This is a note to let you know that I've just added the patch titled bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed to the 4.4-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: bonding-fix-a-use-after-free-problem-when-bond_sysfs.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit dde8d806653b95c189186c554a56bfe4233b6387 Author: Huang Guobin <huangguobin4@xxxxxxxxxx> Date: Tue Nov 2 17:37:33 2021 +0800 bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed [ 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> diff --git a/drivers/net/bonding/bond_sysfs_slave.c b/drivers/net/bonding/bond_sysfs_slave.c index 68bbac4715c35..1e1e77a40f182 100644 --- a/drivers/net/bonding/bond_sysfs_slave.c +++ b/drivers/net/bonding/bond_sysfs_slave.c @@ -112,15 +112,15 @@ 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 }; @@ -141,24 +141,10 @@ 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); }