dm integrity: reject mappings too large for device

WOnder93 · snitm · commit 2ad50606f847 · 2017-06-12T17:05:55.000-04:00
dm-integrity would successfully create mappings with the number of
sectors greater than the provided data sector count.  Attempts to read
sectors of this mapping that were beyond the provided data sector count
would then yield run-time messages of the form "device-mapper:
integrity: Too big sector number: ...".

Fix this by emitting an error when the requested mapping size is bigger
than the provided data sector count.

Signed-off-by: Ondrej Mosnacek &lt;omosnacek@gmail.com&gt;
Acked-by: Mikulas Patocka &lt;mpatocka@redhat.com&gt;
Signed-off-by: Mike Snitzer &lt;snitzer@redhat.com&gt;
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
@@ -3040,6 +3040,11 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		ti->error = "The device is too small";
 		goto bad;
 	}
+	if (ti->len > ic->provided_data_sectors) {
+		r = -EINVAL;
+		ti->error = "Not enough provided sectors for requested mapping size";
+		goto bad;
+	}
 
 	if (!buffer_sectors)
 		buffer_sectors = 1;
