[PATCHv7,06/11] mm/usercopy: Switch to using lm_alias

Commit Message

Laura Abbott Jan. 10, 2017, 9:35 p.m. UTC

The usercopy checking code currently calls __va(__pa(...)) to check for
aliases on symbols. Switch to using lm_alias instead.

Reviewed-by: Mark Rutland <[e-mail]>
Tested-by: Mark Rutland <[e-mail]>
Acked-by: Kees Cook <[e-mail]>
Signed-off-by: Laura Abbott <[e-mail]>
---
 mm/usercopy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch

diff --git a/mm/usercopy.c b/mm/usercopy.c
index 3c8da0a..8345299 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -108,13 +108,13 @@  static inline const char *check_kernel_text_object(const void *ptr,
 	 * __pa() is not just the reverse of __va(). This can be detected
 	 * and checked:
 	 */
-	textlow_linear = (unsigned long)__va(__pa(textlow));
+	textlow_linear = (unsigned long)lm_alias(textlow);
 	/* No different mapping: we're done. */
 	if (textlow_linear == textlow)
 		return NULL;
 
 	/* Check the secondary mapping... */
-	texthigh_linear = (unsigned long)__va(__pa(texthigh));
+	texthigh_linear = (unsigned long)lm_alias(texthigh);
 	if (overlaps(ptr, n, textlow_linear, texthigh_linear))
 		return "<linear kernel text>";