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Commit b51f26b1 authored by Paul Moore's avatar Paul Moore Committed by David S. Miller
Browse files

net: don't unnecessarily load kernel modules in dev_ioctl() 



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 44c02a2c
("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: default avatarDominick Grift <dac.override@gmail.com>
Suggested-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e05836ac

net/core/dev_ioctl.c

+5 −2
Original line number Diff line number Diff line
@@ -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();