alistair23-linux/net/netfilter/nft_set_bitmap.c
Taehee Yoo 4ef360dd6a netfilter: nft_set: fix allocation size overflow in privsize callback.
In order to determine allocation size of set, ->privsize is invoked.
At this point, both desc->size and size of each data structure of set
are used. desc->size means number of element that is given by user.
desc->size is u32 type. so that upperlimit of set element is 4294967295.
but return type of ->privsize is also u32. hence overflow can occurred.

test commands:
   %nft add table ip filter
   %nft add set ip filter hash1 { type ipv4_addr \; size 4294967295 \; }
   %nft list ruleset

splat looks like:
[ 1239.202910] kasan: CONFIG_KASAN_INLINE enabled
[ 1239.208788] kasan: GPF could be caused by NULL-ptr deref or user memory access
[ 1239.217625] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 1239.219329] CPU: 0 PID: 1603 Comm: nft Not tainted 4.18.0-rc5+ #7
[ 1239.229091] RIP: 0010:nft_hash_walk+0x1d2/0x310 [nf_tables_set]
[ 1239.229091] Code: 84 d2 7f 10 4c 89 e7 89 44 24 38 e8 d8 5a 17 e0 8b 44 24 38 48 8d 7b 10 41 0f b6 0c 24 48 89 fa 48 89 fe 48 c1 ea 03 83 e6 07 <42> 0f b6 14 3a 40 38 f2 7f 1a 84 d2 74 16
[ 1239.229091] RSP: 0018:ffff8801118cf358 EFLAGS: 00010246
[ 1239.229091] RAX: 0000000000000000 RBX: 0000000000020400 RCX: 0000000000000001
[ 1239.229091] RDX: 0000000000004082 RSI: 0000000000000000 RDI: 0000000000020410
[ 1239.229091] RBP: ffff880114d5a988 R08: 0000000000007e94 R09: ffff880114dd8030
[ 1239.229091] R10: ffff880114d5a988 R11: ffffed00229bb006 R12: ffff8801118cf4d0
[ 1239.229091] R13: ffff8801118cf4d8 R14: 0000000000000000 R15: dffffc0000000000
[ 1239.229091] FS:  00007f5a8fe0b700(0000) GS:ffff88011b600000(0000) knlGS:0000000000000000
[ 1239.229091] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1239.229091] CR2: 00007f5a8ecc27b0 CR3: 000000010608e000 CR4: 00000000001006f0
[ 1239.229091] Call Trace:
[ 1239.229091]  ? nft_hash_remove+0xf0/0xf0 [nf_tables_set]
[ 1239.229091]  ? memset+0x1f/0x40
[ 1239.229091]  ? __nla_reserve+0x9f/0xb0
[ 1239.229091]  ? memcpy+0x34/0x50
[ 1239.229091]  nf_tables_dump_set+0x9a1/0xda0 [nf_tables]
[ 1239.229091]  ? __kmalloc_reserve.isra.29+0x2e/0xa0
[ 1239.229091]  ? nft_chain_hash_obj+0x630/0x630 [nf_tables]
[ 1239.229091]  ? nf_tables_commit+0x2c60/0x2c60 [nf_tables]
[ 1239.229091]  netlink_dump+0x470/0xa20
[ 1239.229091]  __netlink_dump_start+0x5ae/0x690
[ 1239.229091]  nft_netlink_dump_start_rcu+0xd1/0x160 [nf_tables]
[ 1239.229091]  nf_tables_getsetelem+0x2e5/0x4b0 [nf_tables]
[ 1239.229091]  ? nft_get_set_elem+0x440/0x440 [nf_tables]
[ 1239.229091]  ? nft_chain_hash_obj+0x630/0x630 [nf_tables]
[ 1239.229091]  ? nf_tables_dump_obj_done+0x70/0x70 [nf_tables]
[ 1239.229091]  ? nla_parse+0xab/0x230
[ 1239.229091]  ? nft_get_set_elem+0x440/0x440 [nf_tables]
[ 1239.229091]  nfnetlink_rcv_msg+0x7f0/0xab0 [nfnetlink]
[ 1239.229091]  ? nfnetlink_bind+0x1d0/0x1d0 [nfnetlink]
[ 1239.229091]  ? debug_show_all_locks+0x290/0x290
[ 1239.229091]  ? sched_clock_cpu+0x132/0x170
[ 1239.229091]  ? find_held_lock+0x39/0x1b0
[ 1239.229091]  ? sched_clock_local+0x10d/0x130
[ 1239.229091]  netlink_rcv_skb+0x211/0x320
