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From: Roman Penyaev <rpenyaev@suse.de>
To: unlisted-recipients:; (no To-header on input)
Cc: Roman Penyaev <rpenyaev@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Joe Perches <joe@perches.com>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Subject: [PATCH 1/3] mm/vmalloc: fix size check for remap_vmalloc_range_partial()
Date: Thu,  3 Jan 2019 15:59:52 +0100	[thread overview]
Message-ID: <20190103145954.16942-2-rpenyaev@suse.de> (raw)
In-Reply-To: <20190103145954.16942-1-rpenyaev@suse.de>

area->size can include adjacent guard page but get_vm_area_size()
returns actual size of the area.

This fixes possible kernel crash when userspace tries to map area
on 1 page bigger: size check passes but the following vmalloc_to_page()
returns NULL on last guard (non-existing) page.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Joe Perches <joe@perches.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
---
 mm/vmalloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 871e41c55e23..2cd24186ba84 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2248,7 +2248,7 @@ int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
 	if (!(area->flags & VM_USERMAP))
 		return -EINVAL;
 
-	if (kaddr + size > area->addr + area->size)
+	if (kaddr + size > area->addr + get_vm_area_size(area))
 		return -EINVAL;
 
 	do {
-- 
2.19.1


       reply	other threads:[~2019-01-03 15:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190103145954.16942-1-rpenyaev@suse.de>
2019-01-03 14:59 ` Roman Penyaev [this message]
2019-01-03 15:13   ` [PATCH 1/3] mm/vmalloc: fix size check for remap_vmalloc_range_partial() Michal Hocko
2019-01-03 19:27     ` Roman Penyaev
2019-01-03 19:40       ` Michal Hocko
2019-01-03 20:31         ` Roman Penyaev
2019-01-04  9:38           ` Michal Hocko
2019-01-04 10:21             ` Roman Penyaev
2019-01-04 10:28               ` Michal Hocko
2019-01-03 19:59   ` Michal Hocko
2019-01-04 11:06   ` Roman Penyaev
2019-01-11 19:19   ` Andrey Ryabinin

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