usercopy: Move enum for arch_within_stack_frames()

This patch moves the arch_within_stack_frames() return value enum up in the header files so that per-architecture implementations can reuse the same return values. Signed-off-by: Sahara <[email protected]> Signed-off-by: James Morse <[email protected]> [kees: adjusted naming and commit log] Signed-off-by: Kees Cook <[email protected]>
mrcsosa · Apr 4, 2017 · 96dc4f9 · 96dc4f9
1 parent 4495c08
commit 96dc4f9
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Showing 3 changed files with 20 additions and 13 deletions.
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
@@ -168,9 +168,9 @@ 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,
@@ -197,13 +197,14 @@ 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/thread_info.h b/include/linux/thread_info.h
@@ -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__

diff --git a/mm/usercopy.c b/mm/usercopy.c
@@ -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).