* [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
@ 2017-09-10 10:26 Geert Uytterhoeven
2017-09-19 17:27 ` Rob Herring
2017-09-19 18:27 ` Frank Rowand
0 siblings, 2 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2017-09-10 10:26 UTC (permalink / raw)
To: Pantelis Antoniou, Rob Herring, Frank Rowand, Grant Likely
Cc: Arnd Bergmann, devicetree, linux-kernel, Geert Uytterhoeven
With gcc 4.1.2:
drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
Indeed, if ov->count == 0, both variables are uninitialized, which may
lead to a crash when dereferencing ovinfo later.
Currently this is a false positive, as the sole creator of of_overlay
structures (of_build_overlay_info(), introduced in commit
7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
this.
To prevent future issues, add a check for a zero ov->count to
dup_and_fixup_symbol_prop(). Note that this does not get rid of the
actual compiler warning.
Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/of/overlay.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
int overlay_name_len;
int target_path_len;
- if (!prop->value)
+ if (!ov->count || !prop->value)
return NULL;
symbol_path = prop->value;
--
2.7.4
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
2017-09-10 10:26 [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop() Geert Uytterhoeven
@ 2017-09-19 17:27 ` Rob Herring
2017-09-19 18:27 ` Frank Rowand
1 sibling, 0 replies; 6+ messages in thread
From: Rob Herring @ 2017-09-19 17:27 UTC (permalink / raw)
To: Geert Uytterhoeven
Cc: Pantelis Antoniou, Frank Rowand, Grant Likely, Arnd Bergmann,
devicetree, linux-kernel
On Sun, Sep 10, 2017 at 12:26:04PM +0200, Geert Uytterhoeven wrote:
> With gcc 4.1.2:
>
> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
>
> Indeed, if ov->count == 0, both variables are uninitialized, which may
> lead to a crash when dereferencing ovinfo later.
>
> Currently this is a false positive, as the sole creator of of_overlay
> structures (of_build_overlay_info(), introduced in commit
> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
> this.
>
> To prevent future issues, add a check for a zero ov->count to
> dup_and_fixup_symbol_prop(). Note that this does not get rid of the
> actual compiler warning.
>
> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> drivers/of/overlay.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied.
Rob
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
2017-09-10 10:26 [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop() Geert Uytterhoeven
2017-09-19 17:27 ` Rob Herring
@ 2017-09-19 18:27 ` Frank Rowand
2017-09-19 19:15 ` Rob Herring
2017-09-19 20:16 ` Geert Uytterhoeven
1 sibling, 2 replies; 6+ messages in thread
From: Frank Rowand @ 2017-09-19 18:27 UTC (permalink / raw)
To: Geert Uytterhoeven, Pantelis Antoniou, Rob Herring, Grant Likely
Cc: Arnd Bergmann, devicetree, linux-kernel
On 09/10/17 03:26, Geert Uytterhoeven wrote:
> With gcc 4.1.2:
>
> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
>
> Indeed, if ov->count == 0, both variables are uninitialized, which may
> lead to a crash when dereferencing ovinfo later.
>
> Currently this is a false positive, as the sole creator of of_overlay
> structures (of_build_overlay_info(), introduced in commit
> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
> this.
>
> To prevent future issues, add a check for a zero ov->count to
> dup_and_fixup_symbol_prop(). Note that this does not get rid of the
> actual compiler warning.
>
> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> drivers/of/overlay.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
> int overlay_name_len;
> int target_path_len;
>
> - if (!prop->value)
> + if (!ov->count || !prop->value)
> return NULL;
> symbol_path = prop->value;
>
>
I did not see this patch due to an overzealous spam filter. I noticed it
when Rob replied with his applied email.
This check is not needed to prevent accessing overlay_name_len and ovinfo
when ov->count == 0. That is already prevented by:
if (k >= ov->count)
goto err_free;
because k will be zero and ov->count will be zero.
-Frank
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
2017-09-19 18:27 ` Frank Rowand
@ 2017-09-19 19:15 ` Rob Herring
2017-09-19 20:16 ` Geert Uytterhoeven
1 sibling, 0 replies; 6+ messages in thread
From: Rob Herring @ 2017-09-19 19:15 UTC (permalink / raw)
To: Frank Rowand
Cc: Geert Uytterhoeven, Pantelis Antoniou, Grant Likely,
Arnd Bergmann, devicetree, linux-kernel
On Tue, Sep 19, 2017 at 1:27 PM, Frank Rowand <frowand.list@gmail.com> wrote:
> On 09/10/17 03:26, Geert Uytterhoeven wrote:
>> With gcc 4.1.2:
>>
>> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
>> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
>> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
>>
>> Indeed, if ov->count == 0, both variables are uninitialized, which may
>> lead to a crash when dereferencing ovinfo later.
>>
>> Currently this is a false positive, as the sole creator of of_overlay
>> structures (of_build_overlay_info(), introduced in commit
>> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
>> this.
>>
>> To prevent future issues, add a check for a zero ov->count to
>> dup_and_fixup_symbol_prop(). Note that this does not get rid of the
>> actual compiler warning.
