diff mbox

[v2] av7110: check for negative array offset

Message ID 20110107134651.GH1717@bicker (mailing list archive)
State Superseded, archived
Headers

Commit Message

Dan Carpenter Jan. 7, 2011, 1:46 p.m. UTC 
  info->num comes from the user.  It's type int.  If the user passes
in a negative value that would cause memory corruption.

Signed-off-by: Dan Carpenter <error27@gmail.com>
---
V2: change the check instead of making num and unsigned int

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Comments

Oliver Endriss Jan. 7, 2011, 7:01 p.m. UTC | #1 
Hi,

On Friday 07 January 2011 14:46:51 Dan Carpenter wrote:
> info->num comes from the user.  It's type int.  If the user passes
> in a negative value that would cause memory corruption.
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> ---
> V2: change the check instead of making num and unsigned int
> 
> diff --git a/drivers/media/dvb/ttpci/av7110_ca.c b/drivers/media/dvb/ttpci/av7110_ca.c
> index 122c728..923a8e2 100644
> --- a/drivers/media/dvb/ttpci/av7110_ca.c
> +++ b/drivers/media/dvb/ttpci/av7110_ca.c
> @@ -277,7 +277,7 @@ static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
>  	{
>  		ca_slot_info_t *info=(ca_slot_info_t *)parg;
>  
> -		if (info->num > 1)
> +		if ((unsigned)info->num > 1)
>  			return -EINVAL;
>  		av7110->ci_slot[info->num].num = info->num;
>  		av7110->ci_slot[info->num].type = FW_CI_LL_SUPPORT(av7110->arm_app) ?
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Imho casts are a last resort and should be avoided, if there is a better
way to do it. The obvious fix is

  if (info->num < 0 || info->num > 1)
        return -EINVAL;
   
CU
Oliver
diff mbox

Patch

diff --git a/drivers/media/dvb/ttpci/av7110_ca.c b/drivers/media/dvb/ttpci/av7110_ca.c
index 122c728..923a8e2 100644
--- a/drivers/media/dvb/ttpci/av7110_ca.c
+++ b/drivers/media/dvb/ttpci/av7110_ca.c
@@ -277,7 +277,7 @@  static int dvb_ca_ioctl(struct file *file, unsigned int cmd, void *parg)
 	{
 		ca_slot_info_t *info=(ca_slot_info_t *)parg;
 
-		if (info->num > 1)
+		if ((unsigned)info->num > 1)
 			return -EINVAL;
 		av7110->ci_slot[info->num].num = info->num;
 		av7110->ci_slot[info->num].type = FW_CI_LL_SUPPORT(av7110->arm_app) ?