The devices with size >= 2^63 bytes can't be used reliably by userspace
because the type off_t is a signed 64-bit integer.
Therefore, we limit the maximum size of a device mapper device to
2^63-512 bytes.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-table.c | 4 ++++
1 file changed, 4 insertions(+)
Index: linux-2.6/drivers/md/dm-table.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-table.c 2025-02-24 12:41:49.000000000 +0100
+++ linux-2.6/drivers/md/dm-table.c 2025-03-14 13:42:13.000000000 +0100
@@ -697,6 +697,10 @@ int dm_table_add_target(struct dm_table
DMERR("%s: zero-length target", dm_device_name(t->md));
return -EINVAL;
}
+ if (start + len < start || start + len > LLONG_MAX >> SECTOR_SHIFT) {
+ DMERR("%s: too large device", dm_device_name(t->md));
+ return -EINVAL;
+ }
ti->type = dm_get_target_type(type);
if (!ti->type) {
