User controls @dev_minor which to be used as index of pkt_devs.
So, It can be exploited via Spectre-like attack. (speculative execution)
This kind of attack leaks address of pkt_devs, [1]
It leads an attacker to bypass security mechanism such as KASLR.
So sanitize @dev_minor before using it to prevent attack.
[1] https://github.com/jinb-park/linux-exploit/
tree/master/exploit-remaining-spectre-gadget/leak_pkt_devs.c
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
CVE-2017-5753
(cherry picked from commit
55690c07b44a82cc3359ce0c233f4ba7d80ba145)
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
#include <scsi/scsi.h>
#include <linux/debugfs.h>
#include <linux/device.h>
-
+#include <linux/nospec.h>
#include <linux/uaccess.h>
#define DRIVER_NAME "pktcdvd"
{
if (dev_minor >= MAX_WRITERS)
return NULL;
+
+ dev_minor = array_index_nospec(dev_minor, MAX_WRITERS);
return pkt_devs[dev_minor];
}