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* [bug report] of: overlay: rework overlay apply and remove kfree()s
@ 2022-04-27  7:44 Dan Carpenter
  2022-04-28 18:18 ` Frank Rowand
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2022-04-27  7:44 UTC (permalink / raw)
  To: frank.rowand; +Cc: devicetree

Hello Frank Rowand,

The patch 067c098766c6: "of: overlay: rework overlay apply and remove
kfree()s" from Apr 20, 2022, leads to the following Smatch static
checker warning:

	drivers/of/overlay.c:180 overlay_notify()
	error: buffer overflow 'of_overlay_action_name' 4 <= 4

drivers/of/overlay.c
   155  static char *of_overlay_action_name[] = {

We need to add a "init" string at the start of this array.

   156          "pre-apply",
   157          "post-apply",
   158          "pre-remove",
   159          "post-remove",
   160  };
   161  
    162 static int overlay_notify(struct overlay_changeset *ovcs,
    163                 enum of_overlay_notify_action action)
    164 {
    165         struct of_overlay_notify_data nd;
    166         int i, ret;
    167 
    168         ovcs->notify_state = action;
    169 
    170         for (i = 0; i < ovcs->count; i++) {
    171                 struct fragment *fragment = &ovcs->fragments[i];
    172 
    173                 nd.target = fragment->target;
    174                 nd.overlay = fragment->overlay;
    175 
    176                 ret = blocking_notifier_call_chain(&overlay_notify_chain,
    177                                                    action, &nd);
    178                 if (notifier_to_errno(ret)) {
    179                         ret = notifier_to_errno(ret);
--> 180                         pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
    181                                of_overlay_action_name[action], ret, nd.target);
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
These are all shifted and so post remove is out of bounds.

    182                         return ret;
    183                 }
    184         }
    185 
    186         return 0;
    187 }

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [bug report] of: overlay: rework overlay apply and remove kfree()s
  2022-04-27  7:44 [bug report] of: overlay: rework overlay apply and remove kfree()s Dan Carpenter
@ 2022-04-28 18:18 ` Frank Rowand
  0 siblings, 0 replies; 2+ messages in thread
From: Frank Rowand @ 2022-04-28 18:18 UTC (permalink / raw)
  To: Dan Carpenter, frank.rowand; +Cc: devicetree

On 4/27/22 02:44, Dan Carpenter wrote:
> Hello Frank Rowand,
> 
> The patch 067c098766c6: "of: overlay: rework overlay apply and remove
> kfree()s" from Apr 20, 2022, leads to the following Smatch static
> checker warning:
> 
> 	drivers/of/overlay.c:180 overlay_notify()
> 	error: buffer overflow 'of_overlay_action_name' 4 <= 4
> 
> drivers/of/overlay.c
>    155  static char *of_overlay_action_name[] = {
> 
> We need to add a "init" string at the start of this array.
> 
>    156          "pre-apply",
>    157          "post-apply",
>    158          "pre-remove",
>    159          "post-remove",
>    160  };
>    161  
>     162 static int overlay_notify(struct overlay_changeset *ovcs,
>     163                 enum of_overlay_notify_action action)
>     164 {
>     165         struct of_overlay_notify_data nd;
>     166         int i, ret;
>     167 
>     168         ovcs->notify_state = action;
>     169 
>     170         for (i = 0; i < ovcs->count; i++) {
>     171                 struct fragment *fragment = &ovcs->fragments[i];
>     172 
>     173                 nd.target = fragment->target;
>     174                 nd.overlay = fragment->overlay;
>     175 
>     176                 ret = blocking_notifier_call_chain(&overlay_notify_chain,
>     177                                                    action, &nd);
>     178                 if (notifier_to_errno(ret)) {
>     179                         ret = notifier_to_errno(ret);
> --> 180                         pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
>     181                                of_overlay_action_name[action], ret, nd.target);
>                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> These are all shifted and so post remove is out of bounds.
> 
>     182                         return ret;
>     183                 }
>     184         }
>     185 
>     186         return 0;
>     187 }
> 
> regards,
> dan carpenter

Thanks for the bug report!

I'm working on a patch to fix (easy) and a patch to add some unittest tests
to verify the overlay notifiers (a little bit more time consuming).

-Frank

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2022-04-27  7:44 [bug report] of: overlay: rework overlay apply and remove kfree()s Dan Carpenter
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