static bool enable_checks __initdata = true;
+static bool enable_checks __initdata =
+		IS_ENABLED(CONFIG_HARDENED_USERCOPY_DEFAULT_ON);
 
 static int __init parse_hardened_usercopy(char *str)
 {
@@ -269,8 +269,10 @@ __setup("hardened_usercopy=", parse_hardened_usercopy);
 
 static int __init set_hardened_usercopy(void)
 {
-	if (enable_checks == false)
-		static_branch_enable(&bypass_usercopy_checks);
+	if (enable_checks)
+		static_branch_enable(&validate_usercopy_range);
+	else
+		static_branch_disable(&validate_usercopy_range);
 	return 1;
 }