[PATCH 6.6 177/396] wireguard: netlink: access device through ctx instead of peer

Greg Kroah-Hartman
2024-04-01T16:44:33Z

From: Jason A. Donenfeld <Jason@zx2c4.com>

[ Upstream commit 71cbd32e3db82ea4a74e3ef9aeeaa6971969c86f ]

The previous commit fixed a bug that led to a NULL peer->device being
dereferenced. It's actually easier and faster performance-wise to
instead get the device from ctx->wg. This semantically makes more sense
too, since ctx->wg->peer_allowedips.seq is compared with
ctx->allowedips_seq, basing them both in ctx. This also acts as a
defence in depth provision against freed peers.

Cc: stable@vger.kernel.org
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireguard/netlink.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index 12d80306ff3bc..a6661c9500d40 100644
--- a/drivers/net/wireguard/netlink.c
+++ b/drivers/net/wireguard/netlink.c
@@ -164,8 +164,8 @@ get_peer(struct wg_peer *peer, struct sk_buff *skb, struct dump_ctx *ctx)
if (!allowedips_node)
goto no_allowedips;
if (!ctx->allowedips_seq)
- ctx->allowedips_seq = peer->device->peer_allowedips.seq;
- else if (ctx->allowedips_seq != peer->device->peer_allowedips.seq)
+ ctx->allowedips_seq = ctx->wg->peer_allowedips.seq;
+ else if (ctx->allowedips_seq != ctx->wg->peer_allowedips.seq)
goto no_allowedips;

allowedips_nest = nla_nest_start(skb, WGPEER_A_ALLOWEDIPS);
--
2.43.0