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 A3FE870808; Sun, 7 Jun 2026 10:42:01 +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=1780828922; cv=none; b=smAjF41uwkLpWHrqhiKchR4K3mxJKPztcJWseFdyUC8/YxUAVl/WRN2UP+nvJNtFLifYAoo5vIgvzqt//HYz+gwatKveYWxzPfSQj0SeJs9vVmVFOiSGrNjlTl/RIql7HwXXIjdoCGddQYTo4zSFQShO50FnRgZ/nhgncu8tVCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780828922; c=relaxed/simple; bh=9YJIZM4CD3YTrPzFEB315LhCoLHAJ6PwIZE8i5VpmqE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=icY0ZcjVS6KNwiMrdrTluU4tGgk3YqtGYmjTzEp+r8aE7sAntme/KzQ3O2rediG7Km710yY2jmIrNRzSRuktj7ZWwrDrQ3TJuIUoM0BFE/xIpS2Xv56ZbH3CcNP4X8VtdusW3I3WcPrdIRpKa6rXd/mADwTFAPwa5SRkHU4fCy4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qqtKrK6K; 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="qqtKrK6K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED1181F00893; Sun, 7 Jun 2026 10:42:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780828921; bh=qUda5WrcgpgOYob5V66b6JuTrIGvC7mEVthh5WoJs5o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qqtKrK6KxVK4HDAUL7ZiYrfVnB7EkO7nX7R93EifCc3Js+FMDsTRSY3z9vwBwsy6d f4WVs/lEKfD7xylgrKdwBo8G1Z9PelaGrB4g2L7anfrCkXo1Rj9WPh5kXU+hCTv3SH XLgM05I/CjnUuLtW/EHCtbzvRud5AM3zhVwGVZsE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Steffen Klassert Subject: [PATCH 6.18 202/315] xfrm: ah: use skb_to_full_sk in async output callbacks Date: Sun, 7 Jun 2026 11:59:49 +0200 Message-ID: <20260607095734.991801580@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095727.528828913@linuxfoundation.org> References: <20260607095727.528828913@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: Michael Bommarito commit 79d8be262377f7112cfa3088dfc4142d5a2533f3 upstream. When AH output is offloaded to an asynchronous crypto provider (hardware accelerators such as AMD CCP, or a forced-async software shim used for testing), the digest completion fires ah_output_done() / ah6_output_done() on a workqueue. The egress skb at that point may have been originated by a TCP listener sending a SYN-ACK, which sets skb->sk to a request_sock via skb_set_owner_edemux(); it may also have been originated by an inet_timewait_sock retransmit. Neither is a full struct sock, and passing the raw skb->sk to xfrm_output_resume() then forwards a non-full socket through the rest of the xfrm output chain. xfrm_output_resume() and its downstream consumers expect a full sk where they dereference at all. The natural egress path through ah_output_done() does not crash today because the consumers that read past sock_common are either gated by sk_fullsock() or short-circuit on flags that are clear on a fresh request_sock; an exhaustive walk of the 50 most plausible consumers under sch_fq, dev_queue_xmit, netfilter, tc-egress and cgroup-egress BPF found no current unguarded deref. The bug is still a real type confusion that future consumer changes could turn into a memory-corruption primitive. This is the same bug class fixed for ESP in commit 1620c88887b1 ("xfrm: Fix the usage of skb->sk"). Apply the analogous fix to AH: convert skb->sk to a full socket pointer (or NULL) via skb_to_full_sk() before handing it to xfrm_output_resume(). The same async AH callbacks were touched recently for an independent ESN-related ICV layout bug in commit ec54093e6a8f ("xfrm: ah: account for ESN high bits in async callbacks"); the sk type-confusion addressed here is orthogonal. This patch is part of an ongoing audit of the AH callback paths; an ah_output ihl-validation hardening series is also currently under review on netdev. Reproduced under UML + KASAN + lockdep with a forced-async hmac(sha1) shim that registers at priority 9999 and wraps the sync in-tree hmac-sha1-lib. With the shim loaded, ah_output_done runs on every SYN-ACK egress through a transport-mode AH SA and skb->sk arrives as a request_sock (TCP_NEW_SYN_RECV); after this patch, xfrm_output_resume() receives the listener (the result of sk_to_full_sk()) and consumer derefs land on full-sock fields as intended. Fixes: 9ab1265d5231 ("xfrm: Use actual socket sk instead of skb socket for xfrm_output_resume") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ah4.c | 2 +- net/ipv6/ah6.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv4/ah4.c +++ b/net/ipv4/ah4.c @@ -143,7 +143,7 @@ static void ah_output_done(void *data, i } kfree(AH_SKB_CB(skb)->tmp); - xfrm_output_resume(skb->sk, skb, err); + xfrm_output_resume(skb_to_full_sk(skb), skb, err); } static int ah_output(struct xfrm_state *x, struct sk_buff *skb) --- a/net/ipv6/ah6.c +++ b/net/ipv6/ah6.c @@ -337,7 +337,7 @@ static void ah6_output_done(void *data, ah6_restore_hdrs(top_iph, iph_ext, extlen); kfree(AH_SKB_CB(skb)->tmp); - xfrm_output_resume(skb->sk, skb, err); + xfrm_output_resume(skb_to_full_sk(skb), skb, err); } static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)