From: Lorenzo Bianconi Date: Tue, 2 Jun 2026 09:21:04 +0000 (+0200) Subject: net: airoha: Fix use-after-free in metadata dst teardown X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=b38cae85d1c45ff189d7ecb6ac36f41cdc3d84d0;p=thirdparty%2Flinux.git net: airoha: Fix use-after-free in metadata dst teardown airoha_metadata_dst_free() runs metadata_dst_free() which frees the metadata_dst with kfree() immediately, bypassing the RCU grace period. In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from the skb to the metadata_dst. This function requires RCU read-side protection and the dst must remain valid until all RCU readers complete. Since metadata_dst_free() calls kfree() directly, an use-after-free can occur if any skb still holds a noref pointer to the dst when the driver tears it down. Replace metadata_dst_free() with dst_release() which properly goes through the refcount path: when the refcount drops to zero, it schedules the actual free via call_rcu_hurry(), ensuring all RCU readers have completed before the memory is freed. Fixes: af3cf757d5c9 ("net: airoha: Move DSA tag in DMA descriptor") Signed-off-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260602-airoha-mtk-metadata-uaf-fix-v1-1-3aaa99d83351@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c index cecd66251dba2..eab6a98d62b9c 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.c +++ b/drivers/net/ethernet/airoha/airoha_eth.c @@ -2936,7 +2936,7 @@ static void airoha_metadata_dst_free(struct airoha_gdm_port *port) if (!port->dsa_meta[i]) continue; - metadata_dst_free(port->dsa_meta[i]); + dst_release(&port->dsa_meta[i]->dst); } }