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 1530240860A; Thu, 30 Jul 2026 15:49:15 +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=1785426557; cv=none; b=BNpaGENLlS+KMg3NZ3w1/qE3X/GZvjtigucl1QewkvJU63Upy63XMZ3wVOLaKAnHuh4to3X3lTR4M1fIu/0wXFy7I1LcUOB6r7ILHlUeCB06R1hxj2j5DOKhRpnfzMZqHnQAX3vg0WSgvKeBT/eSFCvZMBA2nAVO2bh9fTcwJGg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785426557; c=relaxed/simple; bh=twa1FPKJxt2svfTZnAN97SnOxSft1l3dWqzg622EEPo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iRChkaKLG93ZGbi3clYa8RWjnDRikTh/kra7ydHZJHf+zJmb0sEmVRrXKdKRQnOnypidVvrfTcsKNAwcVaoqQsj8fBd9lOmF2CXluW73JAhBtwzjZtcVmAzxSnEmfDsgosi36PQDjEn4u8LDlT7gEcDYt/Tx2FWq5T3rJdV5ZA4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HG4lPwqZ; 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="HG4lPwqZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C0161F000E9; Thu, 30 Jul 2026 15:49:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785426555; bh=OL5AUB6grj5wBXvJCcrShX0OXBkfAUip2+oOFZEcKsE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HG4lPwqZfxxYjAipf2HeN81b8tuPPcWQzh5/e/5ejGVhNBP3+I2p6umSFOmdDuQIu l0iW4FexNn2Yx68/vglKftttsFSvZIfXZYhXKYp3Gua1Fv/IX/bl60ThUWpWnAjXv5 Teo4tpk4R6v2lOrycqevOkOklwRvRHAEjeyjkJtY= 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 6.12 424/602] ila: reload IPv6 header after pskb_may_pull in checksum adjust Date: Thu, 30 Jul 2026 16:13:36 +0200 Message-ID: <20260730141444.875234505@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141435.976815864@linuxfoundation.org> References: <20260730141435.976815864@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 6.12-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) {