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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Taehee Yoo](/assets/img/avatar_default.png)
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>
316 lines
8.7 KiB
C
316 lines
8.7 KiB
C
/*
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* Copyright (c) 2017 Pablo Neira Ayuso <pablo@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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struct nft_bitmap_elem {
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struct list_head head;
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struct nft_set_ext ext;
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};
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/* This bitmap uses two bits to represent one element. These two bits determine
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* the element state in the current and the future generation.
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*
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* An element can be in three states. The generation cursor is represented using
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* the ^ character, note that this cursor shifts on every succesful transaction.
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* If no transaction is going on, we observe all elements are in the following
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* state:
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*
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* 11 = this element is active in the current generation. In case of no updates,
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* ^ it stays active in the next generation.
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* 00 = this element is inactive in the current generation. In case of no
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* ^ updates, it stays inactive in the next generation.
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*
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* On transaction handling, we observe these two temporary states:
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*
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* 01 = this element is inactive in the current generation and it becomes active
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* ^ in the next one. This happens when the element is inserted but commit
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* path has not yet been executed yet, so activation is still pending. On
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* transaction abortion, the element is removed.
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* 10 = this element is active in the current generation and it becomes inactive
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* ^ in the next one. This happens when the element is deactivated but commit
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* path has not yet been executed yet, so removal is still pending. On
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* transation abortion, the next generation bit is reset to go back to
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* restore its previous state.
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*/
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struct nft_bitmap {
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struct list_head list;
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u16 bitmap_size;
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u8 bitmap[];
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};
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static inline void nft_bitmap_location(const struct nft_set *set,
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const void *key,
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u32 *idx, u32 *off)
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{
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u32 k;
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if (set->klen == 2)
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k = *(u16 *)key;
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else
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k = *(u8 *)key;
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k <<= 1;
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*idx = k / BITS_PER_BYTE;
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*off = k % BITS_PER_BYTE;
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}
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/* Fetch the two bits that represent the element and check if it is active based
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* on the generation mask.
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*/
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static inline bool
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nft_bitmap_active(const u8 *bitmap, u32 idx, u32 off, u8 genmask)
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{
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return (bitmap[idx] & (0x3 << off)) & (genmask << off);
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}
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static bool nft_bitmap_lookup(const struct net *net, const struct nft_set *set,
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const u32 *key, const struct nft_set_ext **ext)
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{
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const struct nft_bitmap *priv = nft_set_priv(set);
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u8 genmask = nft_genmask_cur(net);
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u32 idx, off;
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nft_bitmap_location(set, key, &idx, &off);
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return nft_bitmap_active(priv->bitmap, idx, off, genmask);
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}
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static struct nft_bitmap_elem *
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nft_bitmap_elem_find(const struct nft_set *set, struct nft_bitmap_elem *this,
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u8 genmask)
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{
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const struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *be;
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list_for_each_entry_rcu(be, &priv->list, head) {
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if (memcmp(nft_set_ext_key(&be->ext),
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nft_set_ext_key(&this->ext), set->klen) ||
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!nft_set_elem_active(&be->ext, genmask))
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continue;
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return be;
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}
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return NULL;
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}
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static void *nft_bitmap_get(const struct net *net, const struct nft_set *set,
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const struct nft_set_elem *elem, unsigned int flags)
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{
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const struct nft_bitmap *priv = nft_set_priv(set);
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u8 genmask = nft_genmask_cur(net);
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struct nft_bitmap_elem *be;
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list_for_each_entry_rcu(be, &priv->list, head) {
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if (memcmp(nft_set_ext_key(&be->ext), elem->key.val.data, set->klen) ||
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!nft_set_elem_active(&be->ext, genmask))
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continue;
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return be;
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}
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return ERR_PTR(-ENOENT);
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}
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static int nft_bitmap_insert(const struct net *net, const struct nft_set *set,
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const struct nft_set_elem *elem,
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struct nft_set_ext **ext)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *new = elem->priv, *be;
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u8 genmask = nft_genmask_next(net);
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u32 idx, off;
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be = nft_bitmap_elem_find(set, new, genmask);
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if (be) {
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*ext = &be->ext;
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return -EEXIST;
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}
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nft_bitmap_location(set, nft_set_ext_key(&new->ext), &idx, &off);
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/* Enter 01 state. */
