commit 7decd1f5904a489d3ccdcf131972f94645681689 upstream.
Syzkaller reported this splat:
==================================================================
BUG: KASAN: slab-use-after-free in mptcp_pm_nl_rm_addr_or_subflow+0xb44/0xcc0 net/mptcp/pm_netlink.c:881
Read of size 4 at addr ffff8880569ac858 by task syz.1.2799/14662
CPU: 0 UID: 0 PID: 14662 Comm: syz.1.2799 Not tainted 6.12.0-rc2-syzkaller-00307-g36c254515dc6 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
mptcp_pm_nl_rm_addr_or_subflow+0xb44/0xcc0 net/mptcp/pm_netlink.c:881
mptcp_pm_nl_rm_subflow_received net/mptcp/pm_netlink.c:914 [inline]
mptcp_nl_remove_id_zero_address+0x305/0x4a0 net/mptcp/pm_netlink.c:1572
mptcp_pm_nl_del_addr_doit+0x5c9/0x770 net/mptcp/pm_netlink.c:1603
genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2551
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901
sock_sendmsg_nosec net/socket.c:729 [inline]
__sock_sendmsg net/socket.c:744 [inline]
____sys_sendmsg+0x9ae/0xb40 net/socket.c:2607
___sys_sendmsg+0x135/0x1e0 net/socket.c:2661
__sys_sendmsg+0x117/0x1f0 net/socket.c:2690
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fe4579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f574556c EFLAGS: 00000296 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 0000000020000140
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Allocated by task 5387:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
subflow_create_ctx+0x87/0x2a0 net/mptcp/subflow.c:1803
subflow_ulp_init+0xc3/0x4d0 net/mptcp/subflow.c:1956
__tcp_set_ulp net/ipv4/tcp_ulp.c:146 [inline]
tcp_set_ulp+0x326/0x7f0 net/ipv4/tcp_ulp.c:167
mptcp_subflow_create_socket+0x4ae/0x10a0 net/mptcp/subflow.c:1764
__mptcp_subflow_connect+0x3cc/0x1490 net/mptcp/subflow.c:1592
mptcp_pm_create_subflow_or_signal_addr+0xbda/0x23a0 net/mptcp/pm_netlink.c:642
mptcp_pm_nl_fully_established net/mptcp/pm_netlink.c:650 [inline]
mptcp_pm_nl_work+0x3a1/0x4f0 net/mptcp/pm_netlink.c:943
mptcp_worker+0x15a/0x1240 net/mptcp/protocol.c:2777
process_one_work+0x958/0x1b30 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Freed by task 113:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2342 [inline]
slab_free mm/slub.c:4579 [inline]
kfree+0x14f/0x4b0 mm/slub.c:4727
kvfree+0x47/0x50 mm/util.c:701
kvfree_rcu_list+0xf5/0x2c0 kernel/rcu/tree.c:3423
kvfree_rcu_drain_ready kernel/rcu/tree.c:3563 [inline]
kfree_rcu_monitor+0x503/0x8b0 kernel/rcu/tree.c:3632
kfree_rcu_shrink_scan+0x245/0x3a0 kernel/rcu/tree.c:3966
do_shrink_slab+0x44f/0x11c0 mm/shrinker.c:435
shrink_slab+0x32b/0x12a0 mm/shrinker.c:662
shrink_one+0x47e/0x7b0 mm/vmscan.c:4818
shrink_many mm/vmscan.c:4879 [inline]
lru_gen_shrink_node mm/vmscan.c:4957 [inline]
shrink_node+0x2452/0x39d0 mm/vmscan.c:5937
kswapd_shrink_node mm/vmscan.c:6765 [inline]
balance_pgdat+0xc19/0x18f0 mm/vmscan.c:6957
kswapd+0x5ea/0xbf0 mm/vmscan.c:7226
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Last potentially related work creation:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
kvfree_call_rcu+0x74/0xbe0 kernel/rcu/tree.c:3810
subflow_ulp_release+0x2ae/0x350 net/mptcp/subflow.c:2009
tcp_cleanup_ulp+0x7c/0x130 net/ipv4/tcp_ulp.c:124
tcp_v4_destroy_sock+0x1c5/0x6a0 net/ipv4/tcp_ipv4.c:2541
inet_csk_destroy_sock+0x1a3/0x440 net/ipv4/inet_connection_sock.c:1293
tcp_done+0x252/0x350 net/ipv4/tcp.c:4870
tcp_rcv_state_process+0x379b/0x4f30 net/ipv4/tcp_input.c:6933
tcp_v4_do_rcv+0x1ad/0xa90 net/ipv4/tcp_ipv4.c:1938
sk_backlog_rcv include/net/sock.h:1115 [inline]
__release_sock+0x31b/0x400 net/core/sock.c:3072
__tcp_close+0x4f3/0xff0 net/ipv4/tcp.c:3142
__mptcp_close_ssk+0x331/0x14d0 net/mptcp/protocol.c:2489
mptcp_close_ssk net/mptcp/protocol.c:2543 [inline]
mptcp_close_ssk+0x150/0x220 net/mptcp/protocol.c:2526
mptcp_pm_nl_rm_addr_or_subflow+0x2be/0xcc0 net/mptcp/pm_netlink.c:878
mptcp_pm_nl_rm_subflow_received net/mptcp/pm_netlink.c:914 [inline]
mptcp_nl_remove_id_zero_address+0x305/0x4a0 net/mptcp/pm_netlink.c:1572
mptcp_pm_nl_del_addr_doit+0x5c9/0x770 net/mptcp/pm_netlink.c:1603
genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2551
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1357
netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1901
sock_sendmsg_nosec net/socket.c:729 [inline]
__sock_sendmsg net/socket.c:744 [inline]
____sys_sendmsg+0x9ae/0xb40 net/socket.c:2607
___sys_sendmsg+0x135/0x1e0 net/socket.c:2661
__sys_sendmsg+0x117/0x1f0 net/socket.c:2690
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
The buggy address belongs to the object at ffff8880569ac800
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 88 bytes inside of
