Revision 924d8696751c4b9e58263bc82efdafcf875596a6 authored by James Morse on 16 August 2016, 09:46:38 UTC, committed by Rafael J. Wysocki on 16 August 2016, 11:16:36 UTC
rtree_next_node() walks the linked list of leaf nodes to find the next block of pages in the struct memory_bitmap. If it walks off the end of the list of nodes, it walks the list of memory zones to find the next region of memory. If it walks off the end of the list of zones, it returns false. This leaves the struct bm_position's node and zone pointers pointing at their respective struct list_heads in struct mem_zone_bm_rtree. memory_bm_find_bit() uses struct bm_position's node and zone pointers to avoid walking lists and trees if the next bit appears in the same node/zone. It handles these values being stale. Swap rtree_next_node()s 'step then test' to 'test-next then step', this means if we reach the end of memory we return false and leave the node and zone pointers as they were. This fixes a panic on resume using AMD Seattle with 64K pages: [ 6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done. [ 6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds) [ 6.896453] PM: Using 3 thread(s) for decompression. [ 6.896453] PM: Loading and decompressing image data (5339 pages)... [ 7.318890] PM: Image loading progress: 0% [ 7.323395] Unable to handle kernel paging request at virtual address 00800040 [ 7.330611] pgd = ffff000008df0000 [ 7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000 [ 7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP [ 7.349825] Modules linked in: [ 7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W I 4.8.0-rc1 #4737 [ 7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016 [ 7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000 [ 7.375020] PC is at set_bit+0x18/0x30 [ 7.378758] LR is at memory_bm_set_bit+0x24/0x30 [ 7.383362] pc : [<ffff00000835bbc8>] lr : [<ffff0000080faf18>] pstate: 60000045 [ 7.390743] sp : ffff8003c0283b00 [ 7.473551] [ 7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020) [ 7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000) [ 7.800075] Call trace: [ 7.887097] [<ffff00000835bbc8>] set_bit+0x18/0x30 [ 7.891876] [<ffff0000080fb038>] duplicate_memory_bitmap.constprop.38+0x54/0x70 [ 7.899172] [<ffff0000080fcc40>] snapshot_write_next+0x22c/0x47c [ 7.905166] [<ffff0000080fe1b4>] load_image_lzo+0x754/0xa88 [ 7.910725] [<ffff0000080ff0a8>] swsusp_read+0x144/0x230 [ 7.916025] [<ffff0000080fa338>] load_image_and_restore+0x58/0x90 [ 7.922105] [<ffff0000080fa660>] software_resume+0x2f0/0x338 [ 7.927752] [<ffff000008083350>] do_one_initcall+0x38/0x11c [ 7.933314] [<ffff000008b40cc0>] kernel_init_freeable+0x14c/0x1ec [ 7.939395] [<ffff0000087ce564>] kernel_init+0x10/0xfc [ 7.944520] [<ffff000008082e90>] ret_from_fork+0x10/0x40 [ 7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22) [ 7.955909] ---[ end trace 0024a5986e6ff323 ]--- [ 7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Here struct mem_zone_bm_rtree's start_pfn has been returned instead of struct rtree_node's addr as the node/zone pointers are corrupt after we walked off the end of the lists during mark_unsafe_pages(). This behaviour was exposed by commit 6dbecfd345a6 ("PM / hibernate: Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking off the end of the memory bitmap. Fixes: 3a20cb177961 (PM / Hibernate: Implement position keeping in radix tree) Signed-off-by: James Morse <james.morse@arm.com> [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 parent 5d87f49
netif.c
/*
* Network interface table.
*
* Network interfaces (devices) do not have a security field, so we
* maintain a table associating each interface with a SID.
*
* Author: James Morris <jmorris@redhat.com>
*
* Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
* Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul@paul-moore.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/rcupdate.h>
#include <net/net_namespace.h>
#include "security.h"
#include "objsec.h"
#include "netif.h"
#define SEL_NETIF_HASH_SIZE 64
#define SEL_NETIF_HASH_MAX 1024
struct sel_netif {
struct list_head list;
struct netif_security_struct nsec;
struct rcu_head rcu_head;
};
static u32 sel_netif_total;
static LIST_HEAD(sel_netif_list);
static DEFINE_SPINLOCK(sel_netif_lock);
static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
/**
* sel_netif_hashfn - Hashing function for the interface table
* @ns: the network namespace
* @ifindex: the network interface
*
* Description:
* This is the hashing function for the network interface table, it returns the
* bucket number for the given interface.
*
*/
static inline u32 sel_netif_hashfn(const struct net *ns, int ifindex)
{
return (((uintptr_t)ns + ifindex) & (SEL_NETIF_HASH_SIZE - 1));
}
/**
* sel_netif_find - Search for an interface record
* @ns: the network namespace
* @ifindex: the network interface
*
* Description:
* Search the network interface table and return the record matching @ifindex.
* If an entry can not be found in the table return NULL.
*
*/
static inline struct sel_netif *sel_netif_find(const struct net *ns,
int ifindex)
{
int idx = sel_netif_hashfn(ns, ifindex);
struct sel_netif *netif;
list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
if (net_eq(netif->nsec.ns, ns) &&
netif->nsec.ifindex == ifindex)
return netif;
return NULL;
}
/**
* sel_netif_insert - Insert a new interface into the table
* @netif: the new interface record
*
* Description:
* Add a new interface record to the network interface hash table. Returns
* zero on success, negative values on failure.
