From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 27C1532E696; Mon, 20 Apr 2026 15:50:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700200; cv=none; b=KadNo8+zTwHYnDUyIF9T98Sot4YqP0R5w/zx5tWWD0kWqe8SPsikQb1azJgMFbQEBfKhwkPBRVLcisKxTVPIsqyuGz3MFrCyo1c5uvTxHtbwLgmBBT25bgALUl3QGMeBhPNXlAgawgHyick2Ip5erzdscCNBw0wyX2DIpmgd1sA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700200; c=relaxed/simple; bh=i/2RTa5pmmIcQZfwo5t6y/MyllIujMydOrg8NbiDYeU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ocQ7QwvaPB9BMWzr9uKbdZwyajax0B5+CRRoMngncs0vRXHFb4OnhcK/79plePpKQQigOpWDb2CaXIRBdXsmK3HiuI6SYqT7TptpJ4sumjOc3eGjvrdYGm/haCXCtvyxyUy9v+mhcxxyK3zd/JLSa/pgnJlD+O/59T8c1HQSVxg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2J9b8FbL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2J9b8FbL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B15ECC19425; Mon, 20 Apr 2026 15:49:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700200; bh=i/2RTa5pmmIcQZfwo5t6y/MyllIujMydOrg8NbiDYeU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2J9b8FbLrCKsqKzJApS1nQb9mXU3R+XIshC35j0wouNjdtMgeA7D4VtXfsa+WFgBB yUJWPJMSN5r03AG8EarunupcSJNGnqYH7z5siOxUMwGUAcd1/evlZbcP/Z9Asp9Egd bDImeDQFIdSqE4Jk0wUTRj353MaYSp7lQPQgEVo4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yiming Qian , Eric Dumazet , Justin Iurman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.19 081/220] ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data() Date: Mon, 20 Apr 2026 17:40:22 +0200 Message-ID: <20260420153936.954187934@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153934.013228280@linuxfoundation.org> References: <20260420153934.013228280@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 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 4e65a8b8daa18d63255ec58964dd192c7fdd9f8b ] We need to check __in6_dev_get() for possible NULL value, as suggested by Yiming Qian. Also add skb_dst_dev_rcu() instead of skb_dst_dev(), and two missing READ_ONCE(). Note that @dev can't be NULL. Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace") Reported-by: Yiming Qian Signed-off-by: Eric Dumazet Reviewed-by: Justin Iurman Link: https://patch.msgid.link/20260402101732.1188059-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/ioam6.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/net/ipv6/ioam6.c b/net/ipv6/ioam6.c index 8db7f965696aa..12350e1e18bde 100644 --- a/net/ipv6/ioam6.c +++ b/net/ipv6/ioam6.c @@ -710,7 +710,9 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, struct ioam6_schema *sc, unsigned int sclen, bool is_input) { - struct net_device *dev = skb_dst_dev(skb); + /* Note: skb_dst_dev_rcu() can't be NULL at this point. */ + struct net_device *dev = skb_dst_dev_rcu(skb); + struct inet6_dev *i_skb_dev, *idev; struct timespec64 ts; ktime_t tstamp; u64 raw64; @@ -721,13 +723,16 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, data = trace->data + trace->remlen * 4 - trace->nodelen * 4 - sclen * 4; + i_skb_dev = skb->dev ? __in6_dev_get(skb->dev) : NULL; + idev = __in6_dev_get(dev); + /* hop_lim and node_id */ if (trace->type.bit0) { byte = ipv6_hdr(skb)->hop_limit; if (is_input) byte--; - raw32 = dev_net(dev)->ipv6.sysctl.ioam6_id; + raw32 = READ_ONCE(dev_net(dev)->ipv6.sysctl.ioam6_id); *(__be32 *)data = cpu_to_be32((byte << 24) | raw32); data += sizeof(__be32); @@ -735,18 +740,18 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, /* ingress_if_id and egress_if_id */ if (trace->type.bit1) { - if (!skb->dev) + if (!i_skb_dev) raw16 = IOAM6_U16_UNAVAILABLE; else - raw16 = (__force u16)READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_id); + raw16 = (__force u16)READ_ONCE(i_skb_dev->cnf.ioam6_id); *(__be16 *)data = cpu_to_be16(raw16); data += sizeof(__be16); - if (dev->flags & IFF_LOOPBACK) + if ((dev->flags & IFF_LOOPBACK) || !idev) raw16 = IOAM6_U16_UNAVAILABLE; else - raw16 = (__force u16)READ_ONCE(__in6_dev_get(dev)->cnf.ioam6_id); + raw16 = (__force u16)READ_ONCE(idev->cnf.ioam6_id); *(__be16 *)data = cpu_to_be16(raw16); data += sizeof(__be16); @@ -822,7 +827,7 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, if (is_input) byte--; - raw64 = dev_net(dev)->ipv6.sysctl.ioam6_id_wide; + raw64 = READ_ONCE(dev_net(dev)->ipv6.sysctl.ioam6_id_wide); *(__be64 *)data = cpu_to_be64(((u64)byte << 56) | raw64); data += sizeof(__be64); @@ -830,18 +835,18 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, /* ingress_if_id and egress_if_id (wide) */ if (trace->type.bit9) { - if (!skb->dev) + if (!i_skb_dev) raw32 = IOAM6_U32_UNAVAILABLE; else - raw32 = READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_id_wide); + raw32 = READ_ONCE(i_skb_dev->cnf.ioam6_id_wide); *(__be32 *)data = cpu_to_be32(raw32); data += sizeof(__be32); - if (dev->flags & IFF_LOOPBACK) + if ((dev->flags & IFF_LOOPBACK) || !idev) raw32 = IOAM6_U32_UNAVAILABLE; else - raw32 = READ_ONCE(__in6_dev_get(dev)->cnf.ioam6_id_wide); + raw32 = READ_ONCE(idev->cnf.ioam6_id_wide); *(__be32 *)data = cpu_to_be32(raw32); data += sizeof(__be32); -- 2.53.0