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| author | Vasily Kulikov <segoon@openwall.com> | 2015-09-09 15:36:00 -0700 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2016-04-13 17:14:30 -0400 |
| commit | 46460a03f44f1915ded434057fa46332438b3a6e (patch) | |
| tree | d4e0a1b8d7715ef53102304d8e3bd0837d61377a /include | |
| parent | d979e967f848caf908a1401b7ad67cf13f06ef9f (diff) | |
| download | lwn-46460a03f44f1915ded434057fa46332438b3a6e.tar.gz lwn-46460a03f44f1915ded434057fa46332438b3a6e.zip | |
include/linux/poison.h: fix LIST_POISON{1,2} offset
[ Upstream commit 8a5e5e02fc83aaf67053ab53b359af08c6c49aaf ]
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@openwall.com>
Cc: Solar Designer <solar@openwall.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/poison.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 2110a81c5e2a..253c9b4198ef 100644 --- a/include/linux/poison.h +++ b/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 **********/ /* |