The patch titled
Subject: include/linux/poison.h: fix LIST_POISON{1,2} offset
has been added to the -mm tree. Its filename is
fix-list_poison12-offset.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fix-list_poison12-offset.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fix-list_poison12-offset.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vasily Kulikov <segoon@xxxxxxxxxxxx>
Subject: include/linux/poison.h: fix LIST_POISON{1,2} offset
Poison pointer values should be small enough to find a room in
non-mmap'able/hardly-mmap'able space. E.g. on x86 "poison pointer space"
is located starting from 0x0. Given unprivileged users cannot mmap
anything below mmap_min_addr, it should be safe to use poison pointers
lower than mmap_min_addr.
The current poison pointer values of LIST_POISON{1,2} might be too big for
mmap_min_addr values equal or less than 1 MB (common case, e.g. Ubuntu
uses only 0x10000). There is little point to use such a big value given
the "poison pointer space" below 1 MB is not yet exhausted. Changing it
to a smaller value solves the problem for small mmap_min_addr setups.
The values are suggested by Solar Designer:
http://www.openwall.com/lists/oss-security/2015/05/02/6
Signed-off-by: Vasily Kulikov <segoon@xxxxxxxxxxxx>
Cc: Solar Designer <solar@xxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/poison.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN include/linux/poison.h~fix-list_poison12-offset include/linux/poison.h
--- a/include/linux/poison.h~fix-list_poison12-offset
+++ a/include/linux/poison.h
@@ -19,8 +19,8 @@
* under normal circumstances, used to verify that nobody uses
* non-initialized list entries.
*/
-#define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA)
-#define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA)
+#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA)
+#define LIST_POISON2 ((void *) 0x200 + POISON_POINTER_DELTA)
/********** include/linux/timer.h **********/
/*
_
Patches currently in -mm which might be from segoon@xxxxxxxxxxxx are
fix-list_poison12-offset.patch
use-poison_pointer_delta-for-poison-pointers.patch
remove-not-used-poison-pointer-macros.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
