[PATCH 5.15.y] mptcp: fix double-free on socket dismantle

Matthieu Baerts (NGI0) posted 1 patch 2 months ago
Failed in applying to current master (apply log)
There is a newer version of this series
net/mptcp/protocol.c | 49 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
[PATCH 5.15.y] mptcp: fix double-free on socket dismantle
Posted by Matthieu Baerts (NGI0) 2 months ago
From: Davide Caratti <dcaratti@redhat.com>

when MPTCP server accepts an incoming connection, it clones its listener
socket. However, the pointer to 'inet_opt' for the new socket has the same
value as the original one: as a consequence, on program exit it's possible
to observe the following splat:

  BUG: KASAN: double-free in inet_sock_destruct+0x54f/0x8b0
  Free of addr ffff888485950880 by task swapper/25/0

  CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Not tainted 6.8.0-rc1+ #609
  Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0  07/26/2013
  Call Trace:
   <IRQ>
   dump_stack_lvl+0x32/0x50
   print_report+0xca/0x620
   kasan_report_invalid_free+0x64/0x90
   __kasan_slab_free+0x1aa/0x1f0
   kfree+0xed/0x2e0
   inet_sock_destruct+0x54f/0x8b0
   __sk_destruct+0x48/0x5b0
   rcu_do_batch+0x34e/0xd90
   rcu_core+0x559/0xac0
   __do_softirq+0x183/0x5a4
   irq_exit_rcu+0x12d/0x170
   sysvec_apic_timer_interrupt+0x6b/0x80
   </IRQ>
   <TASK>
   asm_sysvec_apic_timer_interrupt+0x16/0x20
  RIP: 0010:cpuidle_enter_state+0x175/0x300
  Code: 30 00 0f 84 1f 01 00 00 83 e8 01 83 f8 ff 75 e5 48 83 c4 18 44 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc fb 45 85 ed <0f> 89 60 ff ff ff 48 c1 e5 06 48 c7 43 18 00 00 00 00 48 83 44 2b
  RSP: 0018:ffff888481cf7d90 EFLAGS: 00000202
  RAX: 0000000000000000 RBX: ffff88887facddc8 RCX: 0000000000000000
  RDX: 1ffff1110ff588b1 RSI: 0000000000000019 RDI: ffff88887fac4588
  RBP: 0000000000000004 R08: 0000000000000002 R09: 0000000000043080
  R10: 0009b02ea273363f R11: ffff88887fabf42b R12: ffffffff932592e0
  R13: 0000000000000004 R14: 0000000000000000 R15: 00000022c880ec80
   cpuidle_enter+0x4a/0xa0
   do_idle+0x310/0x410
   cpu_startup_entry+0x51/0x60
   start_secondary+0x211/0x270
   secondary_startup_64_no_verify+0x184/0x18b
   </TASK>

  Allocated by task 6853:
   kasan_save_stack+0x1c/0x40
   kasan_save_track+0x10/0x30
   __kasan_kmalloc+0xa6/0xb0
   __kmalloc+0x1eb/0x450
   cipso_v4_sock_setattr+0x96/0x360
   netlbl_sock_setattr+0x132/0x1f0
   selinux_netlbl_socket_post_create+0x6c/0x110
   selinux_socket_post_create+0x37b/0x7f0
   security_socket_post_create+0x63/0xb0
   __sock_create+0x305/0x450
   __sys_socket_create.part.23+0xbd/0x130
   __sys_socket+0x37/0xb0
   __x64_sys_socket+0x6f/0xb0
   do_syscall_64+0x83/0x160
   entry_SYSCALL_64_after_hwframe+0x6e/0x76

