diff mbox series

[net,3/3] netfilter: flowtable_offload: add missing locking

Message ID 20221122212814.63177-4-pablo@netfilter.org
State Accepted
Delegated to: Pablo Neira
Headers show
Series [net,1/3] netfilter: ipset: regression in ip_set_hash_ip.c | expand

Commit Message

Pablo Neira Ayuso Nov. 22, 2022, 9:28 p.m. UTC 
From: Felix Fietkau <nbd@nbd.name>

nf_flow_table_block_setup and the driver TC_SETUP_FT call can modify the flow
block cb list while they are being traversed elsewhere, causing a crash.
Add a write lock around the calls to protect readers

Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support")
Reported-by: Chad Monroe <chad.monroe@smartrg.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_offload.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
index b04645ced89b..00b522890d77 100644
--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -1098,6 +1098,7 @@  static int nf_flow_table_block_setup(struct nf_flowtable *flowtable,
 	struct flow_block_cb *block_cb, *next;
 	int err = 0;
 
+	down_write(&flowtable->flow_block_lock);
 	switch (cmd) {
 	case FLOW_BLOCK_BIND:
 		list_splice(&bo->cb_list, &flowtable->flow_block.cb_list);
@@ -1112,6 +1113,7 @@  static int nf_flow_table_block_setup(struct nf_flowtable *flowtable,
 		WARN_ON_ONCE(1);
 		err = -EOPNOTSUPP;
 	}
+	up_write(&flowtable->flow_block_lock);
 
 	return err;
 }
@@ -1168,7 +1170,9 @@  static int nf_flow_table_offload_cmd(struct flow_block_offload *bo,
 
 	nf_flow_table_block_offload_init(bo, dev_net(dev), cmd, flowtable,
 					 extack);
+	down_write(&flowtable->flow_block_lock);
 	err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_FT, bo);
+	up_write(&flowtable->flow_block_lock);
 	if (err < 0)
 		return err;