/* -*- linux-c -*-
 * sysctl_net.c: sysctl interface to net subsystem.
 *
 * Begun April 1, 1996, Mike Shaver.
 * Added /proc/sys/net directories for each protocol family. [MS]
 *
 * Revision 1.2  1996/05/08  20:24:40  shaver
 * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
 * NET_IPV4_IP_FORWARD.
 *
 *
 */

#include <linux/mm.h>
#include <linux/export.h>
#include <linux/sysctl.h>
#include <linux/nsproxy.h>

#include <net/sock.h>

#ifdef CONFIG_INET
#include <net/ip.h>
#endif

#ifdef CONFIG_NET
#include <linux/if_ether.h>
#endif

static struct ctl_table_set *
net_ctl_header_lookup(struct ctl_table_root *root)
{
	return &current->nsproxy->net_ns->sysctls;
}

static int is_seen(struct ctl_table_set *set)
{
	return &current->nsproxy->net_ns->sysctls == set;
}

/* Return standard mode bits for table entry. */
static int net_ctl_permissions(struct ctl_table_header *head,
			       struct ctl_table *table)
{
	struct net *net = container_of(head->set, struct net, sysctls);

	/* Allow network administrator to have same access as root. */
	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
		int mode = (table->mode >> 6) & 7;
		return (mode << 6) | (mode << 3) | mode;
	}

	return table->mode;
}

static void net_ctl_set_ownership(struct ctl_table_header *head,
				  struct ctl_table *table,
				  kuid_t *uid, kgid_t *gid)
{
	struct net *net = container_of(head->set, struct net, sysctls);
	kuid_t ns_root_uid;
	kgid_t ns_root_gid;

	ns_root_uid = make_kuid(net->user_ns, 0);
	if (uid_valid(ns_root_uid))
		*uid = ns_root_uid;

	ns_root_gid = make_kgid(net->user_ns, 0);
	if (gid_valid(ns_root_gid))
		*gid = ns_root_gid;
}

static struct ctl_table_root net_sysctl_root = {
	.lookup = net_ctl_header_lookup,
	.permissions = net_ctl_permissions,
	.set_ownership = net_ctl_set_ownership,
};

static int __net_init sysctl_net_init(struct net *net)
{
	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
	return 0;
}

static void __net_exit sysctl_net_exit(struct net *net)
{
	retire_sysctl_set(&net->sysctls);
}

static struct pernet_operations sysctl_pernet_ops = {
	.init = sysctl_net_init,
	.exit = sysctl_net_exit,
};

static struct ctl_table_header *net_header;
__init int net_sysctl_init(void)
{
	static struct ctl_table empty[1];
	int ret = -ENOMEM;
	/* Avoid limitations in the sysctl implementation by
	 * registering "/proc/sys/net" as an empty directory not in a
	 * network namespace.
	 */
	net_header = register_sysctl("net", empty);
	if (!net_header)
		goto out;
	ret = register_pernet_subsys(&sysctl_pernet_ops);
	if (ret)
		goto out1;
	register_sysctl_root(&net_sysctl_root);
out:
	return ret;
out1:
	unregister_sysctl_table(net_header);
	net_header = NULL;
	goto out;
}

struct ctl_table_header *register_net_sysctl(struct net *net,
	const char *path, struct ctl_table *table)
{
	return __register_sysctl_table(&net->sysctls, path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl);

void unregister_net_sysctl_table(struct ctl_table_header *header)
{
	unregister_sysctl_table(header);
}
EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Dan Carpenter &lt;dan.carpenter@oracle.com&gt;</td><td class='right'>2017-01-30 10:55:04 +0100</td></tr>
<tr><th>committer</th><td>David S. Miller &lt;davem@davemloft.net&gt;</td><td class='right'>2017-01-30 16:37:55 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/atm?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4'>cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/atm?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4'>a45096fd9e8aaeea2eac1f1999a3d17dfeb0d02b</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/atm?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4'>net/atm</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/atm?id=1930b60352e7e195f55b27cde15d2a8f43342a8b'>1930b60352e7e195f55b27cde15d2a8f43342a8b</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/atm?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4&amp;id2=1930b60352e7e195f55b27cde15d2a8f43342a8b'>diff</a>)</td></tr></table>
<div class='commit-subject'>smc: some potential use after free bugs</div><div class='commit-msg'>Say we got really unlucky and these failed on the last iteration, then
it could lead to a use after free bug.

Fixes: cd6851f30386 ("smc: remote memory buffers (RMBs)")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Ursula Braun &lt;ubraun@linux.vnet.ibm.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=cdaf25dfc058ee6f7a7b2e2353de00fa288c0cd4'>Diffstat</a> (limited to 'net/atm')</div><table summary='diffstat' class='diffstat'>s to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'net/sunrpc/svcauth.c')</div><table summary='diffstat' class='diffstat'>