From: Subash Abhinov Kasiviswanathan subashab@codeaurora.org
[ Upstream commit d02854dc1999ed3e7fd79ec700c64ac23ac0c458 ]
A null dereference was observed when a sysctl was being set from userspace and rmnet was stuck trying to complete some actions in the NETDEV_REGISTER callback. This is because the real_dev is set only after the device registration handler completes.
sysctl call stack -
<6> Unable to handle kernel NULL pointer dereference at virtual address 00000108 <2> pc : rmnet_vnd_get_iflink+0x1c/0x28 <2> lr : dev_get_iflink+0x2c/0x40 <2> rmnet_vnd_get_iflink+0x1c/0x28 <2> inet6_fill_ifinfo+0x15c/0x234 <2> inet6_ifinfo_notify+0x68/0xd4 <2> ndisc_ifinfo_sysctl_change+0x1b8/0x234 <2> proc_sys_call_handler+0xac/0x100 <2> proc_sys_write+0x3c/0x4c <2> __vfs_write+0x54/0x14c <2> vfs_write+0xcc/0x188 <2> SyS_write+0x60/0xc0 <2> el0_svc_naked+0x34/0x38
device register call stack -
<2> notifier_call_chain+0x84/0xbc <2> raw_notifier_call_chain+0x38/0x48 <2> call_netdevice_notifiers_info+0x40/0x70 <2> call_netdevice_notifiers+0x38/0x60 <2> register_netdevice+0x29c/0x3d8 <2> rmnet_vnd_newlink+0x68/0xe8 <2> rmnet_newlink+0xa0/0x160 <2> rtnl_newlink+0x57c/0x6c8 <2> rtnetlink_rcv_msg+0x1dc/0x328 <2> netlink_rcv_skb+0xac/0x118 <2> rtnetlink_rcv+0x24/0x30 <2> netlink_unicast+0x158/0x1f0 <2> netlink_sendmsg+0x32c/0x338 <2> sock_sendmsg+0x44/0x60 <2> SyS_sendto+0x150/0x1ac <2> el0_svc_naked+0x34/0x38
Fixes: b752eff5be24 ("net: qualcomm: rmnet: Implement ndo_get_iflink") Signed-off-by: Sean Tranchetti stranche@codeaurora.org Signed-off-by: Subash Abhinov Kasiviswanathan subashab@codeaurora.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c index b9a7548ec6a0..2efdf7d2dec8 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c @@ -234,7 +234,7 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev, struct net_device *real_dev, struct rmnet_endpoint *ep) { - struct rmnet_priv *priv; + struct rmnet_priv *priv = netdev_priv(rmnet_dev); int rc;
if (ep->egress_dev) @@ -247,6 +247,8 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev, rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM; rmnet_dev->hw_features |= NETIF_F_SG;
+ priv->real_dev = real_dev; + rc = register_netdevice(rmnet_dev); if (!rc) { ep->egress_dev = rmnet_dev; @@ -255,9 +257,7 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
rmnet_dev->rtnl_link_ops = &rmnet_link_ops;
- priv = netdev_priv(rmnet_dev); priv->mux_id = id; - priv->real_dev = real_dev;
netdev_dbg(rmnet_dev, "rmnet dev created\n"); }