[PATCH] evm: Fix possible memory leak in evm_calc_hmac_or_hash()

[Mimi Zohar]

Thanks, Roberto.

Sorry for the delays in reviewing the miscellaneous set of IMA patches
you previously posted.  They're next on my "todo" list.

Mimi

On Tue, 2020-04-14 at 10:01 +0200, Roberto Sassu wrote:
> Don't immediately return if the signature is portable and security.ima is
> not present. Just set error so that memory allocated is freed before
> returning from evm_calc_hmac_or_hash().
> 
> Cc: stable at vger.kernel.org
> Fixes: 50b977481fce9 ("EVM: Add support for portable signature format")
> Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> ---
>  security/integrity/evm/evm_crypto.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
> index 35682852ddea..499ea01b2edc 100644
> --- a/security/integrity/evm/evm_crypto.c
> +++ b/security/integrity/evm/evm_crypto.c
> @@ -241,7 +241,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
>  
>  	/* Portable EVM signatures must include an IMA hash */
>  	if (type == EVM_XATTR_PORTABLE_DIGSIG && !ima_present)
> -		return -EPERM;
> +		error = -EPERM;
>  out:
>  	kfree(xattr_value);
>  	kfree(desc);