Re: [2.6 patch] drivers/net/wireless/libertas/fw.c: fix use-before-check

Re: [2.6 patch] drivers/net/wireless/libertas/fw.c: fix use-before-check

[John W. Linville]

This should be sent to linux-wireless (and CC'ed to me) as well...

On Sat, May 19, 2007 at 01:06:49AM +0800, Eugene Teo wrote:
> NULL checks should be performed before the dereference.
> 
> Spotted by the Coverity checker.
> 
> Signed-off-by: Eugene Teo <eteo@redhat.com>
> 
> diff --git a/drivers/net/wireless/libertas/fw.c b/drivers/net/wireless/libertas/fw.c
> index 441123c..5c63c9b 100644
> --- a/drivers/net/wireless/libertas/fw.c
> +++ b/drivers/net/wireless/libertas/fw.c
> @@ -333,18 +333,22 @@ static void command_timer_fn(unsigned long data)
>         unsigned long flags;
> 
>         ptempnode = adapter->cur_cmd;
> +       if (ptempnode == NULL) {
> +               lbs_pr_debug(1, "PTempnode Empty\n");
> +               return;
> +       }
> +
>         cmd = (struct cmd_ds_command *)ptempnode->bufvirtualaddr;
> +       if (!cmd) {
> +               lbs_pr_debug(1, "cmd is NULL\n");
> +               return;
> +       }
> 
>         lbs_pr_info("command_timer_fn fired (%x)\n", cmd->command);
> 
>         if (!adapter->fw_ready)
>                 return;
> 
> -       if (ptempnode == NULL) {
> -               lbs_pr_debug(1, "PTempnode Empty\n");
> -               return;
> -       }
> -
>         spin_lock_irqsave(&adapter->driver_lock, flags);
>         adapter->cur_cmd = NULL;
>         spin_unlock_irqrestore(&adapter->driver_lock, flags);
> -
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-- 
John W. Linville
linville@tuxdriver.com

Re: [2.6 patch] drivers/net/wireless/libertas/fw.c: fix use-before-check

[John W. Linville]

On Sat, May 19, 2007 at 01:06:49AM +0800, Eugene Teo wrote:
> NULL checks should be performed before the dereference.
> 
> Spotted by the Coverity checker.
> 
> Signed-off-by: Eugene Teo <eteo@redhat.com>

This does not apply against 2.6.22-rc1.  Please rediff and repost.

Thanks,

John
-- 
John W. Linville
linville@tuxdriver.com

Re: [2.6 patch] drivers/net/wireless/libertas/fw.c: fix use-before-check

[Eugene Teo]

Hi John,

John W. Linville wrote:
> On Sat, May 19, 2007 at 01:06:49AM +0800, Eugene Teo wrote:
>> NULL checks should be performed before the dereference.
>>
>> Spotted by the Coverity checker.
>>
>> Signed-off-by: Eugene Teo <eteo@redhat.com>
> 
> This does not apply against 2.6.22-rc1.  Please rediff and repost.

Ok. Here's a rediff against 2.6.22-rc1. Thanks.
--

NULL checks should be performed before the dereference.

Spotted by the Coverity checker.

Signed-off-by: Eugene Teo <eteo@redhat.com>

diff -uprN -X 2.6.22-rc1/Documentation/dontdiff
2.6.22-rc1.orig/drivers/net/wireless/libertas/fw.c 2.6.22-rc1/drivers/net/wireless/libertas/fw.c
--- 2.6.22-rc1.orig/drivers/net/wireless/libertas/fw.c  2007-05-19 10:48:02.000000000 +0800
+++ 2.6.22-rc1/drivers/net/wireless/libertas/fw.c       2007-05-19 11:01:26.000000000 +0800
@@ -333,18 +333,22 @@ static void command_timer_fn(unsigned lo
        unsigned long flags;

        ptempnode = adapter->cur_cmd;
+       if (ptempnode == NULL) {
+               lbs_pr_debug(1, "PTempnode Empty\n");
+               return;
+       }
+
        cmd = (struct cmd_ds_command *)ptempnode->bufvirtualaddr;
+       if (!cmd) {
+               lbs_pr_debug(1, "cmd is NULL\n");
+               return;
+       }

        lbs_pr_info("command_timer_fn fired (%x)\n", cmd->command);

        if (!adapter->fw_ready)
                return;

-       if (ptempnode == NULL) {
-               lbs_pr_debug(1, "PTempnode Empty\n");
-               return;
-       }
-
        spin_lock_irqsave(&adapter->driver_lock, flags);
        adapter->cur_cmd = NULL;
        spin_unlock_irqrestore(&adapter->driver_lock, flags);