[PATCH 0/2] Fix/improve some error handling related to 'chcr_alloc_shash'

[PATCH 0/2] Fix/improve some error handling related to 'chcr_alloc_shash'

[Christophe JAILLET]

This serie is divided into 2 patches. They are more or less related to the
same issue, but the first patch is not a bug in itself, just a clean-up
(IMHO).
If I'm correct, the 2nd one, is a real (unlikely) issue.

Christophe JAILLET (2):
  crypto: chcr - Improve error checking
  crypto: chcr - Fix error checking

 drivers/crypto/chelsio/chcr_algo.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.11.0

[PATCH 1/2] crypto: chcr - Improve error checking

[Christophe JAILLET]

'chcr_alloc_shash()' can return NULL. Here it is not possible because this
code is reached only if 'get_alg_config()' a few lines above has succeeded.
So we are garanteed that the value of 'max_authsize' is a correct
parameter.
Anyway, this is harmless to add a check for NULL.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/crypto/chelsio/chcr_algo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
index 41bc7f4f58cd..f19590ac8775 100644
--- a/drivers/crypto/chelsio/chcr_algo.c
+++ b/drivers/crypto/chelsio/chcr_algo.c
@@ -2294,7 +2294,7 @@ static int chcr_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
 			    aeadctx->enckey_len << 3);
 
 	base_hash  = chcr_alloc_shash(max_authsize);
-	if (IS_ERR(base_hash)) {
+	if (IS_ERR_OR_NULL(base_hash)) {
 		pr_err("chcr : Base driver cannot be loaded\n");
 		goto out;
 	}
-- 
2.11.0

[PATCH 2/2] crypto: chcr - Fix error checking

[Christophe JAILLET]

If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
error pointer when we 'goto out'.
So checking for NULL here is not enough because it is likely that
'chcr_free_shash' will crash if we pass an error pointer.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Another solution, amybe safer, would be to instrument 'chcr_free_shash' or
'crypto_free_shash' to accept an error pointer and return immediatelly in
such a case.
---
 drivers/crypto/chelsio/chcr_algo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
index f19590ac8775..41750b97f43c 100644
--- a/drivers/crypto/chelsio/chcr_algo.c
+++ b/drivers/crypto/chelsio/chcr_algo.c
@@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
 	}
 out:
 	aeadctx->enckey_len = 0;
-	if (base_hash)
+	if (!IS_ERR_OR_NULL(base_hash))
 		chcr_free_shash(base_hash);
 	return -EINVAL;
 }
-- 
2.11.0

Re: [PATCH 1/2] crypto: chcr - Improve error checking

[Dan Carpenter]

On Thu, Apr 13, 2017 at 02:14:19PM +0200, Christophe JAILLET wrote:
> 'chcr_alloc_shash()' can return NULL. Here it is not possible because this
> code is reached only if 'get_alg_config()' a few lines above has succeeded.
> So we are garanteed that the value of 'max_authsize' is a correct
> parameter.
> Anyway, this is harmless to add a check for NULL.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  drivers/crypto/chelsio/chcr_algo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
> index 41bc7f4f58cd..f19590ac8775 100644
> --- a/drivers/crypto/chelsio/chcr_algo.c
> +++ b/drivers/crypto/chelsio/chcr_algo.c
> @@ -2294,7 +2294,7 @@ static int chcr_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
>  			    aeadctx->enckey_len << 3);
>  
>  	base_hash  = chcr_alloc_shash(max_authsize);
> -	if (IS_ERR(base_hash)) {
> +	if (IS_ERR_OR_NULL(base_hash)) {
>  		pr_err("chcr : Base driver cannot be loaded\n");
>  		goto out;

Ugh...  When you mix NULL and error pointers, it should be because NULL
is a valid return.  We should change chcr_alloc_shash() to return
ERR_PTR(-EINVAL) instead of NULL.

Also the "goto out;" is buggy, of course.  The problem with magical free
everything style error handling is that "base_hash" wasn't allocated so
this will oops for both NULL and error pointers.

regards,
dan carpenter

Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Dan Carpenter]

On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
> error pointer when we 'goto out'.
> So checking for NULL here is not enough because it is likely that
> 'chcr_free_shash' will crash if we pass an error pointer.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> Another solution, amybe safer, would be to instrument 'chcr_free_shash' or
> 'crypto_free_shash' to accept an error pointer and return immediatelly in
> such a case.
> ---
>  drivers/crypto/chelsio/chcr_algo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
> index f19590ac8775..41750b97f43c 100644
> --- a/drivers/crypto/chelsio/chcr_algo.c
> +++ b/drivers/crypto/chelsio/chcr_algo.c
> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
>  	}
>  out:
>  	aeadctx->enckey_len = 0;
> -	if (base_hash)
> +	if (!IS_ERR_OR_NULL(base_hash))
>  		chcr_free_shash(base_hash);

Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
ever be NULL.

regards,
dan carpenter

Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Christophe JAILLET]

Le 13/04/2017 à 16:04, Dan Carpenter a écrit :
> On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
>> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
>> error pointer when we 'goto out'.
>> So checking for NULL here is not enough because it is likely that
>> 'chcr_free_shash' will crash if we pass an error pointer.
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
>> Another solution, amybe safer, would be to instrument 'chcr_free_shash' or
>> 'crypto_free_shash' to accept an error pointer and return immediatelly in
>> such a case.
>> ---
>>   drivers/crypto/chelsio/chcr_algo.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
>> index f19590ac8775..41750b97f43c 100644
>> --- a/drivers/crypto/chelsio/chcr_algo.c
>> +++ b/drivers/crypto/chelsio/chcr_algo.c
>> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
>>   	}
>>   out:
>>   	aeadctx->enckey_len = 0;
>> -	if (base_hash)
>> +	if (!IS_ERR_OR_NULL(base_hash))
>>   		chcr_free_shash(base_hash);
> Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
> ever be NULL.
>
> regards,
> dan carpenter
Hi Dan,

I will update the first patch as you proposed in order to:
    - teach 'chcr_alloc_shash' not to return NULL
    - initialize 'base_hash' with ERR_PTR(-EINVAL)
    - update the above test to !IS_ERR.
The 2 patches will be merged in only 1.

Thanks for your suggestions.

Best regards,
CJ

Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Harsh Jain]

On Thu, Apr 13, 2017 at 8:20 PM, Christophe JAILLET
<christophe.jaillet@wanadoo.fr> wrote:
> Le 13/04/2017 à 16:04, Dan Carpenter a écrit :
>>
>> On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
>>>
>>> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
>>> error pointer when we 'goto out'.
>>> So checking for NULL here is not enough because it is likely that
>>> 'chcr_free_shash' will crash if we pass an error pointer.
>>>
>>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>>> ---
>>> Another solution, amybe safer, would be to instrument 'chcr_free_shash'
>>> or
>>> 'crypto_free_shash' to accept an error pointer and return immediatelly in
>>> such a case.
>>> ---
>>>   drivers/crypto/chelsio/chcr_algo.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/crypto/chelsio/chcr_algo.c
>>> b/drivers/crypto/chelsio/chcr_algo.c
>>> index f19590ac8775..41750b97f43c 100644
>>> --- a/drivers/crypto/chelsio/chcr_algo.c
>>> +++ b/drivers/crypto/chelsio/chcr_algo.c
>>> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead
>>> *authenc, const u8 *key,
>>>         }
>>>   out:
>>>         aeadctx->enckey_len = 0;
>>> -       if (base_hash)
>>> +       if (!IS_ERR_OR_NULL(base_hash))
>>>                 chcr_free_shash(base_hash);
>>
>> Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
>> ever be NULL.
>>
>> regards,
>> dan carpenter
>
> Hi Dan,
>
> I will update the first patch as you proposed in order to:
>    - teach 'chcr_alloc_shash' not to return NULL
>    - initialize 'base_hash' with ERR_PTR(-EINVAL)
>    - update the above test to !IS_ERR.
> The 2 patches will be merged in only 1.
>
> Thanks for your suggestions.

Thanks for pointing the error. or You can simply return instead of
goto. Just like that.

     1.3 @@ -2455,7 +2455,8 @@ static int chcr_authenc_setkey(struct cr
     1.4   base_hash  = chcr_alloc_shash(max_authsize);
     1.5   if (IS_ERR(base_hash)) {
     1.6   pr_err("chcr : Base driver cannot be loaded\n");
     1.7 - goto out;
     1.8 + aeadctx->enckey_len = 0;
     1.9 + return -EINVAL;
    1.10   }
    1.11   {
    1.12   SHASH_DESC_ON_STACK(shash, base_hash);





>
> Best regards,
> CJ
>

Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Dan Carpenter]

