macvlan: fix possible UAF in macvlan_forward_source()

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[ Upstream commit 7470a7a63d ]

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: 79cf79abce ("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: Sasha Levin <sashal@kernel.org>

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Eric Dumazet 2026-01-08 13:36:51 +00:00 • committed by Greg Kroah-Hartman

parent da6d0370eb

commit 6dbead9c76

1 changed files with 13 additions and 7 deletions

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drivers/net/macvlan.c

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