2021-05-24 11:38:10

by Liu Shixin

Subject: [PATCH -next] [media] media: Replaced simple_strtol() with kstrtoint()

It looks like that memcpy() is a superfluous operation in
parse_token()/parse_mtoken(). Simple these two functions and
use kstrtoint() instead of simple_strtol() to avoid data
overflow.

Signed-off-by: Liu Shixin <[email protected]>
---
drivers/media/usb/pvrusb2/pvrusb2-ctrl.c | 25 ++----------------------
1 file changed, 2 insertions(+), 23 deletions(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
index 9f71d8c2a3c6..8ae3ad80cccb 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
@@ -355,11 +355,8 @@ static int parse_token(const char *ptr,unsigned int len,
int *valptr,
const char * const *names, unsigned int namecnt)
{
- char buf[33];
unsigned int slen;
unsigned int idx;
- int negfl;
- char *p2;
*valptr = 0;
if (!names) namecnt = 0;
for (idx = 0; idx < namecnt; idx++) {
@@ -370,18 +367,7 @@ static int parse_token(const char *ptr,unsigned int len,
*valptr = idx;
return 0;
}
- negfl = 0;
- if ((*ptr == '-') || (*ptr == '+')) {
- negfl = (*ptr == '-');
- ptr++; len--;
- }
- if (len >= sizeof(buf)) return -EINVAL;
- memcpy(buf,ptr,len);
- buf[len] = 0;
- *valptr = simple_strtol(buf,&p2,0);
- if (negfl) *valptr = -(*valptr);
- if (*p2) return -EINVAL;
- return 1;
+ return kstrtoint(ptr, 0, valptr) ? -EINVAL : 1;
}


@@ -389,10 +375,8 @@ static int parse_mtoken(const char *ptr,unsigned int len,
int *valptr,
const char **names,int valid_bits)
{
- char buf[33];
unsigned int slen;
unsigned int idx;
- char *p2;
int msk;
*valptr = 0;
for (idx = 0, msk = 1; valid_bits; idx++, msk <<= 1) {
@@ -405,12 +389,7 @@ static int parse_mtoken(const char *ptr,unsigned int len,
*valptr = msk;
return 0;
}
- if (len >= sizeof(buf)) return -EINVAL;
- memcpy(buf,ptr,len);
- buf[len] = 0;
- *valptr = simple_strtol(buf,&p2,0);
- if (*p2) return -EINVAL;
- return 0;
+ return kstrtoint(ptr, 0, valptr);
}


--
2.18.0.huawei.25

2021-05-26 12:13:57

by Hans Verkuil

Subject: Re: [PATCH -next] [media] media: Replaced simple_strtol() with kstrtoint()

On 24/05/2021 14:08, Liu Shixin wrote:
> It looks like that memcpy() is a superfluous operation in
> parse_token()/parse_mtoken(). Simple these two functions and
> use kstrtoint() instead of simple_strtol() to avoid data
> overflow.

Always mention which driver you are changing in the subject line.
Just saying 'media:' suggests a subsystem-wide patch, but this is
just for a single driver.

Regards,

Hans

>
> Signed-off-by: Liu Shixin <[email protected]>
> ---
> drivers/media/usb/pvrusb2/pvrusb2-ctrl.c | 25 ++----------------------
> 1 file changed, 2 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> index 9f71d8c2a3c6..8ae3ad80cccb 100644
> --- a/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> +++ b/drivers/media/usb/pvrusb2/pvrusb2-ctrl.c
> @@ -355,11 +355,8 @@ static int parse_token(const char *ptr,unsigned int len,
> int *valptr,
> const char * const *names, unsigned int namecnt)
> {
> - char buf[33];
> unsigned int slen;
> unsigned int idx;
> - int negfl;
> - char *p2;
> *valptr = 0;
> if (!names) namecnt = 0;
> for (idx = 0; idx < namecnt; idx++) {
> @@ -370,18 +367,7 @@ static int parse_token(const char *ptr,unsigned int len,
> *valptr = idx;
> return 0;
> }
> - negfl = 0;
> - if ((*ptr == '-') || (*ptr == '+')) {
> - negfl = (*ptr == '-');
> - ptr++; len--;
> - }
> - if (len >= sizeof(buf)) return -EINVAL;
> - memcpy(buf,ptr,len);
> - buf[len] = 0;
> - *valptr = simple_strtol(buf,&p2,0);
> - if (negfl) *valptr = -(*valptr);
> - if (*p2) return -EINVAL;
> - return 1;
> + return kstrtoint(ptr, 0, valptr) ? -EINVAL : 1;
> }
>
>
> @@ -389,10 +375,8 @@ static int parse_mtoken(const char *ptr,unsigned int len,
> int *valptr,
> const char **names,int valid_bits)
> {
> - char buf[33];
> unsigned int slen;
> unsigned int idx;
> - char *p2;
> int msk;
> *valptr = 0;
> for (idx = 0, msk = 1; valid_bits; idx++, msk <<= 1) {
> @@ -405,12 +389,7 @@ static int parse_mtoken(const char *ptr,unsigned int len,
> *valptr = msk;
> return 0;
> }
> - if (len >= sizeof(buf)) return -EINVAL;
> - memcpy(buf,ptr,len);
> - buf[len] = 0;
> - *valptr = simple_strtol(buf,&p2,0);
> - if (*p2) return -EINVAL;
> - return 0;
> + return kstrtoint(ptr, 0, valptr);
> }
>
>
>