Subject: Re: [PATCH] isdn: hisax: l3dss1.c: Fix for possible null pointer dereference

From: Sergei Shtylyov <[email-masked]>
Date: Tue, 20 May 2014 01:26:52 +0400

On 05/20/2014 01:24 AM, Rickard Strandqvist wrote:

> There is otherwise a risk of a possible null pointer dereference.

> Was largely found by using a static code analysis program called cppcheck.

> Signed-off-by: Rickard Strandqvist <[email-masked]>
> ---
>   drivers/isdn/hisax/l3dss1.c |   11 ++++++-----
>   1 file changed, 6 insertions(+), 5 deletions(-)

> diff --git a/drivers/isdn/hisax/l3dss1.c b/drivers/isdn/hisax/l3dss1.c
> index cda7006..9ea7377 100644
> --- a/drivers/isdn/hisax/l3dss1.c
> +++ b/drivers/isdn/hisax/l3dss1.c
> @@ -2203,13 +2203,14 @@ static int l3dss1_cmd_global(struct PStack *st, isdn_ctrl *ic)
>   			memcpy(p, ic->parm.dss1_io.data, ic->parm.dss1_io.datalen); /* copy data */
>   			l = (p - temp) + ic->parm.dss1_io.datalen; /* total length */
>
> -			if (ic->parm.dss1_io.timeout > 0)
> -				if (!(pc = dss1_new_l3_process(st, -1)))
> -				{ free_invoke_id(st, id);
> +			if (ic->parm.dss1_io.timeout > 0) {
> +				if (!(pc = dss1_new_l3_process(st, -1))) {

    Assignments shouldn't be put into *if* statement. If you did run the patch 
thru scripts/checkpatch.pl, it would have told you.

> +					free_invoke_id(st, id);
>   					return (-2);

    Parens not needed. Could as well fix it here...

>   				}
> -			pc->prot.dss1.ll_id = ic->parm.dss1_io.ll_id; /* remember id */
> -			pc->prot.dss1.proc = ic->parm.dss1_io.proc; /* and procedure */
> +				pc->prot.dss1.ll_id = ic->parm.dss1_io.ll_id; /* remember id */
> +				pc->prot.dss1.proc = ic->parm.dss1_io.proc; /* and procedure */
> +			}

WBR, Sergei