[ 1239.229091]  ? nfnetlink_bind+0x1d0/0x1d0 [nfnetlink]
[ 1239.229091]  ? netlink_ack+0x7b0/0x7b0
[ 1239.229091]  ? ns_capable_common+0x6e/0x110
[ 1239.229091]  nfnetlink_rcv+0x2d1/0x310 [nfnetlink]
[ 1239.229091]  ? nfnetlink_rcv_batch+0x10f0/0x10f0 [nfnetlink]
[ 1239.229091]  ? netlink_deliver_tap+0x829/0x930
[ 1239.229091]  ? lock_acquire+0x265/0x2e0
[ 1239.229091]  netlink_unicast+0x406/0x520
[ 1239.509725]  ? netlink_attachskb+0x5b0/0x5b0
[ 1239.509725]  ? find_held_lock+0x39/0x1b0
[ 1239.509725]  netlink_sendmsg+0x987/0xa20
[ 1239.509725]  ? netlink_unicast+0x520/0x520
[ 1239.509725]  ? _copy_from_user+0xa9/0xc0
[ 1239.509725]  __sys_sendto+0x21a/0x2c0
[ 1239.509725]  ? __ia32_sys_getpeername+0xa0/0xa0
[ 1239.509725]  ? retint_kernel+0x10/0x10
[ 1239.509725]  ? sched_clock_cpu+0x132/0x170
[ 1239.509725]  ? find_held_lock+0x39/0x1b0
[ 1239.509725]  ? lock_downgrade+0x540/0x540
[ 1239.509725]  ? up_read+0x1c/0x100
[ 1239.509725]  ? __do_page_fault+0x763/0x970
[ 1239.509725]  ? retint_user+0x18/0x18
[ 1239.509725]  __x64_sys_sendto+0x177/0x180
[ 1239.509725]  do_syscall_64+0xaa/0x360
[ 1239.509725]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1239.509725] RIP: 0033:0x7f5a8f468e03
[ 1239.509725] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb d0 0f 1f 84 00 00 00 00 00 83 3d 49 c9 2b 00 00 75 13 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8
[ 1239.509725] RSP: 002b:00007ffd78d0b778 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 1239.509725] RAX: ffffffffffffffda RBX: 00007ffd78d0c890 RCX: 00007f5a8f468e03
[ 1239.509725] RDX: 0000000000000034 RSI: 00007ffd78d0b7e0 RDI: 0000000000000003
[ 1239.509725] RBP: 00007ffd78d0b7d0 R08: 00007f5a8f15c160 R09: 000000000000000c
[ 1239.509725] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd78d0b7e0
[ 1239.509725] R13: 0000000000000034 R14: 00007f5a8f9aff60 R15: 00005648040094b0
[ 1239.509725] Modules linked in: nf_tables_set nf_tables nfnetlink ip_tables x_tables
[ 1239.670713] ---[ end trace 39375adcda140f11 ]---
[ 1239.676016] RIP: 0010:nft_hash_walk+0x1d2/0x310 [nf_tables_set]
[ 1239.682834] Code: 84 d2 7f 10 4c 89 e7 89 44 24 38 e8 d8 5a 17 e0 8b 44 24 38 48 8d 7b 10 41 0f b6 0c 24 48 89 fa 48 89 fe 48 c1 ea 03 83 e6 07 <42> 0f b6 14 3a 40 38 f2 7f 1a 84 d2 74 16
[ 1239.705108] RSP: 0018:ffff8801118cf358 EFLAGS: 00010246
[ 1239.711115] RAX: 0000000000000000 RBX: 0000000000020400 RCX: 0000000000000001
[ 1239.719269] RDX: 0000000000004082 RSI: 0000000000000000 RDI: 0000000000020410
[ 1239.727401] RBP: ffff880114d5a988 R08: 0000000000007e94 R09: ffff880114dd8030
[ 1239.735530] R10: ffff880114d5a988 R11: ffffed00229bb006 R12: ffff8801118cf4d0
[ 1239.743658] R13: ffff8801118cf4d8 R14: 0000000000000000 R15: dffffc0000000000
[ 1239.751785] FS:  00007f5a8fe0b700(0000) GS:ffff88011b600000(0000) knlGS:0000000000000000
[ 1239.760993] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1239.767560] CR2: 00007f5a8ecc27b0 CR3: 000000010608e000 CR4: 00000000001006f0
[ 1239.775679] Kernel panic - not syncing: Fatal exception
[ 1239.776630] Kernel Offset: 0x1f000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 1239.776630] Rebooting in 5 seconds..

