5.4 doesn't have "mddev_destroy_serial_pool" ... More work would be
needed to figure out if the vulnerability exists and how to fix it.
The patch also applies to 5.15, but I haven't tested it.
On Wed, May 15, 2024 at 12:33 AM Greg KH <greg@xxxxxxxxx> wrote:
>
> On Mon, May 13, 2024 at 11:30:58PM +0000, Jeremy Bongio wrote:
> > From: Li Nan <linan122@xxxxxxxxxx>
> >
> > commit 6cf350658736681b9d6b0b6e58c5c76b235bb4c4 upstream.
> >
> > If kobject_add() is fail in bind_rdev_to_array(), 'rdev->serial' will be
> > alloc not be freed, and kmemleak occurs.
> >
> > unreferenced object 0xffff88815a350000 (size 49152):
> > comm "mdadm", pid 789, jiffies 4294716910
> > hex dump (first 32 bytes):
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > backtrace (crc f773277a):
> > [<0000000058b0a453>] kmemleak_alloc+0x61/0xe0
> > [<00000000366adf14>] __kmalloc_large_node+0x15e/0x270
> > [<000000002e82961b>] __kmalloc_node.cold+0x11/0x7f
> > [<00000000f206d60a>] kvmalloc_node+0x74/0x150
> > [<0000000034bf3363>] rdev_init_serial+0x67/0x170
> > [<0000000010e08fe9>] mddev_create_serial_pool+0x62/0x220
> > [<00000000c3837bf0>] bind_rdev_to_array+0x2af/0x630
> > [<0000000073c28560>] md_add_new_disk+0x400/0x9f0
> > [<00000000770e30ff>] md_ioctl+0x15bf/0x1c10
> > [<000000006cfab718>] blkdev_ioctl+0x191/0x3f0
> > [<0000000085086a11>] vfs_ioctl+0x22/0x60
> > [<0000000018b656fe>] __x64_sys_ioctl+0xba/0xe0
> > [<00000000e54e675e>] do_syscall_64+0x71/0x150
> > [<000000008b0ad622>] entry_SYSCALL_64_after_hwframe+0x6c/0x74
> >
> > backport change:
> > mddev_destroy_serial_pool third parameter was removed in mainline,
> > where there is no need to suspend within this function anymore.
> >
> > Fixes: 963c555e75b0 ("md: introduce mddev_create/destroy_wb_pool for the change of member device")
> > Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
> > Signed-off-by: Song Liu <song@xxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20240208085556.2412922-1-linan666@xxxxxxxxxxxxxxx
> > Signed-off-by: Jeremy Bongio <jbongio@xxxxxxxxxx>
> > ---
> >
> > This backport is tested on LTS 5.10, 6.1, 6.6
>
> So this is not needed in 5.15.y or 5.4.y? Why not?
>
> thanks,
>
> greg k-h
