Revert "scsi: qla2xxx: Fix memcpy() field-spanning write issue"

This reverts commit 6f4b102.

We've been testing this patch and it turns out there is a significant
bug here. This leaks memory and causes a driver hang.

Link: https://lore.kernel.org/linux-scsi/yq1zfajqpec.fsf@ca-mkp.ca.oracle.com/
Signed-off-by: John Meneghini <jmeneghi@redhat.com>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: johnmeneghini

drivers/scsi/qla2xxx/qla_def.h

@@ -4890,7 +4890,9 @@ struct purex_item {
 			     struct purex_item *pkt);
 	atomic_t in_use;
 	uint16_t size;
-	uint8_t iocb[] __counted_by(size);
+	struct {
+		uint8_t iocb[64];
+	} iocb;
 };
 
 #include "qla_edif.h"
@@ -5099,6 +5101,7 @@ typedef struct scsi_qla_host {
 		struct list_head head;
 		spinlock_t lock;
 	} purex_list;
+	struct purex_item default_item;
 
 	struct name_list_extended gnl;
 	/* Count of active session/fcport */
@@ -5127,11 +5130,6 @@ typedef struct scsi_qla_host {
 #define DPORT_DIAG_IN_PROGRESS                 BIT_0
 #define DPORT_DIAG_CHIP_RESET_IN_PROGRESS      BIT_1
 	uint16_t dport_status;
-
-	/* Must be last --ends in a flexible-array member. */
-	TRAILING_OVERLAP(struct purex_item, default_item, iocb,
-		uint8_t __default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE];
-	);
 } scsi_qla_host_t;
 
 struct qla27xx_image_status {

drivers/scsi/qla2xxx/qla_isr.c

@@ -1077,17 +1077,17 @@ static struct purex_item *
 qla24xx_alloc_purex_item(scsi_qla_host_t *vha, uint16_t size)
 {
 	struct purex_item *item = NULL;
+	uint8_t item_hdr_size = sizeof(*item);
 
 	if (size > QLA_DEFAULT_PAYLOAD_SIZE) {
-		item = kzalloc(struct_size(item, iocb, size), GFP_ATOMIC);
+		item = kzalloc(item_hdr_size +
+		    (size - QLA_DEFAULT_PAYLOAD_SIZE), GFP_ATOMIC);
 	} else {
 		if (atomic_inc_return(&vha->default_item.in_use) == 1) {
 			item = &vha->default_item;
 			goto initialize_purex_header;
 		} else {
-			item = kzalloc(
-				struct_size(item, iocb, QLA_DEFAULT_PAYLOAD_SIZE),
-				GFP_ATOMIC);
+			item = kzalloc(item_hdr_size, GFP_ATOMIC);
 		}
 	}
 	if (!item) {
@@ -1127,16 +1127,17 @@ qla24xx_queue_purex_item(scsi_qla_host_t *vha, struct purex_item *pkt,
  * @vha: SCSI driver HA context
  * @pkt: ELS packet
  */
-static struct purex_item *
-qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt)
+static struct purex_item
+*qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt)
 {
 	struct purex_item *item;
 
-	item = qla24xx_alloc_purex_item(vha, QLA_DEFAULT_PAYLOAD_SIZE);
+	item = qla24xx_alloc_purex_item(vha,
+					QLA_DEFAULT_PAYLOAD_SIZE);
 	if (!item)
 		return item;
 
-	memcpy(&item->iocb, pkt, QLA_DEFAULT_PAYLOAD_SIZE);
+	memcpy(&item->iocb, pkt, sizeof(item->iocb));
 	return item;
 }
 

drivers/scsi/qla2xxx/qla_nvme.c

@@ -1308,7 +1308,7 @@ void qla2xxx_process_purls_iocb(void **pkt, struct rsp_que **rsp)
 
 	ql_dbg(ql_dbg_unsol, vha, 0x2121,
 	       "PURLS OP[%01x] size %d xchg addr 0x%x portid %06x\n",
-	       item->iocb[3], item->size, uctx->exchange_address,
+	       item->iocb.iocb[3], item->size, uctx->exchange_address,
 	       fcport->d_id.b24);
 	/* +48    0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
 	 * ----- -----------------------------------------------

drivers/scsi/qla2xxx/qla_os.c

@@ -6459,10 +6459,9 @@ void qla24xx_process_purex_rdp(struct scsi_qla_host *vha,
 void
 qla24xx_free_purex_item(struct purex_item *item)
 {
-	if (item == &item->vha->default_item) {
+	if (item == &item->vha->default_item)
 		memset(&item->vha->default_item, 0, sizeof(struct purex_item));
-		memset(&item->vha->__default_item_iocb, 0, QLA_DEFAULT_PAYLOAD_SIZE);
-	} else
+	else
 		kfree(item);
 }