From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8A068306D2A; Wed, 23 Sep 2026 14:54:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790175243; cv=none; b=QgR7mKizVWLT+Ue/I5bvsjpEPpjgTRDwxH85I5LRnNK3Y7rsQdPxvwer/Xq+hR+FqMytlFZOvbM6XK0OIZIT2iKkTh47B1NV3QkdMggQRQXbZoPF9/57YkbsNAOYsMU9N0C2mYR+YdACZDG7Vij0viRZzzlByrSkGUlTKzFEx8g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790175243; c=relaxed/simple; bh=w9x/YYi/6IkHmnvs0qQjH0iErUxpZjULaTlCKWYefZI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tOgrYfSb6C/M6+qABK0epbROc/vuAc9CM3F+v+BD7he6K64aFW2Zp5f9n8oZOY3MqabfqM57oxwomo4U83r0qiJG+KXfbbgB1aNL60Wp3dsxAP3q++woFwvLjNF6/PyNmhGJ2/82BeyxO27kzl0u+msrcAUK2ZFditI60GNGttA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BV1zHV7y; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BV1zHV7y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66B021F000FF; Wed, 23 Sep 2026 14:54:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790175242; bh=X7ewYrk22M1ihG654ya4PnkXUzUDoGr0n1aDeZWvQTw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BV1zHV7yT6mYmEq+s2ELXWWpKqRG0CEsXjKxZVYATgKBSPs4Ey2BpSmD8CoUKXwmJ P3dtg6WxLwXPROnC5R848INrAuBBVSY8eWbHgaxU8h2gik16TvsqVKgDrY5NHOgJf/ 7Ej0dW9vzgUn9tJGVLheWDm/oVvxLpfkXw8Yklvo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xu Chunxiao , Dong Chenchen , Steffen Klassert , Sasha Levin Subject: [PATCH 6.18 366/398] xfrm: Fix dev use-after-free in xfrm async resumption Date: Wed, 23 Sep 2026 16:07:20 +0200 Message-ID: <20260923140652.927563417@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@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: Dong Chenchen [ Upstream commit 8045c0df98d4f14c54e5cb875f1c9c0ce89fe4ff ] xfrm async resumption hold skb->dev refcnt until after transport_finish. However, xfrm_rcv_cb may modify skb->dev to tunnel dev without taking device reference, such as vti_rcv_cb. The subsequent async resumption will decrement the tunnel device's reference count, which lead to uaf of tunnel dev and refcnt leak of orig dev as below: unregister_netdevice: waiting for vti1 to become free. Usage count = -2 Stash the original skb->dev to fix refcnt imbalance. The new skb->dev set by xfrm_rcv_cb can race with device teardown. Extend rcu protection over xfrm_rcv_cb and transport_finish to prevent races. Fixes: 1c428b038400 ("xfrm: hold dev ref until after transport_finish NF_HOOK") Reported-by: Xu Chunxiao Signed-off-by: Dong Chenchen Signed-off-by: Steffen Klassert Stable-dep-of: 3cf5cdecd99c ("xfrm: save input state data before secpath resets") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv4/xfrm4_input.c | 2 -- net/ipv6/xfrm6_input.c | 2 -- net/xfrm/xfrm_input.c | 29 ++++++++++++++++------------- 3 files changed, 16 insertions(+), 17 deletions(-) --- a/net/ipv4/xfrm4_input.c +++ b/net/ipv4/xfrm4_input.c @@ -76,8 +76,6 @@ int xfrm4_transport_finish(struct sk_buf NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, dev_net(dev), NULL, skb, dev, NULL, xfrm4_rcv_encap_finish); - if (async) - dev_put(dev); return 0; } --- a/net/ipv6/xfrm6_input.c +++ b/net/ipv6/xfrm6_input.c @@ -71,8 +71,6 @@ int xfrm6_transport_finish(struct sk_buf NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING, dev_net(dev), NULL, skb, dev, NULL, xfrm6_transport_finish2); - if (async) - dev_put(dev); return 0; } --- a/net/xfrm/xfrm_input.c +++ b/net/xfrm/xfrm_input.c @@ -464,6 +464,7 @@ int xfrm_input(struct sk_buff *skb, int { const struct xfrm_state_afinfo *afinfo; struct net *net = dev_net(skb->dev); + struct net_device *dev = skb->dev; int err; __be32 seq; __be32 seq_hi; @@ -490,7 +491,7 @@ int xfrm_input(struct sk_buff *skb, int LINUX_MIB_XFRMINSTATEINVALID); if (encap_type == -1) - dev_put(skb->dev); + dev_put(dev); goto drop; } @@ -652,16 +653,16 @@ lock: if (!crypto_done) { spin_unlock(&x->lock); - dev_hold(skb->dev); + dev_hold(dev); nexthdr = x->type->input(x, skb); if (nexthdr == -EINPROGRESS) { if (async) - dev_put(skb->dev); + dev_put(dev); return 0; } - dev_put(skb->dev); + dev_put(dev); spin_lock(&x->lock); } resume: @@ -696,7 +697,7 @@ resume: err = xfrm_inner_mode_input(x, skb); if (err == -EINPROGRESS) { if (async) - dev_put(skb->dev); + dev_put(dev); return 0; } else if (err) { XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR); @@ -723,9 +724,12 @@ resume_decapped: crypto_done = false; } while (!err); + rcu_read_lock(); err = xfrm_rcv_cb(skb, family, x->type->proto, 0); - if (err) + if (err) { + rcu_read_unlock(); goto drop; + } nf_reset_ct(skb); @@ -736,8 +740,9 @@ resume_decapped: if (skb_valid_dst(skb)) skb_dst_drop(skb); if (async) - dev_put(skb->dev); + dev_put(dev); gro_cells_receive(&gro_cells, skb); + rcu_read_unlock(); return 0; } else { xo = xfrm_offload(skb); @@ -745,23 +750,21 @@ resume_decapped: xfrm_gro = xo->flags & XFRM_GRO; err = -EAFNOSUPPORT; - rcu_read_lock(); afinfo = xfrm_state_afinfo_get_rcu(x->props.family); if (likely(afinfo)) err = afinfo->transport_finish(skb, xfrm_gro || async); - rcu_read_unlock(); if (xfrm_gro) { sp = skb_sec_path(skb); if (sp) sp->olen = 0; if (skb_valid_dst(skb)) skb_dst_drop(skb); - if (async) - dev_put(skb->dev); gro_cells_receive(&gro_cells, skb); - return err; } + if (async) + dev_put(dev); + rcu_read_unlock(); return err; } @@ -769,7 +772,7 @@ drop_unlock: spin_unlock(&x->lock); drop: if (async) - dev_put(skb->dev); + dev_put(dev); xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1); kfree_skb(skb); return 0;