[PATCH 4/4] mtd: rfd_ftl: fix use-after-free

[Sean Young]

del_mtd_blktrans_dev() will kfree part, so this is a use-after-free. Use
container_of() to make it clearer what the cast is doing.

Signed-off-by: Sean Young <sean at mess.org>
---
 drivers/mtd/rfd_ftl.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/rfd_ftl.c b/drivers/mtd/rfd_ftl.c
index 7f5f6d247cae..af20a0a71108 100644
--- a/drivers/mtd/rfd_ftl.c
+++ b/drivers/mtd/rfd_ftl.c
@@ -239,7 +239,7 @@ static int scan_header(struct partition *part)
 
 static int rfd_ftl_readsect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
 {
-	struct partition *part = (struct partition*)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 	u_long addr;
 	size_t retlen;
 	int rc;
@@ -600,7 +600,7 @@ static int find_free_sector(const struct partition *part, const struct block *bl
 
 static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf, ulong *old_addr)
 {
-	struct partition *part = (struct partition*)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 	struct block *block;
 	u_long addr;
 	int i;
@@ -666,7 +666,7 @@ static int do_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf,
 
 static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *buf)
 {
-	struct partition *part = (struct partition*)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 	u_long old_addr;
 	int i;
 	int rc = 0;
@@ -708,7 +708,7 @@ static int rfd_ftl_writesect(struct mtd_blktrans_dev *dev, u_long sector, char *
 static int rfd_ftl_discardsect(struct mtd_blktrans_dev *dev,
 			       unsigned long sector, unsigned int nr_sects)
 {
-	struct partition *part = (struct partition *)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 	u_long addr;
 	int rc;
 
@@ -735,7 +735,7 @@ static int rfd_ftl_discardsect(struct mtd_blktrans_dev *dev,
 
 static int rfd_ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 {
-	struct partition *part = (struct partition*)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 
 	geo->heads = 1;
 	geo->sectors = SECTORS_PER_TRACK;
@@ -792,7 +792,7 @@ static void rfd_ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 
 static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
 {
-	struct partition *part = (struct partition*)dev;
+	struct partition *part = container_of(dev, struct partition, mbd);
 	int i;
 
 	for (i=0; i<part->total_blocks; i++) {
@@ -800,10 +800,10 @@ static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
 			part->mbd.mtd->name, i, part->blocks[i].erases);
 	}
 
-	del_mtd_blktrans_dev(dev);
 	vfree(part->sector_map);
 	kfree(part->header_cache);
 	kfree(part->blocks);
+	del_mtd_blktrans_dev(&part->mbd);
 }
 
 static struct mtd_blktrans_ops rfd_ftl_tr = {
-- 
2.31.1