Re: [PATCH] net: don't unnecessarily load kernel modules in dev_ioctl()
From: Paul Moore <hidden>
Date: 2018-03-06 22:32:47
Also in:
linux-security-module, selinux
On Tue, Mar 6, 2018 at 5:27 PM, Paul Moore [off-list ref] wrote:
From: Paul Moore <redacted>
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 <redacted>
Suggested-by: Stephen Smalley <redacted>
Signed-off-by: Paul Moore <redacted>
---
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.
quoted hunk ↗ jump to hunk
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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-- paul moore www.paul-moore.com