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 3664C471271; Tue, 21 Jul 2026 18:15:23 +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=1784657724; cv=none; b=CIO5GSmTXiEqdo5flSPsE2Jz3b0zqslziXt9r8DtQzK1NaYsSekHfuJ/NjkBs8aJcAL5sYPMalu/Yv1QnLQ/V5WO6pyRv+AqBaaYgRPWbBGLqBcezi/bw+LdOmH5Ll5sddiRfH1Bm1ihCv3AIJ7LXcevdzEOJpBBO0O3gMSIK4M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657724; c=relaxed/simple; bh=217PbT4W9uLr7HGBHW24G5G2nFTUR3lgnW20TbSw6/E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DZkrysH60r+y1UENRixjCjVyDOLSG1NeMqBsQ48Y8vMrofVT5tNyErKQmCeG+DrQHvYiR8bGSC61XDSdjjL75ygXpWUj4WkbjhBz9rNhFuvnR/7PVOHa54F2QHuNSQ5KlKmyaSI3PYlIfWqkFf7e6QkkIUHM6Y6scXT/Uf8DnLU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=itNzFAYN; 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="itNzFAYN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CE461F000E9; Tue, 21 Jul 2026 18:15:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657723; bh=fAzSA+nQ+OIkA2fhQUH/5DB7sho499Gi9Fhk6ablpBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=itNzFAYNcrkaPEWzKAYUXNKd0yXZItZaOXgRlPq8Px+tkASu1KWaGa9MW5CzRX28D ve7SRGqOf1n93x8A6K7jiG6KGvk3mwvW2/t9EjesgYKwDSECj4IMruIFHtS1EuGeWJ DNXzCjTf8M0runMiTeY0KjB83vLohm1SnVaoy0V0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Justin Iurman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 0872/1611] ipv6: ioam: fix type confusion of dst_entry Date: Tue, 21 Jul 2026 17:16:28 +0200 Message-ID: <20260721152535.005160857@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@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: Jiayuan Chen [ Upstream commit 9ed19e11d2146076d117d51a940643990118449b ] IOAM uses a dummy dst_entry(null_dst) to mark that the destination should not be changed after the transformation. This dst is stored in the IOAM lwt state and may be passed to dst_cache_set_ip6(). However, the IPv6 dst cache path eventually calls rt6_get_cookie(), which treats the dst_entry as part of a struct rt6_info. Since the null_dst was embedded directly as a struct dst_entry in struct ioam6_lwt, this resulted in an invalid cast and rt6_get_cookie() reading fields from the wrong object. In practice, the wrong cookie is not used while dst->obsolete is zero, but rt6_get_cookie() may also access per-cpu value when rt->sernum is zero. In this case, rt->sernum aliases ioam6_lwt::cache::reset_ts, which can become zero, making this a potential invalid pointer access. Fix this by embedding a full struct rt6_info for the dummy IPv6 route and passing its dst member to the dst APIs. Fixes: 47ce7c854563 ("net: ipv6: ioam6: fix double reallocation") Signed-off-by: Jiayuan Chen Reviewed-by: Justin Iurman Link: https://patch.msgid.link/20260618104336.48934-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/ioam6_iptunnel.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv6/ioam6_iptunnel.c b/net/ipv6/ioam6_iptunnel.c index b9f6d892a566c0..cfb2c41634a0b0 100644 --- a/net/ipv6/ioam6_iptunnel.c +++ b/net/ipv6/ioam6_iptunnel.c @@ -35,7 +35,7 @@ struct ioam6_lwt_freq { }; struct ioam6_lwt { - struct dst_entry null_dst; + struct rt6_info null_rt; struct dst_cache cache; struct ioam6_lwt_freq freq; atomic_t pkt_cnt; @@ -176,7 +176,7 @@ static int ioam6_build_state(struct net *net, struct nlattr *nla, * it is stored in the cache. Then, +1/-1 each time we read the cache * and release it. Long story short, we're fine. */ - dst_init(&ilwt->null_dst, NULL, NULL, DST_OBSOLETE_NONE, DST_NOCOUNT); + dst_init(&ilwt->null_rt.dst, NULL, NULL, DST_OBSOLETE_NONE, DST_NOCOUNT); atomic_set(&ilwt->pkt_cnt, 0); ilwt->freq.k = freq_k; @@ -360,7 +360,7 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) /* This is how we notify that the destination does not change after * transformation and that we need to use orig_dst instead of the cache */ - if (dst == &ilwt->null_dst) { + if (dst == &ilwt->null_rt.dst) { dst_release(dst); dst = orig_dst; @@ -429,7 +429,7 @@ static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) local_bh_disable(); if (orig_dst->lwtstate == dst->lwtstate) dst_cache_set_ip6(&ilwt->cache, - &ilwt->null_dst, &fl6.saddr); + &ilwt->null_rt.dst, &fl6.saddr); else dst_cache_set_ip6(&ilwt->cache, dst, &fl6.saddr); local_bh_enable(); -- 2.53.0