diff options
| author | Vasily Kulikov <segoon@openwall.com> | 2015-09-09 15:36:00 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-10 13:29:01 -0700 |
| commit | 8a5e5e02fc83aaf67053ab53b359af08c6c49aaf (patch) | |
| tree | 8e393b49db2ec5256331d3e1afb19110e85415ae /include/linux/poison.h | |
| parent | ecf1a3dfff22bd165532a3af64f32697ae97c1ef (diff) | |
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@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>
Diffstat (limited to 'include/linux/poison.h')
| -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 **********/ /* |