--- /dev/null
+From 3c52c6bb831f6335c176a0fc7214e26f43adbd11 Mon Sep 17 00:00:00 2001
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+Date: Thu, 6 Oct 2022 11:53:45 -0700
+Subject: tcp/udp: Fix memory leak in ipv6_renew_options().
+
+From: Kuniyuki Iwashima <kuniyu@amazon.com>
+
+commit 3c52c6bb831f6335c176a0fc7214e26f43adbd11 upstream.
+
+syzbot reported a memory leak [0] related to IPV6_ADDRFORM.
+
+The scenario is that while one thread is converting an IPv6 socket into
+IPv4 with IPV6_ADDRFORM, another thread calls do_ipv6_setsockopt() and
+allocates memory to inet6_sk(sk)->XXX after conversion.
+
+Then, the converted sk with (tcp|udp)_prot never frees the IPv6 resources,
+which inet6_destroy_sock() should have cleaned up.
+
+setsockopt(IPV6_ADDRFORM) setsockopt(IPV6_DSTOPTS)
++-----------------------+ +----------------------+
+- do_ipv6_setsockopt(sk, ...)
+ - sockopt_lock_sock(sk) - do_ipv6_setsockopt(sk, ...)
+ - lock_sock(sk) ^._ called via tcpv6_prot
+ - WRITE_ONCE(sk->sk_prot, &tcp_prot) before WRITE_ONCE()
+ - xchg(&np->opt, NULL)
+ - txopt_put(opt)
+ - sockopt_release_sock(sk)
+ - release_sock(sk) - sockopt_lock_sock(sk)
+ - lock_sock(sk)
+ - ipv6_set_opt_hdr(sk, ...)
+ - ipv6_update_options(sk, opt)
+ - xchg(&inet6_sk(sk)->opt, opt)
+ ^._ opt is never freed.
+
+ - sockopt_release_sock(sk)
+ - release_sock(sk)
+
+Since IPV6_DSTOPTS allocates options under lock_sock(), we can avoid this
+memory leak by testing whether sk_family is changed by IPV6_ADDRFORM after
+acquiring the lock.
+
+This issue exists from the initial commit between IPV6_ADDRFORM and
+IPV6_PKTOPTIONS.
+
+[0]:
+BUG: memory leak
+unreferenced object 0xffff888009ab9f80 (size 96):
+ comm "syz-executor583", pid 328, jiffies 4294916198 (age 13.034s)
+ hex dump (first 32 bytes):
+ 01 00 00 00 48 00 00 00 08 00 00 00 00 00 00 00 ....H...........
+ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
+ backtrace:
+ [<000000002ee98ae1>] kmalloc include/linux/slab.h:605 [inline]
+ [<000000002ee98ae1>] sock_kmalloc+0xb3/0x100 net/core/sock.c:2566
+ [<0000000065d7b698>] ipv6_renew_options+0x21e/0x10b0 net/ipv6/exthdrs.c:1318
+ [<00000000a8c756d7>] ipv6_set_opt_hdr net/ipv6/ipv6_sockglue.c:354 [inline]
+ [<00000000a8c756d7>] do_ipv6_setsockopt.constprop.0+0x28b7/0x4350 net/ipv6/ipv6_sockglue.c:668
+ [<000000002854d204>] ipv6_setsockopt+0xdf/0x190 net/ipv6/ipv6_sockglue.c:1021
+ [<00000000e69fdcf8>] tcp_setsockopt+0x13b/0x2620 net/ipv4/tcp.c:3789
+ [<0000000090da4b9b>] __sys_setsockopt+0x239/0x620 net/socket.c:2252
+ [<00000000b10d192f>] __do_sys_setsockopt net/socket.c:2263 [inline]
+ [<00000000b10d192f>] __se_sys_setsockopt net/socket.c:2260 [inline]
+ [<00000000b10d192f>] __x64_sys_setsockopt+0xbe/0x160 net/socket.c:2260
+ [<000000000a80d7aa>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
+ [<000000000a80d7aa>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
+ [<000000004562b5c6>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
+
+Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
+Reported-by: syzbot <syzkaller@googlegroups.com>
+Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Meena Shanmugam <meenashanmugam@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/ipv6/ipv6_sockglue.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/net/ipv6/ipv6_sockglue.c
++++ b/net/ipv6/ipv6_sockglue.c
+@@ -417,6 +417,12 @@ static int do_ipv6_setsockopt(struct soc
+ rtnl_lock();
+ lock_sock(sk);
+
++ /* Another thread has converted the socket into IPv4 with
++ * IPV6_ADDRFORM concurrently.
++ */
++ if (unlikely(sk->sk_family != AF_INET6))
++ goto unlock;
++
+ switch (optname) {
+
+ case IPV6_ADDRFORM:
+@@ -976,6 +982,7 @@ done:
+ break;
+ }
+
++unlock:
+ release_sock(sk);
+ if (needs_rtnl)
+ rtnl_unlock();