  Freed by task 6858:
   kasan_save_stack+0x1c/0x40
   kasan_save_track+0x10/0x30
   kasan_save_free_info+0x3b/0x60
   __kasan_slab_free+0x12c/0x1f0
   kfree+0xed/0x2e0
   inet_sock_destruct+0x54f/0x8b0
   __sk_destruct+0x48/0x5b0
   subflow_ulp_release+0x1f0/0x250
   tcp_cleanup_ulp+0x6e/0x110
   tcp_v4_destroy_sock+0x5a/0x3a0
   inet_csk_destroy_sock+0x135/0x390
   tcp_fin+0x416/0x5c0
   tcp_data_queue+0x1bc8/0x4310
   tcp_rcv_state_process+0x15a3/0x47b0
   tcp_v4_do_rcv+0x2c1/0x990
   tcp_v4_rcv+0x41fb/0x5ed0
   ip_protocol_deliver_rcu+0x6d/0x9f0
   ip_local_deliver_finish+0x278/0x360
   ip_local_deliver+0x182/0x2c0
   ip_rcv+0xb5/0x1c0
   __netif_receive_skb_one_core+0x16e/0x1b0
   process_backlog+0x1e3/0x650
   __napi_poll+0xa6/0x500
   net_rx_action+0x740/0xbb0
   __do_softirq+0x183/0x5a4

  The buggy address belongs to the object at ffff888485950880
   which belongs to the cache kmalloc-64 of size 64
  The buggy address is located 0 bytes inside of
   64-byte region [ffff888485950880, ffff8884859508c0)

  The buggy address belongs to the physical page:
  page:0000000056d1e95e refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888485950700 pfn:0x485950
  flags: 0x57ffffc0000800(slab|node=1|zone=2|lastcpupid=0x1fffff)
  page_type: 0xffffffff()
  raw: 0057ffffc0000800 ffff88810004c640 ffffea00121b8ac0 dead000000000006
  raw: ffff888485950700 0000000000200019 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888485950780: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
   ffff888485950800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  >ffff888485950880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                     ^
   ffff888485950900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
   ffff888485950980: 00 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc

Something similar (a refcount underflow) happens with CALIPSO/IPv6. Fix
this by duplicating IP / IPv6 options after clone, so that
ip{,6}_sock_destruct() doesn't end up freeing the same memory area twice.

Fixes: cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming connections")
Cc: stable@vger.kernel.org
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-8-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit 10048689def7e40a4405acda16fdc6477d4ecc5c)
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Notes:
 - Conflicts in protocol.c because mptcp_sk_clone() has been renamed to
   mptcp_sk_clone_init() in commit 7e8b88ec35ee ("mptcp: consolidate
   passive msk socket initialization") which has not been backported to
   v5.15 due to a too long list of dependences.
---
 net/mptcp/protocol.c | 49 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 86bd41a0e187..5db1c0142abb 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2856,8 +2856,50 @@ static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
 
 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
 }
+
+static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
+{
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+	struct ipv6_txoptions *opt;
+	struct ipv6_pinfo *newnp;
+
+	newnp = inet6_sk(newsk);
+
+	rcu_read_lock();
+	opt = rcu_dereference(np->opt);
+	if (opt) {
+		opt = ipv6_dup_options(newsk, opt);
+		if (!opt)
+			net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
+	}
+	RCU_INIT_POINTER(newnp->opt, opt);
+	rcu_read_unlock();
+}
 #endif
 
+static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
+{
+	struct ip_options_rcu *inet_opt, *newopt = NULL;
+	const struct inet_sock *inet = inet_sk(sk);
+	struct inet_sock *newinet;
+
+	newinet = inet_sk(newsk);
+
+	rcu_read_lock();
+	inet_opt = rcu_dereference(inet->inet_opt);
+	if (inet_opt) {
+		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
+				      inet_opt->opt.optlen, GFP_ATOMIC);
+		if (newopt)
+			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
+			       inet_opt->opt.optlen);
+		else
+			net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
+	}
+	RCU_INIT_POINTER(newinet->inet_opt, newopt);
+	rcu_read_unlock();
+}
+
 struct sock *mptcp_sk_clone(const struct sock *sk,
 			    const struct mptcp_options_received *mp_opt,
 			    struct request_sock *req)
@@ -2878,6 +2920,13 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
 	nsk->sk_wait_pending = 0;
 	__mptcp_init_sock(nsk);
 