Fixes: 20a69341f2 ("netfilter: nf_tables: add netlink set API")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-16 19:36:59 +02:00

317 lines
8.7 KiB
C

/*
* Copyright (c) 2017 Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
struct nft_bitmap_elem {
struct list_head head;
struct nft_set_ext ext;
};
/* This bitmap uses two bits to represent one element. These two bits determine
* the element state in the current and the future generation.
*
* An element can be in three states. The generation cursor is represented using
* the ^ character, note that this cursor shifts on every succesful transaction.
* If no transaction is going on, we observe all elements are in the following
* state:
*
* 11 = this element is active in the current generation. In case of no updates,
* ^ it stays active in the next generation.
* 00 = this element is inactive in the current generation. In case of no
* ^ updates, it stays inactive in the next generation.
*
* On transaction handling, we observe these two temporary states:
*
* 01 = this element is inactive in the current generation and it becomes active
* ^ in the next one. This happens when the element is inserted but commit
* path has not yet been executed yet, so activation is still pending. On
* transaction abortion, the element is removed.
* 10 = this element is active in the current generation and it becomes inactive
* ^ in the next one. This happens when the element is deactivated but commit
* path has not yet been executed yet, so removal is still pending. On
* transation abortion, the next generation bit is reset to go back to
* restore its previous state.
*/
struct nft_bitmap {
struct list_head list;
u16 bitmap_size;
u8 bitmap[];
};
static inline void nft_bitmap_location(const struct nft_set *set,
const void *key,
u32 *idx, u32 *off)
{
u32 k;
if (set->klen == 2)
k = *(u16 *)key;
else
k = *(u8 *)key;
k <<= 1;
*idx = k / BITS_PER_BYTE;
*off = k % BITS_PER_BYTE;
}
/* Fetch the two bits that represent the element and check if it is active based
* on the generation mask.
*/
static inline bool
nft_bitmap_active(const u8 *bitmap, u32 idx, u32 off, u8 genmask)
{
return (bitmap[idx] & (0x3 << off)) & (genmask << off);
}
static bool nft_bitmap_lookup(const struct net *net, const struct nft_set *set,
const u32 *key, const struct nft_set_ext **ext)
{
const struct nft_bitmap *priv = nft_set_priv(set);
u8 genmask = nft_genmask_cur(net);
u32 idx, off;
nft_bitmap_location(set, key, &idx, &off);
return nft_bitmap_active(priv->bitmap, idx, off, genmask);
}
static struct nft_bitmap_elem *
nft_bitmap_elem_find(const struct nft_set *set, struct nft_bitmap_elem *this,
u8 genmask)
{
const struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *be;
list_for_each_entry_rcu(be, &priv->list, head) {
if (memcmp(nft_set_ext_key(&be->ext),
nft_set_ext_key(&this->ext), set->klen) ||
!nft_set_elem_active(&be->ext, genmask))
continue;
return be;
}
return NULL;
}
static void *nft_bitmap_get(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem, unsigned int flags)
{
const struct nft_bitmap *priv = nft_set_priv(set);
u8 genmask = nft_genmask_cur(net);
struct nft_bitmap_elem *be;
list_for_each_entry_rcu(be, &priv->list, head) {
if (memcmp(nft_set_ext_key(&be->ext), elem->key.val.data, set->klen) ||
!nft_set_elem_active(&be->ext, genmask))
continue;
return be;
}
return ERR_PTR(-ENOENT);
}
static int nft_bitmap_insert(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem,
struct nft_set_ext **ext)
{
struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *new = elem->priv, *be;
u8 genmask = nft_genmask_next(net);
u32 idx, off;
be = nft_bitmap_elem_find(set, new, genmask);
if (be) {
*ext = &be->ext;
return -EEXIST;
}
nft_bitmap_location(set, nft_set_ext_key(&new->ext), &idx, &off);
/* Enter 01 state. */
priv->bitmap[idx] |= (genmask << off);
list_add_tail_rcu(&new->head, &priv->list);
return 0;
