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 669E93ABD9F; Mon, 17 Aug 2026 14:32:11 +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=1786977132; cv=none; b=VsV2q0r+us59k0JA6DYNnWR6+4h4myVkJyIt8dCAEy5TrzfE82LFIa8zTBgOlzLrk9MKQNO1JQf5nBoaOIbrZp7kKrtcuKryMrZBJGgY5cJqoZOQa6zIURVy/ETnDc0nGnyWNIpgXJlkdErBOD173FMqeP7Dv07qmzcCpi1LwGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977132; c=relaxed/simple; bh=8fOr3Usl+u+Jjigc4wSDY/k6lVdQs8IOd2bpM2GZsO4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EvCUNtKcTcsUtorljBNkKsuwfQnPiz72ejoEV+UtGPenpc1ez5Wa4GvFBuDX4YChQSRTJaBk8czejpD4VjtnPCTqZGCLZgPpCwIYnMN3A3ltXmg4GqE3unlj+mahE+yeQPBcsFfgYLiaTfzlAATLlx3H1n0umXwN1A5nufB4IWI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=weKAZc5Y; 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="weKAZc5Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE79B1F00A3A; Mon, 17 Aug 2026 14:32:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977131; bh=ohXIX8a/I+IpZ9gHGh/jcCsVWG06x6uOAy0ZUMxacZY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=weKAZc5YcTvdvjTnSebOS0kfhiN6KQ6OADD6LsKj2u3zsOm9xrpLmg8SOF6iGlgHa IQV3UnveVIUoDOsoR4v8nY8p4LOpUhtIsiMIa2q5h15pM8AtPNN4+PGRXSvkGD6DRH D+Ez5EkvjF79HdaUzjvBnNW6OatEAI2SEjDs4lG4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Bommarito , Simon Horman , Antoine Tenart , Jakub Kicinski Subject: [PATCH 5.15 222/456] ila: reload IPv6 header after pskb_may_pull in checksum adjust Date: Mon, 17 Aug 2026 15:30:12 +0200 Message-ID: <20260817132548.850936381@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Bommarito commit 92d3817649df2b0b6a008a686c8275c88d7ef594 upstream. ila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling pskb_may_pull(). On a non-linear skb whose transport header sits in a page fragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head() and free the old skb head, leaving ip6h dangling; the following get_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator() uses ip6h (and the iaddr derived from it) again after the csum-adjust call and additionally writes the new locator through that pointer. Impact: a remote IPv6 packet routed through a configured ILA csum-adjust-transport route or receive-side mapping triggers a slab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or mapping requires CAP_NET_ADMIN to configure, but trigger packets are unauthenticated once it exists. Reload ip6h after each pskb_may_pull() in ila_csum_adjust_transport() before the csum-diff read. In ila_update_ipv6_locator() only the ILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in that case alone before the destination-address write; the neutral-map modes never pull and keep their cached pointers. Fixes: 33f11d16142b ("ila: Create net/ipv6/ila directory") Cc: stable@vger.kernel.org Signed-off-by: Michael Bommarito Reviewed-by: Simon Horman Reviewed-by: Antoine Tenart Link: https://patch.msgid.link/20260714114903.3763420-1-michael.bommarito@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ila/ila_common.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/net/ipv6/ila/ila_common.c +++ b/net/ipv6/ila/ila_common.c @@ -84,6 +84,7 @@ static void ila_csum_adjust_transport(st struct tcphdr *th = (struct tcphdr *) (skb_network_header(skb) + nhoff); + ip6h = ipv6_hdr(skb); diff = get_csum_diff(ip6h, p); inet_proto_csum_replace_by_diff(&th->check, skb, diff, true, true); @@ -95,6 +96,7 @@ static void ila_csum_adjust_transport(st (skb_network_header(skb) + nhoff); if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) { + ip6h = ipv6_hdr(skb); diff = get_csum_diff(ip6h, p); inet_proto_csum_replace_by_diff(&uh->check, skb, diff, true, true); @@ -109,6 +111,7 @@ static void ila_csum_adjust_transport(st struct icmp6hdr *ih = (struct icmp6hdr *) (skb_network_header(skb) + nhoff); + ip6h = ipv6_hdr(skb); diff = get_csum_diff(ip6h, p); inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb, diff, true, true); @@ -126,6 +129,15 @@ void ila_update_ipv6_locator(struct sk_b switch (p->csum_mode) { case ILA_CSUM_ADJUST_TRANSPORT: ila_csum_adjust_transport(skb, p); + /* + * ila_csum_adjust_transport() calls pskb_may_pull(), which can + * reallocate the skb head and leave ip6h (and the iaddr derived + * from it) dangling; reload both before the write below. The + * other csum modes do not pull, so their cached pointers stay + * valid. + */ + ip6h = ipv6_hdr(skb); + iaddr = ila_a2i(&ip6h->daddr); break; case ILA_CSUM_NEUTRAL_MAP: if (sir2ila) {