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (nsk->sk_family == AF_INET6)
+		mptcp_copy_ip6_options(nsk, sk);
+	else
+#endif
+		mptcp_copy_ip_options(nsk, sk);
+
 	msk = mptcp_sk(nsk);
 	msk->local_key = subflow_req->local_key;
 	msk->token = subflow_req->token;
-- 
2.43.0
Re: [PATCH 5.15.y] mptcp: fix double-free on socket dismantle
Posted by Greg KH 2 months ago
On Mon, Mar 04, 2024 at 05:25:18PM +0100, Matthieu Baerts (NGI0) wrote:
> From: Davide Caratti <dcaratti@redhat.com>
> 
> when MPTCP server accepts an incoming connection, it clones its listener
> socket. However, the pointer to 'inet_opt' for the new socket has the same
> value as the original one: as a consequence, on program exit it's possible
> to observe the following splat:
> 
>   BUG: KASAN: double-free in inet_sock_destruct+0x54f/0x8b0
>   Free of addr ffff888485950880 by task swapper/25/0
> 
>   CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Not tainted 6.8.0-rc1+ #609
>   Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0  07/26/2013
>   Call Trace:
>    <IRQ>
>    dump_stack_lvl+0x32/0x50
>    print_report+0xca/0x620
>    kasan_report_invalid_free+0x64/0x90
>    __kasan_slab_free+0x1aa/0x1f0
>    kfree+0xed/0x2e0
>    inet_sock_destruct+0x54f/0x8b0
>    __sk_destruct+0x48/0x5b0
>    rcu_do_batch+0x34e/0xd90
>    rcu_core+0x559/0xac0
>    __do_softirq+0x183/0x5a4
>    irq_exit_rcu+0x12d/0x170
>    sysvec_apic_timer_interrupt+0x6b/0x80
>    </IRQ>
>    <TASK>
>    asm_sysvec_apic_timer_interrupt+0x16/0x20
>   RIP: 0010:cpuidle_enter_state+0x175/0x300
>   Code: 30 00 0f 84 1f 01 00 00 83 e8 01 83 f8 ff 75 e5 48 83 c4 18 44 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc fb 45 85 ed <0f> 89 60 ff ff ff 48 c1 e5 06 48 c7 43 18 00 00 00 00 48 83 44 2b
>   RSP: 0018:ffff888481cf7d90 EFLAGS: 00000202
>   RAX: 0000000000000000 RBX: ffff88887facddc8 RCX: 0000000000000000
>   RDX: 1ffff1110ff588b1 RSI: 0000000000000019 RDI: ffff88887fac4588
>   RBP: 0000000000000004 R08: 0000000000000002 R09: 0000000000043080
>   R10: 0009b02ea273363f R11: ffff88887fabf42b R12: ffffffff932592e0
>   R13: 0000000000000004 R14: 0000000000000000 R15: 00000022c880ec80
>    cpuidle_enter+0x4a/0xa0
>    do_idle+0x310/0x410
>    cpu_startup_entry+0x51/0x60
>    start_secondary+0x211/0x270
>    secondary_startup_64_no_verify+0x184/0x18b
>    </TASK>
> 
>   Allocated by task 6853:
>    kasan_save_stack+0x1c/0x40
>    kasan_save_track+0x10/0x30
>    __kasan_kmalloc+0xa6/0xb0
>    __kmalloc+0x1eb/0x450
>    cipso_v4_sock_setattr+0x96/0x360
>    netlbl_sock_setattr+0x132/0x1f0
>    selinux_netlbl_socket_post_create+0x6c/0x110
>    selinux_socket_post_create+0x37b/0x7f0
>    security_socket_post_create+0x63/0xb0
>    __sock_create+0x305/0x450
>    __sys_socket_create.part.23+0xbd/0x130
>    __sys_socket+0x37/0xb0
>    __x64_sys_socket+0x6f/0xb0
>    do_syscall_64+0x83/0x160
>    entry_SYSCALL_64_after_hwframe+0x6e/0x76
> 
>   Freed by task 6858:
>    kasan_save_stack+0x1c/0x40
>    kasan_save_track+0x10/0x30
>    kasan_save_free_info+0x3b/0x60
>    __kasan_slab_free+0x12c/0x1f0
>    kfree+0xed/0x2e0
>    inet_sock_destruct+0x54f/0x8b0
>    __sk_destruct+0x48/0x5b0
>    subflow_ulp_release+0x1f0/0x250
>    tcp_cleanup_ulp+0x6e/0x110
>    tcp_v4_destroy_sock+0x5a/0x3a0
>    inet_csk_destroy_sock+0x135/0x390
>    tcp_fin+0x416/0x5c0
>    tcp_data_queue+0x1bc8/0x4310
>    tcp_rcv_state_process+0x15a3/0x47b0
>    tcp_v4_do_rcv+0x2c1/0x990
>    tcp_v4_rcv+0x41fb/0x5ed0
>    ip_protocol_deliver_rcu+0x6d/0x9f0
>    ip_local_deliver_finish+0x278/0x360
>    ip_local_deliver+0x182/0x2c0
>    ip_rcv+0xb5/0x1c0
>    __netif_receive_skb_one_core+0x16e/0x1b0
>    process_backlog+0x1e3/0x650
>    __napi_poll+0xa6/0x500
>    net_rx_action+0x740/0xbb0
>    __do_softirq+0x183/0x5a4
> 
>   The buggy address belongs to the object at ffff888485950880
>    which belongs to the cache kmalloc-64 of size 64
>   The buggy address is located 0 bytes inside of
>    64-byte region [ffff888485950880, ffff8884859508c0)
> 
>   The buggy address belongs to the physical page:
>   page:0000000056d1e95e refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888485950700 pfn:0x485950
>   flags: 0x57ffffc0000800(slab|node=1|zone=2|lastcpupid=0x1fffff)
>   page_type: 0xffffffff()
>   raw: 0057ffffc0000800 ffff88810004c640 ffffea00121b8ac0 dead000000000006
>   raw: ffff888485950700 0000000000200019 00000001ffffffff 0000000000000000
>   page dumped because: kasan: bad access detected
> 
>   Memory state around the buggy address:
>    ffff888485950780: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>    ffff888485950800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>   >ffff888485950880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>                      ^
>    ffff888485950900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>    ffff888485950980: 00 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc
> 
> Something similar (a refcount underflow) happens with CALIPSO/IPv6. Fix
> this by duplicating IP / IPv6 options after clone, so that
> ip{,6}_sock_destruct() doesn't end up freeing the same memory area twice.
> 
> Fixes: cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming connections")
> Cc: stable@vger.kernel.org
> Signed-off-by: Davide Caratti <dcaratti@redhat.com>
> Reviewed-by: Mat Martineau <martineau@kernel.org>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-8-162e87e48497@kernel.org
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> (cherry picked from commit 10048689def7e40a4405acda16fdc6477d4ecc5c)
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> Notes:
>  - Conflicts in protocol.c because mptcp_sk_clone() has been renamed to
>    mptcp_sk_clone_init() in commit 7e8b88ec35ee ("mptcp: consolidate
>    passive msk socket initialization") which has not been backported to
>    v5.15 due to a too long list of dependences.

