From: Jakub Kicinski > Sent: 31 August 2021 17:30 > > On Thu, 26 Aug 2021 12:46:01 -0700 Peter Collingbourne wrote: > > @@ -3306,6 +3308,8 @@ static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd, > > struct ifreq ifreq; > > u32 data32; > > > > + if (!is_socket_ioctl_cmd(cmd)) > > + return -ENOTTY; > > if (copy_from_user(ifreq.ifr_name, u_ifreq32->ifr_name, IFNAMSIZ)) > > return -EFAULT; > > if (get_user(data32, &u_ifreq32->ifr_data)) > > Hi Peter, when resolving the net -> net-next merge conflict I couldn't > figure out why this chunk is needed. It seems all callers of > compat_ifr_data_ioctl() already made sure it's a socket IOCTL. > Please double check my resolution (tip of net-next) and if this is > indeed unnecessary perhaps send a cleanup? Thanks! To stop the copy_from_user() faulting when the user buffer isn't long enough. In particular for iasatty() on arm with tagged pointers. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
