This patch fixes below.
1. check null pointer of rb_next.
rb_next can return null. so null check routine should be added.
2. add rcu_barrier in destroy routine.
GC uses call_rcu to remove elements. but all elements should be
removed before destroying set and chains. so that rcu_barrier is added.
test script:
%cat test.nft
table inet aa {
map map1 {
type ipv4_addr : verdict; flags interval, timeout;
elements = {
0-1 : jump a0,
3-4 : jump a0,
6-7 : jump a0,
9-10 : jump a0,
12-13 : jump a0,
15-16 : jump a0,
18-19 : jump a0,
21-22 : jump a0,
24-25 : jump a0,
27-28 : jump a0,
}
timeout 1s;
}
chain a0 {
}
}
flush ruleset
table inet aa {
map map1 {
type ipv4_addr : verdict; flags interval, timeout;
elements = {
0-1 : jump a0,
3-4 : jump a0,
6-7 : jump a0,
9-10 : jump a0,
12-13 : jump a0,
15-16 : jump a0,
18-19 : jump a0,
21-22 : jump a0,
24-25 : jump a0,
27-28 : jump a0,
}
timeout 1s;
}
chain a0 {
}
}
flush ruleset
splat looks like:
[ 2402.419838] kasan: GPF could be caused by NULL-ptr deref or user memory access
[ 2402.428433] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
[ 2402.429343] CPU: 1 PID: 1350 Comm: kworker/1:1 Not tainted 4.18.0-rc2+ #1
[ 2402.429343] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 03/23/2017
[ 2402.429343] Workqueue: events_power_efficient nft_rbtree_gc [nft_set_rbtree]
[ 2402.429343] RIP: 0010:rb_next+0x1e/0x130
[ 2402.429343] Code: e9 de f2 ff ff 0f 1f 80 00 00 00 00 41 55 48 89 fa 41 54 55 53 48 c1 ea 03 48 b8 00 00 00 0
[ 2402.429343] RSP: 0018:ffff880105f77678 EFLAGS: 00010296
[ 2402.429343] RAX: dffffc0000000000 RBX: ffff8801143e3428 RCX: 1ffff1002287c69c
[ 2402.429343] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
[ 2402.429343] RBP: 0000000000000000 R08: ffffed0016aabc24 R09: ffffed0016aabc24
[ 2402.429343] R10: 0000000000000001 R11: ffffed0016aabc23 R12: 0000000000000000
[ 2402.429343] R13: ffff8800b6933388 R14: dffffc0000000000 R15: ffff8801143e3440
[ 2402.534486] kasan: CONFIG_KASAN_INLINE enabled
[ 2402.534212] FS: 0000000000000000(0000) GS:ffff88011b600000(0000) knlGS:0000000000000000
[ 2402.534212] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2402.534212] CR2: 0000000000863008 CR3: 00000000a3c16000 CR4: 00000000001006e0
[ 2402.534212] Call Trace:
[ 2402.534212] nft_rbtree_gc+0x2b5/0x5f0 [nft_set_rbtree]
[ 2402.534212] process_one_work+0xc1b/0x1ee0
[ 2402.540329] kasan: GPF could be caused by NULL-ptr deref or user memory access
[ 2402.534212] ? _raw_spin_unlock_irq+0x29/0x40
[ 2402.534212] ? pwq_dec_nr_in_flight+0x3e0/0x3e0
[ 2402.534212] ? set_load_weight+0x270/0x270
[ 2402.534212] ? __schedule+0x6ea/0x1fb0
[ 2402.534212] ? __sched_text_start+0x8/0x8
[ 2402.534212] ? save_trace+0x320/0x320
[ 2402.534212] ? sched_clock_local+0xe2/0x150
[ 2402.534212] ? find_held_lock+0x39/0x1c0
[ 2402.534212] ? worker_thread+0x35f/0x1150
[ 2402.534212] ? lock_contended+0xe90/0xe90
[ 2402.534212] ? __lock_acquire+0x4520/0x4520
[ 2402.534212] ? do_raw_spin_unlock+0xb1/0x350
[ 2402.534212] ? do_raw_spin_trylock+0x111/0x1b0
[ 2402.534212] ? do_raw_spin_lock+0x1f0/0x1f0
[ 2402.534212] worker_thread+0x169/0x1150
V2:
- Do not add interval check routine in nft_set_rbtree.
- Requested by Pablo Neira Ayuso
Fixes: 8d8540c4f5e0("netfilter: nft_set_rbtree: add timeout support")
Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
---
net/netfilter/nft_set_rbtree.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index 1f8f257..09e3a15 100644
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -381,7 +381,7 @@ static void nft_rbtree_gc(struct work_struct *work)
gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
if (!gcb)
- goto out;
+ break;
atomic_dec(&set->nelems);
nft_set_gc_batch_add(gcb, rbe);
@@ -390,10 +390,12 @@ static void nft_rbtree_gc(struct work_struct *work)
rbe = rb_entry(prev, struct nft_rbtree_elem, node);
atomic_dec(&set->nelems);
nft_set_gc_batch_add(gcb, rbe);
+ prev = NULL;
}
node = rb_next(node);
+ if (!node)
+ break;
}
-out:
if (gcb) {
for (i = 0; i < gcb->head.cnt; i++) {
rbe = gcb->elems[i];
@@ -440,9 +442,10 @@ static void nft_rbtree_destroy(const struct nft_set *set)
struct rb_node *node;
cancel_delayed_work_sync(&priv->gc_work);
+ rcu_barrier();
while ((node = priv->root.rb_node) != NULL) {
- rb_erase(node, &priv->root);
rbe = rb_entry(node, struct nft_rbtree_elem, node);
+ rb_erase(node, &priv->root);
nft_set_elem_destroy(set, rbe, true);
}
}
--
2.9.3
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