Now queued up, thanks!

greg k-h
Patch "mptcp: fix double-free on socket dismantle" has been added to the 5.15-stable tree
Posted by gregkh@linuxfoundation.org 2 months ago

This is a note to let you know that I've just added the patch titled

    mptcp: fix double-free on socket dismantle

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mptcp-fix-double-free-on-socket-dismantle.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-25950-greg=kroah.com@vger.kernel.org Mon Mar  4 17:25:46 2024
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Mon,  4 Mar 2024 17:25:18 +0100
Subject: mptcp: fix double-free on socket dismantle
To: stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: MPTCP Upstream <mptcp@lists.linux.dev>, Davide Caratti <dcaratti@redhat.com>, Mat Martineau <martineau@kernel.org>, Matthieu Baerts <matttbe@kernel.org>, Jakub Kicinski <kuba@kernel.org>
Message-ID: <20240304162517.2505910-2-matttbe@kernel.org>

From: Davide Caratti <dcaratti@redhat.com>

commit 10048689def7e40a4405acda16fdc6477d4ecc5c upstream.

when MPTCP server accepts an incoming connection, it clones its listener
socket. However, the pointer to 'inet_opt' for the new socket has the same
value as the original one: as a consequence, on program exit it's possible
to observe the following splat:

  BUG: KASAN: double-free in inet_sock_destruct+0x54f/0x8b0
  Free of addr ffff888485950880 by task swapper/25/0

  CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Not tainted 6.8.0-rc1+ #609
  Hardware name: Supermicro SYS-6027R-72RF/X9DRH-7TF/7F/iTF/iF, BIOS 3.0  07/26/2013
  Call Trace:
   <IRQ>
   dump_stack_lvl+0x32/0x50
   print_report+0xca/0x620
   kasan_report_invalid_free+0x64/0x90
   __kasan_slab_free+0x1aa/0x1f0
   kfree+0xed/0x2e0
   inet_sock_destruct+0x54f/0x8b0
   __sk_destruct+0x48/0x5b0
   rcu_do_batch+0x34e/0xd90
   rcu_core+0x559/0xac0
   __do_softirq+0x183/0x5a4
   irq_exit_rcu+0x12d/0x170
   sysvec_apic_timer_interrupt+0x6b/0x80
   </IRQ>
   <TASK>
   asm_sysvec_apic_timer_interrupt+0x16/0x20
  RIP: 0010:cpuidle_enter_state+0x175/0x300
  Code: 30 00 0f 84 1f 01 00 00 83 e8 01 83 f8 ff 75 e5 48 83 c4 18 44 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc fb 45 85 ed <0f> 89 60 ff ff ff 48 c1 e5 06 48 c7 43 18 00 00 00 00 48 83 44 2b
  RSP: 0018:ffff888481cf7d90 EFLAGS: 00000202
  RAX: 0000000000000000 RBX: ffff88887facddc8 RCX: 0000000000000000
  RDX: 1ffff1110ff588b1 RSI: 0000000000000019 RDI: ffff88887fac4588
  RBP: 0000000000000004 R08: 0000000000000002 R09: 0000000000043080
  R10: 0009b02ea273363f R11: ffff88887fabf42b R12: ffffffff932592e0
  R13: 0000000000000004 R14: 0000000000000000 R15: 00000022c880ec80
   cpuidle_enter+0x4a/0xa0
   do_idle+0x310/0x410
   cpu_startup_entry+0x51/0x60
   start_secondary+0x211/0x270
   secondary_startup_64_no_verify+0x184/0x18b
   </TASK>

  Allocated by task 6853:
   kasan_save_stack+0x1c/0x40
   kasan_save_track+0x10/0x30
   __kasan_kmalloc+0xa6/0xb0
   __kmalloc+0x1eb/0x450
   cipso_v4_sock_setattr+0x96/0x360
   netlbl_sock_setattr+0x132/0x1f0
   selinux_netlbl_socket_post_create+0x6c/0x110
   selinux_socket_post_create+0x37b/0x7f0
   security_socket_post_create+0x63/0xb0
   __sock_create+0x305/0x450
   __sys_socket_create.part.23+0xbd/0x130
   __sys_socket+0x37/0xb0
   __x64_sys_socket+0x6f/0xb0
   do_syscall_64+0x83/0x160
   entry_SYSCALL_64_after_hwframe+0x6e/0x76

  Freed by task 6858:
   kasan_save_stack+0x1c/0x40
   kasan_save_track+0x10/0x30
   kasan_save_free_info+0x3b/0x60
   __kasan_slab_free+0x12c/0x1f0
   kfree+0xed/0x2e0
   inet_sock_destruct+0x54f/0x8b0
   __sk_destruct+0x48/0x5b0
   subflow_ulp_release+0x1f0/0x250
   tcp_cleanup_ulp+0x6e/0x110
   tcp_v4_destroy_sock+0x5a/0x3a0
   inet_csk_destroy_sock+0x135/0x390
   tcp_fin+0x416/0x5c0
   tcp_data_queue+0x1bc8/0x4310
   tcp_rcv_state_process+0x15a3/0x47b0
   tcp_v4_do_rcv+0x2c1/0x990
   tcp_v4_rcv+0x41fb/0x5ed0
   ip_protocol_deliver_rcu+0x6d/0x9f0
   ip_local_deliver_finish+0x278/0x360
   ip_local_deliver+0x182/0x2c0
   ip_rcv+0xb5/0x1c0
   __netif_receive_skb_one_core+0x16e/0x1b0
   process_backlog+0x1e3/0x650
   __napi_poll+0xa6/0x500
   net_rx_action+0x740/0xbb0
   __do_softirq+0x183/0x5a4

