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From: Phil Sutter <phil@nwl.cc>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: [iptables PATCH 4/4] nft: cache: Review flush_cache()
Date: Mon,  2 Mar 2020 18:53:58 +0100	[thread overview]
Message-ID: <20200302175358.27796-5-phil@nwl.cc> (raw)
In-Reply-To: <20200302175358.27796-1-phil@nwl.cc>

While fixing for iptables-nft-restore under stress, I managed to hit
NULL-pointer deref in flush_cache(). Given that nftnl_*_list_free()
functions are not NULL-pointer tolerant, better make sure such are not
passed by accident.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 iptables/nft-cache.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/iptables/nft-cache.c b/iptables/nft-cache.c
index 0429fb32f2ed0..0dd131e1f70f5 100644
--- a/iptables/nft-cache.c
+++ b/iptables/nft-cache.c
@@ -603,17 +603,19 @@ static int flush_cache(struct nft_handle *h, struct nft_cache *c,
 		if (h->tables[i].name == NULL)
 			continue;
 
-		if (!c->table[i].chains)
-			continue;
-
-		nftnl_chain_list_free(c->table[i].chains);
-		c->table[i].chains = NULL;
-		if (c->table[i].sets)
+		if (c->table[i].chains) {
+			nftnl_chain_list_free(c->table[i].chains);
+			c->table[i].chains = NULL;
+		}
+		if (c->table[i].sets) {
 			nftnl_set_list_free(c->table[i].sets);
-		c->table[i].sets = NULL;
+			c->table[i].sets = NULL;
+		}
+	}
+	if (c->tables) {
+		nftnl_table_list_free(c->tables);
+		c->tables = NULL;
 	}
-	nftnl_table_list_free(c->tables);
-	c->tables = NULL;
 
 	return 1;
 }
-- 
2.25.1


  parent reply	other threads:[~2020-03-02 17:54 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-02 17:53 [iptables PATCH 0/4] Fix for iptables-nft-restore under pressure Phil Sutter
2020-03-02 17:53 ` [iptables PATCH 1/4] nft: cache: Fix nft_release_cache() under stress Phil Sutter
2020-03-02 19:19   ` Pablo Neira Ayuso
2020-03-03  1:02     ` Phil Sutter
2020-03-03 20:55       ` Pablo Neira Ayuso
2020-03-04  2:13         ` Phil Sutter
2020-03-04 17:02           ` Pablo Neira Ayuso
2020-03-02 17:53 ` [iptables PATCH 2/4] nft: cache: Make nft_rebuild_cache() respect fake cache Phil Sutter
2020-03-02 19:26   ` Pablo Neira Ayuso
2020-03-03  1:15     ` Phil Sutter
2020-03-02 17:53 ` [iptables PATCH 3/4] nft: cache: Simplify chain list allocation Phil Sutter
2020-03-02 17:53 ` Phil Sutter [this message]
2020-03-02 19:22   ` [iptables PATCH 4/4] nft: cache: Review flush_cache() Pablo Neira Ayuso
2020-03-03  1:22     ` Phil Sutter

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