[PATCH] onenand: test before subtraction on unsigned
Roel Kluin
roel.kluin at gmail.com
Wed Mar 4 10:18:45 EST 2009
Adrian Hunter wrote:
> Roel Kluin wrote:
>> len is unsigned so will wrap around when sizeof(struct otp_info) is
>> greater than
>> len.
>> - len -= sizeof(struct otp_info);
>> - if (len <= 0) {
>> + if (len <= sizeof(struct otp_info)) {
>> + len = 0;
>
> len is not used anymore, so no need to set it to zero.
Right, updated patch below.
>> ret = -ENOSPC;
>> break;
>> }
>> + len -= sizeof(struct otp_info);
> So is there somewhere that is passing a buffer too small for all the
> opt_info?
I don't know, I found it by code inspection.
------------------------------>8-------------8<---------------------------------
len is unsigned so will wrap around when sizeof(struct otp_info) is greater than
len.
Signed-off-by: Roel Kluin <roel.kluin at gmail.com>
---
diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 529af27..1219a18 100644
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -2296,11 +2296,11 @@ static int onenand_otp_walk(struct mtd_info *mtd, loff_t from, size_t len,
if (!action) { /* OTP Info functions */
struct otp_info *otpinfo;
- len -= sizeof(struct otp_info);
- if (len <= 0) {
+ if (len <= sizeof(struct otp_info)) {
ret = -ENOSPC;
break;
}
+ len -= sizeof(struct otp_info);
otpinfo = (struct otp_info *) buf;
otpinfo->start = from;
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