[PATCH 3.19 034/177] mm, hugetlb: remove unnecessary lower bound on sysctl handlers"?

Greg Kroah-Hartman
2015-03-16T14:12:01Z

From: Andrey Ryabinin <a.ryabinin@samsung.com>

commit 3cd7645de624939c38f5124b4ac15f8b35a1a8b7 upstream.

Commit ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and
hugetlb_infinity") replaced 'unsigned long hugetlb_zero' with 'int zero'
leading to out-of-bounds access in proc_doulongvec_minmax(). Use
'.extra1 = NULL' instead of '.extra1 = &zero'. Passing NULL is
equivalent to passing minimal value, which is 0 for unsigned types.

Fixes: ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Manfred Spraul <manfred@colorfullife.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/sysctl.c | 3 ---
1 file changed, 3 deletions(-)

--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1248,7 +1248,6 @@ static struct ctl_table vm_table[] = {
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = hugetlb_sysctl_handler,
- .extra1 = &zero,
},
#ifdef CONFIG_NUMA
{
@@ -1257,7 +1256,6 @@ static struct ctl_table vm_table[] = {
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = &hugetlb_mempolicy_sysctl_handler,
- .extra1 = &zero,
},
#endif
{
@@ -1280,7 +1278,6 @@ static struct ctl_table vm_table[] = {
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = hugetlb_overcommit_handler,
- .extra1 = &zero,
},
#endif
{