diff --git a/examples/iscsiclient.c b/examples/iscsiclient.c
index 476a925..a61d6e0 100644
--- a/examples/iscsiclient.c
+++ b/examples/iscsiclient.c
@@ -86,7 +86,8 @@ void nop_out_cb(struct iscsi_context *iscsi, int status, void *command_data, voi
 
 	printf("NOP-IN status:%d\n", status);
 	if (data->size > 0) {
-		printf("NOP-IN data:%s\n", data->data);
+		printf("NOP-IN (%zu) data:%.*s\n",
+		       data->size, (int)data->size, data->data);
 	}
 	printf("Send SYNCHRONIZECACHE10\n");
 	task = iscsi_synchronizecache10_task(iscsi, 2, 0, 0, 0, 0, synccache10_cb, private_data);
diff --git a/include/iscsi-private.h b/include/iscsi-private.h
index a96caae..8ace255 100644
--- a/include/iscsi-private.h
+++ b/include/iscsi-private.h
@@ -43,8 +43,8 @@ extern "C" {
 #define ISCSI_RAW_HEADER_SIZE			48
 #define ISCSI_DIGEST_SIZE			 4
 
-#define ISCSI_HEADER_SIZE (ISCSI_RAW_HEADER_SIZE	\
-  + (iscsi->header_digest == ISCSI_HEADER_DIGEST_NONE?0:ISCSI_DIGEST_SIZE))
+#define ISCSI_HEADER_SIZE(hdr_digest) (ISCSI_RAW_HEADER_SIZE	\
+  + (hdr_digest == ISCSI_HEADER_DIGEST_NONE?0:ISCSI_DIGEST_SIZE))
 
 #define SMALL_ALLOC_MAX_FREE (128) /* must be power of 2 */
 
diff --git a/lib/nop.c b/lib/nop.c
index b2104cd..b740c7f 100644
--- a/lib/nop.c
+++ b/lib/nop.c
@@ -163,7 +163,7 @@ iscsi_process_nop_out_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 	data.data = NULL;
 	data.size = 0;
 
-	if (in->data_pos > ISCSI_HEADER_SIZE) {
+	if (in->data_pos) {
 		data.data = in->data;
 		data.size = in->data_pos;
 	}
diff --git a/lib/pdu.c b/lib/pdu.c
index 441efa7..043aa75 100644
--- a/lib/pdu.c
+++ b/lib/pdu.c
@@ -111,7 +111,7 @@ iscsi_allocate_pdu(struct iscsi_context *iscsi, enum iscsi_opcode opcode,
 		return NULL;
 	}
 
-	pdu->outdata.size = ISCSI_HEADER_SIZE;
+	pdu->outdata.size = ISCSI_HEADER_SIZE(iscsi->header_digest);
 	pdu->outdata.data = iscsi_szmalloc(iscsi, pdu->outdata.size);
 
 	if (pdu->outdata.data == NULL) {
@@ -236,7 +236,7 @@ iscsi_pdu_add_data(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 
 	/* update data segment length */
 	scsi_set_uint32(&pdu->outdata.data[4], pdu->outdata.size
-					       - ISCSI_HEADER_SIZE);
+				- ISCSI_HEADER_SIZE(iscsi->header_digest));
 
 	return 0;
 }
diff --git a/lib/socket.c b/lib/socket.c
index 4aa0d9a..42db72b 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -596,25 +596,30 @@ static int
 iscsi_read_from_socket(struct iscsi_context *iscsi)
 {
 	struct iscsi_in_pdu *in;
-	ssize_t data_size, count, padding_size;
+	ssize_t hdr_size, data_size, count, padding_size;
 
 	do {
+		hdr_size = ISCSI_HEADER_SIZE(iscsi->header_digest);
 		if (iscsi->incoming == NULL) {
 			iscsi->incoming = iscsi_szmalloc(iscsi, sizeof(struct iscsi_in_pdu));
-			iscsi->incoming->hdr = iscsi_smalloc(iscsi, ISCSI_HEADER_SIZE);
 			if (iscsi->incoming == NULL) {
 				iscsi_set_error(iscsi, "Out-of-memory: failed to malloc iscsi_in_pdu");
 				return -1;
 			}
+			iscsi->incoming->hdr = iscsi_smalloc(iscsi, hdr_size);
+			if (iscsi->incoming->hdr == NULL) {
+				iscsi_set_error(iscsi, "Out-of-memory");
+				return -1;
+			}
 		}
 		in = iscsi->incoming;
 
 		/* first we must read the header, including any digests */
-		if (in->hdr_pos < ISCSI_HEADER_SIZE) {
+		if (in->hdr_pos < hdr_size) {
 			/* try to only read the header, the socket is nonblocking, so
 			 * no need to limit the read to what is available in the socket
 			 */
-			count = ISCSI_HEADER_SIZE - in->hdr_pos;
+			count = hdr_size - in->hdr_pos;
 			count = recv(iscsi->fd, &in->hdr[in->hdr_pos], count, 0);
 			if (count == 0) {
 				/* remote side has closed the socket. */
@@ -631,7 +636,7 @@ iscsi_read_from_socket(struct iscsi_context *iscsi)
 			in->hdr_pos  += count;
 		}
 
-		if (in->hdr_pos < ISCSI_HEADER_SIZE) {
+		if (in->hdr_pos < hdr_size) {
 			/* we don't have the full header yet, so return */
 			break;
 		}