From 7a84477c4acebf6299b6a8bd6a1d5894eb838ffa Mon Sep 17 00:00:00 2001 From: Will Newton Date: Fri, 30 Mar 2012 11:51:02 +0100 Subject: [PATCH] mtd: fix oops in dataflash driver I'm seeing an oops in mtd_dataflash.c with Linux 3.3. What appears to be happening is that otp_select_filemode calls mtd_read_fact_prot_reg with -1 for offset and length and a NULL buffer to test if OTP operations are supported. This finds its way down to otp_read in mtd_dataflash.c and causes an oops when memcpying the returned data into the NULL buf. None of the checks in otp_read catches the negative length and offset. Changing the length of the dummy read to 0 prevents the oops. Cc: stable@kernel.org [3.3+] Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/mtdchar.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index 58fc65f5c817..f2f482bec573 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -376,7 +376,7 @@ static int otp_select_filemode(struct mtd_file_info *mfi, int mode) * Make a fake call to mtd_read_fact_prot_reg() to check if OTP * operations are supported. */ - if (mtd_read_fact_prot_reg(mtd, -1, -1, &retlen, NULL) == -EOPNOTSUPP) + if (mtd_read_fact_prot_reg(mtd, -1, 0, &retlen, NULL) == -EOPNOTSUPP) return -EOPNOTSUPP; switch (mode) { -- 2.39.5