From: Miquel Raynal Date: Sun, 18 Nov 2018 20:11:47 +0000 (+0100) Subject: mtd: fix Coverity integer handling issue X-Git-Tag: v2019.07-rc1~24^2~6 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=3f3aef4b9dc88278f31567fe6f26095fd9477b1a;p=oweals%2Fu-boot.git mtd: fix Coverity integer handling issue A Coverity robot reported an integer handling issue (OVERFLOW_BEFORE_WIDEN) in the potentially overflowing expression: (mtd_div_by_ws(mtd->size, mtd) - mtd_div_by_ws(offs, mtd)) * mtd_oobavail(mtd, ops) While such overflow will certainly never happen due to the numbers handled, it is cleaner to fix this operation anyway. The problem is that all the maths include 32-bit quantities, while the result is stored in an explicit 64-bit value. As maxooblen will just be compared with a size_t, let's change the type of the variable to a size_t. This will not fix anything but will clarify a bit the situation. Then, do an explicit cast to fix Coverity warning. Addresses-Coverity-ID: 184180 ("Integer handling issues") Signed-off-by: Miquel Raynal --- diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index cb7ca38d07..89ac8229f5 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1051,13 +1051,13 @@ static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs, return -EINVAL; if (ops->ooblen) { - u64 maxooblen; + size_t maxooblen; if (ops->ooboffs >= mtd_oobavail(mtd, ops)) return -EINVAL; - maxooblen = ((mtd_div_by_ws(mtd->size, mtd) - - mtd_div_by_ws(offs, mtd)) * + maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) - + mtd_div_by_ws(offs, mtd)) * mtd_oobavail(mtd, ops)) - ops->ooboffs; if (ops->ooblen > maxooblen) return -EINVAL;