* [kernel-hardening] [PATCH 1/3] fix LIST_POISON{1,2} offset
@ 2015-07-26 13:43 Vasily Kulikov
2015-07-26 13:45 ` [kernel-hardening] [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Vasily Kulikov
0 siblings, 1 reply; 4+ messages in thread
From: Vasily Kulikov @ 2015-07-26 13:43 UTC (permalink / raw)
To: linux-kernel; +Cc: Randy Dunlap, Andrew Morton, kernel-hardening, Ingo Molnar
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>
---
include/linux/poison.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/poison.h b/include/linux/poison.h
index 7b2a7fc..ee697b9 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 **********/
/*
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kernel-hardening] [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers
2015-07-26 13:43 [kernel-hardening] [PATCH 1/3] fix LIST_POISON{1,2} offset Vasily Kulikov
@ 2015-07-26 13:45 ` Vasily Kulikov
2015-07-26 13:46 ` [kernel-hardening] [PATCH 3/3] remove not-used poison pointer macros Vasily Kulikov
2015-07-26 18:42 ` [kernel-hardening] Re: [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Thomas Gleixner
0 siblings, 2 replies; 4+ messages in thread
From: Vasily Kulikov @ 2015-07-26 13:45 UTC (permalink / raw)
To: linux-kernel
Cc: Randy Dunlap, Andrew Morton, kernel-hardening, Thomas Gleixner,
Kirill A. Shutemov
TIMER_ENTRY_STATIC and TAIL_MAPPING are defined as poison pointers which
should point to nowhere. Redefine them using POISON_POINTER_DELTA arithmetics
to make sure they really point to non-mappable area declared by the
target architecture.
Signed-off-by: Vasily Kulikov <segoon@openwall.com>
---
include/linux/poison.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/poison.h b/include/linux/poison.h
index ee697b9..a721bcd 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -27,14 +27,14 @@
* Magic number "tsta" to indicate a static timer initializer
* for the object debugging code.
*/
-#define TIMER_ENTRY_STATIC ((void *) 0x74737461)
+#define TIMER_ENTRY_STATIC ((void *) 0x300 + POISON_POINTER_DELTA)
/********** mm/debug-pagealloc.c **********/
#define PAGE_POISON 0xaa
/********** mm/page_alloc.c ************/
-#define TAIL_MAPPING ((void *) 0x01014A11 + POISON_POINTER_DELTA)
+#define TAIL_MAPPING ((void *) 0x400 + POISON_POINTER_DELTA)
/********** mm/slab.c **********/
/*
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kernel-hardening] [PATCH 3/3] remove not-used poison pointer macros
2015-07-26 13:45 ` [kernel-hardening] [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Vasily Kulikov
@ 2015-07-26 13:46 ` Vasily Kulikov
2015-07-26 18:42 ` [kernel-hardening] Re: [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Thomas Gleixner
1 sibling, 0 replies; 4+ messages in thread
From: Vasily Kulikov @ 2015-07-26 13:46 UTC (permalink / raw)
To: linux-kernel; +Cc: Randy Dunlap, Andrew Morton, kernel-hardening
Signed-off-by: Vasily Kulikov <segoon@openwall.com>
---
include/linux/poison.h | 7 -------
1 file changed, 7 deletions(-)
diff --git a/include/linux/poison.h b/include/linux/poison.h
index a721bcd..4a27153 100644
--- a/include/linux/poison.h
+++ b/include/linux/poison.h
@@ -73,10 +73,6 @@
#define ATM_POISON_FREE 0x12
#define ATM_POISON 0xdeadbeef
-/********** net/ **********/
-#define NEIGHBOR_DEAD 0xdeadbeef
-#define NETFILTER_LINK_POISON 0xdead57ac
-
/********** kernel/mutexes **********/
#define MUTEX_DEBUG_INIT 0x11
#define MUTEX_DEBUG_FREE 0x22
@@ -87,7 +83,4 @@
/********** security/ **********/
#define KEY_DESTROY 0xbd
-/********** sound/oss/ **********/
-#define OSS_POISON_FREE 0xAB
-
#endif
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [kernel-hardening] Re: [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers
2015-07-26 13:45 ` [kernel-hardening] [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Vasily Kulikov
2015-07-26 13:46 ` [kernel-hardening] [PATCH 3/3] remove not-used poison pointer macros Vasily Kulikov
@ 2015-07-26 18:42 ` Thomas Gleixner
1 sibling, 0 replies; 4+ messages in thread
From: Thomas Gleixner @ 2015-07-26 18:42 UTC (permalink / raw)
To: Vasily Kulikov
Cc: linux-kernel, Randy Dunlap, Andrew Morton, kernel-hardening,
Kirill A. Shutemov
On Sun, 26 Jul 2015, Vasily Kulikov wrote:
> TIMER_ENTRY_STATIC and TAIL_MAPPING are defined as poison pointers which
> should point to nowhere. Redefine them using POISON_POINTER_DELTA arithmetics
> to make sure they really point to non-mappable area declared by the
> target architecture.
>
> Signed-off-by: Vasily Kulikov <segoon@openwall.com>
> ---
> include/linux/poison.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/poison.h b/include/linux/poison.h
> index ee697b9..a721bcd 100644
> --- a/include/linux/poison.h
> +++ b/include/linux/poison.h
> @@ -27,14 +27,14 @@
> * Magic number "tsta" to indicate a static timer initializer
> * for the object debugging code.
> */
> -#define TIMER_ENTRY_STATIC ((void *) 0x74737461)
> +#define TIMER_ENTRY_STATIC ((void *) 0x300 + POISON_POINTER_DELTA)
Acked-by: Thomas Gleixner <tglx@linutronix.de>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-07-26 18:42 UTC | newest]
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2015-07-26 13:43 [kernel-hardening] [PATCH 1/3] fix LIST_POISON{1,2} offset Vasily Kulikov
2015-07-26 13:45 ` [kernel-hardening] [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Vasily Kulikov
2015-07-26 13:46 ` [kernel-hardening] [PATCH 3/3] remove not-used poison pointer macros Vasily Kulikov
2015-07-26 18:42 ` [kernel-hardening] Re: [PATCH 2/3] use POISON_POINTER_DELTA for poison pointers Thomas Gleixner
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