1 files changed, 24 insertions, 8 deletions

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index c120c8761fcd..3e7e5b51eafd 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -363,9 +363,6 @@ static ssize_t dev_attribute_show(struct device *dev,
 	 * we still can use 'ubi->ubi_num'.
 	 */
 	ubi = container_of(dev, struct ubi_device, dev);
-	ubi = ubi_get_device(ubi->ubi_num);
-	if (!ubi)
-		return -ENODEV;
 
 	if (attr == &dev_eraseblock_size)
 		ret = sprintf(buf, "%d\n", ubi->leb_size);
@@ -394,7 +391,6 @@ static ssize_t dev_attribute_show(struct device *dev,
 	else
 		ret = -EINVAL;
 
-	ubi_put_device(ubi);
 	return ret;
 }
 
@@ -484,6 +480,7 @@ static int uif_init(struct ubi_device *ubi)
 			err = ubi_add_volume(ubi, ubi->volumes[i]);
 			if (err) {
 				ubi_err(ubi, "cannot add volume %d", i);
+				ubi->volumes[i] = NULL;
 				goto out_volumes;
 			}
 		}
@@ -677,6 +674,21 @@ static int io_init(struct ubi_device *ubi, int max_beb_per1024)
 						ubi->vid_hdr_aloffset;
 	}
 
+	/*
+	 * Memory allocation for VID header is ubi->vid_hdr_alsize
+	 * which is described in comments in io.c.
+	 * Make sure VID header shift + UBI_VID_HDR_SIZE not exceeds
+	 * ubi->vid_hdr_alsize, so that all vid header operations
+	 * won't access memory out of bounds.
+	 */
+	if ((ubi->vid_hdr_shift + UBI_VID_HDR_SIZE) > ubi->vid_hdr_alsize) {
+		ubi_err(ubi, "Invalid VID header offset %d, VID header shift(%d)"
+			" + VID header size(%zu) > VID header aligned size(%d).",
+			ubi->vid_hdr_offset, ubi->vid_hdr_shift,
+			UBI_VID_HDR_SIZE, ubi->vid_hdr_alsize);
+		return -EINVAL;
+	}
+
 	/* Similar for the data offset */
 	ubi->leb_start = ubi->vid_hdr_offset + UBI_VID_HDR_SIZE;
 	ubi->leb_start = ALIGN(ubi->leb_start, ubi->min_io_size);
@@ -866,6 +878,13 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 		return -EINVAL;
 	}
 
+	/* UBI cannot work on flashes with zero erasesize. */
+	if (!mtd->erasesize) {
+		pr_err("ubi: refuse attaching mtd%d - zero erasesize flash is not supported\n",
+			mtd->index);
+		return -EINVAL;
+	}
+
 	if (ubi_num == UBI_DEV_NUM_AUTO) {
 		/* Search for an empty slot in the @ubi_devices array */
 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
@@ -969,9 +988,6 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 			goto out_detach;
 	}
 
-	/* Make device "available" before it becomes accessible via sysfs */
-	ubi_devices[ubi_num] = ubi;
-
 	err = uif_init(ubi);
 	if (err)
 		goto out_detach;
@@ -1016,6 +1032,7 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 	wake_up_process(ubi->bgt_thread);
 	spin_unlock(&ubi->wl_lock);
 
+	ubi_devices[ubi_num] = ubi;
 	ubi_notify_all(ubi, UBI_VOLUME_ADDED, NULL);
 	return ubi_num;
 
@@ -1024,7 +1041,6 @@ out_debugfs:
 out_uif:
 	uif_close(ubi);
 out_detach:
-	ubi_devices[ubi_num] = NULL;
 	ubi_wl_close(ubi);
 	ubi_free_internal_volumes(ubi);
 	vfree(ubi->vtbl);