From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B84243396EE; Mon, 20 Apr 2026 16:01:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700908; cv=none; b=RIauXghjDZqtpO0mIVPftHsGEpckTbNmScEoWTpvsPRp+aJQ3TXYqmQEGSg5N3AGmkHzEi3kEI1Z/dHA0b46a2nUZ66uMnjSchW6jo4ku3tO+Y+x0qCfu4p6M0pw7Uef/S1dUOFZR1l5ZWeBljyakGxhVbpcAOa1GUwWilA4ztQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700908; c=relaxed/simple; bh=ldM3gqXnx/RQnu56kMuXsbi5nrJ/9acujqCmTkeSUYk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LBpOyTJvOQWQUJ/R/1S8VyueNwM4bwkxjY5+DIUYWRCCeuvaF7aJf2EwOr8y7fjtrrZg45YIJQKf1VVNXFPJ17CXxw6WpSGyh+GvJsFsHorORHwi7WAKhzMfjozIm3dI925HaqSdQgy0cLFDTATJPM0kCVvsHzkdHd5+Us4w6W0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rSaVhoLz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rSaVhoLz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0748BC19425; Mon, 20 Apr 2026 16:01:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700908; bh=ldM3gqXnx/RQnu56kMuXsbi5nrJ/9acujqCmTkeSUYk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rSaVhoLzeHxbA/pX1NhWJWKCSn6vxOBtXAUrMbIVb5kSuLNmH7mfx7/5GjBcdLq/w w5MPDFVFYbI1i4HoVhzutOpFJU/3yL1nGLUUqyJTepudUakQm/6ItVCP3yfb7vnkT/ gcbU38shIVSCaXMr1MFR50rp9DoGYAmDN7/qJX2k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zijing Yin , Ido Schimmel , Nikolay Aleksandrov , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 074/198] bridge: guard local VLAN-0 FDB helpers against NULL vlan group Date: Mon, 20 Apr 2026 17:40:53 +0200 Message-ID: <20260420153938.274119015@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zijing Yin [ Upstream commit 1979645e1842cb7017525a61a0e0e0beb924d02a ] When CONFIG_BRIDGE_VLAN_FILTERING is not set, br_vlan_group() and nbp_vlan_group() return NULL (br_private.h stub definitions). The BR_BOOLOPT_FDB_LOCAL_VLAN_0 toggle code is compiled unconditionally and reaches br_fdb_delete_locals_per_vlan_port() and br_fdb_insert_locals_per_vlan_port(), where the NULL vlan group pointer is dereferenced via list_for_each_entry(v, &vg->vlan_list, vlist). The observed crash is in the delete path, triggered when creating a bridge with IFLA_BR_MULTI_BOOLOPT containing BR_BOOLOPT_FDB_LOCAL_VLAN_0 via RTM_NEWLINK. The insert helper has the same bug pattern. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000056: 0000 [#1] KASAN NOPTI KASAN: null-ptr-deref in range [0x00000000000002b0-0x00000000000002b7] RIP: 0010:br_fdb_delete_locals_per_vlan+0x2b9/0x310 Call Trace: br_fdb_toggle_local_vlan_0+0x452/0x4c0 br_toggle_fdb_local_vlan_0+0x31/0x80 net/bridge/br.c:276 br_boolopt_toggle net/bridge/br.c:313 br_boolopt_multi_toggle net/bridge/br.c:364 br_changelink net/bridge/br_netlink.c:1542 br_dev_newlink net/bridge/br_netlink.c:1575 Add NULL checks for the vlan group pointer in both helpers, returning early when there are no VLANs to iterate. This matches the existing pattern used by other bridge FDB functions such as br_fdb_add() and br_fdb_delete(). Fixes: 21446c06b441 ("net: bridge: Introduce UAPI for BR_BOOLOPT_FDB_LOCAL_VLAN_0") Signed-off-by: Zijing Yin Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260402140153.3925663-1-yzjaurora@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/bridge/br_fdb.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 0501ffcb8a3dd..e2c17f620f009 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -597,6 +597,9 @@ static void br_fdb_delete_locals_per_vlan_port(struct net_bridge *br, dev = br->dev; } + if (!vg) + return; + list_for_each_entry(v, &vg->vlan_list, vlist) br_fdb_find_delete_local(br, p, dev->dev_addr, v->vid); } @@ -630,6 +633,9 @@ static int br_fdb_insert_locals_per_vlan_port(struct net_bridge *br, dev = br->dev; } + if (!vg) + return 0; + list_for_each_entry(v, &vg->vlan_list, vlist) { if (!br_vlan_should_use(v)) continue; -- 2.53.0