freed 512-byte region [ffff8880569ac800, ffff8880569aca00)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x569ac
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801ac42c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000
head: 04fff00000000040 ffff88801ac42c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000080100010 00000001f5000000 0000000000000000
head: 04fff00000000002 ffffea00015a6b01 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 10238, tgid 10238 (kworker/u32:6), ts 597403252405, free_ts 597177952947
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1537
prep_new_page mm/page_alloc.c:1545 [inline]
get_page_from_freelist+0x101e/0x3070 mm/page_alloc.c:3457
__alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4733
alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
alloc_slab_page mm/slub.c:2412 [inline]
allocate_slab mm/slub.c:2578 [inline]
new_slab+0x2ba/0x3f0 mm/slub.c:2631
___slab_alloc+0xd1d/0x16f0 mm/slub.c:3818
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
__kmalloc_cache_noprof+0x2c5/0x310 mm/slub.c:4290
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
mld_add_delrec net/ipv6/mcast.c:743 [inline]
igmp6_leave_group net/ipv6/mcast.c:2625 [inline]
igmp6_group_dropped+0x4ab/0xe40 net/ipv6/mcast.c:723
__ipv6_dev_mc_dec+0x281/0x360 net/ipv6/mcast.c:979
addrconf_leave_solict net/ipv6/addrconf.c:2253 [inline]
__ipv6_ifa_notify+0x3f6/0xc30 net/ipv6/addrconf.c:6283
addrconf_ifdown.isra.0+0xef9/0x1a20 net/ipv6/addrconf.c:3982
addrconf_notify+0x220/0x19c0 net/ipv6/addrconf.c:3781
notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1996
call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
call_netdevice_notifiers net/core/dev.c:2048 [inline]
dev_close_many+0x333/0x6a0 net/core/dev.c:1589
page last free pid 13136 tgid 13136 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1108 [inline]
free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2638
stack_depot_save_flags+0x2da/0x900 lib/stackdepot.c:666
kasan_save_stack+0x42/0x60 mm/kasan/common.c:48
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:247 [inline]
slab_post_alloc_hook mm/slub.c:4085 [inline]
slab_alloc_node mm/slub.c:4134 [inline]
kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4141
skb_clone+0x190/0x3f0 net/core/skbuff.c:2084
do_one_broadcast net/netlink/af_netlink.c:1462 [inline]
netlink_broadcast_filtered+0xb11/0xef0 net/netlink/af_netlink.c:1540
netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1564
uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
kobject_uevent_env+0xacd/0x1670 lib/kobject_uevent.c:608
device_del+0x623/0x9f0 drivers/base/core.c:3882
snd_card_disconnect.part.0+0x58a/0x7c0 sound/core/init.c:546
snd_card_disconnect+0x1f/0x30 sound/core/init.c:495
snd_usx2y_disconnect+0xe9/0x1f0 sound/usb/usx2y/usbusx2y.c:417
usb_unbind_interface+0x1e8/0x970 drivers/usb/core/driver.c:461
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x122/0x170 drivers/base/dd.c:561
That's because 'subflow' is used just after 'mptcp_close_ssk(subflow)',
which will initiate the release of its memory. Even if it is very likely
the release and the re-utilisation will be done later on, it is of
course better to avoid any issues and read the content of 'subflow'
before closing it.
Fixes: 1c1f72137598 ("mptcp: pm: only decrement add_addr_accepted for MPJ req")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: syzbot+3c8b7a8e7df6a2a226ca@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/670d7337.050a0220.4cbc0.004f.GAE@xxxxxxxxxx
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Link: https://patch.msgid.link/20241015-net-mptcp-uaf-pm-rm-v1-1-c4ee5d987a64@xxxxxxxxxx
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
[ Conflicts in pm_netlink.c, because commit a88c9e496937 ("mptcp: do not
block subflows creation on errors") is linked to a new feature, not
available in this version. This commit modifies the context. Resolving
the conflicts is easy, simply moving the lines the same way it was
done in the original patch, ignoring the comment that is not in this
version. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/mptcp/pm_netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index e524171291bc..133c5f2b3ba6 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -793,10 +793,10 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
i, rm_list->ids[i], subflow->local_id, subflow->remote_id);
spin_unlock_bh(&msk->pm.lock);
mptcp_subflow_shutdown(sk, ssk, how);
+ removed |= subflow->request_join;
mptcp_close_ssk(sk, ssk, subflow);
spin_lock_bh(&msk->pm.lock);
- removed |= subflow->request_join;
msk->pm.subflows--;
if (rm_type == MPTCP_MIB_RMSUBFLOW)
__MPTCP_INC_STATS(sock_net(sk), rm_type);
--
2.45.2
