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[PATCH] iio: multiplexer: add NULL check on devm_kzalloc() and devm_kmemdup() return values

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  [PATCH] iio: multiplexer: add NULL check on devm_kzalloc() and  devm_kmemdup() return values "Gustavo A. R. Silva" <garsilva@embeddedor.com> - 2017-07-07 07:00 +0200
    Re: [PATCH] iio: multiplexer: add NULL check on devm_kzalloc() and  devm_kmemdup() return values Jonathan Cameron <jic23@kernel.org> - 2017-07-09 19:20 +0200
      Re: [PATCH] iio: multiplexer: add NULL check on devm_kzalloc() and  devm_kmemdup() return values "Gustavo A. R. Silva" <garsilva@embeddedor.com> - 2017-07-10 21:50 +0200

#1682909 — [PATCH] iio: multiplexer: add NULL check on devm_kzalloc() and devm_kmemdup() return values

Check return values from call to devm_kzalloc() and devm_kmemup()
in order to prevent a NULL pointer dereference.

This issue was detected using Coccinelle and the following semantic patch:

@@
expression x;
identifier fld;
@@

* x = devm_kzalloc(...);
   ... when != x == NULL
   x->fld

Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
Changes in v2:
 Add NULL check on devm_kmemup() return value.

 drivers/iio/multiplexer/iio-mux.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/iio/multiplexer/iio-mux.c b/drivers/iio/multiplexer/iio-mux.c
index 37ba007..74831fc 100644
--- a/drivers/iio/multiplexer/iio-mux.c
+++ b/drivers/iio/multiplexer/iio-mux.c
@@ -285,6 +285,9 @@ static int mux_configure_channel(struct device *dev, struct mux *mux,
 	child->ext_info_cache = devm_kzalloc(dev,
 					     sizeof(*child->ext_info_cache) *
 					     num_ext_info, GFP_KERNEL);
+	if (!child->ext_info_cache)
+		return -ENOMEM;
+
 	for (i = 0; i < num_ext_info; ++i) {
 		child->ext_info_cache[i].size = -1;
 
@@ -309,6 +312,9 @@ static int mux_configure_channel(struct device *dev, struct mux *mux,
 
 		child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1,
 							     GFP_KERNEL);
+		if (!child->ext_info_cache[i].data)
+			return -ENOMEM;
+
 		child->ext_info_cache[i].data[ret] = 0;
 		child->ext_info_cache[i].size = ret;
 	}
-- 
2.5.0

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#1683768

On Fri, 7 Jul 2017 11:26:35 +0200
Peter Rosin <peda@axentia.se> wrote:

> On 2017-07-07 06:57, Peter Rosin wrote:
> > On 2017-07-07 06:53, Gustavo A. R. Silva wrote:  
> >> Check return values from call to devm_kzalloc() and devm_kmemup()  
> > 
> > If someone cares enough: s/devm_kmemup/evm_kmemdup/  
> 
> Strange, there seems to be some inherent shortage of 'd' characters...
> 
> Cheers,
> pea :-)
> 
> >   
> >> in order to prevent a NULL pointer dereference.
> >>
> >> This issue was detected using Coccinelle and the following semantic patch:
> >>
> >> @@
> >> expression x;
> >> identifier fld;
> >> @@
> >>
> >> * x = devm_kzalloc(...);
> >>    ... when != x == NULL
> >>    x->fld
> >>
> >> Cc: Peter Rosin <peda@axentia.se>
> >> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>  
> > 
> > Either way,
> > 
> > Reviewed-by: Peter Rosin <peda@axentia.se>
> > 
> > Thanks!
> > 
The relevant patch adding the file in questions hasn't yet worked it's
way back to the iio tree so I can't apply this until it does.

That is likely to be a few weeks away yet.  Please give me a poke if
I seem to have forgotten it!

Jonathan  
> 
> --
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#1684608

Hi Jonathan,

Quoting Jonathan Cameron <jic23@kernel.org>:

> On Fri, 7 Jul 2017 11:26:35 +0200
> Peter Rosin <peda@axentia.se> wrote:
>
>> On 2017-07-07 06:57, Peter Rosin wrote:
>> > On 2017-07-07 06:53, Gustavo A. R. Silva wrote:
>> >> Check return values from call to devm_kzalloc() and devm_kmemup()
>> >
>> > If someone cares enough: s/devm_kmemup/evm_kmemdup/
>>
>> Strange, there seems to be some inherent shortage of 'd' characters...
>>
>> Cheers,
>> pea :-)
>>
>> >
>> >> in order to prevent a NULL pointer dereference.
>> >>
>> >> This issue was detected using Coccinelle and the following  
>> semantic patch:
>> >>
>> >> @@
>> >> expression x;
>> >> identifier fld;
>> >> @@
>> >>
>> >> * x = devm_kzalloc(...);
>> >>    ... when != x == NULL
>> >>    x->fld
>> >>
>> >> Cc: Peter Rosin <peda@axentia.se>
>> >> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>> >
>> > Either way,
>> >
>> > Reviewed-by: Peter Rosin <peda@axentia.se>
>> >
>> > Thanks!
>> >
> The relevant patch adding the file in questions hasn't yet worked it's
> way back to the iio tree so I can't apply this until it does.
>
> That is likely to be a few weeks away yet.  Please give me a poke if
> I seem to have forgotten it!
>

OK, I will do that. :)

Thanks!
--
Gustavo A. R. Silva

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