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
| ||
|
Date: Thu, 10 Oct 2019 16:12:00 +0200 From: David Hildenbrand <david@...hat.com> To: linux-kernel@...r.kernel.org Cc: linux-mm@...ck.org, David Hildenbrand <david@...hat.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, "Rafael J. Wysocki" <rafael@...nel.org>, Michal Hocko <mhocko@...nel.org>, Andrew Morton <akpm@...ux-foundation.org> Subject: [PATCH v1] drivers/base/memory.c: Don't access uninitialized memmaps in soft_offline_page_store() Uninitialized memmaps contain garbage and in the worst case trigger kernel BUGs, especially with CONFIG_PAGE_POISONING. They should not get touched. Right now, when trying to soft-offline a PFN that resides on a memory block that was never onlined, one gets a misleading error with CONFIG_PAGE_POISONING: :/# echo 5637144576 > /sys/devices/system/memory/soft_offline_page [ 23.097167] soft offline: 0x150000 page already poisoned But the actual result depends on the garbage in the memmap. soft_offline_page() can only work with online pages, it returns -EIO in case of ZONE_DEVICE. Make sure to only forward pages that are online (iow, managed by the buddy) and, therefore, have an initialized memmap. Add a check against pfn_to_online_page() and similarly return -EIO. Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visible after d0dc12e86b319 Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@...nel.org> Cc: Michal Hocko <mhocko@...nel.org> Cc: Andrew Morton <akpm@...ux-foundation.org> Signed-off-by: David Hildenbrand <david@...hat.com> --- drivers/base/memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 6bea4f3f8040..55907c27075b 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -540,6 +540,9 @@ static ssize_t soft_offline_page_store(struct device *dev, pfn >>= PAGE_SHIFT; if (!pfn_valid(pfn)) return -ENXIO; + /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ + if (!pfn_to_online_page(pfn)) + return -EIO; ret = soft_offline_page(pfn_to_page(pfn), 0); return ret == 0 ? count : ret; } -- 2.21.0
Powered by blists - more mailing lists