*
*/
static int sel_netif_insert(struct sel_netif *netif)
{
int idx;
if (sel_netif_total >= SEL_NETIF_HASH_MAX)
return -ENOSPC;
idx = sel_netif_hashfn(netif->nsec.ns, netif->nsec.ifindex);
list_add_rcu(&netif->list, &sel_netif_hash[idx]);
sel_netif_total++;
return 0;
}
/**
* sel_netif_destroy - Remove an interface record from the table
* @netif: the existing interface record
*
* Description:
* Remove an existing interface record from the network interface table.
*
*/
static void sel_netif_destroy(struct sel_netif *netif)
{
list_del_rcu(&netif->list);
sel_netif_total--;
kfree_rcu(netif, rcu_head);
}
/**
* sel_netif_sid_slow - Lookup the SID of a network interface using the policy
* @ns: the network namespace
* @ifindex: the network interface
* @sid: interface SID
*
* Description:
* This function determines the SID of a network interface by quering the
* security policy. The result is added to the network interface table to
* speedup future queries. Returns zero on success, negative values on
* failure.
*
*/
static int sel_netif_sid_slow(struct net *ns, int ifindex, u32 *sid)
{
int ret;
struct sel_netif *netif;
struct sel_netif *new = NULL;
struct net_device *dev;
/* NOTE: we always use init's network namespace since we don't
* currently support containers */
dev = dev_get_by_index(ns, ifindex);
if (unlikely(dev == NULL)) {
printk(KERN_WARNING
"SELinux: failure in sel_netif_sid_slow(),"
" invalid network interface (%d)\n", ifindex);
return -ENOENT;
}
spin_lock_bh(&sel_netif_lock);
netif = sel_netif_find(ns, ifindex);
if (netif != NULL) {
*sid = netif->nsec.sid;
ret = 0;
goto out;
}
new = kzalloc(sizeof(*new), GFP_ATOMIC);
if (new == NULL) {
ret = -ENOMEM;
goto out;
}
ret = security_netif_sid(dev->name, &new->nsec.sid);
if (ret != 0)
goto out;
new->nsec.ns = ns;
new->nsec.ifindex = ifindex;
ret = sel_netif_insert(new);
if (ret != 0)
goto out;
*sid = new->nsec.sid;
out:
spin_unlock_bh(&sel_netif_lock);
dev_put(dev);
if (unlikely(ret)) {
printk(KERN_WARNING
"SELinux: failure in sel_netif_sid_slow(),"
" unable to determine network interface label (%d)\n",
ifindex);
kfree(new);
}
return ret;
}
/**
* sel_netif_sid - Lookup the SID of a network interface
* @ns: the network namespace
* @ifindex: the network interface
* @sid: interface SID
*
* Description:
* This function determines the SID of a network interface using the fastest
* method possible. First the interface table is queried, but if an entry
* can't be found then the policy is queried and the result is added to the
* table to speedup future queries. Returns zero on success, negative values
* on failure.
*
*/
int sel_netif_sid(struct net *ns, int ifindex, u32 *sid)
{
struct sel_netif *netif;
rcu_read_lock();
netif = sel_netif_find(ns, ifindex);
if (likely(netif != NULL)) {
*sid = netif->nsec.sid;
rcu_read_unlock();
return 0;
}
rcu_read_unlock();
return sel_netif_sid_slow(ns, ifindex, sid);
}
/**
* sel_netif_kill - Remove an entry from the network interface table
* @ns: the network namespace
* @ifindex: the network interface
*
* Description:
* This function removes the entry matching @ifindex from the network interface
* table if it exists.
*
*/
static void sel_netif_kill(const struct net *ns, int ifindex)
{
struct sel_netif *netif;
rcu_read_lock();
spin_lock_bh(&sel_netif_lock);
netif = sel_netif_find(ns, ifindex);
if (netif)
sel_netif_destroy(netif);
spin_unlock_bh(&sel_netif_lock);
rcu_read_unlock();
}
/**
* sel_netif_flush - Flush the entire network interface table
*
* Description:
* Remove all entries from the network interface table.
*
*/
void sel_netif_flush(void)
{
int idx;
struct sel_netif *netif;
spin_lock_bh(&sel_netif_lock);
for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
list_for_each_entry(netif, &sel_netif_hash[idx], list)
sel_netif_destroy(netif);
spin_unlock_bh(&sel_netif_lock);
}
static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
if (event == NETDEV_DOWN)
sel_netif_kill(dev_net(dev), dev->ifindex);
return NOTIFY_DONE;
}
static struct notifier_block sel_netif_netdev_notifier = {
.notifier_call = sel_netif_netdev_notifier_handler,
};
static __init int sel_netif_init(void)
{
int i;
if (!selinux_enabled)
return 0;
for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
INIT_LIST_HEAD(&sel_netif_hash[i]);
register_netdevice_notifier(&sel_netif_netdev_notifier);
return 0;
}
__initcall(sel_netif_init);
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