From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> [ Upstream commit ccfb62f27beb295103e9392462b20a6ed807d0ea ] The user can change the device_name with the IMSETDEVNAME ioctl, but we need to ensure that the user's name is NUL terminated. Otherwise it could result in a buffer overflow when we copy the name back to the user with IMGETDEVINFO ioctl. I also changed two strcpy() calls which handle the name to strscpy(). Hopefully, there aren't any other ways to create a too long name, but it's nice to do this as a kernel hardening measure. Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/isdn/mISDN/socket.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/isdn/mISDN/socket.c b/drivers/isdn/mISDN/socket.c index b2abc44fa5cb..a73337b74f41 100644 --- a/drivers/isdn/mISDN/socket.c +++ b/drivers/isdn/mISDN/socket.c @@ -394,7 +394,7 @@ data_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) memcpy(di.channelmap, dev->channelmap, sizeof(di.channelmap)); di.nrbchan = dev->nrbchan; - strcpy(di.name, dev_name(&dev->dev)); + strscpy(di.name, dev_name(&dev->dev), sizeof(di.name)); if (copy_to_user((void __user *)arg, &di, sizeof(di))) err = -EFAULT; } else @@ -677,7 +677,7 @@ base_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) memcpy(di.channelmap, dev->channelmap, sizeof(di.channelmap)); di.nrbchan = dev->nrbchan; - strcpy(di.name, dev_name(&dev->dev)); + strscpy(di.name, dev_name(&dev->dev), sizeof(di.name)); if (copy_to_user((void __user *)arg, &di, sizeof(di))) err = -EFAULT; } else @@ -691,6 +691,7 @@ base_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) err = -EFAULT; break; } + dn.name[sizeof(dn.name) - 1] = '\0'; dev = get_mdevice(dn.id); if (dev) err = device_rename(&dev->dev, dn.name); -- 2.20.1
