From: Ben Hutchings <ben@decadent.org.uk>
Date: Sun, 05 May 2019 13:45:06 +0100
Subject: MODSIGN: Make shash allocation failure fatal

mod_is_hash_blacklisted() currently returns 0 (suceess) if
crypto_alloc_shash() fails.  This should instead be a fatal error,
so unwrap and pass up the error code.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
Index: linux/kernel/module_signing.c
===================================================================
--- linux.orig/kernel/module_signing.c
+++ linux/kernel/module_signing.c
@@ -51,11 +51,13 @@ static int mod_is_hash_blacklisted(const
 	struct shash_desc *desc;
 	size_t digest_size, desc_size;
 	u8 *digest;
-	int ret = 0;
+	int ret;
 
 	tfm = crypto_alloc_shash("sha256", 0, 0);
-	if (IS_ERR(tfm))
+	if (IS_ERR(tfm)) {
+		ret = PTR_ERR(tfm);
 		goto error_return;
+	}
 
 	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
 	digest_size = crypto_shash_digestsize(tfm);
