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[6.6.y,2/2] netfilter: nf_tables: split async and sync catchall in two functions

Message ID 20231121121431.8612-3-fw@strlen.de
State Awaiting Upstream
Delegated to: Pablo Neira
Headers show
Series netfilter: fix catchall element double-free | expand

Commit Message

Florian Westphal Nov. 21, 2023, 12:14 p.m. UTC 
From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 8837ba3e58ea1e3d09ae36db80b1e80853aada95 ]

list_for_each_entry_safe() does not work for the async case which runs
under RCU, therefore, split GC logic for catchall in two functions
instead, one for each of the sync and async GC variants.

The catchall sync GC variant never sees a _DEAD bit set on ever, thus,
this handling is removed in such case, moreover, allocate GC sync batch
via GFP_KERNEL.

Fixes: 93995bf4af2c ("netfilter: nf_tables: remove catchall element in GC sync path")
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nf_tables_api.c | 61 ++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 29 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d300e9fc5d62..f51876bc0947 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -9639,16 +9639,14 @@  void nft_trans_gc_queue_sync_done(struct nft_trans_gc *trans)
 	call_rcu(&trans->rcu, nft_trans_gc_trans_free);
 }
 
-static struct nft_trans_gc *nft_trans_gc_catchall(struct nft_trans_gc *gc,
-						  unsigned int gc_seq,
-						  bool sync)
+struct nft_trans_gc *nft_trans_gc_catchall_async(struct nft_trans_gc *gc,
+						 unsigned int gc_seq)
 {
-	struct nft_set_elem_catchall *catchall, *next;
+	struct nft_set_elem_catchall *catchall;
 	const struct nft_set *set = gc->set;
-	struct nft_elem_priv *elem_priv;
 	struct nft_set_ext *ext;
 
-	list_for_each_entry_safe(catchall, next, &set->catchall_list, list) {
+	list_for_each_entry_rcu(catchall, &set->catchall_list, list) {
 		ext = nft_set_elem_ext(set, catchall->elem);
 
 		if (!nft_set_elem_expired(ext))
@@ -9658,39 +9656,44 @@  static struct nft_trans_gc *nft_trans_gc_catchall(struct nft_trans_gc *gc,
 
 		nft_set_elem_dead(ext);
 dead_elem:
-		if (sync)
-			gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
-		else
-			gc = nft_trans_gc_queue_async(gc, gc_seq, GFP_ATOMIC);
-
+		gc = nft_trans_gc_queue_async(gc, gc_seq, GFP_ATOMIC);
 		if (!gc)
 			return NULL;
 
-		elem_priv = catchall->elem;
-		if (sync) {
-			struct nft_set_elem elem = {
-				.priv = elem_priv,
-			};
-
-			nft_setelem_data_deactivate(gc->net, gc->set, &elem);
-			nft_setelem_catchall_destroy(catchall);
-		}
-
-		nft_trans_gc_elem_add(gc, elem_priv);
+		nft_trans_gc_elem_add(gc, catchall->elem);
 	}
 
 	return gc;
 }
 
-struct nft_trans_gc *nft_trans_gc_catchall_async(struct nft_trans_gc *gc,
-						 unsigned int gc_seq)
-{
-	return nft_trans_gc_catchall(gc, gc_seq, false);
-}
-
 struct nft_trans_gc *nft_trans_gc_catchall_sync(struct nft_trans_gc *gc)
 {
-	return nft_trans_gc_catchall(gc, 0, true);
+	struct nft_set_elem_catchall *catchall, *next;
+	const struct nft_set *set = gc->set;
+	struct nft_set_elem elem;
+	struct nft_set_ext *ext;
+
+	WARN_ON_ONCE(!lockdep_commit_lock_is_held(gc->net));
+
+	list_for_each_entry_safe(catchall, next, &set->catchall_list, list) {
+		ext = nft_set_elem_ext(set, catchall->elem);
+
+		if (!nft_set_elem_expired(ext))
+			continue;
+
+		gc = nft_trans_gc_queue_sync(gc, GFP_KERNEL);
+		if (!gc)
+			return NULL;
+
+		memset(&elem, 0, sizeof(elem));
+		elem.priv = catchall->elem;
+
+		nft_setelem_data_deactivate(gc->net, gc->set, &elem);
+		nft_setelem_catchall_destroy(catchall);
+		nft_trans_gc_elem_add(gc, elem.priv);
+	}
+
+	return gc;
 }
 
 static void nf_tables_module_autoload_cleanup(struct net *net)