On Tue, Mar 6, 2018 at 5:27 PM, Paul Moore <pmoore@xxxxxxxxxx> wrote:
> From: Paul Moore <paul@xxxxxxxxxxxxxx>
>
> Starting with v4.16-rc1 we've been seeing a higher than usual number
> of requests for the kernel to load networking modules, even on events
> which shouldn't trigger a module load (e.g. ioctl(TCGETS)). Stephen
> Smalley suggested the problem may lie in commit 44c02a2c3dc5
> ("dev_ioctl(): move copyin/copyout to callers") which moves changes
> the network dev_ioctl() function to always call dev_load(),
> regardless of the requested ioctl.
>
> This patch moves the dev_load() calls back into the individual ioctls
> while preserving the rest of the original patch.
>
> Reported-by: Dominick Grift <dac.override@xxxxxxxxx>
> Suggested-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
> Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
> ---
> net/core/dev_ioctl.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
In the interest of full disclosure, I've compiled this code but I
haven't booted it yet (test kernel building now). I just wanted to
post this sooner rather than later in case the networking folks, or
Al, had a different solution they would prefer.
> diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
> index 0ab1af04296c..a04e1e88bf3a 100644
> --- a/net/core/dev_ioctl.c
> +++ b/net/core/dev_ioctl.c
> @@ -402,8 +402,6 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> if (colon)
> *colon = 0;
>
> - dev_load(net, ifr->ifr_name);
> -
> /*
> * See which interface the caller is talking about.
> */
> @@ -423,6 +421,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> case SIOCGIFMAP:
> case SIOCGIFINDEX:
> case SIOCGIFTXQLEN:
> + dev_load(net, ifr->ifr_name);
> rcu_read_lock();
> ret = dev_ifsioc_locked(net, ifr, cmd);
> rcu_read_unlock();
> @@ -431,6 +430,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> return ret;
>
> case SIOCETHTOOL:
> + dev_load(net, ifr->ifr_name);
> rtnl_lock();
> ret = dev_ethtool(net, ifr);
> rtnl_unlock();
> @@ -447,6 +447,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> case SIOCGMIIPHY:
> case SIOCGMIIREG:
> case SIOCSIFNAME:
> + dev_load(net, ifr->ifr_name);
> if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
> return -EPERM;
> rtnl_lock();
> @@ -494,6 +495,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> /* fall through */
> case SIOCBONDSLAVEINFOQUERY:
> case SIOCBONDINFOQUERY:
> + dev_load(net, ifr->ifr_name);
> rtnl_lock();
> ret = dev_ifsioc(net, ifr, cmd);
> rtnl_unlock();
> @@ -518,6 +520,7 @@ int dev_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr, bool *need_c
> cmd == SIOCGHWTSTAMP ||
> (cmd >= SIOCDEVPRIVATE &&
> cmd <= SIOCDEVPRIVATE + 15)) {
> + dev_load(net, ifr->ifr_name);
> rtnl_lock();
> ret = dev_ifsioc(net, ifr, cmd);
> rtnl_unlock();
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
paul moore
www.paul-moore.com
