From patchwork Wed Feb 26 17:13:42 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 13992828 X-Patchwork-Delegate: kuba@kernel.org 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 65A1321CA1B for ; Wed, 26 Feb 2025 17:13:56 +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=1740590036; cv=none; b=OOWxIQJ/Dq8uNBomuas9An6d7xS/JCZeihn4p4QC5fullBqpsbioJ8CG9q6DZun9DfoYv/aCMLiWagymIytw9tBvhCOiQ0qCrMZhV89rAe5in2D/nbwp3u6/CGCrCYc2qiVBD4JQZnK2UtoX+6YiwCF9MpQV4XVqqlrFjBoJS2Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740590036; c=relaxed/simple; bh=xeFuvmiK6yJyfBkZp/pDcBfAXa39Zzm+f1oT0x6JpPE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=N6FLlCYoxTn1aKq7OQz9pocl7FO0gv/APC5FhKM07FEpstkuB/EbJsCp4OAHDHQ6Zr7cbkgn7M2NC+KMZsAtAamThKfaapicldot2l8W+m4IvT2Z1A2q5xdASAEYSm7NpYN/y9Ohk/xugMrPO+TY7bl4KBKBMXlnlEqrFLzK7TI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iiL9z13G; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iiL9z13G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 383EFC4CEE9; Wed, 26 Feb 2025 17:13:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740590035; bh=xeFuvmiK6yJyfBkZp/pDcBfAXa39Zzm+f1oT0x6JpPE=; h=From:To:Cc:Subject:Date:From; b=iiL9z13G01PfsB92Wd7SY5U2YxwCCqdxtg3NpbkEaXM2b9Tsfs/maHZX3QbhOh5H0 P8Xc/M2paKIAz/kIrND6SBS7lRtogcgI6Pkqh7psBJ7KRBVyEwRNn4i90mR/OCo6qh kA/uPBEfS/91EiCdhF9Np0eXnCMxgNOMKQe4niyzNUAiq0NXudeBxboPPMVALk3s89 uXECX8Dq4aLhICp0EVo5zCGiGoFUKO1dPSvJTaV6dXYZmgL3yjtyiueha9V2mWNRkW 4GRQOird31Ff+n5tJ3l7yqFuiJphPgeurVerWgsJjjZPfS1h/PG1jiX1mapW5CFSaX 7o8vBrv7zbxnQ== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com Cc: Antoine Tenart , netdev@vger.kernel.org, willemdebruijn.kernel@gmail.com, pshelar@ovn.org Subject: [PATCH net] net: gso: fix ownership in __udp_gso_segment Date: Wed, 26 Feb 2025 18:13:42 +0100 Message-ID: <20250226171352.258045-1-atenart@kernel.org> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug: kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace: ip_rcv+0xab/0x6e0 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action: 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed. 2. The segments' data are copied and sent to userspace. 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path. 4. If it later hits skb_orphan, we hit the bug. Fix this by also removing the reference to the socket in __udp_gso_segment. Fixes: ad405857b174 ("udp: better wmem accounting on gso") Signed-off-by: Antoine Tenart --- net/ipv4/udp_offload.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index a5be6e4ed326..ecfca59f31f1 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -321,13 +321,17 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, /* clear destructor to avoid skb_segment assigning it to tail */ copy_dtor = gso_skb->destructor == sock_wfree; - if (copy_dtor) + if (copy_dtor) { gso_skb->destructor = NULL; + gso_skb->sk = NULL; + } segs = skb_segment(gso_skb, features); if (IS_ERR_OR_NULL(segs)) { - if (copy_dtor) + if (copy_dtor) { gso_skb->destructor = sock_wfree; + gso_skb->sk = sk; + } return segs; }