[PATCH AUTOSEL 6.1 057/212] dm: restrict dm device size to 2^63-512 bytes

[Sasha Levin]

From: Mikulas Patocka <mpato...@redhat.com>

[ 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 <mpato...@redhat.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/md/dm-table.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index aabb2435070b8..9e3f8c737c487 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -670,6 +670,10 @@ 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) {
-- 
2.39.5