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SubjectRe: [PATCH v2] kobject: Fix slab-out-of-bounds in fill_kobj_path()
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在 2022/12/20 9:21, Wang Hai 写道:
> In kobject_get_path(), if kobj->name is changed between calls
> get_kobj_path_length() and fill_kobj_path() and the length becomes
> longer, then fill_kobj_path() will have an out-of-bounds bug.
>
> The actual current problem occurs when the ixgbe probe.
>
> In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name
> length becomes longer, out-of-bounds will occur.
>
> cpu0 cpu1
> ixgbe_probe
> register_netdev(netdev)
> netdev_register_kobject
> device_add
> kobject_uevent // Sending ADD events
> systemd-udevd // rename netdev
> dev_change_name
> device_rename
> kobject_rename
> ixgbe_mii_bus_init |
> mdiobus_register |
> __mdiobus_register |
> device_register |
> device_add |
> kobject_uevent |
> kobject_get_path |
> len = get_kobj_path_length // old name |
> path = kzalloc(len, gfp_mask); |
> kobj->name = name;
> /* name length becomes
> * longer
> */
> fill_kobj_path /* kobj path length is
> * longer than path,
> * resulting in out of
> * bounds when filling path
> */
>
> This is the kasan report:
>
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0
> Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673
>
> Workqueue: events work_for_cpu_fn
> Call Trace:
> <TASK>
> dump_stack_lvl+0x34/0x48
> print_address_description.constprop.0+0x86/0x1e7
> print_report+0x36/0x4f
> kasan_report+0xad/0x130
> kasan_check_range+0x35/0x1c0
> memcpy+0x39/0x60
> fill_kobj_path+0x50/0xc0
> kobject_get_path+0x5a/0xc0
> kobject_uevent_env+0x140/0x460
> device_add+0x5c7/0x910
> __mdiobus_register+0x14e/0x490
> ixgbe_probe.cold+0x441/0x574 [ixgbe]
> local_pci_probe+0x78/0xc0
> work_for_cpu_fn+0x26/0x40
> process_one_work+0x3b6/0x6a0
> worker_thread+0x368/0x520
> kthread+0x165/0x1a0
> ret_from_fork+0x1f/0x30
>
> This reproducer triggers that bug:
>
> while:
> do
> rmmod ixgbe
> sleep 0.5
> modprobe ixgbe
> sleep 0.5
>
> When calling fill_kobj_path() to fill path, if the name length of
> kobj becomes longer, return failure and retry. This fixes the problem.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Wang Hai <wanghai38@huawei.com>
> ---
Hi, greg k-h.
Sorry to bother you. Can this patch be merged into the mainline?

--
Wang Hai

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