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| author | Jinbum Park <jinb.park7@gmail.com> | 2018-07-28 13:20:44 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-19 22:41:34 +0200 |
| commit | 2cf9708981e7810cd7b1e4c46ac09685120bfbad (patch) | |
| tree | 54cb72d4539372c48760a9e03bb7f4db259b4b51 | |
| parent | bf5cde3c685bec12de368379cbe8ecfaa32ff9d3 (diff) | |
pktcdvd: Fix possible Spectre-v1 for pkt_devs
[ Upstream commit 55690c07b44a82cc3359ce0c233f4ba7d80ba145 ]
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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/block/pktcdvd.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index b3f83cd96f33..01f59be71433 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" @@ -2231,6 +2231,8 @@ 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]; } |