From: Eric Dumazet <edumazet@google.com> mainline inclusion from mainline-v6.19-rc6 commit 7470a7a63dc162f07c26dbf960e41ee1e248d80e category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13512 CVE: CVE-2026-23001 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Add RCU protection on (struct macvlan_source_entry)->vlan. Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts. This allows macvlan_forward_source() to skip over entries queued for freeing. Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)). Fixes: 79cf79abce71 ("macvlan: add source mode") Reported-by: syzbot+7182fbe91e58602ec1fe@syzkaller.appspotmail.com https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260108133651.1130486-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- drivers/net/macvlan.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index c8da94af4161..09db43ce3176 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -58,7 +58,7 @@ struct macvlan_port { struct macvlan_source_entry { struct hlist_node hlist; - struct macvlan_dev *vlan; + struct macvlan_dev __rcu *vlan; unsigned char addr[6+2] __aligned(sizeof(u16)); struct rcu_head rcu; }; @@ -145,7 +145,7 @@ static struct macvlan_source_entry *macvlan_hash_lookup_source( hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) { if (ether_addr_equal_64bits(entry->addr, addr) && - entry->vlan == vlan) + rcu_access_pointer(entry->vlan) == vlan) return entry; } return NULL; @@ -167,7 +167,7 @@ static int macvlan_hash_add_source(struct macvlan_dev *vlan, return -ENOMEM; ether_addr_copy(entry->addr, addr); - entry->vlan = vlan; + RCU_INIT_POINTER(entry->vlan, vlan); h = &port->vlan_source_hash[macvlan_eth_hash(addr)]; hlist_add_head_rcu(&entry->hlist, h); vlan->macaddr_count++; @@ -186,6 +186,7 @@ static void macvlan_hash_add(struct macvlan_dev *vlan) static void macvlan_hash_del_source(struct macvlan_source_entry *entry) { + RCU_INIT_POINTER(entry->vlan, NULL); hlist_del_rcu(&entry->hlist); kfree_rcu(entry, rcu); } @@ -389,7 +390,7 @@ static void macvlan_flush_sources(struct macvlan_port *port, int i; hash_for_each_safe(port->vlan_source_hash, i, next, entry, hlist) - if (entry->vlan == vlan) + if (rcu_access_pointer(entry->vlan) == vlan) macvlan_hash_del_source(entry); vlan->macaddr_count = 0; @@ -432,9 +433,14 @@ static bool macvlan_forward_source(struct sk_buff *skb, hlist_for_each_entry_rcu(entry, h, hlist) { if (ether_addr_equal_64bits(entry->addr, addr)) { - if (entry->vlan->flags & MACVLAN_FLAG_NODST) + struct macvlan_dev *vlan = rcu_dereference(entry->vlan); + + if (!vlan) + continue; + + if (vlan->flags & MACVLAN_FLAG_NODST) consume = true; - macvlan_forward_source_one(skb, entry->vlan); + macvlan_forward_source_one(skb, vlan); } } @@ -1685,7 +1691,7 @@ static int macvlan_fill_info_macaddr(struct sk_buff *skb, struct macvlan_source_entry *entry; hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) { - if (entry->vlan != vlan) + if (rcu_access_pointer(entry->vlan) != vlan) continue; if (nla_put(skb, IFLA_MACVLAN_MACADDR, ETH_ALEN, entry->addr)) return 1; -- 2.25.1