4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg <johannes.berg@xxxxxxxxx> [ Upstream commit 1cebf8f143c21eb422cd0f4e27ab2ae366eb4d04 ] As reported by Reobert O'Callahan, since Viro's commit to kill dev_ifsioc() we attempt to copy too much data in compat mode, which may lead to EFAULT when the 32-bit version of struct ifreq sits at/near the end of a page boundary, and the next page isn't mapped. Fix this by passing the approprate compat/non-compat size to copy and using that, as before the dev_ifsioc() removal. This works because only the embedded "struct ifmap" has different size, and this is only used in SIOCGIFMAP/SIOCSIFMAP which has a different handler. All other parts of the union are naturally compatible. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=199469. Fixes: bf4405737f9f ("kill dev_ifsioc()") Reported-by: Robert O'Callahan <robert@xxxxxxxxxxxxx> Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/socket.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) --- a/net/socket.c +++ b/net/socket.c @@ -962,7 +962,8 @@ void dlci_ioctl_set(int (*hook) (unsigne EXPORT_SYMBOL(dlci_ioctl_set); static long sock_do_ioctl(struct net *net, struct socket *sock, - unsigned int cmd, unsigned long arg) + unsigned int cmd, unsigned long arg, + unsigned int ifreq_size) { int err; void __user *argp = (void __user *)arg; @@ -988,11 +989,11 @@ static long sock_do_ioctl(struct net *ne } else { struct ifreq ifr; bool need_copyout; - if (copy_from_user(&ifr, argp, sizeof(struct ifreq))) + if (copy_from_user(&ifr, argp, ifreq_size)) return -EFAULT; err = dev_ioctl(net, cmd, &ifr, &need_copyout); if (!err && need_copyout) - if (copy_to_user(argp, &ifr, sizeof(struct ifreq))) + if (copy_to_user(argp, &ifr, ifreq_size)) return -EFAULT; } return err; @@ -1091,7 +1092,8 @@ static long sock_ioctl(struct file *file err = open_related_ns(&net->ns, get_net_ns); break; default: - err = sock_do_ioctl(net, sock, cmd, arg); + err = sock_do_ioctl(net, sock, cmd, arg, + sizeof(struct ifreq)); break; } return err; @@ -2762,7 +2764,8 @@ static int do_siocgstamp(struct net *net int err; set_fs(KERNEL_DS); - err = sock_do_ioctl(net, sock, cmd, (unsigned long)&ktv); + err = sock_do_ioctl(net, sock, cmd, (unsigned long)&ktv, + sizeof(struct compat_ifreq)); set_fs(old_fs); if (!err) err = compat_put_timeval(&ktv, up); @@ -2778,7 +2781,8 @@ static int do_siocgstampns(struct net *n int err; set_fs(KERNEL_DS); - err = sock_do_ioctl(net, sock, cmd, (unsigned long)&kts); + err = sock_do_ioctl(net, sock, cmd, (unsigned long)&kts, + sizeof(struct compat_ifreq)); set_fs(old_fs); if (!err) err = compat_put_timespec(&kts, up); @@ -3084,7 +3088,8 @@ static int routing_ioctl(struct net *net } set_fs(KERNEL_DS); - ret = sock_do_ioctl(net, sock, cmd, (unsigned long) r); + ret = sock_do_ioctl(net, sock, cmd, (unsigned long) r, + sizeof(struct compat_ifreq)); set_fs(old_fs); out: @@ -3197,7 +3202,8 @@ static int compat_sock_ioctl_trans(struc case SIOCBONDSETHWADDR: case SIOCBONDCHANGEACTIVE: case SIOCGIFNAME: - return sock_do_ioctl(net, sock, cmd, arg); + return sock_do_ioctl(net, sock, cmd, arg, + sizeof(struct compat_ifreq)); } return -ENOIOCTLCMD;
