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

From: Christophe JAILLET
Date: Thu Apr 13 2017 - 12:39:13 EST


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@xxxxxxxxxx> 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@xxxxxxxxxx>
---
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