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    Subject[PATCH AUTOSEL 5.12 56/80] media: dvb_net: avoid speculation from net slot
    Date
    From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

    [ Upstream commit abc0226df64dc137b48b911c1fe4319aec5891bb ]

    The risk of especulation is actually almost-non-existing here,
    as there are very few users of TCP/IP using the DVB stack,
    as, this is mainly used with DVB-S/S2 cards, and only by people
    that receives TCP/IP from satellite connections, which limits
    a lot the number of users of such feature(*).

    (*) In thesis, DVB-C cards could also benefit from it, but I'm
    yet to see a hardware that supports it.

    Yet, fixing it is trivial.

    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/media/dvb-core/dvb_net.c | 25 +++++++++++++++++++------
    1 file changed, 19 insertions(+), 6 deletions(-)

    diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c
    index 89620da983ba..dddebea644bb 100644
    --- a/drivers/media/dvb-core/dvb_net.c
    +++ b/drivers/media/dvb-core/dvb_net.c
    @@ -45,6 +45,7 @@
    #include <linux/module.h>
    #include <linux/kernel.h>
    #include <linux/netdevice.h>
    +#include <linux/nospec.h>
    #include <linux/etherdevice.h>
    #include <linux/dvb/net.h>
    #include <linux/uio.h>
    @@ -1462,14 +1463,20 @@ static int dvb_net_do_ioctl(struct file *file,
    struct net_device *netdev;
    struct dvb_net_priv *priv_data;
    struct dvb_net_if *dvbnetif = parg;
    + int if_num = dvbnetif->if_num;

    - if (dvbnetif->if_num >= DVB_NET_DEVICES_MAX ||
    - !dvbnet->state[dvbnetif->if_num]) {
    + if (if_num >= DVB_NET_DEVICES_MAX) {
    ret = -EINVAL;
    goto ioctl_error;
    }
    + if_num = array_index_nospec(if_num, DVB_NET_DEVICES_MAX);

    - netdev = dvbnet->device[dvbnetif->if_num];
    + if (!dvbnet->state[if_num]) {
    + ret = -EINVAL;
    + goto ioctl_error;
    + }
    +
    + netdev = dvbnet->device[if_num];

    priv_data = netdev_priv(netdev);
    dvbnetif->pid=priv_data->pid;
    @@ -1522,14 +1529,20 @@ static int dvb_net_do_ioctl(struct file *file,
    struct net_device *netdev;
    struct dvb_net_priv *priv_data;
    struct __dvb_net_if_old *dvbnetif = parg;
    + int if_num = dvbnetif->if_num;
    +
    + if (if_num >= DVB_NET_DEVICES_MAX) {
    + ret = -EINVAL;
    + goto ioctl_error;
    + }
    + if_num = array_index_nospec(if_num, DVB_NET_DEVICES_MAX);

    - if (dvbnetif->if_num >= DVB_NET_DEVICES_MAX ||
    - !dvbnet->state[dvbnetif->if_num]) {
    + if (!dvbnet->state[if_num]) {
    ret = -EINVAL;
    goto ioctl_error;
    }

    - netdev = dvbnet->device[dvbnetif->if_num];
    + netdev = dvbnet->device[if_num];

    priv_data = netdev_priv(netdev);
    dvbnetif->pid=priv_data->pid;
    --
    2.30.2
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