On Thu, Apr 13, 2017 at 08:37:50PM +0530, Harsh Jain wrote:
> On Thu, Apr 13, 2017 at 8:20 PM, Christophe JAILLET
> <christophe.jaillet@wanadoo.fr> wrote:
> > Le 13/04/2017 à 16:04, Dan Carpenter a écrit :
> >>
> >> On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
> >>>
> >>> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
> >>> error pointer when we 'goto out'.
> >>> So checking for NULL here is not enough because it is likely that
> >>> 'chcr_free_shash' will crash if we pass an error pointer.
> >>>
> >>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> >>> ---
> >>> Another solution, amybe safer, would be to instrument 'chcr_free_shash'
> >>> or
> >>> 'crypto_free_shash' to accept an error pointer and return immediatelly in
> >>> such a case.
> >>> ---
> >>>   drivers/crypto/chelsio/chcr_algo.c | 2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/crypto/chelsio/chcr_algo.c
> >>> b/drivers/crypto/chelsio/chcr_algo.c
> >>> index f19590ac8775..41750b97f43c 100644
> >>> --- a/drivers/crypto/chelsio/chcr_algo.c
> >>> +++ b/drivers/crypto/chelsio/chcr_algo.c
> >>> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead
> >>> *authenc, const u8 *key,
> >>>         }
> >>>   out:
> >>>         aeadctx->enckey_len = 0;
> >>> -       if (base_hash)
> >>> +       if (!IS_ERR_OR_NULL(base_hash))
> >>>                 chcr_free_shash(base_hash);
> >>
> >> Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
> >> ever be NULL.
> >>
> >> regards,
> >> dan carpenter
> >
> > Hi Dan,
> >
> > I will update the first patch as you proposed in order to:
> >    - teach 'chcr_alloc_shash' not to return NULL
> >    - initialize 'base_hash' with ERR_PTR(-EINVAL)
> >    - update the above test to !IS_ERR.
> > The 2 patches will be merged in only 1.
> >
> > Thanks for your suggestions.
> 
> Thanks for pointing the error. or You can simply return instead of
> goto. Just like that.
> 
>      1.3 @@ -2455,7 +2455,8 @@ static int chcr_authenc_setkey(struct cr
>      1.4   base_hash  = chcr_alloc_shash(max_authsize);
>      1.5   if (IS_ERR(base_hash)) {
>      1.6   pr_err("chcr : Base driver cannot be loaded\n");
>      1.7 - goto out;
>      1.8 + aeadctx->enckey_len = 0;
>      1.9 + return -EINVAL;

Don't do that.  There should be a goto.

regards,
dan carpenter

Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Christophe JAILLET]

Le 13/04/2017 à 18:13, Dan Carpenter a écrit :
> On Thu, Apr 13, 2017 at 08:37:50PM +0530, Harsh Jain wrote:
>> On Thu, Apr 13, 2017 at 8:20 PM, Christophe JAILLET
>> <christophe.jaillet@wanadoo.fr> wrote:
>>> Le 13/04/2017 à 16:04, Dan Carpenter a écrit :
>>>> On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
>>>>> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
>>>>> error pointer when we 'goto out'.
>>>>> So checking for NULL here is not enough because it is likely that
>>>>> 'chcr_free_shash' will crash if we pass an error pointer.
>>>>>
>>>>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>>>>> ---
>>>>> Another solution, amybe safer, would be to instrument 'chcr_free_shash'
>>>>> or
>>>>> 'crypto_free_shash' to accept an error pointer and return immediatelly in
>>>>> such a case.
>>>>> ---
>>>>>    drivers/crypto/chelsio/chcr_algo.c | 2 +-
>>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/crypto/chelsio/chcr_algo.c
>>>>> b/drivers/crypto/chelsio/chcr_algo.c
>>>>> index f19590ac8775..41750b97f43c 100644
>>>>> --- a/drivers/crypto/chelsio/chcr_algo.c
>>>>> +++ b/drivers/crypto/chelsio/chcr_algo.c
>>>>> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead
>>>>> *authenc, const u8 *key,
>>>>>          }
>>>>>    out:
>>>>>          aeadctx->enckey_len = 0;
>>>>> -       if (base_hash)
>>>>> +       if (!IS_ERR_OR_NULL(base_hash))
>>>>>                  chcr_free_shash(base_hash);
>>>> Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
>>>> ever be NULL.
>>>>
>>>> regards,
>>>> dan carpenter
>>> Hi Dan,
>>>
>>> I will update the first patch as you proposed in order to:
>>>     - teach 'chcr_alloc_shash' not to return NULL
>>>     - initialize 'base_hash' with ERR_PTR(-EINVAL)
>>>     - update the above test to !IS_ERR.
>>> The 2 patches will be merged in only 1.
>>>
>>> Thanks for your suggestions.
>> Thanks for pointing the error. or You can simply return instead of
>> goto. Just like that.
>>
>>       1.3 @@ -2455,7 +2455,8 @@ static int chcr_authenc_setkey(struct cr
>>       1.4   base_hash  = chcr_alloc_shash(max_authsize);
>>       1.5   if (IS_ERR(base_hash)) {
>>       1.6   pr_err("chcr : Base driver cannot be loaded\n");
>>       1.7 - goto out;
>>       1.8 + aeadctx->enckey_len = 0;
>>       1.9 + return -EINVAL;
> Don't do that.  There should be a goto.
>
> regards,
> dan carpenter
>
>
Agreed.

Having direct return after some other gotos statement puzzles my 
coccinelle scripts and are spurious (at least IMHO).

best regards,
CJ