evm: Fix possible memory leak in evm_calc_hmac_or_hash()

commit 0c4395fb2aa77341269ea619c5419ea48171883f upstream.

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().

Fixes: 50b977481fce9 ("EVM: Add support for portable signature format")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index e034dc2..b0440cf 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -240,7 +240,7 @@ 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);