dm: restrict dm device size to 2^63-512 bytes

[ Upstream commit 45fc728515c14f53f6205789de5bfd72a95af3b8 ]

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@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index efc6ec25e0c5d1e5534b671c7c4bdd4d1612242a..4752966fdb3f4d1fc90d2d1347db05e9ba08235e 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -698,6 +698,10 @@ int dm_table_add_target(struct dm_table *t, const char *type,
                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) {