kexec_file: use crypto_free_shash to free memory

[Pan Bian]

In function kexec_calculate_store_digests(), kfree() is used to free
memory allocated by crypto_alloc_shash(). It is better to use function
crypto_free_shash(), which also zeroizes the memory to be freed.

Signed-off-by: Pan Bian <bianpan2016 at 163.com>
---
 kernel/kexec_file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 9f48f44..94eeb38 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -627,7 +627,7 @@ static int kexec_calculate_store_digests(struct kimage *image)
 out_free_desc:
 	kfree(desc);
 out_free_tfm:
-	kfree(tfm);
+	crypto_free_shash(tfm);
 out:
 	return ret;
 }
-- 
1.9.1