net/tls: Mark the end in scatterlist table

Function zerocopy_from_iter() unmarks the 'end' in input sgtable while
adding new entries in it. The last entry in sgtable remained unmarked.
This results in KASAN error report on using apis like sg_nents(). Before
returning, the function needs to mark the 'end' in the last entry it
adds.
Signed-off-by: NVakul Garg <vakul.garg@nxp.com>
Acked-by: NDave Watson <davejwatson@fb.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tls/tls_sw.c

@@ -311,6 +311,9 @@ static int zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
 		}
 	}
 
+	/* Mark the end in the last sg entry if newly added */
+	if (num_elem > *pages_used)
+		sg_mark_end(&to[num_elem - 1]);
 out:
 	if (rc)
 		iov_iter_revert(from, size - *size_used);