[PATCH 5.14 740/849] bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed

From: Greg Kroah-Hartman
Date: Mon Nov 15 2021 - 18:21:55 EST

From: Huang Guobin <huangguobin4@xxxxxxxxxx>

[ Upstream commit b93c6a911a3fe926b00add28f3b932007827c4ca ]

When I do fuzz test for bonding device interface, I got the following
use-after-free Calltrace:

==================================================================
BUG: KASAN: use-after-free in bond_enslave+0x1521/0x24f0
Read of size 8 at addr ffff88825bc11c00 by task ifenslave/7365

CPU: 5 PID: 7365 Comm: ifenslave Tainted: G E 5.15.0-rc1+ #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
Call Trace:
dump_stack_lvl+0x6c/0x8b
print_address_description.constprop.0+0x48/0x70
kasan_report.cold+0x82/0xdb
__asan_load8+0x69/0x90
bond_enslave+0x1521/0x24f0
bond_do_ioctl+0x3e0/0x450
dev_ifsioc+0x2ba/0x970
dev_ioctl+0x112/0x710
sock_do_ioctl+0x118/0x1b0
sock_ioctl+0x2e0/0x490
__x64_sys_ioctl+0x118/0x150
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f19159cf577
Code: b3 66 90 48 8b 05 11 89 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 78
RSP: 002b:00007ffeb3083c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffeb3084bca RCX: 00007f19159cf577
RDX: 00007ffeb3083ce0 RSI: 0000000000008990 RDI: 0000000000000003
RBP: 00007ffeb3084bc4 R08: 0000000000000040 R09: 0000000000000000
R10: 00007ffeb3084bc0 R11: 0000000000000246 R12: 00007ffeb3083ce0
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffeb3083cb0

Allocated by task 7365:
kasan_save_stack+0x23/0x50
__kasan_kmalloc+0x83/0xa0
kmem_cache_alloc_trace+0x22e/0x470
bond_enslave+0x2e1/0x24f0
bond_do_ioctl+0x3e0/0x450
dev_ifsioc+0x2ba/0x970
dev_ioctl+0x112/0x710
sock_do_ioctl+0x118/0x1b0
sock_ioctl+0x2e0/0x490
__x64_sys_ioctl+0x118/0x150
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 7365:
kasan_save_stack+0x23/0x50
kasan_set_track+0x20/0x30
kasan_set_free_info+0x24/0x40
__kasan_slab_free+0xf2/0x130
kfree+0xd1/0x5c0
slave_kobj_release+0x61/0x90
kobject_put+0x102/0x180
bond_sysfs_slave_add+0x7a/0xa0
bond_enslave+0x11b6/0x24f0
bond_do_ioctl+0x3e0/0x450
dev_ifsioc+0x2ba/0x970
dev_ioctl+0x112/0x710
sock_do_ioctl+0x118/0x1b0
sock_ioctl+0x2e0/0x490
__x64_sys_ioctl+0x118/0x150
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae

Last potentially related work creation:
kasan_save_stack+0x23/0x50
kasan_record_aux_stack+0xb7/0xd0
insert_work+0x43/0x190
__queue_work+0x2e3/0x970
delayed_work_timer_fn+0x3e/0x50
call_timer_fn+0x148/0x470
run_timer_softirq+0x8a8/0xc50
__do_softirq+0x107/0x55f

Second to last potentially related work creation:
kasan_save_stack+0x23/0x50
kasan_record_aux_stack+0xb7/0xd0
insert_work+0x43/0x190
__queue_work+0x2e3/0x970
__queue_delayed_work+0x130/0x180
queue_delayed_work_on+0xa7/0xb0
bond_enslave+0xe25/0x24f0
bond_do_ioctl+0x3e0/0x450
dev_ifsioc+0x2ba/0x970
dev_ioctl+0x112/0x710
sock_do_ioctl+0x118/0x1b0
sock_ioctl+0x2e0/0x490
__x64_sys_ioctl+0x118/0x150
do_syscall_64+0x35/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88825bc11c00
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
1024-byte region [ffff88825bc11c00, ffff88825bc12000)
The buggy address belongs to the page:
page:ffffea00096f0400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25bc10
head:ffffea00096f0400 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea0009a71c08 ffff888240001968 ffff88810004dbc0
raw: 0000000000000000 00000000000a000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88825bc11b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88825bc11b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88825bc11c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88825bc11c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88825bc11d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Put new_slave in bond_sysfs_slave_add() will cause use-after-free problems
when new_slave is accessed in the subsequent error handling process. Since
new_slave will be put in the subsequent error handling process, remove the
unnecessary put to fix it.
In addition, when sysfs_create_file() fails, if some files have been crea-
ted successfully, we need to call sysfs_remove_file() to remove them.
Since there are sysfs_create_files() & sysfs_remove_files() can be used,
use these two functions instead.

Fixes: 7afcaec49696 (bonding: use kobject_put instead of _del after kobject_add)
Signed-off-by: Huang Guobin <huangguobin4@xxxxxxxxxx>
Reviewed-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/bonding/bond_sysfs_slave.c | 36 ++++++++------------------
1 file changed, 11 insertions(+), 25 deletions(-)

diff --git a/drivers/net/bonding/bond_sysfs_slave.c b/drivers/net/bonding/bond_sysfs_slave.c
index fd07561da0348..6a6cdd0bb2585 100644
--- a/drivers/net/bonding/bond_sysfs_slave.c
+++ b/drivers/net/bonding/bond_sysfs_slave.c
@@ -108,15 +108,15 @@ static ssize_t ad_partner_oper_port_state_show(struct slave *slave, char *buf)
}
static SLAVE_ATTR_RO(ad_partner_oper_port_state);

-static const struct slave_attribute *slave_attrs[] = {
- &slave_attr_state,
- &slave_attr_mii_status,
- &slave_attr_link_failure_count,
- &slave_attr_perm_hwaddr,
- &slave_attr_queue_id,
- &slave_attr_ad_aggregator_id,
- &slave_attr_ad_actor_oper_port_state,
- &slave_attr_ad_partner_oper_port_state,
+static const struct attribute *slave_attrs[] = {
+ &slave_attr_state.attr,
+ &slave_attr_mii_status.attr,
+ &slave_attr_link_failure_count.attr,
+ &slave_attr_perm_hwaddr.attr,
+ &slave_attr_queue_id.attr,
+ &slave_attr_ad_aggregator_id.attr,
+ &slave_attr_ad_actor_oper_port_state.attr,
+ &slave_attr_ad_partner_oper_port_state.attr,
NULL
};

@@ -137,24 +137,10 @@ const struct sysfs_ops slave_sysfs_ops = {

int bond_sysfs_slave_add(struct slave *slave)
{
- const struct slave_attribute **a;
- int err;
-
- for (a = slave_attrs; *a; ++a) {
- err = sysfs_create_file(&slave->kobj, &((*a)->attr));
- if (err) {
- kobject_put(&slave->kobj);
- return err;
- }
- }
-
- return 0;
+ return sysfs_create_files(&slave->kobj, slave_attrs);
}

void bond_sysfs_slave_del(struct slave *slave)
{
- const struct slave_attribute **a;
-
- for (a = slave_attrs; *a; ++a)
- sysfs_remove_file(&slave->kobj, &((*a)->attr));
+ sysfs_remove_files(&slave->kobj, slave_attrs);
}
--
2.33.0