ecryptfs: Replace memcpy + NUL termination in ecryptfs_new_file_context

Use strscpy() to copy the NUL-terminated '->global_default_cipher_name'
to the destination buffer instead of using memcpy() followed by a manual
NUL termination. Remove the now-unused local variable 'cipher_name_len'.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Tyler Hicks <code@tyhicks.com>

Author: toblux

fs/ecryptfs/crypto.c

@@ -679,7 +679,6 @@ int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 	    &ecryptfs_superblock_to_private(
 		    ecryptfs_inode->i_sb)->mount_crypt_stat;
-	int cipher_name_len;
 	int rc = 0;
 
 	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
@@ -693,12 +692,8 @@ int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
 		       "to the inode key sigs; rc = [%d]\n", rc);
 		goto out;
 	}
-	cipher_name_len =
-		strlen(mount_crypt_stat->global_default_cipher_name);
-	memcpy(crypt_stat->cipher,
-	       mount_crypt_stat->global_default_cipher_name,
-	       cipher_name_len);
-	crypt_stat->cipher[cipher_name_len] = '\0';
+	strscpy(crypt_stat->cipher,
+		mount_crypt_stat->global_default_cipher_name);
 	crypt_stat->key_size =
 		mount_crypt_stat->global_default_cipher_key_size;
 	ecryptfs_generate_new_key(crypt_stat);