ksmbd: use SHA-256 library API instead of crypto_shash API

ksmbd_gen_sd_hash() does not support any other algorithm, so the
crypto_shash abstraction provides no value.  Just use the SHA-256
library API instead, which is much simpler and easier to use.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: ebiggers

fs/smb/server/Kconfig

@@ -11,6 +11,7 @@ config SMB_SERVER
 	select CRYPTO_HMAC
 	select CRYPTO_ECB
 	select CRYPTO_LIB_DES
+	select CRYPTO_LIB_SHA256
 	select CRYPTO_SHA256
 	select CRYPTO_CMAC
 	select CRYPTO_SHA512

fs/smb/server/auth.c

@@ -979,40 +979,6 @@ int ksmbd_gen_preauth_integrity_hash(struct ksmbd_conn *conn, char *buf,
 	return rc;
 }
 
-int ksmbd_gen_sd_hash(struct ksmbd_conn *conn, char *sd_buf, int len,
-		      __u8 *pi_hash)
-{
-	int rc;
-	struct ksmbd_crypto_ctx *ctx = NULL;
-
-	ctx = ksmbd_crypto_ctx_find_sha256();
-	if (!ctx) {
-		ksmbd_debug(AUTH, "could not alloc sha256\n");
-		return -ENOMEM;
-	}
-
-	rc = crypto_shash_init(CRYPTO_SHA256(ctx));
-	if (rc) {
-		ksmbd_debug(AUTH, "could not init shashn");
-		goto out;
-	}
-
-	rc = crypto_shash_update(CRYPTO_SHA256(ctx), sd_buf, len);
-	if (rc) {
-		ksmbd_debug(AUTH, "could not update with n\n");
-		goto out;
-	}
-
-	rc = crypto_shash_final(CRYPTO_SHA256(ctx), pi_hash);
-	if (rc) {
-		ksmbd_debug(AUTH, "Could not generate hash err : %d\n", rc);
-		goto out;
-	}
-out:
-	ksmbd_release_crypto_ctx(ctx);
-	return rc;
-}
-
 static int ksmbd_get_encryption_key(struct ksmbd_work *work, __u64 ses_id,
 				    int enc, u8 *key)
 {

fs/smb/server/auth.h

@@ -66,6 +66,4 @@ int ksmbd_gen_smb311_encryptionkey(struct ksmbd_conn *conn,
 				   struct ksmbd_session *sess);
 int ksmbd_gen_preauth_integrity_hash(struct ksmbd_conn *conn, char *buf,
 				     __u8 *pi_hash);
-int ksmbd_gen_sd_hash(struct ksmbd_conn *conn, char *sd_buf, int len,
-		      __u8 *pi_hash);
 #endif

fs/smb/server/crypto_ctx.c

@@ -75,9 +75,6 @@ static struct shash_desc *alloc_shash_desc(int id)
 	case CRYPTO_SHASH_CMACAES:
 		tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
 		break;
-	case CRYPTO_SHASH_SHA256:
-		tfm = crypto_alloc_shash("sha256", 0, 0);
-		break;
 	case CRYPTO_SHASH_SHA512:
 		tfm = crypto_alloc_shash("sha512", 0, 0);
 		break;
@@ -198,11 +195,6 @@ struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void)
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_CMACAES);
 }
 
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha256(void)
-{
-	return ____crypto_shash_ctx_find(CRYPTO_SHASH_SHA256);
-}
-
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha512(void)
 {
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_SHA512);

fs/smb/server/crypto_ctx.h

@@ -13,7 +13,6 @@ enum {
 	CRYPTO_SHASH_HMACMD5	= 0,
 	CRYPTO_SHASH_HMACSHA256,
 	CRYPTO_SHASH_CMACAES,
-	CRYPTO_SHASH_SHA256,
 	CRYPTO_SHASH_SHA512,
 	CRYPTO_SHASH_MAX,
 };
@@ -39,14 +38,12 @@ struct ksmbd_crypto_ctx {
 #define CRYPTO_HMACMD5(c)	((c)->desc[CRYPTO_SHASH_HMACMD5])
 #define CRYPTO_HMACSHA256(c)	((c)->desc[CRYPTO_SHASH_HMACSHA256])
 #define CRYPTO_CMACAES(c)	((c)->desc[CRYPTO_SHASH_CMACAES])
-#define CRYPTO_SHA256(c)	((c)->desc[CRYPTO_SHASH_SHA256])
 #define CRYPTO_SHA512(c)	((c)->desc[CRYPTO_SHASH_SHA512])
 
 #define CRYPTO_HMACMD5_TFM(c)	((c)->desc[CRYPTO_SHASH_HMACMD5]->tfm)
 #define CRYPTO_HMACSHA256_TFM(c)\
 				((c)->desc[CRYPTO_SHASH_HMACSHA256]->tfm)
 #define CRYPTO_CMACAES_TFM(c)	((c)->desc[CRYPTO_SHASH_CMACAES]->tfm)
-#define CRYPTO_SHA256_TFM(c)	((c)->desc[CRYPTO_SHASH_SHA256]->tfm)
 #define CRYPTO_SHA512_TFM(c)	((c)->desc[CRYPTO_SHASH_SHA512]->tfm)
 
 #define CRYPTO_GCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_GCM])
@@ -57,7 +54,6 @@ struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacsha256(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha512(void);
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha256(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_gcm(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_ccm(void);
 void ksmbd_crypto_destroy(void);

fs/smb/server/vfs.c

@@ -4,6 +4,7 @@
  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
  */
 
+#include <crypto/sha2.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/filelock.h>
@@ -1476,11 +1477,7 @@ int ksmbd_vfs_set_sd_xattr(struct ksmbd_conn *conn,
 	acl.sd_buf = (char *)pntsd;
 	acl.sd_size = len;
 
-	rc = ksmbd_gen_sd_hash(conn, acl.sd_buf, acl.sd_size, acl.hash);
-	if (rc) {
-		pr_err("failed to generate hash for ndr acl\n");
-		return rc;
-	}
+	sha256(acl.sd_buf, acl.sd_size, acl.hash);
 
 	smb_acl = ksmbd_vfs_make_xattr_posix_acl(idmap, inode,
 						 ACL_TYPE_ACCESS);
@@ -1495,12 +1492,7 @@ int ksmbd_vfs_set_sd_xattr(struct ksmbd_conn *conn,
 		goto out;
 	}
 
-	rc = ksmbd_gen_sd_hash(conn, acl_ndr.data, acl_ndr.offset,
-			       acl.posix_acl_hash);
-	if (rc) {
-		pr_err("failed to generate hash for ndr acl\n");
-		goto out;
-	}
+	sha256(acl_ndr.data, acl_ndr.offset, acl.posix_acl_hash);
 
 	rc = ndr_encode_v4_ntacl(&sd_ndr, &acl);
 	if (rc) {
@@ -1557,11 +1549,7 @@ int ksmbd_vfs_get_sd_xattr(struct ksmbd_conn *conn,
 		goto out_free;
 	}
 
-	rc = ksmbd_gen_sd_hash(conn, acl_ndr.data, acl_ndr.offset, cmp_hash);
-	if (rc) {
-		pr_err("failed to generate hash for ndr acl\n");
-		goto out_free;
-	}
+	sha256(acl_ndr.data, acl_ndr.offset, cmp_hash);
 
 	if (memcmp(cmp_hash, acl.posix_acl_hash, XATTR_SD_HASH_SIZE)) {
 		pr_err("hash value diff\n");