From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793214791; b=iTTNZG6VE+or3qwNWJlJoVSvpvJBvgxZvKtH3XHB9yuCghq6450x0FdtdLWWO4Nwl8ye dAHwQyHd874LxufoAQFmM8nsoLxp3u2rQzCib/1/sfEBlfRzwr8tI/lOObf/TiV5doFMC 7Txqzg8Adup/oAd1Yntx1IfAKwmskvpxxchy7297B+GMn9aHJnuCcE4BtRA9FJ9/cL+zO 8onOoKNDzhCNwPu8CKIL5pYrORQgPM8yyeOK912lJdMFrhbh4N+Kk9iwSQfCyZ+Onze2q zNaGxYtw7+4Ojc+G75fCrF+KOB0TsW6vP6eiAPn2M1eCOTjzcq4AOUBK3MN+pvdu8Ag== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793214791; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=/V7thOG9tN7Ax/1sA8/KakwLOeCZfC2AP6ySxawEo3U=; b=vyIgG0b3ZkUgijrzkrAFRQcG2IiabMPpyF4tRMi4Av4Rawth4VserWLTUqLxv1TXCa+6 x2QEQ8r8vxebLcpvUhvbDBHmdgp9PyFVG5OmMsFeGn8doLrqNzKqhXDDlOXkiPTb/DB/h 8ikIsOXOZEq0SuRT0TftQfJGa9orhY4yncc2/S2YUWCadGGiqJtLrWQSBa1le5kvL4ccE 2A4jy7PMb2lHAZBQeX97I8HVBPcWsCChKGv2JI7B9BFj1J8F9aXv/yrMtHHKA160edZdu 97Wgcyj+6lSb2Zo9ifH0Gxq2n410ELOkDNOAgQ+BXvhMHMtAKCZiUMk0CqXbq4aZN0w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=TJlhDhjd; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F160C606B7E4; Wed, 28 Oct 2026 19:13:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=TJlhDhjd Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20C271F01825; Wed, 28 Oct 2026 19:13:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793214790; bh=/V7thOG9tN7Ax/1sA8/KakwLOeCZfC2AP6ySxawEo3U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TJlhDhjdNUZkCni8osbN56qN0lfH+vwD5cIQ6dgF8FDzBQIkNGje8Elw8Huoumtik essQd4qfs0AwP1kK2rtH/W7jzonzopXhkyYXvhoW3tSMxfrow0vX3HMQshQxlX6CRj ib0QvXsT4sHv2NVNXstiF00sPEkL3ekgxc8hHRgs= 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 6.1 0982/1887] ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data() Date: Wed, 28 Oct 2026 17:51:18 +0100 Message-ID: <20261028170521.757809828@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-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 | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/net/ipv6/ioam6.c b/net/ipv6/ioam6.c index 8db53f4da6604..05d8d9a5b3537 100644 --- a/net/ipv6/ioam6.c +++ b/net/ipv6/ioam6.c @@ -650,6 +650,9 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, struct ioam6_schema *sc, unsigned int sclen, bool is_input) { + /* 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; @@ -660,13 +663,16 @@ 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(skb_dst(skb)->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); @@ -674,18 +680,18 @@ 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)__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 (skb_dst(skb)->dev->flags & IFF_LOOPBACK) + if ((dev->flags & IFF_LOOPBACK) || !idev) raw16 = IOAM6_U16_UNAVAILABLE; else - raw16 = (__force u16)__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id; + raw16 = (__force u16)READ_ONCE(idev->cnf.ioam6_id); *(__be16 *)data = cpu_to_be16(raw16); data += sizeof(__be16); @@ -765,7 +771,7 @@ static void __ioam6_fill_trace_data(struct sk_buff *skb, if (is_input) byte--; - raw64 = dev_net(skb_dst(skb)->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); @@ -773,18 +779,18 @@ 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 = __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 (skb_dst(skb)->dev->flags & IFF_LOOPBACK) + if ((dev->flags & IFF_LOOPBACK) || !idev) raw32 = IOAM6_U32_UNAVAILABLE; else - raw32 = __in6_dev_get(skb_dst(skb)->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