From: Ido Schimmel <idosch@idosch.org>
To: "Johannes Wiesböck" <johannes.wiesboeck@aisec.fraunhofer.de>
Cc: "David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Kuniyuki Iwashima" <kuniyu@google.com>,
"Stanislav Fomichev" <sdf@fomichev.me>,
"Xiao Liang" <shaw.leon@gmail.com>,
"Vlad Yasevich" <vyasevic@redhat.com>,
"Jitendra Kalsaria" <jitendra.kalsaria@qlogic.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
gyroidos@aisec.fraunhofer.de, sw@simonwunderlich.de,
"Michael Weiß" <michael.weiss@aisec.fraunhofer.de>,
"Harshal Gohel" <hg@simonwunderlich.de>
Subject: Re: [PATCH net v2] rtnetlink: Allow deleting FDB entries in user namespace
Date: Thu, 16 Oct 2025 10:59:44 +0300 [thread overview]
Message-ID: <aPCl8EO8xkRVzaQi@shredder> (raw)
In-Reply-To: <20251015201548.319871-1-johannes.wiesboeck@aisec.fraunhofer.de>
On Wed, Oct 15, 2025 at 10:15:43PM +0200, Johannes Wiesböck wrote:
> Creating FDB entries is possible from a non-initial user namespace when
> having CAP_NET_ADMIN, yet, when deleting FDB entries, processes receive
> an EPERM because the capability is always checked against the initial
> user namespace. This restricts the FDB management from unprivileged
> containers.
>
> Drop the netlink_capable check in rtnl_fdb_del as it was originally
> dropped in c5c351088ae7 and reintroduced in 1690be63a27b without
> intention.
>
> This patch was tested using a container on GyroidOS, where it was
> possible to delete FDB entries from an unprivileged user namespace and
> private network namespace.
>
> Fixes: 1690be63a27b ("bridge: Add vlan support to static neighbors")
> Reviewed-by: Michael Weiß <michael.weiss@aisec.fraunhofer.de>
> Tested-by: Harshal Gohel <hg@simonwunderlich.de>
> Signed-off-by: Johannes Wiesböck <johannes.wiesboeck@aisec.fraunhofer.de>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
next prev parent reply other threads:[~2025-10-16 7:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-15 20:15 [PATCH net v2] rtnetlink: Allow deleting FDB entries in user namespace Johannes Wiesböck
2025-10-16 7:59 ` Ido Schimmel [this message]
2025-10-16 11:45 ` Nikolay Aleksandrov
2025-10-16 23:20 ` patchwork-bot+netdevbpf
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