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The array is allocated with a fixed size of NF_FLOW_RULE_ACTION_MAX (16) entries, but certain combinations of IPv6 + SNAT + DNAT + double VLAN (QinQ) require 17 or more entries, causing a slab-out-of-bounds write in the kmalloc-4k slab. The maximum possible entry count is: tunnel(2) + eth(4) + VLAN(4) + IPv6_NAT(10) + redirect(1) = 21 Increase NF_FLOW_RULE_ACTION_MAX to 24 (with headroom) to cover the worst case. Fixes: efce49dfe6a8 ("netfilter: flowtable: add vlan pop action offload support") Signed-off-by: Hyunwoo Kim --- net/netfilter/nf_flow_table_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 9b677e116487..e843f6d0355e 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -727,7 +727,7 @@ int nf_flow_rule_route_ipv6(struct net *net, struct flow_offload *flow, } EXPORT_SYMBOL_GPL(nf_flow_rule_route_ipv6); -#define NF_FLOW_RULE_ACTION_MAX 16 +#define NF_FLOW_RULE_ACTION_MAX 24 static struct nf_flow_rule * nf_flow_offload_rule_alloc(struct net *net, -- 2.43.0