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 <keun-o.park@darkmatter.ae>
Signed-off-by: James Morse <james.morse@arm.com>
[kees: adjusted naming and commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index ad6f5eb0..920ca1f 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -168,9 +168,9 @@
* 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 @@
* 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
index 5837387..0dbe41b 100644
--- 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
index d155e12..1eba99b 100644
--- 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).