mtd: always initialize 'stats' in struct mtd_oob_ops

As the 'stats' field in struct mtd_oob_ops is used in conditional
expressions, ensure it is always zero-initialized in all such structures
to prevent random stack garbage from being interpreted as a pointer.

Strictly speaking, this problem currently only needs to be fixed for
struct mtd_oob_ops structures subsequently passed to mtd_read_oob().
However, this commit goes a step further and makes all instances of
struct mtd_oob_ops in the tree zero-initialized, in hope of preventing
future problems, e.g. if struct mtd_req_stats gets extended with write
statistics at some point.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220629125737.14418-3-kernel@kempniu.pl

4 files changed, 8 insertions, 8 deletions

diff --git a/drivers/mtd/nand/onenand/onenand_base.c b/drivers/mtd/nand/onenand/onenand_base.c
index 958bac54b190..5810104420a2 100644
--- a/drivers/mtd/nand/onenand/onenand_base.c
+++ b/drivers/mtd/nand/onenand/onenand_base.c
@@ -2935,7 +2935,7 @@ static int do_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct onenand_chip *this = mtd->priv;
 	unsigned char *pbuf = buf;
 	int ret;
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 
 	/* Force buffer page aligned */
 	if (len < mtd->writesize) {
@@ -2977,7 +2977,7 @@ static int do_otp_lock(struct mtd_info *mtd, loff_t from, size_t len,
 		size_t *retlen, u_char *buf)
 {
 	struct onenand_chip *this = mtd->priv;
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 	int ret;
 
 	if (FLEXONENAND(this)) {
diff --git a/drivers/mtd/nand/onenand/onenand_bbt.c b/drivers/mtd/nand/onenand/onenand_bbt.c
index b17315f8e1d4..d7fe35bc45cb 100644
--- a/drivers/mtd/nand/onenand/onenand_bbt.c
+++ b/drivers/mtd/nand/onenand/onenand_bbt.c
@@ -61,7 +61,7 @@ static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr
 	int startblock;
 	loff_t from;
 	size_t readlen;
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 	int rgn;
 
 	printk(KERN_INFO "Scanning device for bad blocks\n");
diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c
index a3723da2e0a0..e4664fa6fd9e 100644
--- a/drivers/mtd/nand/raw/nand_bbt.c
+++ b/drivers/mtd/nand/raw/nand_bbt.c
@@ -313,7 +313,7 @@ static int scan_read_oob(struct nand_chip *this, uint8_t *buf, loff_t offs,
 			 size_t len)
 {
 	struct mtd_info *mtd = nand_to_mtd(this);
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 	int res, ret = 0;
 
 	ops.mode = MTD_OPS_PLACE_OOB;
@@ -354,7 +354,7 @@ static int scan_write_bbt(struct nand_chip *this, loff_t offs, size_t len,
 			  uint8_t *buf, uint8_t *oob)
 {
 	struct mtd_info *mtd = nand_to_mtd(this);
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 
 	ops.mode = MTD_OPS_PLACE_OOB;
 	ops.ooboffs = 0;
@@ -416,7 +416,7 @@ static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
 {
 	struct mtd_info *mtd = nand_to_mtd(this);
 
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 	int ret, page_offset;
 
 	ops.ooblen = mtd->oobsize;
@@ -756,7 +756,7 @@ static int write_bbt(struct nand_chip *this, uint8_t *buf,
 	uint8_t rcode = td->reserved_block_code;
 	size_t retlen, len = 0;
 	loff_t to;
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 
 	ops.ooblen = mtd->oobsize;
 	ops.ooboffs = 0;
diff --git a/drivers/mtd/nand/raw/sm_common.c b/drivers/mtd/nand/raw/sm_common.c
index b2b42dd1a2de..24f52a30fb13 100644
--- a/drivers/mtd/nand/raw/sm_common.c
+++ b/drivers/mtd/nand/raw/sm_common.c
@@ -99,7 +99,7 @@ static const struct mtd_ooblayout_ops oob_sm_small_ops = {
 static int sm_block_markbad(struct nand_chip *chip, loff_t ofs)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
-	struct mtd_oob_ops ops;
+	struct mtd_oob_ops ops = { };
 	struct sm_oob oob;
 	int ret;