Jinbum, I just noticed this patch does not apply to linux-next. Please try again, but this time work from linux-next rather than from a stable tree. Thanks -- Gustavo On 07/27/2018 09:47 PM, Gustavo A. R. Silva wrote: > > > On 07/27/2018 09:30 PM, Jinbum Park wrote: >> 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@xxxxxxxxx> >> --- >> v2: Fix coding style by Gustavo. >> >> drivers/block/pktcdvd.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c >> index c61d20c..8ec2eaa 100644 >> --- a/drivers/block/pktcdvd.c >> +++ b/drivers/block/pktcdvd.c >> @@ -67,8 +67,8 @@ >> #include <scsi/scsi.h> >> #include <linux/debugfs.h> >> #include <linux/device.h> >> - >> #include <linux/uaccess.h> >> +#include <linux/nospec.h> >> >> #define DRIVER_NAME "pktcdvd" >> >> @@ -2231,6 +2231,7 @@ 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); > > Adding a blank line here would be even better. > >> return pkt_devs[dev_minor]; >> } >> >> > > Acked-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> > > Thanks > -- > Gustavo >