  The buggy address belongs to the object at ffff888485950880
   which belongs to the cache kmalloc-64 of size 64
  The buggy address is located 0 bytes inside of
   64-byte region [ffff888485950880, ffff8884859508c0)

  The buggy address belongs to the physical page:
  page:0000000056d1e95e refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888485950700 pfn:0x485950
  flags: 0x57ffffc0000800(slab|node=1|zone=2|lastcpupid=0x1fffff)
  page_type: 0xffffffff()
  raw: 0057ffffc0000800 ffff88810004c640 ffffea00121b8ac0 dead000000000006
  raw: ffff888485950700 0000000000200019 00000001ffffffff 0000000000000000
  page dumped because: kasan: bad access detected

  Memory state around the buggy address:
   ffff888485950780: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
   ffff888485950800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  >ffff888485950880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                     ^
   ffff888485950900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
   ffff888485950980: 00 00 00 00 00 01 fc fc fc fc fc fc fc fc fc fc

Something similar (a refcount underflow) happens with CALIPSO/IPv6. Fix
this by duplicating IP / IPv6 options after clone, so that
ip{,6}_sock_destruct() doesn't end up freeing the same memory area twice.

Fixes: cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming connections")
Cc: stable@vger.kernel.org
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-8-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mptcp/protocol.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2856,8 +2856,50 @@ static struct ipv6_pinfo *mptcp_inet6_sk
 
 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
 }
+
+static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
+{
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+	struct ipv6_txoptions *opt;
+	struct ipv6_pinfo *newnp;
+
+	newnp = inet6_sk(newsk);
+
+	rcu_read_lock();
+	opt = rcu_dereference(np->opt);
+	if (opt) {
+		opt = ipv6_dup_options(newsk, opt);
+		if (!opt)
+			net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
+	}
+	RCU_INIT_POINTER(newnp->opt, opt);
+	rcu_read_unlock();
+}
 #endif
 
+static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
+{
+	struct ip_options_rcu *inet_opt, *newopt = NULL;
+	const struct inet_sock *inet = inet_sk(sk);
+	struct inet_sock *newinet;
+
+	newinet = inet_sk(newsk);
+
+	rcu_read_lock();
+	inet_opt = rcu_dereference(inet->inet_opt);
+	if (inet_opt) {
+		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
+				      inet_opt->opt.optlen, GFP_ATOMIC);
+		if (newopt)
+			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
+			       inet_opt->opt.optlen);
+		else
+			net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
+	}
+	RCU_INIT_POINTER(newinet->inet_opt, newopt);
+	rcu_read_unlock();
+}
+
 struct sock *mptcp_sk_clone(const struct sock *sk,
 			    const struct mptcp_options_received *mp_opt,
 			    struct request_sock *req)
@@ -2878,6 +2920,13 @@ struct sock *mptcp_sk_clone(const struct
 	nsk->sk_wait_pending = 0;
 	__mptcp_init_sock(nsk);
 
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (nsk->sk_family == AF_INET6)
+		mptcp_copy_ip6_options(nsk, sk);
+	else
+#endif
+		mptcp_copy_ip_options(nsk, sk);
+
 	msk = mptcp_sk(nsk);
 	msk->local_key = subflow_req->local_key;
 	msk->token = subflow_req->token;


Patches currently in stable-queue which might be from kroah.com@vger.kernel.org are

queue-5.15/mptcp-fix-double-free-on-socket-dismantle.patch
queue-5.15/selftests-mptcp-add-missing-kconfig-for-nf-filter.patch
queue-5.15/selftests-mptcp-add-missing-kconfig-for-nf-filter-in-v6.patch
queue-5.15/mptcp-add-needs_id-for-netlink-appending-addr.patch
queue-5.15/mptcp-rename-timer-related-helper-to-less-confusing-names.patch
queue-5.15/mptcp-process-pending-subflow-error-on-close.patch
queue-5.15/mptcp-clean-up-harmless-false-expressions.patch
queue-5.15/mptcp-move-__mptcp_error_report-in-protocol.c.patch