diff mbox

[v2,1/3] usercopy: create usercopy.h and move enum stack_type

Message ID 1486039824-8470-1-git-send-email-kpark3469@gmail.com
State New, archived
Headers show

Commit Message

kpark3469@gmail.com Feb. 2, 2017, 12:50 p.m. UTC
From: Sahara <keun-o.park@darkmatter.ae>

This patch creates linux/usercopy.h and moves the enum which is
only used in usercopy.c so as to make it usable to x86 and other
architecture's thread_info.h, which may have arch_within_stack_frames().

Signed-off-by: Sahara <keun-o.park@darkmatter.ae>
Suggested-by: James Morse <james.morse@arm.com>
---
 arch/x86/include/asm/thread_info.h | 20 +++++++++++---------
 include/linux/usercopy.h           | 11 +++++++++++
 mm/usercopy.c                      |  8 +-------
 3 files changed, 23 insertions(+), 16 deletions(-)
 create mode 100644 include/linux/usercopy.h

Comments

Kees Cook Feb. 2, 2017, 4:23 p.m. UTC | #1
On Thu, Feb 2, 2017 at 4:50 AM,  <kpark3469@gmail.com> wrote:
> From: Sahara <keun-o.park@darkmatter.ae>
>
> This patch creates linux/usercopy.h and moves the enum which is
> only used in usercopy.c so as to make it usable to x86 and other
> architecture's thread_info.h, which may have arch_within_stack_frames().

Yeah, I had meant to do this; thanks! See my nit below...

> Signed-off-by: Sahara <keun-o.park@darkmatter.ae>
> Suggested-by: James Morse <james.morse@arm.com>
> ---
>  arch/x86/include/asm/thread_info.h | 20 +++++++++++---------
>  include/linux/usercopy.h           | 11 +++++++++++
>  mm/usercopy.c                      |  8 +-------
>  3 files changed, 23 insertions(+), 16 deletions(-)
>  create mode 100644 include/linux/usercopy.h
>
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
> index ad6f5eb0..c991126 100644
> --- a/arch/x86/include/asm/thread_info.h
> +++ b/arch/x86/include/asm/thread_info.h
> @@ -51,6 +51,7 @@
>  struct task_struct;
>  #include <asm/cpufeature.h>
>  #include <linux/atomic.h>
> +#include <linux/usercopy.h>
>
>  struct thread_info {
>         unsigned long           flags;          /* low level flags */
> @@ -168,13 +169,13 @@ 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,
> -                                          const void *obj, unsigned long len)
> +static inline enum stack_type arch_within_stack_frames(const void * const stack,
> +                                       const void * const stackend,
> +                                       const void *obj, unsigned long len)
>  {
>  #if defined(CONFIG_FRAME_POINTER)
>         const void *frame = NULL;
> @@ -197,13 +198,14 @@ 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
>  }
>
> diff --git a/include/linux/usercopy.h b/include/linux/usercopy.h
> new file mode 100644
> index 0000000..974859e
> --- /dev/null
> +++ b/include/linux/usercopy.h
> @@ -0,0 +1,11 @@
> +#ifndef __LINUX_USERCOPY_H
> +#define __LINUX_USERCOPY_H
> +
> +enum stack_type {
> +       BAD_STACK = -1,
> +       NOT_STACK = 0,
> +       GOOD_FRAME,
> +       GOOD_STACK,
> +};
> +
> +#endif

I think this should live with the declaration of
arch_within_stack_frames in include/linux/thread_info.h instead of
creating a new usercopy.h.

-Kees

> diff --git a/mm/usercopy.c b/mm/usercopy.c
> index 3c8da0a..ee7bced 100644
> --- a/mm/usercopy.c
> +++ b/mm/usercopy.c
> @@ -16,15 +16,9 @@
>
>  #include <linux/mm.h>
>  #include <linux/slab.h>
> +#include <linux/usercopy.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).
> --
> 2.7.4
>
diff mbox

Patch

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ad6f5eb0..c991126 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -51,6 +51,7 @@ 
 struct task_struct;
 #include <asm/cpufeature.h>
 #include <linux/atomic.h>
+#include <linux/usercopy.h>
 
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
@@ -168,13 +169,13 @@  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,
-					   const void *obj, unsigned long len)
+static inline enum stack_type arch_within_stack_frames(const void * const stack,
+					const void * const stackend,
+					const void *obj, unsigned long len)
 {
 #if defined(CONFIG_FRAME_POINTER)
 	const void *frame = NULL;
@@ -197,13 +198,14 @@  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
 }
 
diff --git a/include/linux/usercopy.h b/include/linux/usercopy.h
new file mode 100644
index 0000000..974859e
--- /dev/null
+++ b/include/linux/usercopy.h
@@ -0,0 +1,11 @@ 
+#ifndef __LINUX_USERCOPY_H
+#define __LINUX_USERCOPY_H
+
+enum stack_type {
+	BAD_STACK = -1,
+	NOT_STACK = 0,
+	GOOD_FRAME,
+	GOOD_STACK,
+};
+
+#endif
diff --git a/mm/usercopy.c b/mm/usercopy.c
index 3c8da0a..ee7bced 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -16,15 +16,9 @@ 
 
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/usercopy.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).