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On Tue, Feb 07, 2023 at 10:21:40PM -0600, Benjamin Marzinski wrote:
> If a dm device table references itself, it will crash the kernel with an
> infinite recursion. Check for a self-reference in dm_get_device(). This
> is a quick check, but it won't catch more complicated circular
> references.
>
> Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> ---
> drivers/md/dm-table.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 8541d5688f3a..24ad42b385c1 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -364,6 +364,8 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
> if (!dev)
> return -ENODEV;
> }
> + if (dev == disk_devt(t->md->disk))
> + return -EINVAL;
>
> dd = find_device(&t->devices, dev);
> if (!dd) {
> --
> 2.30.2
I like this! More generally, should the kernel fail with -ELOOP if
devices are stacked too deeply?
- --
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
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