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authorJinbum Park <jinb.park7@gmail.com>2018-07-28 13:20:44 +0900
committerJens Axboe <axboe@kernel.dk>2018-07-28 09:08:42 -0600
commit55690c07b44a82cc3359ce0c233f4ba7d80ba145 (patch)
tree1e73133269563bae2dd59e2790da18ee72618e18
parentd43fdae7bac2def8c4314b5a49822cb7f08a45f1 (diff)
pktcdvd: Fix possible Spectre-v1 for pkt_devs
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>
-rw-r--r--drivers/block/pktcdvd.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index a4b4d524c3af..9bb7721c26fc 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -67,7 +67,7 @@
#include <scsi/scsi.h>
#include <linux/debugfs.h>
#include <linux/device.h>
-
+#include <linux/nospec.h>
#include <linux/uaccess.h>
#define DRIVER_NAME "pktcdvd"
@@ -2254,6 +2254,8 @@ static struct pktcdvd_device *pkt_find_dev_from_minor(unsigned int dev_minor)
{
if (dev_minor >= MAX_WRITERS)
return NULL;
+
+ dev_minor = array_index_nospec(dev_minor, MAX_WRITERS);
return pkt_devs[dev_minor];
}