[PATCH v2] ipmi: Fix NULL pointer dereference in ssif_probe

[PATCH v2] ipmi: Fix NULL pointer dereference in ssif_probe

[Gustavo A. R. Silva]

There is a potential execution path in which function ssif_info_find()
returns NULL, hence there is a NULL pointer dereference when accessing
pointer *addr_info*

Fix this by null checking *addr_info* before dereferencing it.

Addresses-Coverity-ID: 1473145 ("Explicit null dereferenced")
Fixes: e333054a91d1 ("ipmi: Fix I2C client removal in the SSIF driver")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Changes in v2:
 - Fix typo in commit log.

 drivers/char/ipmi/ipmi_ssif.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 2ff3679..764d305 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1641,7 +1641,9 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
  out:
 	if (rv) {
-		addr_info->client = NULL;
+		if (addr_info)
+			addr_info->client = NULL;
+
 		dev_err(&client->dev, "Unable to start IPMI SSIF: %d\n", rv);
 		kfree(ssif_info);
 	}
-- 
2.7.4

Re: [PATCH v2] ipmi: Fix NULL pointer dereference in ssif_probe

[Corey Minyard]

On 08/31/2018 10:00 AM, Gustavo A. R. Silva wrote:
> There is a potential execution path in which function ssif_info_find()
> returns NULL, hence there is a NULL pointer dereference when accessing
> pointer *addr_info*
>
> Fix this by null checking *addr_info* before dereferencing it.

Thanks for catching this quickly, before it went out.  It's merged into 
my next tree.

-corey

> Addresses-Coverity-ID: 1473145 ("Explicit null dereferenced")
> Fixes: e333054a91d1 ("ipmi: Fix I2C client removal in the SSIF driver")
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> Changes in v2:
>   - Fix typo in commit log.
>
>   drivers/char/ipmi/ipmi_ssif.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index 2ff3679..764d305 100644
> --- a/drivers/char/ipmi/ipmi_ssif.c
> +++ b/drivers/char/ipmi/ipmi_ssif.c
> @@ -1641,7 +1641,9 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id)
>   
>    out:
>   	if (rv) {
> -		addr_info->client = NULL;
> +		if (addr_info)
> +			addr_info->client = NULL;
> +
>   		dev_err(&client->dev, "Unable to start IPMI SSIF: %d\n", rv);
>   		kfree(ssif_info);
>   	}

Re: [PATCH v2] ipmi: Fix NULL pointer dereference in ssif_probe

[Gustavo A. R. Silva]

On 8/31/18 2:15 PM, Corey Minyard wrote:
> On 08/31/2018 10:00 AM, Gustavo A. R. Silva wrote:
>> There is a potential execution path in which function ssif_info_find()
>> returns NULL, hence there is a NULL pointer dereference when accessing
>> pointer *addr_info*
>>
>> Fix this by null checking *addr_info* before dereferencing it.
> 
> Thanks for catching this quickly, before it went out.  It's merged into my next tree.
> 

Glad to help. :)

Thanks
--
Gustavo