[PATCH net 0/2] ovpn: fix peer float use-after-free and key slot NULL deref
Junrui Luo <[email protected]> Wed, 05 Aug 2026 21:29:35 +0800
| Newsgroups | org.kernel.feeds.b4-sent,org.kernel.vger.linux-kernel,org.kernel.vger.netdev,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
Two independent fixes for the ovpn driver, both in lifetime handling: one for a crypto key slot that can legitimately be empty, one for a peer that can be re-linked into a hash table after it has been removed. Patch 1 fixes a NULL dereference in ovpn_crypto_kill_key(). It locates the slot holding a given key ID by reading both cs->slots[] entries and comparing ->key_id, without checking either pointer first. An empty slot is a normal state: the ordinary rekey sequence - install into the secondary slot, swap, delete the retired one - leaves primary_idx at 1 with slots[0] empty, and key_id sits at offset 0, so the first comparison faults on a read of address 0. Patch 2 fixes a use-after-free in the peer float path. ovpn_peer_endpoints_update() releases peer->lock to send the float notification, then re-acquires ovpn->lock and re-links the peer into by_transp_addr unconditionally - even if ovpn_peer_remove() unlinked it while the lock was not held. The teardown path never unlinks hash nodes again, so the peer ends up freed while still on the chain, and every later datagram walks it in ovpn_peer_get_by_transp_addr(). Reproduced under KASAN on 7.0-rc3; the splat is included in the patch. The two patches are independent and touch different files; they can be applied in either order. Signed-off-by: Junrui Luo <[email protected]> --- Junrui Luo (2): ovpn: don't deref NULL key slot in ovpn_crypto_kill_key() ovpn: don't re-hash a removed peer on float drivers/net/ovpn/crypto.c | 6 ++++-- drivers/net/ovpn/peer.c | 7 ++++++- 2 files changed, 10 insertions(+), 3 deletions(-) --- base-commit: 075b74841bd0065a3bda3440873c747938e69b68 change-id: 20260805-ovpn-fixes-52c198458a2a Best regards, -- Junrui Luo <[email protected]>