[MTD] [OneNAND] Fix access the past of the real oobfree array

Here it's not the case: all the entries are occupied by
OOB chunks. Therefore, once we get into a loop like

        for (free = this->ecclayout->oobfree; free->length; ++free) {
	}

we might end up scanning past the real oobfree array.

Probably the best way out, as the same thing might happen for common NAND
as well, is to check index against MTD_MAX_OOBFREE_ENTRIES.
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/onenand/onenand_base.c

@@ -836,9 +836,11 @@ static int onenand_transfer_auto_oob(struct mtd_info *mtd, uint8_t *buf, int col
 	int readcol = column;
 	int readend = column + thislen;
 	int lastgap = 0;
+	unsigned int i;
 	uint8_t *oob_buf = this->oob_buf;
 
-	for (free = this->ecclayout->oobfree; free->length; ++free) {
+	free = this->ecclayout->oobfree;
+	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES && free->length; i++, free++) {
 		if (readcol >= lastgap)
 			readcol += free->offset - lastgap;
 		if (readend >= lastgap)
@@ -846,7 +848,8 @@ static int onenand_transfer_auto_oob(struct mtd_info *mtd, uint8_t *buf, int col
 		lastgap = free->offset + free->length;
 	}
 	this->read_bufferram(mtd, ONENAND_SPARERAM, oob_buf, 0, mtd->oobsize);
-	for (free = this->ecclayout->oobfree; free->length; ++free) {
+	free = this->ecclayout->oobfree;
+	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES && free->length; i++, free++) {
 		int free_end = free->offset + free->length;
 		if (free->offset < readend && free_end > readcol) {
 			int st = max_t(int,free->offset,readcol);
@@ -1280,15 +1283,18 @@ static int onenand_fill_auto_oob(struct mtd_info *mtd, u_char *oob_buf,
 	int writecol = column;
 	int writeend = column + thislen;
 	int lastgap = 0;
+	unsigned int i;
 
-	for (free = this->ecclayout->oobfree; free->length; ++free) {
+	free = this->ecclayout->oobfree;
+	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES && free->length; i++, free++) {
 		if (writecol >= lastgap)
 			writecol += free->offset - lastgap;
 		if (writeend >= lastgap)
 			writeend += free->offset - lastgap;
 		lastgap = free->offset + free->length;
 	}
-	for (free = this->ecclayout->oobfree; free->length; ++free) {
+	free = this->ecclayout->oobfree;
+	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES && free->length; i++, free++) {
 		int free_end = free->offset + free->length;
 		if (free->offset < writeend && free_end > writecol) {
 			int st = max_t(int,free->offset,writecol);
@@ -2386,7 +2392,8 @@ int onenand_scan(struct mtd_info *mtd, int maxchips)
 	 * the out of band area
 	 */
 	this->ecclayout->oobavail = 0;
-	for (i = 0; this->ecclayout->oobfree[i].length; i++)
+	for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES &&
+	    this->ecclayout->oobfree[i].length; i++)
 		this->ecclayout->oobavail +=
 			this->ecclayout->oobfree[i].length;
 	mtd->oobavail = this->ecclayout->oobavail;