From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 19 Mar 2026 11:36:57 +0000 (+0100)
Subject: 6.1-stable patches
X-Git-Tag: v6.18.19~11
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f9034ba24a9798412ab2aa83a5adc412f85b37b0;p=thirdparty%2Fkernel%2Fstable-queue.git

6.1-stable patches

added patches:
	ipv6-use-rcu-in-ip6_xmit.patch
---

diff --git a/queue-6.1/ipv6-use-rcu-in-ip6_xmit.patch b/queue-6.1/ipv6-use-rcu-in-ip6_xmit.patch
new file mode 100644
index 0000000000..8f979512b0
--- /dev/null
+++ b/queue-6.1/ipv6-use-rcu-in-ip6_xmit.patch
@@ -0,0 +1,109 @@
+From 9085e56501d93af9f2d7bd16f7fcfacdde47b99c Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Thu, 28 Aug 2025 19:58:18 +0000
+Subject: ipv6: use RCU in ip6_xmit()
+
+From: Eric Dumazet <edumazet@google.com>
+
+commit 9085e56501d93af9f2d7bd16f7fcfacdde47b99c upstream.
+
+Use RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent
+possible UAF.
+
+Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Reviewed-by: David Ahern <dsahern@kernel.org>
+Link: https://patch.msgid.link/20250828195823.3958522-4-edumazet@google.com
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Keerthana K <keerthana.kalyanasundaram@broadcom.com>
+Signed-off-by: Shivani Agarwal <shivani.agarwal@broadcom.com>
+---
+ net/ipv6/ip6_output.c |   35 +++++++++++++++++++++--------------
+ 1 file changed, 21 insertions(+), 14 deletions(-)
+
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -258,35 +258,36 @@ bool ip6_autoflowlabel(struct net *net,
+ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
+ 	     __u32 mark, struct ipv6_txoptions *opt, int tclass, u32 priority)
+ {
+-	struct net *net = sock_net(sk);
+ 	const struct ipv6_pinfo *np = inet6_sk(sk);
+ 	struct in6_addr *first_hop = &fl6->daddr;
+ 	struct dst_entry *dst = skb_dst(skb);
+-	struct net_device *dev = dst->dev;
+ 	struct inet6_dev *idev = ip6_dst_idev(dst);
+ 	struct hop_jumbo_hdr *hop_jumbo;
+ 	int hoplen = sizeof(*hop_jumbo);
++	struct net *net = sock_net(sk);
+ 	unsigned int head_room;
++	struct net_device *dev;
+ 	struct ipv6hdr *hdr;
+ 	u8  proto = fl6->flowi6_proto;
+ 	int seg_len = skb->len;
+-	int hlimit = -1;
++	int ret, hlimit = -1;
+ 	u32 mtu;
+ 
++	rcu_read_lock();
++
++	dev = dst_dev_rcu(dst);
+ 	head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
+ 	if (opt)
+ 		head_room += opt->opt_nflen + opt->opt_flen;
+ 
+ 	if (unlikely(head_room > skb_headroom(skb))) {
+-		/* Make sure idev stays alive */
+-		rcu_read_lock();
++		/* idev stays alive while we hold rcu_read_lock(). */
+ 		skb = skb_expand_head(skb, head_room);
+ 		if (!skb) {
+ 			IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
+-			rcu_read_unlock();
+-			return -ENOBUFS;
++			ret = -ENOBUFS;
++			goto unlock;
+ 		}
+-		rcu_read_unlock();
+ 	}
+ 
+ 	if (opt) {
+@@ -348,17 +349,21 @@ int ip6_xmit(const struct sock *sk, stru
+ 		 * skb to its handler for processing
+ 		 */
+ 		skb = l3mdev_ip6_out((struct sock *)sk, skb);
+-		if (unlikely(!skb))
+-			return 0;
++		if (unlikely(!skb)) {
++			ret = 0;
++			goto unlock;
++		}
+ 
+ 		/* hooks should never assume socket lock is held.
+ 		 * we promote our socket to non const
+ 		 */
+-		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
+-			       net, (struct sock *)sk, skb, NULL, dev,
+-			       dst_output);
++		ret = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
++			      net, (struct sock *)sk, skb, NULL, dev,
++			      dst_output);
++		goto unlock;
+ 	}
+ 
++	ret = -EMSGSIZE;
+ 	skb->dev = dev;
+ 	/* ipv6_local_error() does not require socket lock,
+ 	 * we promote our socket to non const
+@@ -367,7 +372,9 @@ int ip6_xmit(const struct sock *sk, stru
+ 
+ 	IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
+ 	kfree_skb(skb);
+-	return -EMSGSIZE;
++unlock:
++	rcu_read_unlock();
++	return ret;
+ }
+ EXPORT_SYMBOL(ip6_xmit);
+ 
diff --git a/queue-6.1/series b/queue-6.1/series
index 000fec5eeb..c073a6a549 100644
--- a/queue-6.1/series
+++ b/queue-6.1/series
@@ -274,3 +274,4 @@ i3c-mipi-i3c-hci-use-etimedout-instead-of-etime-for-timeout-errors.patch
 i3c-mipi-i3c-hci-restart-dma-ring-correctly-after-dequeue-abort.patch
 i3c-mipi-i3c-hci-add-missing-tid-field-to-no-op-command-descriptor.patch
 drm-bridge-ti-sn65dsi86-add-support-for-displayport-mode-with-hpd.patch
+ipv6-use-rcu-in-ip6_xmit.patch