From a1d2eb51f0a33c28f5399a1610e66b3fbd24e884 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Fri, 19 Aug 2022 17:00:19 -0300 Subject: [PATCH] cifs: skip extra NULL byte in filenames Since commit: cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty alloc_path_with_tree_prefix() function was no longer including the trailing separator when @path is empty, although @out_len was still assuming a path separator thus adding an extra byte to the final filename. This has caused mount issues in some Synology servers due to the extra NULL byte in filenames when sending SMB2_CREATE requests with SMB2_FLAGS_DFS_OPERATIONS set. Fix this by checking if @path is not empty and then add extra byte for separator. Also, do not include any trailing NULL bytes in filename as MS-SMB2 requires it to be 8-byte aligned and not NULL terminated. Cc: stable@vger.kernel.org Fixes: 7eacba3b00a3 ("cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty") Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French --- fs/cifs/smb2pdu.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 91cfc5b..128e44e 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -2572,19 +2572,15 @@ alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len, path_len = UniStrnlen((wchar_t *)path, PATH_MAX); - /* - * make room for one path separator between the treename and - * path - */ - *out_len = treename_len + 1 + path_len; + /* make room for one path separator only if @path isn't empty */ + *out_len = treename_len + (path[0] ? 1 : 0) + path_len; /* - * final path needs to be null-terminated UTF16 with a - * size aligned to 8 + * final path needs to be 8-byte aligned as specified in + * MS-SMB2 2.2.13 SMB2 CREATE Request. */ - - *out_size = roundup((*out_len+1)*2, 8); - *out_path = kzalloc(*out_size, GFP_KERNEL); + *out_size = roundup(*out_len * sizeof(__le16), 8); + *out_path = kzalloc(*out_size + sizeof(__le16) /* null */, GFP_KERNEL); if (!*out_path) return -ENOMEM; -- 2.7.4