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authorFlorian Westphal <fw@strlen.de>2017-04-16 01:29:19 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2017-04-19 17:55:17 +0200
commitb3a5db109e0670d6d168e9cd9de4d272a68f7c35 (patch)
treeae23e5a9d0b2fd061130076bedc9560852cb11ef /net
parentfaec865db9a79e7452d7fc01a4a409b06d02b479 (diff)
downloadlinux-b3a5db109e0670d6d168e9cd9de4d272a68f7c35.tar.bz2
netfilter: conntrack: use u8 for extension sizes again
commit 223b02d923ecd7c84cf9780bb3686f455d279279 ("netfilter: nf_conntrack: reserve two bytes for nf_ct_ext->len") had to increase size of the extension offsets because total size of the extensions had increased to a point where u8 did overflow. 3 years later we've managed to diet extensions a bit and we no longer need u16. Furthermore we can now add a compile-time assertion for this problem. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_conntrack_core.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 03150f60714d..62368b05cef5 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1804,12 +1804,45 @@ EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
&nf_conntrack_htable_size, 0600);
+static unsigned int total_extension_size(void)
+{
+ /* remember to add new extensions below */
+ BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
+
+ return sizeof(struct nf_ct_ext) +
+ sizeof(struct nf_conn_help)
+#if IS_ENABLED(CONFIG_NF_NAT)
+ + sizeof(struct nf_conn_nat)
+#endif
+ + sizeof(struct nf_conn_seqadj)
+ + sizeof(struct nf_conn_acct)
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ + sizeof(struct nf_conntrack_ecache)
+#endif
+#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
+ + sizeof(struct nf_conn_tstamp)
+#endif
+#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+ + sizeof(struct nf_conn_timeout)
+#endif
+#ifdef CONFIG_NF_CONNTRACK_LABELS
+ + sizeof(struct nf_conn_labels)
+#endif
+#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
+ + sizeof(struct nf_conn_synproxy)
+#endif
+ ;
+};
+
int nf_conntrack_init_start(void)
{
int max_factor = 8;
int ret = -ENOMEM;
int i;
+ /* struct nf_ct_ext uses u8 to store offsets/size */
+ BUILD_BUG_ON(total_extension_size() > 255u);
+
seqcount_init(&nf_conntrack_generation);
for (i = 0; i < CONNTRACK_LOCKS; i++)