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Commit 5958cc49 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'usercopy-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux 

Pull hardened usercopy updates from Kees Cook:
 "A couple hardened usercopy changes:

   - drop now unneeded is_vmalloc_or_module() check (Laura Abbott)

   - use enum instead of literals for stack frame API (Sahara)"

* tag 'usercopy-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm/usercopy: Drop extra is_vmalloc_or_module() check
  usercopy: Move enum for arch_within_stack_frames()
parents 2575be8a 517e1fbe

arch/x86/include/asm/thread_info.h

+7 −6
Original line number Diff line number Diff line
@@ -170,9 +170,9 @@ static inline unsigned long current_stack_pointer(void) 
 * entirely contained by a single stack frame.

 *

 * Returns:

 *		 1 if within a frame

 *		-1 if placed across a frame boundary (or outside stack)

 *		 0 unable to determine (no frame pointers, etc)

 *	GOOD_FRAME	if within a frame

 *	BAD_STACK	if placed across a frame boundary (or outside stack)

 *	NOT_STACK	unable to determine (no frame pointers, etc)

 */

static inline int arch_within_stack_frames(const void * const stack,

					   const void * const stackend,
@@ -199,13 +199,14 @@ static inline int arch_within_stack_frames(const void * const stack, 
		 * the copy as invalid.

		 */

		if (obj + len <= frame)

			return obj >= oldframe + 2 * sizeof(void *) ? 1 : -1;

			return obj >= oldframe + 2 * sizeof(void *) ?

				GOOD_FRAME : BAD_STACK;

		oldframe = frame;

		frame = *(const void * const *)frame;

	}

	return -1;

	return BAD_STACK;

#else

	return 0;

	return NOT_STACK;

#endif

}

include/linux/thread_info.h

+12 −0
Original line number Diff line number Diff line
@@ -22,6 +22,18 @@ 
#endif



#include <linux/bitops.h>



/*

 * For per-arch arch_within_stack_frames() implementations, defined in

 * asm/thread_info.h.

 */

enum {

	BAD_STACK = -1,

	NOT_STACK = 0,

	GOOD_FRAME,

	GOOD_STACK,

};



#include <asm/thread_info.h>



#ifdef __KERNEL__

mm/usercopy.c

+1 −18
Original line number Diff line number Diff line
@@ -19,15 +19,9 @@ 
#include <linux/sched.h>

#include <linux/sched/task.h>

#include <linux/sched/task_stack.h>

#include <linux/thread_info.h>

#include <asm/sections.h>



enum {

	BAD_STACK = -1,

	NOT_STACK = 0,

	GOOD_FRAME,

	GOOD_STACK,

};



/*

 * Checks if a given pointer and length is contained by the current

 * stack frame (if possible).
@@ -206,17 +200,6 @@ static inline const char *check_heap_object(const void *ptr, unsigned long n, 
{

	struct page *page;



	/*

	 * Some architectures (arm64) return true for virt_addr_valid() on

	 * vmalloced addresses. Work around this by checking for vmalloc

	 * first.

	 *

	 * We also need to check for module addresses explicitly since we

	 * may copy static data from modules to userspace

	 */

	if (is_vmalloc_or_module_addr(ptr))

		return NULL;



	if (!virt_addr_valid(ptr))

		return NULL;