linux-kernel - [PATCH AUTOSEL 4.14 153/170] mm/page_owner: clamp read count to PAGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190128161200.55107-153-sashal@kernel.org>
Date:   Mon, 28 Jan 2019 11:11:43 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Miles Chen <miles.chen@...iatek.com>,
        Joe Perches <joe@...ches.com>,
        Matthew Wilcox <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>, linux-mm@...ck.org
Subject: [PATCH AUTOSEL 4.14 153/170] mm/page_owner: clamp read count to PAGE_SIZE

From: Miles Chen <miles.chen@...iatek.com>

[ Upstream commit c8f61cfc871fadfb73ad3eacd64fda457279e911 ]

The (root-only) page owner read might allocate a large size of memory with
a large read count.  Allocation fails can easily occur when doing high
order allocations.

Clamp buffer size to PAGE_SIZE to avoid arbitrary size allocation
and avoid allocation fails due to high order allocation.

[akpm@...ux-foundation.org: use min_t()]
Link: http://lkml.kernel.org/r/1541091607-27402-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@...iatek.com>
Acked-by: Michal Hocko <mhocko@...e.com>
Cc: Joe Perches <joe@...ches.com>
Cc: Matthew Wilcox <willy@...radead.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 mm/page_owner.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index a71fe4c623ef..7232c6e24234 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 		.skip = 0
 	};
 
+	count = min_t(size_t, count, PAGE_SIZE);
 	kbuf = kmalloc(count, GFP_KERNEL);
 	if (!kbuf)
 		return -ENOMEM;
-- 
2.19.1