Since 4fefee5 ("netfilter: nf_tables: allow to delete several objects
from a batch"), every new rule bumps the chain use counter. However,
this is limited to 16 bits, which means that it will overrun after
2^16 rules.
Use a u32 chain counter and check for overflows (just like we do for
table objects).
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/net/netfilter/nf_tables.h | 6 +++---
net/netfilter/nf_tables_api.c | 3 +++
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 7ee6ce6..713b0b8 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -503,9 +503,9 @@ enum nft_chain_flags {
* @net: net namespace that this chain belongs to
* @table: table that this chain belongs to
* @handle: chain handle
- * @flags: bitmask of enum nft_chain_flags
* @use: number of jump references to this chain
* @level: length of longest path to this chain
+ * @flags: bitmask of enum nft_chain_flags
* @name: name of the chain
*/
struct nft_chain {
@@ -514,9 +514,9 @@ struct nft_chain {
struct net *net;
struct nft_table *table;
u64 handle;
- u8 flags;
- u16 use;
+ u32 use;
u16 level;
+ u8 flags;
char name[NFT_CHAIN_MAXNAMELEN];
};
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ba37c10..5586426 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1730,6 +1730,9 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
if (!create || nlh->nlmsg_flags & NLM_F_REPLACE)
return -EINVAL;
handle = nf_tables_alloc_handle(table);
+
+ if (chain->use == UINT_MAX)
+ return -EOVERFLOW;
}
if (nla[NFTA_RULE_POSITION]) {
--
1.7.10.4
--
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