From: Dan Carpenter Date: Wed, 22 May 2019 08:45:13 +0000 (+0300) Subject: mISDN: make sure device name is NUL terminated X-Git-Tag: v4.4.183~16 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4678b7808e7783d67cc02f41f6dca3f158a9a5f;p=thirdparty%2Fkernel%2Fstable.git mISDN: make sure device name is NUL terminated [ 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- diff --git a/drivers/isdn/mISDN/socket.c b/drivers/isdn/mISDN/socket.c index 0d29b5a6356d7..8cbb75d09a1d2 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 @@ -678,7 +678,7 @@ 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 @@ -692,6 +692,7 @@ 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);