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priv->bitmap[idx] |= (genmask << off);
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list_add_tail_rcu(&new->head, &priv->list);
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return 0;
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}
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static void nft_bitmap_remove(const struct net *net,
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const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *be = elem->priv;
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u8 genmask = nft_genmask_next(net);
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u32 idx, off;
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nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
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/* Enter 00 state. */
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priv->bitmap[idx] &= ~(genmask << off);
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list_del_rcu(&be->head);
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}
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static void nft_bitmap_activate(const struct net *net,
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const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *be = elem->priv;
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u8 genmask = nft_genmask_next(net);
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u32 idx, off;
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nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
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/* Enter 11 state. */
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priv->bitmap[idx] |= (genmask << off);
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nft_set_elem_change_active(net, set, &be->ext);
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}
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static bool nft_bitmap_flush(const struct net *net,
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const struct nft_set *set, void *_be)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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u8 genmask = nft_genmask_next(net);
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struct nft_bitmap_elem *be = _be;
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u32 idx, off;
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nft_bitmap_location(set, nft_set_ext_key(&be->ext), &idx, &off);
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/* Enter 10 state, similar to deactivation. */
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priv->bitmap[idx] &= ~(genmask << off);
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nft_set_elem_change_active(net, set, &be->ext);
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return true;
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}
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static void *nft_bitmap_deactivate(const struct net *net,
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const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *this = elem->priv, *be;
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u8 genmask = nft_genmask_next(net);
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u32 idx, off;
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nft_bitmap_location(set, elem->key.val.data, &idx, &off);
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be = nft_bitmap_elem_find(set, this, genmask);
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if (!be)
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return NULL;
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/* Enter 10 state. */
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priv->bitmap[idx] &= ~(genmask << off);
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nft_set_elem_change_active(net, set, &be->ext);
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return be;
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}
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static void nft_bitmap_walk(const struct nft_ctx *ctx,
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struct nft_set *set,
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struct nft_set_iter *iter)
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{
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const struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *be;
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struct nft_set_elem elem;
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list_for_each_entry_rcu(be, &priv->list, head) {
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if (iter->count < iter->skip)
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goto cont;
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if (!nft_set_elem_active(&be->ext, iter->genmask))
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goto cont;
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elem.priv = be;
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iter->err = iter->fn(ctx, set, iter, &elem);
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if (iter->err < 0)
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return;
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cont:
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iter->count++;
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}
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}
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/* The bitmap size is pow(2, key length in bits) / bits per byte. This is
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* multiplied by two since each element takes two bits. For 8 bit keys, the
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* bitmap consumes 66 bytes. For 16 bit keys, 16388 bytes.
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*/
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static inline u32 nft_bitmap_size(u32 klen)
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{
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return ((2 << ((klen * BITS_PER_BYTE) - 1)) / BITS_PER_BYTE) << 1;
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}
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static inline u64 nft_bitmap_total_size(u32 klen)
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{
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return sizeof(struct nft_bitmap) + nft_bitmap_size(klen);
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}
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static u64 nft_bitmap_privsize(const struct nlattr * const nla[],
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const struct nft_set_desc *desc)
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{
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u32 klen = ntohl(nla_get_be32(nla[NFTA_SET_KEY_LEN]));
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return nft_bitmap_total_size(klen);
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}
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static int nft_bitmap_init(const struct nft_set *set,
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const struct nft_set_desc *desc,
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const struct nlattr * const nla[])
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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INIT_LIST_HEAD(&priv->list);
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priv->bitmap_size = nft_bitmap_size(set->klen);
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return 0;
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}
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static void nft_bitmap_destroy(const struct nft_set *set)
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{
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struct nft_bitmap *priv = nft_set_priv(set);
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struct nft_bitmap_elem *be, *n;
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list_for_each_entry_safe(be, n, &priv->list, head)
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nft_set_elem_destroy(set, be, true);
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}
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static bool nft_bitmap_estimate(const struct nft_set_desc *desc, u32 features,
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struct nft_set_estimate *est)
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{
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/* Make sure bitmaps we don't get bitmaps larger than 16 Kbytes. */
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if (desc->klen > 2)
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return false;
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est->size = nft_bitmap_total_size(desc->klen);
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est->lookup = NFT_SET_CLASS_O_1;
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est->space = NFT_SET_CLASS_O_1;
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return true;
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}
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struct nft_set_type nft_set_bitmap_type __read_mostly = {
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.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,
|
|
},
|
|
};
|