}
static void nft_bitmap_remove(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *be = elem->priv;
u8 genmask = nft_genmask_next(net);
u32 idx, off;
nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
/* Enter 00 state. */
priv->bitmap[idx] &= ~(genmask << off);
list_del_rcu(&be->head);
}
static void nft_bitmap_activate(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *be = elem->priv;
u8 genmask = nft_genmask_next(net);
u32 idx, off;
nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
/* Enter 11 state. */
priv->bitmap[idx] |= (genmask << off);
nft_set_elem_change_active(net, set, &be->ext);
}
static bool nft_bitmap_flush(const struct net *net,
const struct nft_set *set, void *_be)
{
struct nft_bitmap *priv = nft_set_priv(set);
u8 genmask = nft_genmask_next(net);
struct nft_bitmap_elem *be = _be;
u32 idx, off;
nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
/* Enter 10 state, similar to deactivation. */
priv->bitmap[idx] &= ~(genmask << off);
nft_set_elem_change_active(net, set, &be->ext);
return true;
}
static void *nft_bitmap_deactivate(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *this = elem->priv, *be;
u8 genmask = nft_genmask_next(net);
u32 idx, off;
nft_bitmap_location(set, elem->key.val.data, &idx, &off);
be = nft_bitmap_elem_find(set, this, genmask);
if (!be)
return NULL;
/* Enter 10 state. */
priv->bitmap[idx] &= ~(genmask << off);
nft_set_elem_change_active(net, set, &be->ext);
return be;
}
static void nft_bitmap_walk(const struct nft_ctx *ctx,
struct nft_set *set,
struct nft_set_iter *iter)
{
const struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *be;
struct nft_set_elem elem;
list_for_each_entry_rcu(be, &priv->list, head) {
if (iter->count < iter->skip)
goto cont;
if (!nft_set_elem_active(&be->ext, iter->genmask))
goto cont;
elem.priv = be;
iter->err = iter->fn(ctx, set, iter, &elem);
if (iter->err < 0)
return;
cont:
iter->count++;
}
}
/* The bitmap size is pow(2, key length in bits) / bits per byte. This is
* multiplied by two since each element takes two bits. For 8 bit keys, the
* bitmap consumes 66 bytes. For 16 bit keys, 16388 bytes.
*/
static inline u32 nft_bitmap_size(u32 klen)
{
return ((2 << ((klen * BITS_PER_BYTE) - 1)) / BITS_PER_BYTE) << 1;
}
static inline u64 nft_bitmap_total_size(u32 klen)
{
return sizeof(struct nft_bitmap) + nft_bitmap_size(klen);
}
static u64 nft_bitmap_privsize(const struct nlattr * const nla[],
const struct nft_set_desc *desc)
{
u32 klen = ntohl(nla_get_be32(nla[NFTA_SET_KEY_LEN]));
return nft_bitmap_total_size(klen);
}
static int nft_bitmap_init(const struct nft_set *set,
const struct nft_set_desc *desc,
const struct nlattr * const nla[])
{
struct nft_bitmap *priv = nft_set_priv(set);
INIT_LIST_HEAD(&priv->list);
priv->bitmap_size = nft_bitmap_size(set->klen);
return 0;
}
static void nft_bitmap_destroy(const struct nft_set *set)
{
struct nft_bitmap *priv = nft_set_priv(set);
struct nft_bitmap_elem *be, *n;
list_for_each_entry_safe(be, n, &priv->list, head)
nft_set_elem_destroy(set, be, true);
}
static bool nft_bitmap_estimate(const struct nft_set_desc *desc, u32 features,
struct nft_set_estimate *est)
{
/* Make sure bitmaps we don't get bitmaps larger than 16 Kbytes. */
if (desc->klen > 2)
return false;
est->size = nft_bitmap_total_size(desc->klen);
est->lookup = NFT_SET_CLASS_O_1;
est->space = NFT_SET_CLASS_O_1;
return true;
}
struct nft_set_type nft_set_bitmap_type __read_mostly = {
.owner = THIS_MODULE,
.ops = {
.privsize = nft_bitmap_privsize,
.elemsize = offsetof(struct nft_bitmap_elem, ext),
.estimate = nft_bitmap_estimate,
.init = nft_bitmap_init,
.destroy = nft_bitmap_destroy,
.insert = nft_bitmap_insert,
.remove = nft_bitmap_remove,
.deactivate = nft_bitmap_deactivate,
.flush = nft_bitmap_flush,
.activate = nft_bitmap_activate,
.lookup = nft_bitmap_lookup,
.walk = nft_bitmap_walk,
.get = nft_bitmap_get,
},
};