Index: sys/geom/eli/g_eli_integrity.c
===================================================================
--- sys/geom/eli/g_eli_integrity.c
+++ sys/geom/eli/g_eli_integrity.c
@@ -515,6 +515,17 @@
 			if (bp->bio_cmd == BIO_WRITE)
 				memset(data + sc->sc_alen + data_secsize, 0,
 				    encr_secsize - sc->sc_alen - data_secsize);
+		} else if (data_secsize + sc->sc_alen != encr_secsize) {
+			/*
+			 * If the HMAC size is not a multiple of 128 bits, the
+			 * per-sector data size is rounded down to ensure that
+			 * encryption can be performed without requiring any
+			 * padding.  In this case, each sector contains unused
+			 * bytes.
+			 */
+			if (bp->bio_cmd == BIO_WRITE)
+				memset(data + sc->sc_alen + data_secsize, 0,
+				    encr_secsize - sc->sc_alen - data_secsize);
 		}
 
 		if (bp->bio_cmd == BIO_WRITE) {