>>
>> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>> ---
>> drivers/of/overlay.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
>> --- a/drivers/of/overlay.c
>> +++ b/drivers/of/overlay.c
>> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
>> int overlay_name_len;
>> int target_path_len;
>>
>> - if (!prop->value)
>> + if (!ov->count || !prop->value)
>> return NULL;
>> symbol_path = prop->value;
>>
>>
>
> I did not see this patch due to an overzealous spam filter. I noticed it
> when Rob replied with his applied email.
>
> This check is not needed to prevent accessing overlay_name_len and ovinfo
> when ov->count == 0. That is already prevented by:
>
> if (k >= ov->count)
> goto err_free;
>
> because k will be zero and ov->count will be zero.
Okay, will drop.
Rob
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
2017-09-19 18:27 ` Frank Rowand
2017-09-19 19:15 ` Rob Herring
@ 2017-09-19 20:16 ` Geert Uytterhoeven
2017-09-20 0:20 ` Frank Rowand
1 sibling, 1 reply; 6+ messages in thread
From: Geert Uytterhoeven @ 2017-09-19 20:16 UTC (permalink / raw)
To: Frank Rowand
Cc: Pantelis Antoniou, Rob Herring, Grant Likely, Arnd Bergmann,
devicetree, linux-kernel
Hi Frank,
On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowand <frowand.list@gmail.com> wrote:
> On 09/10/17 03:26, Geert Uytterhoeven wrote:
>> With gcc 4.1.2:
>>
>> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
>> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
>> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
>>
>> Indeed, if ov->count == 0, both variables are uninitialized, which may
>> lead to a crash when dereferencing ovinfo later.
>>
>> Currently this is a false positive, as the sole creator of of_overlay
>> structures (of_build_overlay_info(), introduced in commit
>> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
>> this.
>>
>> To prevent future issues, add a check for a zero ov->count to
>> dup_and_fixup_symbol_prop(). Note that this does not get rid of the
>> actual compiler warning.
>>
>> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>> ---
>> drivers/of/overlay.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
>> --- a/drivers/of/overlay.c
>> +++ b/drivers/of/overlay.c
>> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
>> int overlay_name_len;
>> int target_path_len;
>>
>> - if (!prop->value)
>> + if (!ov->count || !prop->value)
>> return NULL;
>> symbol_path = prop->value;
>>
>
> I did not see this patch due to an overzealous spam filter. I noticed it
> when Rob replied with his applied email.
>
> This check is not needed to prevent accessing overlay_name_len and ovinfo
> when ov->count == 0. That is already prevented by:
>
> if (k >= ov->count)
> goto err_free;
>
> because k will be zero and ov->count will be zero.
Thank you, I stand corrected.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
2017-09-19 20:16 ` Geert Uytterhoeven
@ 2017-09-20 0:20 ` Frank Rowand
0 siblings, 0 replies; 6+ messages in thread
From: Frank Rowand @ 2017-09-20 0:20 UTC (permalink / raw)
To: Geert Uytterhoeven
Cc: Pantelis Antoniou, Rob Herring, Grant Likely, Arnd Bergmann,
devicetree, linux-kernel
On 09/19/17 13:16, Geert Uytterhoeven wrote:
> Hi Frank,
>
> On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowand <frowand.list@gmail.com> wrote:
>> On 09/10/17 03:26, Geert Uytterhoeven wrote:
>>> With gcc 4.1.2:
>>>
>>> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’:
>>> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used uninitialized in this function
>>> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in this function
>>>
>>> Indeed, if ov->count == 0, both variables are uninitialized, which may
>>> lead to a crash when dereferencing ovinfo later.
>>>
>>> Currently this is a false positive, as the sole creator of of_overlay
>>> structures (of_build_overlay_info(), introduced in commit
>>> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for
>>> this.
>>>
>>> To prevent future issues, add a check for a zero ov->count to
>>> dup_and_fixup_symbol_prop(). Note that this does not get rid of the
>>> actual compiler warning.
>>>
>>> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
>>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>>> ---
>>> drivers/of/overlay.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>>> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
>>> --- a/drivers/of/overlay.c
>>> +++ b/drivers/of/overlay.c
>>> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
>>> int overlay_name_len;
>>> int target_path_len;
>>>
>>> - if (!prop->value)
>>> + if (!ov->count || !prop->value)
>>> return NULL;
>>> symbol_path = prop->value;
>>>
>>
>> I did not see this patch due to an overzealous spam filter. I noticed it
>> when Rob replied with his applied email.
>>
>> This check is not needed to prevent accessing overlay_name_len and ovinfo
>> when ov->count == 0. That is already prevented by:
>>
>> if (k >= ov->count)
>> goto err_free;
>>
>> because k will be zero and ov->count will be zero.
>
> Thank you, I stand corrected.
No problem. It's not real obvious, you really need to stop and
ponder.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2017-09-20 0:21 UTC | newest]
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2017-09-10 10:26 [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop() Geert Uytterhoeven
2017-09-19 17:27 ` Rob Herring
2017-09-19 18:27 ` Frank Rowand
2017-09-19 19:15 ` Rob Herring
2017-09-19 20:16 ` Geert Uytterhoeven
2017-09-20 0:20 ` Frank Rowand
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